GB2626791A

GB2626791A - Communication system

Info

Publication number: GB2626791A
Application number: GB2301599.3A
Authority: GB
Inventors: Chen Yuhua; Deogun Pravjyot; Chen Zhe; Wang Xuelong; Arnott Robert; Hisashi Futaki
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 2023-02-03
Filing date: 2023-02-03
Publication date: 2024-08-07
Also published as: EP4659519A1; WO2024162027A1; CN120642535A

Abstract

A method of a user equipment (UE) the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; determining, based on an amount of uplink data in a buffer of the UE, whether to use the first or second table to determine a first or second index; determining the first or second index based on the amount of uplink data the UE’s buffer; transmitting (e.g. in a buffer status report (BSR)) an indication of the first or second index to an access network node; and also transmitting an indication of which of the first or second table was used to generate the index. The indication may be provided in a MAC control element (MAC CE). Also provided are methods and apparatuses for transmitting or receiving indexes based on an amount of uplink data in a UE’s buffer (e.g. transmitting and receiving a buffer status report (BSR)).

Description

Communication System The present invention relates to a communication system. The invention has particular but not exclusive relevance to wireless communication systems and devices thereof operating according to the 3rd Generation Partnership Project (3GPP) standards or equivalents or derivatives thereof (including LTE-Advanced, Next Generation or 5G networks, future generations, and beyond). The disclosure has particular but not exclusive relevance to improvements relating to buffer status reports (BSR) in the so-called '5G' or New Radio' systems (also referred to as 'Next Generation' systems) and similar systems.

Background to the Invention

Recent developments of the 3GPP standards are referred to as the Long-Term Evolution (LTE) of Evolved Packet Core (EPC) network and Evolved UMTS Terrestrial Radio Access Network (E-UTRAN), also commonly referred as '4G'. In addition, the term '5G' and 'new radio' (NR) refer to an evolving communication technology that is expected to support a variety of applications and services. Various details of 5G networks are described in, for example, the NGMN 5G White Paper' V1.0 by the Next Generation Mobile Networks (NGMN) Alliance, which document is available from https://www.ngmn.org/5g-white-paper.html. 3GPP intends to support 5G by way of the so-called 3GPP Next Generation (NextGen) radio access network (RAN) and the 3GPP NextGen core network.

Under the 3GPP standards, a NodeB (or an eNB in LTE, gNB in 5G) is the radio access network (RAN) node (or simply 'access node', 'access network node' or 'base station') via which communication devices (user equipment or UE') connect to a core network and communicate with other communication devices or remote servers. For simplicity, the present application will use the term RAN node, base station, or access network node to refer to any such access nodes.

The next-generation mobile networks support diversified service requirements, which have been classified into three categories by the International Telecommunication Union (ITU): Enhanced Mobile Broadband (eMBB); Ultra-Reliable and Low-Latency Communications (URLLC); and Massive Machine Type Communications (mMTC). eM BB aims to provide enhanced support of conventional mobile broadband, with focus on services requiring large and guaranteed bandwidth such as High Definition (HD) video, Virtual Reality (VR), and Augmented Reality (AR). UR LLC is a requirement for critical applications such as automated driving and factory automation, which require guaranteed access within a very short time. MMTC needs to support massive number of connected devices such as smart metering and environment monitoring but can usually tolerate certain access delay. It will be appreciated that some of these applications may have relatively lenient Quality of Service/Quality of Experience (QoS/QoE) requirements, while some applications may have relatively stringent QoS/QoE requirements (e.g. high bandwidth and/or low latency).

The term extended reality (XR) refers to all real-and-virtual combined environments and associated human-machine interactions generated by computer technology and wearables. It includes representative forms such as augmented reality (AR), mixed reality (MR), and virtual reality (VR) and the areas interpolated among them. 3GPP Technical Report (TR) 26.928 V16.1.0 discusses eXtended Reality (XR) in the context of 5G radio and network services. This document introduces baseline technologies for XR type of services and applications, outlining the quality of experience (QoE) / quality of service (QoS) issues of XR-based services, the delivery of XR in 5G systems, and an architectural model of 5G media streaming defined in 3GPP IS 26.501 V16.9.0. In addition to the conventional service category, interactive, streaming, download, and split compute/rendering are identified as new delivery categories for XR. 3GPP TR 38.838 V17.0.0 is a study on XR service and in particular the traffic models and characteristics aspects of XR in Release 17.

Buffer status reports (BSR) are transmitted from a UE to a base station to indicate an amount of data for uplink transmission stored in a buffer of the UE. This information can be used by the base station to schedule uplink resources to be used by the UE to transmit the stored data. A BSR may include a number of bits that indicate a logical channel (LCH) or logical channel group (LCG), and a number of bits that indicate a corresponding buffer size at the UE.

XR implementations present challenging service requirements, and there is a need for more efficient resource scheduling and allocation. The inventors have realised that there is a need for more reliable and accurate buffer status reporting, since more accurate BSR enable more efficient scheduling of uplink communication resources by the network, for transmission of the uplink data from a UE. However, current buffer status reports use lookup tables and a corresponding index to indicate the amount of uplink data in the buffer of the UE 3, and there is a problem that the precision of the indication of the amount of uplink data stored in the buffer depends on the reported buffer size. It is desirable for UE buffer estimations to be more precise and closer to the actual UE buffer values, since this can result in improved network efficiency and decreased resource utilisation (e.g. uplink radio resources), which is particularly useful for resource-intensive applications such as XR.

Moreover, there is also a problem that transmission of a BSR may not always be reliably triggered. For example, for a Regular BSR, there is a problem that transmission of the BSR may not be triggered when additional data arrives in the buffer for the same LCH or LOG. Similarly, for a Padding BSR (that is included in an uplink data message when there are sufficient padding bits in the message), there is a problem that the BSR has a lower priority than the data transmission and is not included in the transmission unless there are sufficient padding bits, and so may not be reliably transmitted to the base station. For periodical (or 'periodic') BSR there is a problem that the frequency of transmission of the BSR may be insufficient (for example, for Burst Data Arrival), and configuring periodical BSR having very short periodicifies may be impractical (e.g. inefficient).

More generally, there is a need for improved mechanisms that provide more accurate and precise BSR, that can be reliably and efficiently transmitted from the UE to the base station.

Accordingly, the present invention seeks to provide methods and associated apparatus that address or at least alleviate (at least some of) the above-described issues.

In one aspect the invention provides a method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; determining, based on an amount of uplink data in one or more buffers of UE, whether to use the first table to determine a first index that indicates a first range of an amount of uplink data that is in the one or more buffers of UE, or to use the second table to determine a second index that indicates a second range of an amount of uplink data that is in the one or more buffers of UE; determining the first index or the second index based on the amount of uplink data that is in the one or more buffers of UE; transmitting an indication of the first index or the second index to an access network node; transmitting, to the access network node, if the UE transmits an indication of the first index to the access network node, an indication that the first table was used to generate the first index; and transmitting, to the access network node, if the UE transmits an indication of the second index to the access network node, an indication that the second table was used to generate the second index.

The method may comprise receiving, from the access network node: the second table; or information for generating the second table at the UE.

The method may comprise: determining to use the first table to determine the first index when the amount of uplink data in one or more buffers of UE falls within a first range; and determining to use the second table to determine the second index when the amount of uplink data in one or more buffers of UE falls within a second range.

The method may comprise: determining whether to use the first table to determine the first index or to use the second table to determine the second index based on a comparison of the amount of uplink data in one or more buffers of UE with a threshold value.

The first index may indicate a first range for the amount of uplink data in the one or more buffers of UE; the second index may indicate a second range for the amount of uplink data in the one or more buffers of UE; and the method may comprise transmitting, to the base station, the indication of the first index when the first range is smaller than the second range, and transmitting, to the base station, the indication of the second index when the second range is smaller than the first range.

Transmitting the indication of the first index or the second index may comprise transmitting the indication of the first index or the second index in a buffer status report, BSR.

The indication that the first table was used to generate the first index or the indication that the second table was used to generate the second index may be provided in a medium access control, MAC, control element, CE.

The method may comprise transmitting an indication of a logical channel identity, LCD to the access network node, wherein the LCID indicates a format of a message used to transmit the indication of the first index or the second index to the access network node.

The indication that the first table was used to generate the first index may be provided using a set of one or more bits that are adjacent to a set of one or more bits used to indicate the first index in a transmission to the access network node, or the indication that the second table was used to generate the second index may be provided using a set of one or more bits that are adjacent to a set of one or more bits used to indicate the second index in a transmission to the access network node.

The indication that the first table was used to generate the first index or the indication that the second table was used to generate the second index may be provided using one or more bits of a subheader.

The subheader may be a subheader associated with a medium access control, MAC, control element, CE The method may comprise: determining to use the first table to determine the first index based on a first amount of uplink data in one or more buffers of the UE, and determining the first index based on the first amount of uplink data; determining to use the second table to determine the second index based on a second amount of uplink data in one or more buffers of the UE, and determining the second index based on the second amount of uplink; transmitting an indication of the first index and an indication of the second index to the access network node; transmitting an indication that the first table was used to generate the first index; and transmitting an indication that the second table was used to generate the second index.

One or more bits used to indicate that the first table was used to generate the first index may be adjacent to one or more bits used to indicate that the second table was used to generate the second index.

In another aspect the invention provides a method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE; in a first case where the UE has received, from an access network node, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE, or information for generating the second table at the UE, and the second table is stored at the UE: using the first table or the second table to determine, based on an amount of uplink data in the one or more buffers of the UE, an index that indicates a range of the amount of uplink data in the one or more buffers, transmitting an indication of the first index or the second index to the access network node in a buffer status report having a first format that includes an indication of whether the first table or the second table has been used to determine the index; or in a second case where the UE has not received the second table or the information for generating the second table from the access network node, or the second table is not stored at the UE: using the first table to determine, based on the amount of uplink data in the one or more buffers of UE, the index; and transmitting an indication of the index to the access network node in a buffer status report having a second format, wherein the second format is different from the first format.

Transmitting the indication of the index may comprise transmitting, to the access network node, the indication of the index in a medium access control, MAC, control element, CE.

The first format may be a first MAC CE format of the MAC CE, and the second format may be a second MAC CE format of the MAC CE.

The method may further comprise transmitting, to the access network node, a subheader with the MAC CE, wherein a subheader format of the subheader used for the first MAC CE format is the same as a subheader format used for the second MAC CE format.

The UE may transmit every buffer status report using the first format in the first case.

In the first case, use of the first format may be based on control signalling received from the access network node.

The control signalling may comprise an activation signal that indicates that the first format is to be activated, or a setup message for the second table; and the method may comprise determining, in the first case, to transmit the indication of the index to the access network node in the buffer status report having the first format based on having received the activation signal or the setup message for the second table.

The control signalling may comprise a deactivation signal that indicates that the first format is to be deactivated, or a release message for the second table; and the method may comprise: determining, in the first case, to transmit the indication the index to the access network node in the buffer status report having the second format based on having received the deactivation signal or the release message for the second table.

In another aspect the invention provides a method of a user equipment, UE, the method comprising: storing a first table that maps, for an amount of uplink data within a first range, each of a plurality of first indices to a respective sub-range of the first range; storing a second table that maps, for an amount of uplink data within a second range, each of a plurality of second indices to a respective sub-range of the second range; wherein each of the plurality of first indices are different from each of the plurality of second indices; wherein the method further comprises transmitting, to an access network node, when an amount of uplink data in one or more buffers of the UE falls within the second range, the index of the plurality of second indices that indicates the sub-range of the amount of uplink data in the one or more buffers of the UE; and transmitting, to the access network node, when the amount of uplink data in the one or more buffers of the UE falls within the first range but does not fall within the second range, the index of the plurality of first indices that indicates the sub-range of the amount of uplink data in one or more buffers of the UE.

The second range may be a subset of the first range.

The number of first indices of the first table may be different from the number of second indices of the second table.

At least one subrange mapped to an index of the second table may be smaller than a subrange mapped to an index of the first table.

In another aspect the invention provides a method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; receiving, from an access network node, table activation information that indicates whether the second table is to be activated at the UE; determining, if the table activation information indicates that the second table is to be activated at the UE, to use the second table to determine an index of the second plurality of indices that indicates the range of an amount of uplink data in one or more buffers of UE; and transmitting an indication of the index to the access network node.

The method may further comprise: receiving, from the access network node, table activation information that indicates that the second table is to be deactivated at the UE; and determining, based on the indication that the second table is to be deactivated at the UE, to use the first table to determine an index of the first plurality of indices that indicates the range of an amount of uplink data in the one or more buffers of UE; and transmitting an indication of the index to the access network node.

In another aspect the invention provides a method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data; receiving, from an access network node, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; determining, based on the table setup information, to use the second table to determine an index of the second plurality of indices that indicates a range of an amount of uplink data in one or more buffers of UE; transmitting an indication of the index to the access network node.

The method may further comprise: receiving, from an access network node, table release information that indicates that the second table is to be released; and determining, based on the table release information, to use the first table to determine an index of the first plurality of indices that indicates the range of an amount of uplink data in the one or more buffers of UE; and transmitting an indication of the index to the access network node.

The table setup information may comprise the second table; or information for generating the second table at the UE.

In another aspect the invention provides a method of a user equipment, UE, the method comprising: storing a table that maps each of a plurality of indices to a respective range of uplink data; wherein a first index of the plurality of indices is mapped to a first range of uplink data; a second index of the plurality of indices is mapped to a second range of uplink data; a third index of the plurality of indices is mapped to a third range of uplink data; the first range and the third range are smaller than the second range; the upper limit of the first range is smaller than the lower limit of the second range, and the upper limit of the second range is smaller than the lower limit of the third range; and wherein the method further comprises determining, based on an amount of uplink data in one or more buffers of the UE, the index of the table that indicates the range of the amount of uplink data in the one or more buffers of the UE; and transmitting the index to an access network node.

In another aspect the invention provides a method of an access network node, the method comprising: transmitting, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or information for generating the second table at the UE; receiving, from the UE, an indication of an index that indicates a range of an amount of uplink data in one or more buffers of the UE; receiving, from the UE, if the index is an index determined using a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, an indication that the first table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the first table; and receiving, from the UE, if the index is an index determined using the second table, an indication that the second table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.

In another aspect the invention provides a method of an access network node, the method comprising: in a first case where the access network node has transmitted, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or the access network node has transmitted information for generating the second table at the UE, and the second table is stored at the UE: receiving, from the UE, an indication of an index in a buffer status report, wherein the buffer status report has a first format that includes an indication of whether a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE or the second table has been used to determine the index; or in a second case where the base station has not transmitted the second table or the information for generating the second table to the UE, or the second table is not stored at the UE: receiving, from the UE, an indication of the index in a buffer status report having a second format, wherein the second format is different from the first format.

In another aspect the invention provides a method of an access network node, the method comprising: transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table activation information that indicates whether a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE is to be activated at the UE; receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.

The method may further comprise: transmitting, to the UE, table activation information that indicates that the second table is to be deactivated at the UE; receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the first table.

In another aspect the invention provides a method of an access network node, the method comprising: transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE; receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.

The method may further comprise: transmitting, to the UE, table release information that indicates that the second table is to be released; receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the first table.

In another aspect the invention provides a user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; means for determining configured for: determining, based on an amount of uplink data in one or more buffers of UE, whether to use the first table to determine a first index that indicates a first range of an amount of uplink data that is in the one or more buffers of UE, or to use the second table to determine a second index that indicates a second range of an amount of uplink data that is in the one or more buffers of UE; and determining the first index or the second index based on the amount of uplink data that is in the one or more buffers of UE; and means for transmitting configured for: transmitting an indication of the first index or the second index to an access network node; transmitting, to the access network node, if the UE transmits an indication of the first index to the access network node, an indication that the first table was used to generate the first index; and transmitting, to the access network node, if the UE transmits an indication of the second index to the access network node, an indication that the second table was used to generate the second index.

In another aspect the invention provides a user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE; wherein the UE is configured for: in a first case where the UE has received, from an access network node, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE, or information for generating the second table at the UE, and the second table is stored at the UE: using the first table or the second table to determine, based on an amount of uplink data in the one or more buffers of the UE, an index that indicates a range of the amount of uplink data in the one or more buffers, transmitting an indication of the first index or the second index to the access network node in a buffer status report having a first format that includes an indication of whether the first table or the second table has been used to determine the index; or in a second case where the UE has not received the second table or the information for generating the second table from the access network node, or the second table is not stored at the UE: using the first table to determine, based on the amount of uplink data in the one or more buffers of UE, the index; and transmitting an indication of the index to the access network node in a buffer status report having a second format, wherein the second format is different from the first format.

In another aspect the invention provides a user equipment, UE, comprising: means for storing configured for: storing a first table that maps, for an amount of uplink data within a first range, each of a plurality of first indices to a respective sub-range of the first range; and storing a second table that maps, for an amount of uplink data within a second range, each of a plurality of second indices to a respective sub-range of the second range; wherein each of the plurality of first indices are different from each of the plurality of second indices; and wherein the UE further comprises means for transmitting configured for: transmitting, to an access network node, when an amount of uplink data in one or more buffers of the UE falls within the second range, the index of the plurality of second indices that indicates the sub-range of the amount of uplink data in the one or more buffers of the UE; and transmitting, to the access network node, when the amount of uplink data in the one or more buffers of the UE falls within the first range but does not fall within the second range, the index of the plurality of first indices that indicates the sub-range of the amount of uplink data in one or more buffers of the UE.

In another aspect the invention provides a user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; means for receiving, from an access network node, table activation information that indicates whether the second table is to be activated at the UE; means for determining, if the table activation information indicates that the second table is to be activated at the UE, to use the second table to determine an index of the second plurality of indices that indicates the range of an amount of uplink data in one or more buffers of UE; and means for transmitting an indication of the index to the access network node.

In another aspect the invention provides a user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data; means for receiving, from an access network node, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; means for determining, based on the table setup information, to use the second table to determine an index of the second plurality of indices that indicates a range of an amount of uplink data in one or more buffers of UE; and means for transmitting an indication of the index to the access network node.

In another aspect the invention provides a user equipment, UE, comprising: means for storing a table that maps each of a plurality of indices to a respective range of uplink data; wherein a first index of the plurality of indices is mapped to a first range of uplink data; a second index of the plurality of indices is mapped to a second range of uplink data; a third index of the plurality of indices is mapped to a third range of uplink data; the first range and the third range are smaller than the second range; the upper limit of the first range is smaller than the lower limit of the second range, and the upper limit of the second range is smaller than the lower limit of the third range; and wherein the UE further comprises means for determining, based on an amount of uplink data in one or more buffers of the UE, the index of the table that indicates the range of the amount of uplink data in the one or more buffers of the UE; and means for transmitting the index to an access network node.

In another aspect the invention provides an access network node comprising: means for transmitting, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or information for generating the second table at the UE; and means for receiving configured for: receiving, from the UE, an indication of an index that indicates a range of an amount of uplink data in one or more buffers of the UE; receiving, from the UE, if the index is an index determined using a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, an indication that the first table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the first table; and receiving, from the UE, if the index is an index determined using the second table, an indication that the second table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.

In another aspect the invention provides an access network node, wherein the access network node is configured for: in a first case where the access network node has transmitted, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or the access network node has transmitted information for generating the second table at the UE, and the second table is stored at the UE: receiving, from the UE, an indication of an index in a buffer status report, wherein the buffer status report has a first format that includes an indication of whether a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE or the second table has been used to determine the index; or in a second case where the base station has not transmitted the second table or the information for generating the second table to the UE, or the second table is not stored at the UE: receiving, from the UE, an indication of the index in a buffer status report having a second format, wherein the second format is different from the first format.

In another aspect the invention provides an access network node comprising: means for transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table activation information that indicates whether a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE is to be activated at the UE; means for receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and means for determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.

In another aspect the invention provides an access network node comprising: means for transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE; means for receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and means for determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 schematically illustrates a mobile ('cellular' or 'wireless') telecommunication system; Figure 2 illustrates a typical frame structure that may be used in the telecommunication system of Figure 1; Figure 3 is a schematic block diagram illustrating the main components of a DU 50 that may be used as part of the RAN equipment 5 for the communication system 1 shown in Figure 1; Figure 4 is a schematic block diagram illustrating the main components of a CU 60 that may be used as part of the RAN equipment 5 for the communication system 1 shown in Figure 1; Figure 5 shows a short buffer status report; Figure 6 shows a lookup table for a buffer status report; Figure 7 shows a long buffer status report; Figure 8 shows an extended short buffer status report; Figure 9 shows an extended long buffer status report; Figures 10 to 22 are schematic diagrams illustrating some examples related to transmission of BSR; Figure 23 shows an example of a MAC PDU; Figure 24 shows an example of a subheader and a corresponding MAC CE; Figure 25 shows a further example of a subheader and a corresponding MAC CE; Figure 26 shows a method in which a UE 3 and a base station 5 exchange information regarding one or more BSR tables; Figure 27 shows an example of a MAC CE that may be used to transmit an indication of a BSR table that was used to generate a BSR; Figure 28 shows a further example of a MAC CE that may be used to transmit an indication of a BSR table that was used to generate a BSR; Figure 29 shows a modified MAC CE in which 8 bits are used for the Buffer Size fields; Figure 30 shows a further example of how a MAC CE can be used to indicated the BSR tables used by the UE 3; Figure 31 shows an example in which the Buffer Size fields have a variable length; Figure 32 shows an example in which the indications of the BSR tables used by the UE 3 (17 to TO) are provided in a sequence of consecutive bits following the fields identifying the LCGs; Figure 33 shows an example in which the subheader of the example of Fig. 24 has been modified to include an eLCID; Figure 34 shows a further example in which the subheader additionally includes a length field; Figure 35 shows an example in which the UE 3 receives a BSR table from a base station; Figure 36 shows an example of a first BSR table and an extension BSR table; Figure 37 shows an example in which the base station controls activation/deactivation of BSR tables using BSR table setup/release indications; Figure 38 shows an example of a BSR table for which improved precision is provided for both low buffer size values, and for a further range of buffer size values; Figure 39 is a schematic block diagram illustrating the main components of a UE for the telecommunication system of Figure 1; Figure 40 is a schematic block diagram illustrating the main components of a base station for the telecommunication system of Figure 1; and Figure 41 is a schematic block diagram illustrating the main components of a core network node or function for the telecommunication system of Figure 1.

Overview An exemplary telecommunication system will now be described in general terms, by way of example only, with reference to Figs. 1 and 2.

Fig. 1 schematically illustrates a mobile ('cellular' or 'wireless') telecommunication system 1 to which embodiments of the present invention are applicable.

In the network 1 user equipment (UEs) 3-1, 3-2, 3-3 (e.g. mobile telephones and/or other mobile devices) can communicate with each other via a radio access network (RAN) node 5 that operates according to one or more compatible radio access technologies (RATs). In the illustrated example, the RAN node 5 comprises a NR/5G base station or gNB' 5 operating one or more associated cells 9. Communication via the base station 5 is typically routed through a core network 7 (e.g. a 5G core network or evolved packet core network (EPC)).

As those skilled in the art will appreciate, whilst three UEs 3 and one base station 5 are shown in Fig. 1 for illustration purposes, the system, when implemented, will typically include other base stations 5 and UEs 3.

Each base station 5 controls the associated cell(s) 9 either directly, or indirectly via one or more other nodes (such as home base stations, relays, remote radio heads, distributed units, and/or the like). It will be appreciated that the base stations 5 may be configured to support 43, 53, 63, and/or any other 3GPP or non-3GPP communication protocols.

The UEs 3 and their serving base station 5 are connected via an appropriate air interface (for example the so-called 'Liu' interface and/or the like). Neighbouring base stations 5 may be connected to each other via an appropriate base station to base station interface (such as the so-called X2' interface, Xn' interface and/or the like).

The core network 7 includes a number of logical nodes (or 'functions') for supporting communication in the telecommunication system 1. In this example, the core network 7 comprises control plane functions (CPFs) 10 and one or more user plane functions (UPFs) 11. The CPFs 10 include one or more Access and Mobility Management Functions (AMFs) 10-1, one or more Session Management Functions (SMFs) and a number of other functions 10-n.

The base station 5 is connected to the core network nodes via appropriate interfaces (or 'reference points') such as an N2 reference point between the base station 5 and the AMF 10-1 for the communication of control signalling, and an N3 reference point between the base station 5 and each UPF 11 for the communication of user data. The UEs 3 are each connected to the AMF 10-1 via a logical non-access stratum (NAS) connection over an Ni reference point (analogous to the Si reference point in LTE). It will be appreciated, that Ni communications are routed transparently via the base station 5.

The UPF(s) 11 are connected to an external data network (e.g. an IP network such as the internet) via reference point N6 for communication of the user data.

The AMF 10-1 performs mobility management related functions, maintains the non- NAS signalling connection with each UE 3 and manages UE registration. The AMF 10- 1 is also responsible for managing paging. The SMF 10-2 provides session management functionality (that formed part of MME functionality in LTE) and additionally combines some control plane functions (provided by the serving gateway and packet data network gateway in LTE). The SMF 10-2 also allocates IP addresses to each UE 3.

The base station 5 of the communication system 1 is configured to operate at least one cell 9 on an associated TDD carrier that operates in unpaired spectrum. It will be appreciated that the base station 5 may also operate at least one cell 9 on an associated FDD carrier that operates in paired spectrum.

The base stations is also configured for transmission of, and the UEs 3 are configured for the reception of, control information and user data via a number of downlink (DL) physical channels and for transmission of a number of physical signals. The DL physical channels correspond to resource elements (REs) carrying information originated from a higher layer, and the DL physical signals are used in the physical layer and correspond to REs which do not carry information originated from a higher layer.

The physical channels may include, for example, a physical downlink shared channel (PDSCH), a physical broadcast channel (PBCH), and a physical downlink control channel (PDCCH). The PDSCH carries data sharing the PDSCH's capacity on a time and frequency basis. The PDSCH can carry a variety of items of data including, for example, user data, UE-specific higher layer control messages mapped down from higher channels, system information blocks (SIBs), and paging. The PDCCH carries downlink control information (DCI) for supporting a number of functions including, for example, scheduling the downlink transmissions on the PDSCH and also the uplink data transmissions on a physical uplink shared channel (PUSCH). The PBCH provides UEs 3 with the Master Information Block, MIB. It also, in conjunction with the PDCCH, supports the synchronisation of time and frequency, which aids cell acquisition, selection and re-selection. The UE 3 may receive a Synchronization Signal Block (SSB), and the UE 3 may assume that reception occasions of a PBCH, primary synchronization signal (PSS) and secondary synchronization signal (SSS) are in consecutive symbols and form a SS/PBCH block. The base station 5 may transmit a number of synchronization signal (SS) blocks corresponding to different DL beams. The total number of SS blocks may be confined, for example, within a 5 ms duration 1 0 as an SS burst. The periodicity of the SSB transmissions may be indicated to the UE using any suitable signalling (e.g. per serving cell using ssb-periodicityServingCell). The periodicity value for the SSB may be, for example, greater than or equal to 20 ms. For initial cell selection, the UE 3 may be configured to assume that an SS burst occurs with a periodicity of 2 frames. The UE 3 may also be provided with an indication of which SSBs within a 5 ms duration are transmitted (e.g. using ssb-PositionsInBurst).

The DL physical signals may include, for example, reference signals (RSs) and synchronization signals (SSs). A reference signal (sometimes known as a pilot signal) is a signal with a predefined special waveform known to both the UE 3 and the base station 5. The reference signals may include, for example, cell specific reference signals, UE-specific reference signal (UE-RS), downlink demodulation signals (DMRS), and channel state information reference signal (CSI-RS).

Similarly, the UEs 3 are configured for transmission of, and the base station 5 is configured for the reception of, control information and user data via a number of uplink (UL) physical channels corresponding to REs carrying information originated from a higher layer, and UL physical signals which are used in the physical layer and correspond to REs which do not carry information originated from a higher layer. The physical channels may include, for example, the PUSCH, a physical uplink control channel (PUCCH), and/or a physical random-access channel (PRACH). The UL physical signals may include, for example, demodulation reference signals (DMRS) for a UL control/data signal, and/or sounding reference signals (SRS) used for UL channel measurement.

When the UE 3 initially establishes a radio resource control (RRC) connection with a base station 5 via a cell it registers with an appropriate core network node (e.g, AMF, MME). The UE 3 is in the so-called RRC connected state and an associated UE context is maintained by the network. When the UE 3 is in the so-called RRC idle or in the RRC inactive state, it selects an appropriate cell for camping so that the network is aware of the approximate location of the UE 3 (although not necessarily on a cell level).

It will be appreciated that UE 3 may support one or more services, and that each service will typically have associated requirements (e.g. latency/data rate/packet loss requirements, etc.), which may be different for different services. Each UE 3 may be configured with appropriate power saving operation such as Discontinuous Reception (DRX), Discontinuous Transmission (DTX), and/or the like. The power saving operation may depend on the category of the service(s) used, UE 3 capabilities, and other factors (such as QoE/QoS, throughput, serving cell(s), network load, and/or the like). The DRX configuration used by a UE 3 may be adapted dynamically to suite a wide range of services, such as extended reality (XR) data.

The base station 5 may be a base station 5 that is split between one or more distributed units (DUs) 50 and a central unit (CU) 60, with a CU 60 typically performing higher level functions and communication with the next generation core, and with the DU 50 performing lower level functions and communication over an air interface with UEs 3 in the vicinity (i.e. in a cell operated by the base station 5). This type of base station may be referred to as a 'distributed' base station 5 or gNB 5. A distributed gNB 5 includes the following functional units: gNB Central Unit (gNB-CU): a logical node hosting Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) layers of the gNB (or RRC and PDCP layers of an en-gNB) that controls the operation of one or more gNB-DUs. The gNB-CU terminates the so-called Fl interface connected with the gNB-DU.

gNB Distributed Unit (gNB-DU): a logical node hosting Radio Link Control (RLC), Medium Access Control (MAC) and Physical (PHY) layers of the gNB or en-gNB, and its operation is partly controlled by gNB-CU. One gNB-DU supports one or multiple cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface connected with the gNB-CU.

gNB-CU-Control Plane (gNB-CU-CP): a logical node hosting the RRC and the control plane part of the PDCP protocol of the gNB-CU for an en-gNB or a gNB. The gN B-CU-CP terminates the so-called El interface connected with the gNB-CU-UP and the Fl-C (F1 control plane) interface connected with the gNB-DU.

gNB-CU-User Plane (gNB-CU-UP): a logical node hosting the user plane part of the PDCP protocol of the gNB-CU for an en-gNB, and the user plane part of the PDCP protocol and the SDAP protocol of the gNB-CU for a gNB. The gNB-CU-UP terminates the El interface connected with the gNB-CU-CP and the Fl-U (F1 user plane) interface connected with the gNB-DU.

It will be appreciated that when a distributed base station or a similar control plane -user plane (CP-UP) split is employed, the base station 5 may be split into separate control-plane and user-plane entities, each of which may include an associated transceiver circuit, antenna, network interface, controller, memory, operating system, and communications control module. When the base station 5 comprises a distributed base station, the network interface also includes an El interface and an Fl interface (Fl-C for the control plane and Fl-U for the user plane) to communicate signals between respective functions of the distributed base station.

Frame Structure Referring to Fig. 2, which illustrates a typical frame structure that may be used in the telecommunication system 1, the base station 5 and UEs 3 of the telecommunication system 1 communicate with one another using resources that are organised, in the time domain, into frames of length 10ms. Each frame comprises ten equally sized subframes of 1 ms length. Each subframe is divided into one or more slots comprising 14 Orthogonal frequency-division multiplexing (OFDM) symbols of equal length.

As seen in Fig. 2, the communication system 1 supports multiple different numerologies (subcarrier spacing (SCS), slot lengths and hence OFDM symbol lengths). Specifically, each numerology is identified by a parameter, p, where p=0 represents 15 kHz (corresponding to the LTE SCS). Currently, the SCS for other values of p can, in effect, be derived from p=0 by scaling up in powers of 2 (i.e. SCS = 15 x 2P kHz). The relationship between the parameter, p, and SCS (At) is as shown in Table 1: /1 At = 2" * 1 5[kHz-. Number of slots Slot length (ms) per subframe 0 15 1 1 1 30 2 0.5 2 60 4 0.25 3 120 8 0.125 4 240 16 0.0625 Table '1 -5G Numerology RAN Equipment DU Fig. 3 is a schematic block diagram illustrating the main components of a DU 50 that may be used as part of the RAN equipment 5 for the communication system 1 shown in Fig. 1. As shown, the DU 50 has a transceiver circuit 451 for: transmitting signals to, and for receiving signals from, the communication devices (such as UEs 3) via the radio unit (RU) and the associated DU-RU interface 453; and for transmitting signals to, and for receiving signals from, the CU 60 of the RAN equipment 5 via a CU interface 454 (e.g. comprising an Fl interface which may be split into an Fl-U and an Fl-C interface for user plane and control plane signalling respectively).

The DU 50 has a controller 457 to control the operation of the DU 50. The controller 457 is associated with a memory 459. Software may be pre-installed in the memory 459 and/or may be downloaded via the communications network 1 or from a removable data storage device (RMD) for example. The controller 457 is configured to control the overall operation of the DU 50 by, in this example, program instructions or software instructions stored within memory 459.

As shown, these software instructions include, among other things, an operating system 461, a communications control module 463, an Fl module 465, a DU-RU module 468, a UE profile management module 473 and a mobility module.

The communications control module 463 is operable to control the communication between the DU 50 and the RU(s) 5a (and hence between the DU 50 and the UE 3), and between the DU 50 and the CU 60. The communications control module 463 is configured for the overall control of the reception of signals corresponding to uplink communications from the UE 3 and for handling the transmission of downlink communications destined for the UE 3. The communications control module 463 may be configured to control the allocation of uplink resources for a UE 3 (for example, in response to receiving a corresponding buffer status report from the UE 3).

The Fl module 465 is responsible for the appropriate processing of signals received from, or transmitted to, the CU 60 via the CU (e.g. Fl) interface(s) 454. These signals may be separated into: user plane signals received from, or transmitted to, the CU-UP part of the CU 60 via the Fl-U interface; and control plane signals received from, or transmitted to, the CU-CP part of the CU 60 via the Fl-C interface.

The DU-RU module 468 is responsible for the appropriate processing of signals received from, or transmitted to, the RU via the RU (e.g. DU-RU) interface(s) 453.

The DU management module 472 is responsible for managing the overall operation of the DU 50 and the overall performance of the tasks required of the DU 50. These tasks include, among other things, the generation and transmission of appropriate messages using appropriate signalling application protocols, depending on the functional split between the RU, DU 50 and CU 60, such as interpretation of received MAC signalling and the generation of MAC signalling for transmission.

The UE profile management module 473 is responsible for carrying out functions related to the UE profile including (where applicable): the reception and storage of the UE profile or related assistance/preference information from the UE 3 or from elsewhere in the network; the determination (where applicable) of appropriate mobility specific configurations, based on the UE profile / assistance information / preference information, for implementation at the UE 3 and/or RAN equipment; and/or the provision of configuration information (where applicable) for configuring the UE appropriately with mobility based configurations. The UE profile management module 473 may also store previous mobility information for a UE 3 (e.g. previous movements of the UE 3 between different communication cells of the network). It will be appreciated that, depending on implementation, the gNB-DU may not implement at least some of these features.

The mobility module 475 is responsible for controlling mobility procedures of one or more UEs 3. For example, the mobility module 475 may be configured to perform one or more measurements for UE 3 mobility, or to select a candidate cell for handover. It will be appreciated that the mobility module 475 may be configured to perform control in any of the mobility methods (e.g. handover) described below.

CU

Fig. 4 is a schematic block diagram illustrating the main components of the CU 60 of the RAN equipment for the communication system 1 shown in Fig. 1. As shown, the CU 60 has a transceiver circuit 551 for: transmitting signals to, and for receiving signals from, the DU 50 via the DU interface(s) 554 (e.g. comprising an Fl interface which may be split into an Fl-U and an Fl-C interface for user plane and control plane signalling respectively); and for transmitting signals to, and for receiving signals from, the functions of the core network 7 via core network interface(s) 555 (e.g. comprising the N2 and N3 interfaces or the like).

The CU 60 has a controller 557 to control the operation of the CU 60. The controller 557 is associated with a memory 559. Software may be pre-installed in the memory 559 and/or may be downloaded via the communications network 1 or from a removable data storage device (RMD) for example. The controller 557 is configured to control the overall operation of the CU 60 by, in this example, program instructions or software instructions stored within memory 559.

As shown, these software instructions include, among other things, an operating system 561, a communications control module 563, an Fl module 565, an El module 566, an N2 module 568, an N3 module 569, a CU-UP management module 571, a CU-CP management module 572, a UE profile management module 573, and a mobility module 575. The functions of the mobility module 575 are the same as described above with reference to Fig. 3.

The communications control module 563 is operable to control the communication between the CU 60 and the DU(s) 50 (and hence between the CU 60 and the UE 3), and between the CU 60 and the core network 7. The communications control module 563 is configured for the overall control of the reception of signals corresponding to uplink communications from the UE 3 and for handling the transmission of downlink communications destined for the UE 3.

The Fl module 565 is responsible for the appropriate processing of signals received from, or transmitted to, the DU 50 via the DU (e.g. Fl) interface(s) 554. These signals may be separated into: user plane signals received at, or transmitted by, the CU-UP part of the CU via the Fl-U interface; and control plane signals received at, or transmitted by, the CU-CP part of the CU via the Fl-C interface.

The El module 566 is responsible for the appropriate processing of signals transmitted between the CU-UP part of the CU 60 and the CU-CP part of the CU 60 via the corresponding internal CU interface (e.g. El).

The N2 module 568 is responsible for the appropriate processing of signals received from, or transmitted to, the AMF 8-1 via the corresponding core network interface(s) (e.g. N2) 555 The N3 module 569 is responsible for the appropriate processing of signals received from, or transmitted to, the core network user plane function(s) via the corresponding core network interface(s) (e.g. N3) 555.

The CU-UP management module 571 is responsible for managing the overall operation of the CU-UP part of the CU 60 and the overall performance of the tasks required of the CU-UP.

The CU-CP management module 572 is responsible for managing the overall operation of the CU-CP part of the CU 60 and the overall performance of the tasks required of the CU-CP. These tasks include, among other things, the generation and transmission of appropriate messages using appropriate signalling application protocols, depending on the functional split between the RU, DU 50 and CU 60, such as interpretation of received RRC signalling and the generation of RRC signalling for transmission.

The UE profile management module 573 is responsible for carrying out functions related to the UE (mobility) profile including (where applicable): the reception and storage of the UE profile or related assistance/preference information from the UE 3 or from elsewhere in the network; the determination of appropriate mobility specific configurations, based on the UE profile / assistance information / preference information, for implementation at the UE 3 and/or RAN equipment 5; and/or the provision of configuration information for configuring the UE appropriately with mobility based configurations. The UE profile management module 573 may also store previous mobility information for a UE 3 (e.g. previous movements of the UE 3 between different communication cells of the network). It will be appreciated that, depending on implementation, the gNB-CU 60 may not implement at least some of these features.

System information and SIB It will be appreciated that transmissions in a cell 9 of a base station 5 may include one or more broadcast transmissions and one or more unicast transmissions for reception by a UE 3. System information (SI) transmitted in a cell may include 'minimum SI' (MSI) and 'other SI' (0S1). The OSI may be broadcast on-demand, for example using a downlink shared channel (DL-SCH). The OSI may be broadcast upon request from a UE 3 that is in a radio resource control (RRC) idle or RRC inactive state. The OSI may also be requested by a UE 3 that is in the RRC connected state, for example via one or more dedicated RRC transmissions.

The SI may include information for enabling (e.g. configuring) the UE 3 to complete a cell selection, may include information for enabling the UE 3 to complete a cell reselection procedure, or for enabling the UE 3 to receive one or more paging messages transmitted in a cell. SI may be broadcast using a Master Information Block (MIB) and one or more System Information Blocks (SIB).

The MSI comprises the MIB and system information block 1 (SIB1). The MIB includes information for use by a UE 3 to receive SIB1, for example a subcarrier spacing for SIB1. The MIB provides information corresponding to a Control Resource Set (CORESET) and Search Space. SIB1 may be referred to as 'remaining MSI' (RMSI). SIB1 may be transmitted in a dedicated RRC message, and other SIB (e.g. 5IB2 to 5IB9) may be transmitting using one or more other suitable RRC transmissions. The MIB and SIB1 may provide the UE 3 with an indication of scheduling information for receiving and decoding the other SIB, such as SIB2 to 5I59, and may provide information for use by the UE 3 to receive one or more paging messages. The OSI may comprise, for example, SI 52 to 51 59 transmitted using a DL-SCH in SI messages. A mapping of SIB2 to SIB9 to corresponding SI messages may be provided to the UE 3 by the base station 5. MIB and SIB1 to 5IB9 are described in more detail, for example, in 3GPP TS 38.331. For example, SIB2 provides information for intra-frequency, inter-frequency and inter-system cell reselection, 5I53 provides cell-specific information for intra-frequency cell reselection, and 5IB4 provides information for inter-frequency cell reselection. 5IB5 provides information regarding inter-system cell reselection towards 4G (LTE). 5IB6 and 5IB7 provide information for an earthquake and tsunami warning system (ETVVS). 5IB8 provides information for a commercial mobile alert service (CMAS) notification, for example to provide warning text messages to the UE 3. 5IB9 includes information regarding coordinated universal time (UTC), global positioning system (GPS) time (e.g. for GPS initialisation) and local time.

SIB may be broadcast periodically (e.g. according to a predetermined periodic pattern), or alternatively may be provided 'on-demand', for example in response to a request from a UE 3. For example, MIS may be transmitted with a periodicity of 80 ms and repetitions made within 80 ms, and SIB1 may be transmitted with a periodicity of 160 ms and a variable transmission repetition periodicity within 160 ms (e.g. 20 ms). SIB1 can be used to indicate to a UE 3 which SIB are transmitted periodically and which SIB are available on-demand in response to a request from the UE 3. A UE 3 may be configured to request on-demand SIB using MSG1 (random access preamble (RA)), which may be referred to as a MSG1-based on-demand SI request, or M533 (RRC Connection Request), which may be referred to as a MSG3-based on-demand SI request.

A physical broadcast channel (PBCH) can be used to broadcast the MIB. The base station 5 may transmit the PBCH with synchronisation signals (SS) (e.g. primary synchronisation signal (PSS) and secondary synchronisation signal (SSS)) in a SS/PBCH Block. The SS/PBCH block comprises four orthogonal frequency-division multiplexed (OFDM) symbols that are mapped to PSS, SSS and PBCH associated with a demodulation reference signal (DM-RS). In the frequency domain, an SS/PBCH block consists of 240 contiguous subcarriers. When the UE 3 is in an RRC connected mode, the base station 5 may provide the UE 3 with an indication of resources used for the SS/PBCH, for example using dedicated signalling (e.g. for an anchor NES cell or a non-anchor NES cell). SIB1 may be transmitted using a physical downlink shared channel (PDSCH). The 051 may be similarly transmitted, for example, using a PDSCH.

When one or more beamformed transmissions are transmitted in a cell provided by the base station 5, some of the SI (e.g. some of the SIB) may only be transmitted using particular beams, or using a particular transmission/reception point (TRP).

Buffer Status Reports (BSR) A buffer status report (BSR), that indicates an amount of uplink data in a buffer of the UE 3, may be transmitted from the UE 3 to the base station 5. The network is then able to determine, based on the BSR received from the UE 3, uplink communication resources (e.g. radio resources, including frequency and/or time resources) to allocate to the UE 3 for transmission of the uplink data. The allocated uplink communication resources can be indicated to the UE 3 using a corresponding Uplink Grant message transmitted to the UE 3. It will be appreciated, that accurate and precise BSR are useful for more efficiently allocating uplink resources to the UE 3.

As will be described in more detail below, a number of different possible formats can be used for a BSR. The format (e.g. number of bits used to indicate the amount of uplink data in a buffer of the UE 3) used for the BSR may depend on how the transmission of the BSR is triggered, which can be different for regular BSR, periodical BSR and padding BSR, as described in more detail below. The BSR may indicate an amount of uplink data in a buffer of the UE 3 for a particular logical channel (LCH) or logical channel group (LCG), and the format of the BSR may depend on the number of LCGs that have uplink data available for transmission. For a padding BSR, which is transmitted when a number of padding bits are available for transmission of the BSR, the format of the BSR may depend on the number of available padding bits.

A logical channel may be identified using a corresponding logical channel ID (LCID), and the LCID may be used to indicate a format of the BSR. An extended LCID (eLCID) may also be provided (for example using a number of bits following the LCID, e.g. 8 bits) that extends the range of the LCID field. For example, an LCID value of 61 may indicate that the BSR is a short BSR, a value of 62 may indicate that the BSR is a long BSR, a value of 59 may indicate that the BSR is a short truncated BSR, and a value of 60 may indicate that the BSR is a long truncated BSR. The LCID may be included in a MAC subheader of a transmission from the UE 3 to the base station 5. Some examples of types of BSR that may be transmitted from the UE 3 to the base station 5 will now be described.

A Short BSR has a fixed size, uses 5 bits to indicate the amount of uplink data in one or more buffers of the UE 3, and is a report associated with one LCG. A Long BSR has a variable size, uses 8 bits to indicate the amount of uplink data in one or more buffers of the UE 3, and can provide a buffer status for multiple LCGs. A Short b Truncated BSR has a fixed size, uses 5 bits to indicate the amount of uplink data in one or more buffers of the UE 3, and is a report associated with one LCG. A Long Truncated BSR has a variable size, uses 8 bits to indicate the amount of uplink data in one or more buffers of the UE 3, and can provide a buffer status for multiple LCGs.

A BSR may be transmitted from the UE 3 to the base station 5 as a MAC control element (MAC CE) in a corresponding transport block (TB), for example as part of a MAC protocol data unit (PDU). The MAC PDU may comprise a subheader and a MAC service data unit (SDU). The subheader may include an indication of the LCID (which can be used as an indication of the format of the BSR). The subheader may include a length field that indicates of the length of the corresponding MAC SDU. The subheader may also include a format field that indicates the length of the length field (e.g. using a value of 0 to indicate that the length field has a length of 8 bits, and a value of 1 to indicate that the length field has a length of 16 bits, although any other suitable type of indication could alternatively be used and the values need not necessarily be 0 or 1).

Fig. 5 shows an example of a Short BSR MAC CE, that may be included in a TB for transmission from the UE 3 to the base station 5, e.g. as part of a MAC PDU. As shown in the figure, the short BSR comprise 3 bits for indicating an LCG ID, and also includes 5 bits for indicating a corresponding buffer size (the amount of uplink data stored in a buffer). The total size of the short BSR is therefore 8 bits.

The Buffer Size field provides an indication of the amount of uplink data in a buffer of the UE 3 and available for transmission to the base station 5 (according to a data volume calculation procedure) across all logical channels of the logical channel group after the MAC PDU has been built (e.g. after the logical channel prioritization procedure). The size of the RLC headers and MAC subheaders are not considered in the buffer size computation. The value indicated in the buffer size field is used by the base station 5 to identify a corresponding entry of a lookup table that indicates the number of bytes of data in the buffer of the UE 3.

The 5 bits for indicating the buffer size can be used to indicate an index between 0 and 31. Fig. 6 shows an exemplary table that can be used to map the indicated index to the buffer size On this example in bytes, however this need not necessarily be the case, and any other suitable unit of data size could alternatively be used). The table may be stored and used at the base station 5. For example, when the 5 bit field of the BSR used to indicate the buffer size indicates a value of 22, the corresponding buffer size identified using the lookup table is greater than 7587 bytes, and smaller than or equal to 10570 bytes. It will be appreciated, therefore, that the base station 5 can use the table of Fig. 6 to determine the buffer size at the UE 3 based on the BSR The index mapped to each buffer size value may also be referred to as a icodepoint.

As shown in Fig. 6, the range for the buffer size value becomes less precise for larger BSR indices (larger buffer size values). For example, when the indicated index is 3, the buffer size value is greater than 14 and less than or equal to 20, corresponding to a range of 6 bytes. In contrast, when the indicated index is 28, the buffer size value is greater than or equal to 55474 and 77284, corresponding to a range of 21810 bytes. Improved methods for mitigating against this variation in the precision of the buffer size value will be described in more detail later.

Figs. 7 to 9 show further examples of BSR that may be transmitted from the UE 3 to the base station 5. Fig. 7 shows an example of a Long BSR MAC CE, which indicates a plurality of buffer sizes associated with each of a respective plurality of LCG. The LC& field indicates the presence of the Buffer Size field for the logical channel group L An LCG, field set to 1 indicates that the Buffer Size field for the logical channel group i is reported in the BSR. An LCG, field set to 0 indicates that the Buffer Size field for the logical channel group i is not reported in the BSR. For the Long Truncated BSR and the Extended Long Truncated BSR formats, this field indicates whether logical channel group i has data available. An LOG, field set to 1 indicates that logical channel group i has data available. An LOG, field set to 0 indicates that logical channel group i does not have data available.

Fig. 8 shows an extended short buffer status report, and Fig. 9 shows an extended long buffer status report. As can be seen in the figures, eight bits are used to indicate each of the buffer sizes (corresponding to an index of between 0 and 255). For the Long BSR format, the Long Truncated BSR format, the Extended Long BSR format, and the Extended Long Truncated format, the Buffer Size fields are included in ascending order based on the LCGi (in another words, in order of ascending LCGi value). For the Long Truncated BSR format and the Extended Long Truncated format, the number of Buffer Size fields included is maximised, while not exceeding a number of available padding bits. An exemplary lookup table for the 8 bit indication of buffer size, similar to that shown in Fig. 6 for 5 bits, is shown in Table 1 below.

Table 1 -Buffer Size Table for 8 bit indication: Index BS value Index BS value Index BS value Index BS value 0 0 64 s560 128 s31342 192 s1754595 1 s10 65 s597 129 s33376 193 s1868488 2 s11 66 s635 130 s35543 194 s1989774 3 s12 67 s677 131 s37850 195 s2118933 4 s13 68 s720 132 s40307 196 s2256475 s14 69 s767 133 s42923 197 s2402946 6 s15 70 s817 134 s45709 198 s2558924 7 s16 71 s870 135 s48676 199 s2725027 8 s17 72 s926 136 s51836 200 s2901912 9 s18 73 s987 137 s55200 201 s3090279 s19 74 s1051 138 s58784 202 s3290873 11 s20 75 s1119 139 s62599 203 s3504487 12 s22 76 s1191 140 s66663 204 s3731968 13 s23 77 s1269 141 s70990 205 s3974215 14 s25 78 s1351 142 s75598 206 s4232186 s26 79 s1439 143 s80505 207 s4506902 16 s28 80 s1532 144 s85730 208 s4799451 17 s30 81 s1631 145 s91295 209 s5110989 18 s32 82 s1737 146 s97221 210 s5442750 19 s34 83 s1850 147 s103532 211 s5796046 s36 84 s1970 148 s110252 212 s6172275 21 s38 85 s2098 149 s117409 213 s6572925 22 s40 86 s2234 150 s125030 214 s6999582 23 s43 87 s 2379 151 s133146 215 s 7453933 24 s46 88 s2533 152 s141789 216 s7937777 s49 89 s2698 153 s150992 217 s8453028 26 s52 90 s2873 154 s160793 218 s9001725 27 s55 91 s3059 155 s171231 219 s9586039 28 s59 92 s3258 156 s182345 220 s10208280 29 s62 93 s3469 157 s194182 221 s10870913 s66 94 s3694 158 s206786 222 s11576557 31 s71 95 s3934 159 s220209 223 s12328006 32 s75 96 s4189 160 s234503 224 s13128233 33 s80 97 s4461 161 s249725 225 s13980403 34 s85 98 s4751 162 s265935 226 s14887889 Index BS value Index BS value Index BS value Index BS value s91 99 s5059 163 s283197 227 s15854280 36 97 100 5387 164 301579 228 16883401 37 103 101 5737 165 321155 229 17979324 38 110 102 6109 166 342002 230 19146385 39 117 103 6506 167 364202 231 20389201 124 104 6928 168 387842 232 21712690 41 s 132 105 s 7378 169 5 413018 233 5 23122088 42 s 141 106 s 7857 170 5 439827 234 5 24622972 43 s 150 107 s 8367 171 5 468377 235 5 26221280 44 s160 108 s8910 172 498780 236 27923336 170 109 9488 173 531156 237 29735875 46 181 110 10104 174 565634 238 31666069 47 193 111 10760 175 602350 239 33721553 48 205 112 11458 176 641449 240 35910462 49 218 113 12202 177 683087 241 38241455 s233 114 s12994 178 s727427 242 s40723756 51 s248 115 s13838 179 s774645 243 s43367187 52 s264 116 s14736 180 s824928 244 s46182206 53 s281 117 s15692 181 s878475 245 s49179951 54 s299 118 s16711 182 s935498 246 s52372284 318 119 17795 183 996222 247 55771835 56 339 120 18951 184 1060888 248 59392055 57 361 121 20181 185 1129752 249 63247269 58 384 122 21491 186 1203085 250 67352729 59 s 409 123 s 22885 187 s1281179 251 5 71724679 s436 124 s24371 188 s1364342 252 s76380419 61 s464 125 s25953 189 s1452903 253 s81338368 62 s494 126 s27638 190 s1547213 254 >81338368 63 s526 127 s29431 191 s1647644 255 Reserved As mentioned above, BSR MAC CEs may use the following formats: Short BSR format (fixed size); or Extended Short BSR format (fixed size) or Long BSR format (variable size); or Extended Long BSR format (variable size); or Short Truncated BSR format (fixed size); or Extended Short Truncated BSR format (fixed size); or Long Truncated BSR format (variable size); or Extended Long Truncated BSR format (variable size).

A BSR can be triggered for transmission from the UE 3 to the base station 5. For example, a BSR can be triggered if UL data, for a logical channel which belongs to an LCG, becomes available to the MAC entity of the UE 3; and either: * this UL data belongs to a logical channel with higher priority than the priority of any logical channel containing available UL data which belong to any LCG; or * none of the logical channels which belong to an LCG contains any available UL data, in which case the BSR can be referred to as 'Regular BSR'.

A BSR can also be triggered if a number of padding bits (which can be used to transmit a BSR) in an uplink data message is equal to or larger than the size of a Buffer Status Report MAC CE plus the corresponding subheader. This type of BSR can be referred to as a 'Padding BSR'.

A BSR can also be triggered based on a timer (e.g. a retxBSR-Timer), when at least one of the logical channels which belong to a LCG contains UL data, in which case the BSR may be referred to as 'Regular BSR'. The MAC entity may restart the timer upon reception of a grant for transmission of new data on any UL-SCH.

A BSR can also be scheduled for periodic transmission based on a timer (e.g. a periodicBSR-Timer), in which case the BSR can be referred to as 'Periodic BSR' or Periodical BSR'.

In some examples a MAC PDU may include at most one BSR MAC CE, even when multiple events have triggered a BSR. A regular BSR and a Periodic BSR may have a higher priority for transmission to the base station 5, compared to a Padding BSR.

It will be appreciated that the methods of transmitting (and determining to transmit) buffer status reports described below can be applied to any suitable type of BSR.

The BSR is received at the base station 5, and may be used by the base station 5 to configure and/or schedule uplink resources for transmission of uplink data from the UE 3 to the base station 5. For example, in configured grant Type 1, an uplink grant is provided by RRC, and stored as a configured uplink grant. In configured grant Type 2, an uplink grant is provided by physical downlink control channel (PDCCH), and stored or cleared as configured uplink grant based on L1 signalling indicating configured uplink grant activation or deactivation. Type 1 and Type 2 are configured by RRC for a Serving Cell per bandwidth part (BWP). Multiple configurations can be active simultaneously in the same BWP. For Type 2, activation and deactivation are independent among the Serving Cells. For the same BWP, the MAC entity can be configured with both Type 1 and Type 2. The base station 5 may also (or alternatively) perform semi-persistent scheduling (SPS) or dynamic grant (DG).

Further examples of BSR are provided in Technical Specification (TS) 38.321 V17.0.0.

BSR Transmission Exemplary methods for transmission of a BSR from a UE 3 to a base station 5 will now be described.

BSR Polling Fig. 10 shows an example of BSR polling via physical downlink control channel (POOCH) signalling.

As shown in the figure, the base station 5 transmits, to the UE 3, an indication of whether a BSR is to be transmitted. For example, a BSR polling field may be included in the POOCH to indicate whether a regular BSR is to be included in a transmission to the base station 5. The BSR polling field may be a 1-bit field (e.g. for which a value of 1 indicates that a BSR is to be transmitted to the base station, and a value of 0 indicates that transmission of the BSR is not requested). However, any other suitable number of bits could be used for the BSR polling field.

Fig. 11 shows an alternative in which a MAC CE includes the indication of whether BSR is to be transmitted. The indication may indicate whether BSR is to be transmitted per logical channel group.

When the UE 3 receives the indication, the UE triggers/transmits a regular BSR to the base station 5 for all, or indicated, logical channel groups.

Advantageously, therefore, the UE 3 is able to reliably determine that BSR is to be transmitted to the base station 5.

Transmitted data volume threshold Fig. 12 shows an example in which the UE 3 receives a threshold for determining whether a BSR is to be transmitted. The UE 3 transmits a BSR to the base station 5 when a volume of data transmitted by the UE 3 exceeds a value corresponding to the threshold received from the base station 5.

The threshold is obtained (e.g. generated, or received from the core network or any another suitable network node) at the base station 5 and transmitted to the UE 3. The threshold may be received at the base station 5 from any suitable entity in the core network 7, or alternatively may be stored at the base station 5 (e.g. configured in a memory of the base station 5). In other words, the threshold may be configured by any suitable entity in the network 1.

In this example, the threshold corresponds to a volume of transmitted data. Fig. 13 shows an example of how the threshold may be used by the UE 3 to determine that a BSR is to be transmitted to the base station 5.

In step S130, the UE 3 receives the information indicating the threshold for transmission of a BSR, from the base station 5 In step 3131, the UE 3 transmits one or more uplink transmissions, to transmit uplink data to the base station 5.

In step S132, the UE 3 determines whether the volume of data (which may also be referred to as a 'size' or 'amount' of data) transmitted to the base station 5 exceeds the volume indicated by the threshold received in step S130. If the volume of transmitted uplink data exceeds the threshold value, then the UE 3 determines that a BSR (e.g. a Regular BSR) is to be transmitted to the base station 5. If the volume of transmitted uplink data does not exceed the threshold value, then the UE 3 determines that a BSR (e.g. a Regular BSR) is not to be transmitted to the base station 5 (or could alternatively determine that a BSR is not required, but can be optionally transmitted to the base station 5).

The UE 3 may additionally determine whether there is uplink data present in a corresponding buffer, and only determine that the BSR is to be transmitted if there is data present in the corresponding buffer, in addition to the volume of data transmitted having exceeded the volume indicated by the threshold.

In order to determine the volume of data that has been transmitted, the UE 3 may count the data transmitted for each LCH or LCG separately, or alternatively may count the data for all LCH (or another suitable group or subset of LCH) collectively.

In step S133, the UE 3 transmits the BSR to the base station 5.

After the UE 3 has transmitted the BSR to the base station 5, the UE 3 resets the count of the volume of data transmitted by the UE 3, and the method returns to step 3131.

Advantageously, therefore, the UE 3 is able to more reliably transmit BSR to the base station 5, by comparing the volume of uplink data transmitted to the base station 5 to the threshold value received from the base station 5.

Data volume compared to previous reported buffer size Fig. 14 shows a method in which the UE 3 determines to transmit a BSR based on a comparison between a volume of transmitted or scheduled UL data since a previous BSR was transmitted to the base station 5 and the buffer size reported in the previous BSR.

In step S140, the UE 3 transmits a BSR to the base station 5. The BSR includes an indication of a buffer size at the UE 3.

In step S141, the UE 3 transmits uplink data to the base station 5.

In step 142, the UE 3 determines that the volume of data (for a LCH or LCG) transmitted to the base station 5 exceeds the buffer size reported in the BSR in step S140, and therefore determines that a BSR is to be transmitted to the base station 5. The UE 3 may optionally include data that is scheduled for transmission (e.g. data for transmission based on an UL grant received from the base station) along with the data that has already been transmitted to the base station 5, when comparing to the buffer size reported in the previous BSR. In other words, the UE 3 may determine whether the sum of the data transmitted from the UE 3 to the base station 5 since the previous BSR was transmitted, and the volume of data currently scheduled for transmission to the base station 5, exceeds the buffer size reported in the BSR in step 5140.

In step S143, the UE 3 transmits a BSR to the base station 5.

Whilst in this example the UE 3 determines to transmit the BSR when the volume of data transmitted to the base station 5 from the UE 3 is greater than the buffer size reported in the previous BSR, the UE 3 may alternatively determine to transmit the BSR when the volume of data transmitted to the base station 5 is greater than or equal to the buffer size reported in the previous BSR, or may determine to transmit the BSR when the volume of data transmitted to the base station 5 is within a threshold range of the buffer size reported in the previous BSR.

The method illustrated in Fig. 14 may be referred to an 'implicit transmitted data volume' based method.

The UE may store a variable that corresponds to the unscheduled but reported buffer size for each LCG (e.g. cunscheduledbutReportedBufferSize). This variable may be set (or reset) to the reported buffer size (e.g. the minimum possible size of the buffer size range corresponding to the index indicated in the BSR) when a BSR corresponding to the LCG has been transmitted to the base station 5 (e.g in step 5140).

The value of the variable stored at the UE 3 may then be reduced based on the amount of data for the LCG transmitted to the base station 5 (e.g. in step S141). When the value of the variable is less than a threshold value (e.g. 0), and if there is data in the corresponding buffer, the UE 3 determines that a BSR is to be transmitted to the base station 5.

Advantageously, therefore, the UE 3 is able to more reliably transmit BSR to the base station 5, based on the volume of data that has been transmitted to the base station 5 since a BSR was previously transmitted.

Volume of buffered data Fig. 15 shows a method in which the UE 3 determines that a BSR is to be transmitted to the base station 5, based on a volume of data buffered at the UE 3.

In step S150, the UE 3 determines that a volume of data buffered at the UE 3 (e.g. for all LOG, or per LCG) is less (or alternatively 'less than or equal to') a configured threshold value, and therefore determines that a BSR is to be transmitted to the base station 5. The threshold value UE 3 may be preconfigured at the UE 3, or could alternatively be received from any other suitable entity of the network 1.

In step S151, the UE 3 transmits the BSR to the base station 5.

Advantageously, therefore, the UE 3 is able to more reliably transmit BSR to the base station 5, based on the volume of data buffered at the UE 3.

UL Grant size Fig. 16 shows a method in which the UE 3 determines that a BSR is to be transmitted to the base station 5, based on an UL grant size.

In step 3160, the UE 3 determines than an UL grant size (e.g. an UL grant size received from the base station 5) is larger than a threshold grant size. The threshold grant size may be preconfigured at the UE 3, or could alternatively be received from any other suitable entity of the network 1.

A large volume of data may require several uplink dynamic grants. Therefore, when the UL grant size is large, it is advantageous to have an updated and precise BSR available at the base station 5 for assigning suitable UL grant size(s). Moreover, when the UL grant size is large, the overhead of including the BSR in a corresponding transmission to the base station 5 is relatively low.

Advantageously, therefore, the UE 3 is able to more reliably transmit BSR to the base station 5 based on the UL grant size, and the base station 5 can assign more suitable UL grant sizes and reduce overall resource usage (e.g. radio resource usage). Moreover, the BSR is advantageously transmitted when the relative overhead of the BSR is low.

Determination based on size of buffered data and buffer size reported in previous BSR Fig. 17 shows a method in which the UE 3 determines whether to transmit a BSR based on the amount of data in the UE buffer, and based on a buffer size reported (or 'indicated') in a previous BSR.

In step S170, the UE 3 transmits a BSR to the base station 5.

In step S171, the UE 3 transmits data from the buffer to the base station 5 (e.g. after receiving an UL grant from the base station 5).

In step S172, the UE 3 determines that a difference based on the largest value of the buffer size reported in step S170 and the amount of data currently in the buffer is greater than a threshold value (or alternatively is greater than or equal to a threshold value), and therefore determines that a BSR is to be transmitted to the base station 5. The UE 3 takes into account the volume of data that has been transmitted to the base station 5 in step S171, when performing this determination. In other words, as shown in the example below, the UE determines whether the difference between the value of the current buffer size that could be calculated by the base station 5 and the actual buffer size exceeds a threshold value.

In step S173, the UE 3 transmits the BSR to the base station 5.

The 'largest value of the buffer size reported' is the upper value of the range indicated in the BSR. For example, referring to Fig. 6, when the reported index in the previous BSR was 11, the largest value of the reported buffer size is 276 (the upper value of the range of possible buffer size values corresponding to that index).

When B represents the amount of data currently in the UE 3 buffer, and E represents the largest possible buffer size based on the previously transmitted buffer size index (and based on the data transmitted from the UE 3 to the base station 5 since the BSR was transmitted), the UE 3 determines whether E-B On case of E>=B), or B-E (in case of B>=E) is greater than a threshold value T. For example, referring to Table 1 above, when the buffer of the UE 3 is initially empty and the UE 3 then receives a packet of size 60000 bytes in the buffer, the size of the buffer is 60000 bytes, and the index included in the BSR in step S170 is therefore '139' (because the buffer size is greater than 58784 and less than or equal to 62599). In this case, E-B = 62599 -60000 = 2599. Therefore, if the threshold T is 1000, then E-B > T. However, the UE does not yet transmit another BSR, because the BSR is triggered to be sent based on data arrival. If then UE is then scheduled to transmit, and transmits, 50000 bytes of data from the buffer in step S171, then B=10000, E=12599 (because E is calculated taking into account the volume of transmitted data: E=62599-50000), and E-B = 2599. Since E-B is greater than the threshold value of 1000, and therefore there is a relatively large discrepancy between the buffer size that could be calculated or estimated by the base station 5 and the actual buffer size, the UE determines to transmit a new BSR to reduce the value of E-B, or if then there are more data e.g., 2000 bytes arriving in the buffer, then B=30000, E=12599, and B-E = 17401. Since BE is greater than the threshold value of 1000, and therefore there is a relatively large discrepancy between the buffer size that could be calculated or estimated by the base station 5 and the actual buffer size, the UE determines to transmit a new BSR to reduce the value of B-E.

In other words, the transmission of the BSR in step 173 is based on the difference between the actual volume of buffered data at the UE 3, and the volume of buffered data at the UE 3 that the base station 5 could determine or estimate (based on the previous BSR and the subsequent UL data transmissions received from the UE 3).

Advantageously, therefore, the UE 3 is able to provide a more accurate indication of the buffer size to the base station 5, enabling the base station 5 to schedule UL resources more efficiently.

Fig. 18 shows a modification of the method of Fig. 17, in which the UE 3 instead determines that a difference based on the smallest value of the buffer size reported in step 5170 and the amount of data currently in the buffer is greater than a threshold value (or alternatively is greater than or equal to a threshold value).

Steps S180, 5181 and S183 are the same as steps S170, S171 and S173, respectively.

In this example, the UE 3 uses the smallest value of the buffer size reported in step S180. The 'smallest value of the buffer size reported' is the lower value of the range indicated in the BSR. For example, referring to Fig. 6, when the reported index in the previous BSR was 11, the largest value of the reported buffer size is 199 (the lowest value of the range of possible buffer size values corresponding to that index).

When B represents the amount of data currently in the UE 3 buffer, and E' represents the smallest possible buffer size based on the BSR transmitted in S180 (and based on the data transmitted from the UE 3 to the base station 5 in S181), the UE 3 determines whether B -E' is greater than a threshold value T For example, referring to Table 1 above, when the buffer of the UE 3 is initially empty and the UE 3 then receives a packet of size 60000 bytes in the buffer, the size of the buffer is 60000 bytes, and the index included in the BSR in step S170 is therefore '139' (because the buffer size is greater than 58784 and less than or equal to 62599). In this case, B -E' = 60000- 58784= 1216. Therefore, if the threshold T is 1000, then B -E' > T. However, the UE does not yet transmit another BSR, because the BSR is triggered to be sent based on data arrival. If then UE is then scheduled to transmit, and transmits, 50000 bytes of data from the buffer in step S181, then B=10000, E'=8784 (because E' is calculated taking into account the volume of transmitted data: E'=58784-50000), and B -E' = 1216. Since B -E' is greater than the threshold value of 1000, and therefore there is a relatively large discrepancy between the buffer size that could be calculated or estimated by the base station 5 and the actual buffer size, the UE determines to transmit a new BSR to reduce the value of B -E'.

BSR Difference Information Fig. 19 shows an example in which the UE 3 transmits an indication of a difference between the largest possible buffer size based on the current regular/periodical BSR, and current size of data in buffer, in addition to transmitting the regular/periodical BSR.

As shown in the figure, the UE transmits a BSR to the base station 5, and also transmits an indication of a difference between the largest possible buffer size based on the BSR, and current size of data in buffer.

For example, where B represents the amount of data currently in the buffer, and E represents the largest possible buffer size based on the buffer size index in the BSR, the UE 3 may transmit the value of E -B (in this example, as a MAC CE) to the base station 5. The 'largest possible buffer size' is the upper value of the range indicated in the BSR. For example, referring to Fig. 6, when the reported index in the BSR is 11, the largest value of the reported buffer size is 276 (the upper value of the range of possible buffer size values corresponding to that index). The base station 5 may use the value of E -B in order to obtain a more accurate determination of the actual buffer size at the UE 3 (e.g., using the buffer size values provided in Table 1 above), and is therefore able to schedule UL resources more efficiently.

Fig. 20 shows a modification of Fig. 19 in which the UE 3 transmits an indication of a difference between the actual amount of data in the buffer and the smallest possible data volume based on the BSR index/Buffer size included in the BSR. For example, where B represents the amount of data currently in the buffer, and E represents the smallest possible buffer size based on the buffer size index in the BSR, the UE 3 may transmit the value of B -E (in this example, as a MAC CE) to the base station 5.

Whilst in the examples of Figs. 19 and 20 the indications are transmitted as a MAC CE, another other suitable type of transmission from the UE 3 to the base station 5 could alternatively be used.

The value of E -B in the example of Fig. 19, and the value of B -E in the example of Fig. 20 (both of which may be referred to as the 'buffer size difference') may be transmitted (or triggered) when one or more of the following conditions are met: * The transmission of the buffer size difference is enabled by the network * Regular/periodical/truncated BSR report has been triggered and is to be included in an available Uplink scheduled grant * The buffer size difference is larger than a threshold value (e.g. as determined by the UE 3) * A grant size of a regular/periodical/truncated BSR that has been triggered and is going to be included in an available Uplink scheduled grant is larger than a threshold value

Buffer Size Tables

As mentioned above, a 5-bit table or an 8-bit table could be used with a corresponding 5-bit indication or 8-bit indication in a buffer size field of a BSR. However, with reference to Fig. 6, the range for the buffer size value becomes less precise for larger BSR indices (larger buffer size values). For example, when a 5-bit Buffer Size field is used for the BSR report, and the indicated index is 3, the buffer size value is larger than 14 bytes and smaller than or equal to 20 bytes, corresponding to a range of 6 bytes. In contrast, when the indicated index is 28, the buffer size value is larger than 55474 bytes and smaller than or equal to 77284 bytes, corresponding to a range of 21810 bytes. In other words the granularity of the indicated buffer level becomes less fine as the size of the index becomes larger. However, it is desirable for the base station 5 to have a more precise range for the buffer size value. When a UE is using an XR service, which generate large data packets, a typical amount of data in the buffer of the UE 3 may be, for example, approximately 20 MB, and it would therefore be beneficial for the granularity to be finer for buffer size values around 20 MB in size.

It is advantageous to provide an additional or new table that maps the BSR indices to the corresponding buffer size values, based on a particular service or device type. For example, for video streaming in an XR implementation, the typical packet size may fall within a particular range. The table can be configured to provide smaller ranges (i.e. finer granularity) of the buffer size values for the typical packet sizes, which increases the overall precision of the BSRs for particular service scenarios (albeit at the cost of coarser granularity for some buffer sizes that are not close to the typical buffer size values).

Fig. 21 shows a modified version of the table of Fig. 6, in which the mapping between the indices and the buffer size values has been modified to provide finer granularity for buffer size values between 4000 bytes and 5000 bytes (e.g. because a typical packet size for a particular application or service is between 4000 bytes and 5000 bytes). For example, when the actual buffer size at the UE 3 is 4150 bytes, if the table of Fig. 6 were used then an index value of 20 would be included in the BSR, which indicates that the buffer size value is larger than 3909 bytes and less than or equal to 5446 bytes (a range of 1537 bytes). In contrast, when using the table of Fig. 21, an index value of 18 would be included in the BSR, which indicates that the buffer size value is larger I 0 than 4100 bytes and smaller than or equal to 4200 bytes (a smaller range of 100 bytes).

Therefore, the BSR provides a more precise indication to the base station 5 of the actual buffer size when the actual buffer size is between 4000 bytes and 5000 bytes, and the base station is able to schedule UL resources more efficiently.

The UE 3 may store or be configured with (e.g. receive from the base station 5) a b plurality of mapping tables, such as the tables illustrated in Figs. 6 and 21, and the network may provide an indication to the UE 3 of which table to use to generate a BSR. For example, the network may provide an indication that the UE 3 is to use a particular mapping table based on a type of the UE 3, based on a service used or requested by the UE 3 (the UE 3 may use a particular table based on a network configuration), and/or based on a typical buffer size reported by one or more UEs 3. Alternatively, the UE 3 may select a table to use, and may provide an indication of the selected table to the base station 5.

Alternatively (or additionally), a new BSR MAC CE in which more than 8 bits (e.g. 16 bits) are used to indicate the buffer size value could be used, enabling a larger number of indices to be used to map to the buffer size values, and therefore mapping each index to a smaller range of buffer sizes.

Grant Assistance Information Fig. 22 shows an example in which the UE 3 transmits configured grant (CG)/scheduling request (SR) assistance information to the base station, which advantageously helps to address a problem that a mismatch between the data arrival timing at the UE 3 and the CG position can occur. This can occur, for example, due to jitter (which can be difficult to predict), or non-integer periodicity. This problem can be at least partially ameliorated by providing a UE-assisted CG configuration (and in particular the timing of the CG).

The base station 5 may optimise power consumption for the UE(s) by configuring a so-called Discontinuous Reception (DRX) and/or Discontinuous Transmission (DTX) operation. Both DRX and DTX are based on reducing the UE's 3 transceiver duty cycle while in active operation. In DRX mode, the base station 5 sets a cycle during which the UE 3 is operational for a certain period of time (referred to as 'active time' or 'on duration') and the base station 5 transmits all scheduling and paging information (for this UE) during this period only. The UE 3 can thus turn off its transceiver for the rest of the DRX cycle (which may also be referred to as 'inactive time' or 'off duration'). In DTX mode, the UE 3 does not turn off its transceiver completely, but keeps monitoring the Physical Downlink Control Channel (PDCCH) to be able to receive data from the base station 5 without undue delay. The longer the 'off duration relative to the duty cycle, the more power saving can be achieved. However, when operating in DRX and/or DTX mode, the UE's 3 data throughput is reduced in proportion to the achieved power savings since the UE 3 can transmit/receive data during the active time only.

Jitter may cause misalignment between data arrival and the on period of the DRX cycle.

The effect of jitter is that the exact frame arrival timing would be a bit earlier or later than expected due to a random delay, which is caused by the operation of frame encoders in edge servers, network transfer time in the core network, etc. A further issue may be referred to as 'non-integer periodicity' of XR data packets (i.e. non-integer number of subframes). Specifically, in case of XR, the packet arrival rate is determined by the frame generation rate (e.g. 60fps). Accordingly, the average packet arrival periodicity is given by the inverse of the frame rate (e.g. 1/60fps = 16.6667ms), without considering jitter (i.e. assuming fixed video encoding time, fixed network transfer delay). Thus, the arrival time at the base station for a packet with index k (k=1,2,3,...) is given as k/F*1000 [ms] where F is the given frame generation rate (per second). The difference between the non-integer arrival rate (in this example 16.6667ms) and the nearest periodicity given in units of subframes (e.g. 17ms) causes the buffer time of subsequent packets to get longer and longer (accumulated). In other words, an additional 0.3333ms delay may be added (and accumulated) at each new data packet corresponding to a new frame.

As illustrated in Fig. 22, in this example in step S220 the UE 3 transmits assistance information for CG and/or SR to the base station 5. The assistance information may comprise information related to traffic characteristics (and the assistance information may simply be referred to as 'traffic information). In step 5221 the base station 5 then configures CG/SR based on the received assistance information.

The information related to traffic characteristics may comprise: * Periodical traffic timing information represented by: o Periodicity / packet generate rate and offset of the traffic (e.g. an offset of a packet arrival timing from the start of the corresponding period) * Possible jitter range * Desired/Requested configurations, e.g: o uplink CG request including periodicity, offset and optionally transport block (TB) size (to match to the periodical packets arrival timing) o SR configuration including periodicity, offset (to match to the periodical packets arrival timing) The UE may transmit the assistance information when requested by the network.

Alternatively, for example, the UE 3 may transmit the assistance information periodically.

Advantageously, therefore, the base station 5 can use the assistance information to provide an improved configuration of CG / SR.

BSR Tables

Improved methods in which BSR tables are used to indicate the amount of uplink data in one or more buffers of the UE 3 will now be described. It will be appreciated that these improved methods may be combined with any of the methods described above (e.g. for triggering the transmission of a BSR), where appropriate. However, it will also be appreciated that the BSR in the methods described below may be triggered for transmission to the base station 5 using any other suitable method, and are not restricted to the methods of triggering transmission of the BSR described above.

An example of a MAC PDU is illustrated in Fig. 23. A MAC PDU is a bit string that is byte-aligned (e.g. in multiples of 8 bits) in length. A MAC PDU comprises one or more MAC sub-PDUs. Each sub-PDU may comprise: A MAC subheader only (including padding); a MAC subheader and a MAC SDU; a MAC subheader and a MAC CE; or a MAC subheader and padding. The MAC SDUs are of variable size, and each MAC subheader corresponds to either a MAC SDU, a MAC CE or padding.

As shown in the figure, a part of the MAC PDU (which may be referred to as a sub-PDU) includes a subheader and a corresponding SDU. Examples of a short/short truncated BSR having a fixed size, and a long/long truncated BSR having a variable size are also illustrated. A sub-PDU having a number of optional padding bits On which a padding BSR could be transmitted) is also illustrated.

A modified version of Fig. 5 in which the subheader is also illustrated is shown in Fig. 24. As shown in Fig. 24, the subheader and the MAC CE each comprise 8 bits. The bits labelled 'R' in the subheader are reserved bits (which may be set to 0). The [CID field includes an indication of the LCID On this example, 59 or 61), which as described above can be used to identify the format of the BSR (e.g. short BSR). The MAC CE is the same as described above with reference to Fig. 5 -the LCG ID field identifies the group of logical channels whose buffer status is being reported, and the Buffer Size field identifies the total amount of uplink data available (e.g. based on a data volume calculation procedure), for example using an index that identifies an entry of the lookup

table of Fig. 6.

A modified version of Fig. 7 in which the subheader is also illustrated is shown in Fig. 25. The bit labelled 'R' in the subheader is a reserved bits (which may be set to 0). The bit labelled 'F' is a format field, and indicates the length of the length field, L' (e.g. using a value of 0 to indicate that the length field has a length of 8 bits, and a value of 1 to b indicate that the length field has a length of 16 bits). The [CID field includes an indication of the [CID (in this example, 60 or 62), which as described above can be used to identify the format of the BSR (e.g. long BSR). The length field, L, indicates of the length of the corresponding MAC SDU or MAC CE.

As described above, a corresponding lookup table is used at the base station to determine the buffer size based on the indication in the buffer size field of the BSR received from the UE 3. One or more additional lookup tables may be generated for which different buffer size ranges are mapped to each index. The buffer size ranges may be based on an expected amount of data in a buffer (e.g. to provide finer precision of the BSR reports for buffer sizes that are close to a typical buffer size). However, there remains a problem that even lookup tables that use more codepoints (indices) for a particular buffer size range to increase the precision of the report may use fewer codepoints for another range of buffer sizes, decreasing the precision of the report for other buffer sizes. In some examples, a particular lookup table may be used when the buffer size is large (e.g. having a higher precision for large buffer size values) and another lookup table may be used when the buffer size is small (e.g. having a higher precision for smaller buffer size values). However, there is a need for the UE 3 to be able to determine which lookup table to use to generate the buffer size field of the BSR. Similarly, there is a need for the base station 5 to be able determine to which lookup table the buffer size field of the BSR transmitted by the UE 3 corresponds. Improved methods which address, or at least partially ameliorate this issue, will now be described.

Dynamic BSR Table Switch Improved methods in which the lookup table (which may also be referred to as a BSR table) used by the UE 3 may be dynamically changed will now be described.

A method in which a UE 3 and a base station 5 exchange information regarding one or more BSR tables is illustrated in Fig. 26. In step S260 the UE 3 transmits, to the base station 5, an indication of one or more BSR tables that are supported by the UE 3. The indication may be an indication of a particular BSR table that is supported by the UE 3, or alternatively may be an indication that the UE 3 is capable of supporting a new BSR table that is configured by the network (e.g. by the base station 5).

In step S261 the base station 5 transmits BSR table configuration information to the UE 3. The BSR table configuration information may include an explicit indication of one or more BSR table(s) (or one or more additional BSR table(s)) for use by the UE 3, or an implicit indication of one or more BSR table(s) (or one or more additional BSR table(s)) for use by the UE 3. The BSR table configuration information may comprise an indication of whether the UE 3 is to use one or more BSR tables that are preconfigured at the UE 3, or whether the UE 3 is to use one or more additional BSR tables configured by the base station 5. The BSR table configuration information may include an indication of indices/codepoints and corresponding buffer size ranges/intervals to use as a BSR table. In other words, the base station 5 may transmit one or more BSR table parameters to the UE 3. The BSR table parameters may include an indication of a first buffer size interval and a step size (which could then be used to generate the remaining buffer size intervals associated with the other indices/codepoints), or alternatively the BSR table parameters may simply comprise an explicit indication of the buffer size interval associated with each index/codepoint. It will be appreciated that any other suitable parameter(s) or indication(s) may alternatively, or additionally, be used. For example, the base station 5 may transmit a function (e.g. distribution function) to the UE 3 for generating a BSR table.

In step S262 the UE 3 generates a BSR for subsequent transmission to the base station 5. Advantageously, the UE 3 is able to determine which BSR table to use to generate the BSR. The UE 3 may be configured to use a particular BSR table received from the base station 5 when the buffer size (amount of uplink data in one or more buffers of the UE 3) at the UE 3 is within a particular buffer size range, which may be configured by the base station 5 using the BSR table configuration information received by the UE 3 in step S261. The UE 3 may be configured to use a particular BSR table when the buffer size at the UE 3 exceeds a threshold buffer size value, or when the buffer size at the UE 3 falls within a particular range of buffer size values. The UE 3 may be configured to use a default or preconfigured BSR table (e.g. the table described above with reference to Fig. 6) when one or more conditions for using an additional BSR table are not met.

In a particularly advantageous example, the UE 3 is configured to select the BSR table that would provide the greatest amount of precision in the BSR report based on the buffer size that is to be reported. For example, the UE 3 may have a buffer size of 8 bytes, which could be indicated using a first BSR table that would indicate that the buffer size falls between 7 bytes and 9 bytes, or using a second BSR table that would indicate that that the buffer size falls between 0 bytes and 10 bytes (e.g. the table illustrated in Fig. 6, for which an index of 1 would be used). In this case, the UE 3 is configured to select the first BSR table to use to generate the BSR report, since the range of possible buffer size values indicated in the BSR is smaller (in other words, the BSR report is more precise).

In step S263 the UE 3 transmits the BSR to the base station 5.

The UE 3 may also transmit, to the base station 5, an indication of the BSR table used to generate the BSR. The indication of the BSR table used to generate the BSR may be transmitted to the base station 5 either with the corresponding BSR, or separately from the BSR in another transmission. Alternatively, transmitting the indication of the BSR table used to generate the BSR to the base station 5 may not be necessary (e.g. if the rules used by the UE 3 to determine which BSR table to use are also stored at the base station 5, and the base station 5 is able to determine which BSR was used by the UE 3). The indication of the BSR table used to generate the BSR may be an explicit or implicit indication of a particular BSR table, or may be an indication of whether the UE 3 used a default BSR table or a BSR table received from the base station 5.

The indication of the BSR table used to generate the BSR may be transmitted to the base station using one or more bits of the subheader for the corresponding MAC CE. For example, the indication may be transmitted to the base station 5 using one or both of the reserved fields in the subheader (labelled 'RI illustrated in Fig. 24 for the case of a short BSR or a short truncated BSR. Similarly, for the long BSR or long truncated BSR, the reserved bit and/or format field ('F') illustrated in Fig. 25 may be used for the indication of the BSR table used to generate the BSR. One or more of bits of the length field (I') may alternatively, or additionally, be used (since not all of the bits of the length field may be needed to indicate the length of the MAC CE). For example, when the reserved bit, format field, and one bit of the length field are used to indicate the BSR table used to generate the BSR, the 3 bits may be used together to indicate a total of 8 possible values.

Advantageously, therefore, the UE 3 is able to determine which BSR table to use to generate the BSR, resulting in improved precision for the indication of the buffer size, and the base station 5 is able to determine which BSR table was used by the UE 3 to generate the BSR.

In the example described above, since the indication of which BSR table to use to generate the BSR is provided in the subheader for the MAC CE, the buffer sizes for each LCG are generated using the same BSR table (or using the same set of BSR tables, for example when the indication in the subheader indicates that the UE 3 is using a set of default BSR tables according to a set of preconfigured rules). A further improved method will now be described in which the indication of which BSR table was used to generate the BSR can be provided for each LCG, providing greater flexibility in the BSR tables that may be used by the UE 3 for reporting each buffer size.

Fig. 27 shows an example of a MAC CE that may be used to transmit an indication of a BSR table that was used to generate a BSR. In this example a modified version of the MAC CE of Fig. 8 is shown. The MAC CE includes the LCG ID and Buffer size, as described above with reference to Fig. 8. However, advantageously, in this example the MAC CE also includes one or more bits for indicating the BSR table associated with the index/codepoint identified in the buffe size field. The BSR table indication field may be either 1 bit or multiple bits (e.g. depending on how many possible BSR tables may be used by the UE to generate the BSR).

Fig. 28 shows a further example of a MAC CE that may be used to transmit an indication of a BSR table that was used to generate a BSR. In this example, similar to Fig. 7 described above, buffer sizes for a corresponding plurality of LCG are reported.

However, advantageously, in this example an indication of the BSR table associated with the index/codepoint identified in the buffer size field is provided (in this example, in the field labelled T: Ti, T2, ...). The BSR Table Indication in field Ti indicates that BSR table associated with the index in Buffer Size 1 (i.e. the lookup table to use to identify the data size in the buffer(s) using the index in the Buffer Size 1 field). Similarly, the BSR Table Indication in field T2 indicates that BSR table associated with the index in Buffer Size 2. It will be appreciated that the example of Fig. 28 some of the Buffer Size fields are spread over multiple rows of the table. For example one bit of the Buffer Size 2 field is in one row next to field T2, and the remaining 4 bits are in the subsequent row (similarly, the Buffer Size 3 and Buffer Size m fields are split over multiple rows, but each comprise 5 bits).

In this example 'm' buffer sizes are reported, and the BSR Table Indication in field Tm indicates that BSR table associated with the index in Buffer Size cm'. Advantageously, the UE 3 is able to indicate the BSR table used by the UE 3 for each Buffer Size field (e.g. for each LCG). Therefore, different BSR tables may be used by the UE 3 for each Buffer Size field. For example, the UE 3 may select the BSR table that would result in the most precise indication of the buffer size to generate the corresponding index for each Buffer Size field, and the base station 5 is nevertheless able to determine the BSR tables used by the UE 3 for each Buffer Size field.

It will be appreciated that whilst in the example of Fig. 28 each Buffer Size field uses 5 bits, this need not necessarily be the case. For example, Fig. 29 shows a modified MAC CE in which 8 bits are used for the Buffer Size fields (and therefore the corresponding BSR tables use an 8 bit index).

Fig. 30 shows a further example of how a MAC CE can be used to indicated the BSR tables used by the UE 3 to the base station 5. In the example shown in Fig. 30, 6 bits are used for the Buffer Size fields. It will be appreciated that even though 6 bits are used, a smaller number of bits could be used within the 6 bit field to indicate the index for the lookup table. For example, the 6 bit field could include one ignored bit (e.g. set as 0) followed by 5 bits used to identify the index for a 5 bit lookup table (e.g. the table illustrated in Fig. 6). In the example of Fig. 30 two bits are used for each of the 'T' fields used to indicate the BSR table used by the UE 3 for each Buffer Size field.

Fig. 31 shows a further example in which the Buffer Size fields have a variable length. As shown in the figure, the Buffer Size 1 has a length of 8 bits, Buffer Size 2 has a length of 5 bits, and buffer size m has a length of 10 bits.

Fig. 32 shows a further example in which the indications of the BSR tables used by the UE 3 (17 to TO) are provided in a sequence of consecutive bits following the fields identifying the LCGs (LCG7 to LCG0). In this example all of the indications of the BSR tables used by the UE 3 (17 to TO) are arranged before the corresponding set of Buffer Size fields, and are arranged after the corresponding LCG fields (which may indicate, for example, whether a Buffer Size field is included for that LCG).

Whilst in the examples of Figs. 28 to 32 one or two bits are used for the 'T' fields (indicating the BSR tables used by the UE 3), this need not necessarily be the case, and any other suitable number of bits may alternatively be used. eLCID

Fig. 33 shows an example in which the subheader of the example of Fig. 24 has been modified to include an eLCID. As described above, the eLCID can be used to extend the LCID field, in this example by 8 bits. Advantageously, the eLCID can be used as an indication to the base station 5 of the BSR tables used by the UE 3 to generated the Buffer Size fields in the corresponding MAC CE, or the format of the MAC CE. The bits of the eLCID can be used to indicate one or more BSR tables used by the UE 3. The eLCID may explicitly indicate the one or more BSR tables used by the UE 3, or may implicitly indicate the one or more BSR tables used by the UE 3 (e.g. by indicating the format of the corresponding MAC CE). The eLCID may alternatively be used to indicate that the UE 3 has used a default or preconfigured BSR table (or set of BSR tables) to generate the Buffer Size fields in the corresponding MAC CE. The example illustrated in Fig. 33 may be used, for example, for the short BSR or short truncated BSR formats (which have a fixed size).

Fig. 34 shows a further example in which the subheader additionally includes the length field '12, that indicates of the length of the corresponding MAC CE. The example illustrated in Fig. 34 may be used, for example, for the long BSR or long truncated BSR formats (which have a variable size).

Same LCID but different MAC CE formats An example in which the UE reuses the same LCIDs, but switches to use a new MAC CE format once configured by the base station 5 with additional BSR tables, will now be described.

Referring now to Fig. 35, in this example the UE 3 is in the RRC connected state. In step S351 the UE 3 transmits one or more BSR to the base station 5 (for example, using the BSR format illustrated in Fig. 5 or Fig. 7).

A first option includes steps S352 and S353. In step S352 the base station 5 transmits an RRC Reconfiguration message to the UE 3. The RRC Reconfiguration message includes an indication of one or more additional BSR tables for use by the UE 3. As described above, an indication of a BSR table may include a first buffer size interval and step size (that the UE 3 can use to determine all of the fields of the BSR table), or alternatively the mapping between each index of the lookup table and the corresponding buffer size interval could be explicitly indicated. The UE 3 determines to use the BSR tables received in step 5352 for subsequent BSR transmitted to the base station 5, based on the new BSR having been received from the base station 5.

In other words, in the first option, if the UE 3 receives new BSR tables from the base station 5, then the UE 3 determines to use the new BSR tables to generate subsequent BSR for transmission to the base station. The RRC reconfiguration information may also include an indication of the MAC CE format to use when transmitting the BSR to the base station 5. The indicated MAC CE format may be, for example, any of the MAC CE formats illustrated in Figs. 27 to 32. For example, the MAC CE format of Fig. 32 may be used, in which indications of each BSR table used to generate each Buffer Size field are included.

In step 5353 the UE 3 transmits a BSR to the base station 5 that is generated using one or more of the BSR tables received from the base station 5 in step S352. The UE 3 may use the same LCIDs used for the BSR transmitted in step S351 to indicate the BSR type (e.g. short BSR, short truncated BSR, long BSR, or long truncated BSR), even when the corresponding MAC CE is using the new format received from (or indicated by) the base station in step S352.

A second option includes steps S354 to 5356. In step 5354 the UE 3 receives the one or more BSR tables from the base station 5, as described above with reference to step S352.

In step S355 the base station 5 transmits BSR format information to the UE 3. The BSR format information includes an indication of whether the UE 3 is to use the one or more BSR tables received in step S354. In other words, the BSR formation information includes information for activating or deactivating the use of the BSR tables received in step S354 to generate the corresponding BSR for transmission to the base station 5. Advantageously, therefore, the base station 5 is able to control whether or not the UE 3 uses the BSR tables transmitted to the UE 3 in step 5354. Moreover, the more precise control by the base station 5 of which BSR tables are used at the UE 3 helps to ensure that the base station 5 and the UE 3 maintain a common understanding of which BSR tables and MAC CE formats are to be used, reducing the risk of decoding issues at the base station 5 (for example, in which the base station 5 attempts to use a BSR table to map the Buffer Size field of the MAC CE to a buffer size in bytes, but the UE 3 used a different BSR to generate the Buffer Size field).

In this example the BSR format information includes an indication that the new BSR tables indicated to the UE 3 in step S354 are to be used (activated), and in step S356 the UE 3 transmits a BSR to the base station 5 that is generated using one or more of the BSR tables received from the base station 5 in step S354. The UE 3 may use the same LCIDs used for the BSR transmitted in step S351 to indicate the BSR type (e.g. short BSR, short truncated BSR, long BSR, or long truncated BSR), even when the corresponding MAC CE is using the new format received from (or indicated by) the base station in step S354.

Whilst in the example described above with reference to Fig. 35 an RRC Reconfiguration message is used to indicate the new BSR tables (and corresponding MAC CE format) to the UE 3, any other suitable transmission from the base station 5 to the UE 3 could alternatively be used.

Extended BSR Table

An example in which an additional BSR table is used to extend another BSR table will now be described.

Fig. 36 shows an example of a first BSR table and an extension BSR table. In this example, the first BSR table is the 5 bit table of Fig. 6 having indices from 0 to 31. The extension table uses a further set of indices from 32 to 63. Advantageously the extension table can be used to provide greater precision of the reported buffer size, over a particular range of buffer sizes.

In this example, the buffer size values of the extension table correspond to indices 18 to 22 of the first table. Therefore, the UE 3 does not use indices 18 to 22, and instead uses the corresponding index of the extension table. In other words, the UE 3 determines which table to use based on the buffer size that is to be reported in the BSR. For example, when a buffer size value of 3565 is to be indicated, rather than using index 19 (corresponding to a buffer size of between 2807 and 3909, a range of 1103 values), the UE 3 uses index 37 (corresponding to a buffer size of between 3561 and 3872, a range of 311 values). Advantageously, therefore, the UE 3 is able to provide a more precise indication of the buffer size in the BSR transmitted to the base station 5.

Whilst in the example of Fig 36 both the first table and the extension table have 32 elements (32 indices and corresponding buffer size intervals), this need not necessarily be the case. The extension table need not necessarily have the same number of elements as the first table, and the number of elements need not necessarily be 32. Any suitable number of indices could be used for either table. In this example, the total number of indices is increased from 32 to 64, and so the Buffer Size field of the MAC CE could indicate the index using a 6 bit field. As a further example, if the first table was the 8 bit table described above (having indices from 0 to 255), the extension table could have (for example) indices from 256 from 511. In this case a 9 bit Buffer Size field could be used to indicate the index in the MAC CE. In another example, if the first table was the 8 bit table described above (having indices from 0 to 255), the extension table could have indices from 256 to 1023, in which case a 10 bit Buffer Size field could be used to indicate the index in the MAC CE (e.g. as illustrated for Buffer Size m in Fig. 31).

The extension table may be transmitted or indicated to the UE 3 using any of the methods described above. The format of the extension table (e.g. the buffer size intervals mapped to each index, or the number of indices) may be configurable by the network. For example, the extension table may be transmitted or indicated to the UE 3 in step S352 of Fig. 35 (and the use of the extension table by the UE 3 could be activated/deactivated as described above with reference to step S355). Alternatively, the extension table may simply be preconfigured at the UE 3. Similarly, the BSR table used by the UE 3 may be indicated to the base station 5 using any of the methods described above (e.g. using one or more bits of the corresponding subheader such as the reserved bits illustrated in Fig. 24, or using one or more bits of the MAC CE, for example as illustrated in any of Figs. 27 to 32).

Semi-static BSR Table Switch An example in which the base station 5 semi-statically activates/deactivates one or more BSR tables will now be described.

As described above, the UE 3 may transmit an indication to the base station 5 that the UE 3 supports one or more additional BSR tables (e.g. in addition to default BSR tables that are preconfigured at the UE 3), and the base station may transmit the additional BSR tables (or an implicit indication of the BSR tables) to the UE 3. For example, as described above, the base station 5 may transmit an explicit mapping between each index of the table and the corresponding buffer size interval, or the base station 5 may provide the UE 3 with information for generating the BSR table (e.g. a starting buffer size value and a step size, or alternatively a function or set of equations could be provided).

In this example, similar to step 3355 of Fig. 35, the base station is configured to activate or deactivate use of the additional BSR tables. However, in this example the base station 5 activates/deactivates use of the additional BSR tables using lower layer signalling, for example using a MAC CE or physical signalling.

If the additional tables are not configured at the UE 3 or are deactivated, then the UE 3 may use default or preconfigured BSR tables available at the UE 3 to set the Buffer Size fields of the MAC CE. The default or preconfigured BSR tables may also be referred to as legacy tables. However, if the additional tables are configured and activated at the UE 3 (e.g. in response to receiving a MAC CE from the base station 5 that indicates that the additional tables are to be used), then the UE 3 uses the one or more additional BSR tables to set the Buffer Size fields of the MAC CE.

Static BSR Table Switch An example in which the base station 5 statically activates/deactivates one or more BSR tables will now be described.

In this example, similar to step 5355 of Fig. 35, the base station is configured to activate or deactivate use of the additional BSR tables. However, in this example controls the activation deactivation by transmitting a transmission that includes a BSR table setup indication or a BSR table release indication to the UE 3.

Fig. 37 shows an example in which the base station controls activation/deactivation of use of BSR tables by the UE 3 using BSR table setup/release messages. In step 5371, the base station transmits a BSR table step message to the UE 3. The BSR table setup message includes an indication that one or more BSR tables are to be used at the UE 3. The BSR table setup message may also include the configuration of the BSR tables to be used (e.g. the indices and the corresponding set of buffer size intervals, which may be indicated either explicitly or implicitly), but this need not necessarily be the case (for example, if the BSR tables are already available at the UE 3).

In step S372 the UE 3 transmits one or more BSR to the base station 5, and set the Buffer Size fields using the one or more BSR tables indicated/activated in step S371. It will be appreciated that the MAC CE format may be any of the MAC CE formats described above (and that the BSR tables may also have any of the formats described above).

In step S373 the base station 5 transmits a BSR table release message to the UE 3. The BSR table release message indicates that the UE 3 is to no longer use one or more associated BSR tables (e.g. the tables activated in step S371). In this example the UE 3 reverts to using one or more default or preconfigured (or legacy) BSR tables after receiving the transmission of step 5373, and transmits one or more corresponding BSR in step S374.

Whilst in the example of Fig. 37 the BSR Table Setup and BSR Table Release messages are illustrated as dedicated messages, this need not necessarily be the case. Alternatively, the information of the BSR Table Setup message may be included in any suitable information element in any other suitable transmission from the base station 5 to the UE 3. Similarly, the information of the BSR Table Release message may be included in any suitable information element in any other suitable transmission from the base station 5 to the UE 3.

Further BSR Table

A further example of an improved BSR table will now be described.

As described above, the size of the buffer size interval mapped to each index of the table may vary, and therefore the precision of the reported buffer size may also vary.

Also as described above, the BSR table may be configured such that the buffer size intervals are smaller for a particular range of buffer sizes (e.g. as illustrated in Fig. 21, where some indices correspond to buffer size interval of 250 bytes, whereas other indices correspond to a buffer size interval of 100 bytes).

In this particularly advantageous example, the BSR table is configured for improved precision for multiple ranges of buffer sizes. Fig. 38 shows an example of a BSR table for which improved precision is provided for both low buffer size values, and for a further range of buffer size values (which may be, for example, a typical or expected amount of data in the buffer). In this example a buffer size interval of 2 bytes is used for buffer size values between 0 and 10 bytes. Between 10 bytes and 510 bytes a lower precision is used, as the size of the buffer size intervals is 100 bytes. However, between 510 bytes and 550 bytes there is a second region of increased precision, in which the buffer size intervals are of 10 bytes in size. For buffer sizes above 550 bytes an large buffer size interval of 300 bytes is used. Advantageously, therefore, increased precision can be achieved for both the low buffer size values, and a further range of buffer size values. This type of configuration is particular advantageous, as the precision is improved for both the lower buffer sizes that are likely to occur as uplink data is transmitted (and for which if the buffer size interval is large then the fractional uncertainty becomes very large), and the further region of improved precision can be configured for a typical or expected buffer size that is likely to occur. For example, when the typical or expected size of data in the one or more buffers is 530 bytes, the table of Fig. 38 could be used. The typical or expected buffer size may be, for example, a typical pack size for XR data.

Whilst 32 indices (corresponding to 5 bits) are used in the example of Fig. 38, this need not necessarily be the case. Any other suitable number of indices (and corresponding number of bits for the Buffer Size field in the MAC CE) could alternatively be used.

User Equipment Fig. 39 is a schematic block diagram illustrating the main components of a UE 3 as shown in Fig. 1.

As shown, the UE 3 has a transceiver circuit 310 that is operable to transmit signals to and to receive signals from a base station 5 via one or more antenna 330 (e.g., comprising one or more antenna elements). The UE 3 has a controller 370 to control the operation of the UE 3. The controller 370 is associated with a memory 390 and is coupled to the transceiver circuit 310. Although not necessarily required for its operation, the UE 3 might, of course, have all the usual functionality of a conventional UE 3 (e.g. a user interface 350, such as a touch screen / keypad / microphone / speaker and/or the like for, allowing direct control by and interaction with a user) and this may be provided by any one or any combination of hardware, software, and firmware, as appropriate. Software may be pre-installed in the memory 390 and/or may be downloaded via the telecommunications network or from a removable data storage device (RMD), for example.

The controller 370 is configured to control overall operation of the UE 3 by, in this example, program instructions or software instructions stored within memory 390. As shown, these software instructions include, among other things, an operating system 410, and a communications control module 430.

The communications control module 430 is operable to control the communication between the UE 3 and its serving base station(s) 5 (and other communication devices connected to the base station 5, such as further UEs and/or core network nodes). The communications control module 430 is configured for the overall handling uplink communications via associated uplink channels (e.g. via a physical uplink control channel (PUCCH), random access channel (RACH), and/or a physical uplink shared channel (PUSCH)) including both dynamic and semi-static signalling (e.g., SRS). The communications control module 430 is also configured for the overall handling of receipt of downlink communications via associated downlink channels (e.g. via a physical downlink control channel (PDCCH) and/or a physical downlink shared channel (PDSCH)) including both dynamic and semi-static signalling (e.g., CSI-RS). The communications control module 430 is responsible, for example: for determining where to monitor for downlink control information (e.g., the location of CSSs / USSs, CORESETs, and associated PDCCH candidates to monitor); for determining the resources to be used by the UE 3 for transmission/reception of UL/DL communications (including interleaved resources and resources subject to frequency hopping); for managing frequency hopping at the UE side; for determining how slots/symbols are configured (e.g., for UL, DL or SBFD communication, or the like); for determining which bandwidth part(s) are configured for the UE 3; for determining how uplink transmissions should be encoded; for applying any SBFD specific communication configurations appropriately; and the like. The communications control module 43 may be configured to control communications in accordance with any of the methods described above (e.g any of the methods of transmitting a BSR to the base station 5 described above).

The BSR module 440 is responsible for generating a BSR (e.g. as part of a MAC CE), and for determining to transmit the BSR to the base station 5. The BSR module 45 may also be responsible for generating and transmitting any other suitable information related to the BSR. The BSR module 45 may be configured to perform any of the methods including generation or transmission of a BSR described above.

Base Station Fig. 40 is a schematic block diagram illustrating the main components of the base station 5 for the communication system 1 shown in Fig. 1. As shown, the base station 5 has a transceiver circuit 510 for transmitting signals to and for receiving signals from the communication devices (such as UEs 3) via one or more antenna 530 (e.g. a single or multi-panel antenna array / massive antenna), and a core network interface 550 (e.g. comprising the N2, N3 and other reference points/interfaces) for transmitting signals to and for receiving signals from network nodes in the core network 7. Although not shown, the base station 5 may also be coupled to other base stations via an appropriate interface (e.g. the so-called Xn' interface in NR). The base station 5 has a controller 570 to control the operation of the base station 5. The controller 570 is associated with a memory 590. Software may be pre-installed in the memory 590 and/or may be downloaded via the communications network 1 or from a removable data storage device (RMD), for example. The controller 570 is configured to control the overall operation of the base station 5 by, in this example, program instructions or software instructions stored within memory 590.

As shown, these software instructions include, among other things, an operating system 610 and a communications control module 630.

The communications control module 630 is operable to control the communication between the base station 5 and UEs 3 and other network entities that are connected to the base station 5. The communications control module 630 is configured for the overall control of the reception and decoding of uplink communications, via associated uplink channels (e.g. via a physical uplink control channel (PUCCH), a random-access channel (RACH), and/or a physical uplink shared channel (PUSCH)) including both dynamic and semi-static signalling (e.g., SRS). The communications control module 630 is also configured for the overall handling the transmission of downlink communications via associated downlink channels (e.g. via a physical downlink control channel (PDCCH) and/or a physical downlink shared channel (PDSCH)) including both dynamic and semi-static signalling (e.g., CSI-RS). The communications control module 630 is responsible for managing full duplex (e.g., SBFD) communication including, where appropriate, the segregation of UL and DL communication via different physical antenna elements. The communications control module 630 is responsible, for example: for determining where to configure the UE 3 to monitor for downlink control information (e.g., the location of CSSs / USSs, CORESETs, and associated PDCCH candidates to monitor); for determining the resources to be scheduled for UE transmission/reception of UUDL communications (including interleaved resources and resources subject to frequency hopping); for managing frequency hopping at the base station side; for configuring slots/symbols appropriately (e.g., for UL, DL or SBFD communication, or the like); for configuring bandwidth part(s) for the UE 3; for providing related configuration signalling to the UE 3; and the like. The communications control module 43 may be configured to control communications in accordance with any of the methods described above (for example, transmitting information for activating/deactivating a BSR table at the UE 3, or for receiving a BSR from the UE) The BSR module 650 is responsible for the transmission/reception of any BSR-related information transmitted/received to or from the UE 3, for example as part of any of the methods described above. For example, the BSR module 65 may generate an indication that a UE 3 is to transmit a BSR to the base station 5.

The uplink (UL) scheduling module 670 is responsible for generating an UL grant for the transmission of data from a UE 3 to the base station 5, for example as part of any of the methods described above. The base station may schedule or allocate resources for an UL transmission for a UE 3 based on a BSR received from the UE 3.

Core Network Node/Function Fig. 41 is a block diagram illustrating the main components of a core network node or function, such as the AMF, CPF, the UPF, the SMF or OAM. As shown, the core network function includes a transceiver circuit 710 which is operable to transmit signals to and to receive signals from other nodes (including the UE 3, the base station 5, and other core network nodes) via a network interface 720. A controller 730 controls the operation of the core network function in accordance with software stored in a memory 740. The software may be pre-installed in the memory 74 and/or may be downloaded via the telecommunication network 1 or from a removable data storage device (RMD), for example. The software includes, among other things, an operating system 750, and a communications control module 760.

The communications control module 83 is responsible for handling (generating/sending/ receiving) signalling between the core network function and other nodes, such as the UE 3, the base station 5, and other core network nodes (e.g. as part of any of the methods described above).

Modifications and Alternatives As those skilled in the art will appreciate, a number of modifications and alternatives can be made to the above embodiments whilst still benefiting from the inventions embodied therein.

VVhilst the BSR have been described above with reference to uplink data for XR, this need not necessarily be the case. Alternatively, the BSR may be for any other suitable method in which a status of a buffer is reported.

Whilst in some of the examples described above the buffer size is reported per LCG, this need not necessarily be the case. Alternatively, the buffer size may be reported per LCH, or using a smaller granularity.

It will be appreciated that any of the methods described above may be combined, where appropriate. For example, the extended BSR table described with reference to Fig. 36 or the BSR table described with reference to Fig. 38 could be used with the semi-static BSR table switch method or the static BSR table switch method (illustrated in Fig. 37) described above. Indeed, the extended BSR table or the BSR table of Fig. 38 may be particular advantageous to use with the semi-static BSR table switch method or the static BSR table switch method, since these tables are able to provide relatively small buffer size intervals (i.e. improved precision) for both lower buffer sizes and another range of buffer sizes (e.g. buffer sizes typical for XR data), which makes them particularly suitable for use with static or semi-static configuration methods.

New BSR tables and extended BSR tables have been described above. The new BSR tables and extended BSR tables may be configured (or reconfigured) per LCG, per LCH or per data radio bearer (DRB). The size of each Buffer Size field in the MAC CE corresponding to different LCG/LCH/DRB may be different, and may be provided withing one long/long truncated MAC CE. However, the length of each buffer size field is nevertheless determinable and decodable at the base station 5 (e.g. using information provided in the MAC CE or the corresponding subheader, as described above).

In the examples of MAC CE illustrated in Figs. 28 to 32, the fields that indicate the BSR table used by the UE 3 (the 'T' fields, e.g. T7 to TO in Fig. 32) may be used even when the UE 3 uses a default or preconfigured BSR table (e.g. legacy BSR table). In this case, the field that indicates the BSR table used by the UE 3 for a particular LCG/LCH/DRB may simply indicate that the default/preconfigured/legacy BSR table was used.

In any of the examples described above, the MAC CE may also include data volume information associated with delay information (e.g. remaining time, for example for uplink transmission of the uplink data). The delay information may be reported depending on the BSR format. If the BSR format is selected dynamically (e.g. by the UE), then the UE may always report the delay information whenever the UE selects the new BSR format. Alternatively, the UE 3 may follow a RRC configuration or preconfiguration procedure controlled by a base station 5. For example, the UE may select the new BSR format, and the UE 3 may include the delay information if a RRC configuration message indicates that the UE 3 is to include the delay information (or is conditionally to include the delay information, depending on one or more conditions). If the base station 5 explicitly indicates that a BSR table is to be switched/activated/deactivated (e.g. according to any of the methods described above), then the UE 3 may be configured to always report the delay information whenever the base station 5 indicates that a BSR table is to be used/activated. Alternatively, an explicit indication of whether the UE 3 is to report the delay information may be used.

It will be appreciated, for example, that whilst cellular communication generation (2G, 36, 46, 56, 63 etc.) specific terminology may be used, in the interests of clarity, to refer to specific communication entities, the technical features described for a given entity are not limited to devices of that specific communication generation. The technical features may be implemented in any functionally equivalent communication entity regardless of any differences in the terminology used to refer to them.

In the above description, the UEs and the base station are described for ease of understanding as having a number of discrete functional components or modules. Whilst these modules may be provided in this way for certain applications, for example where an existing system has been modified to implement the invention, in other applications, for example in systems designed with the inventive features in mind from the outset, these modules may be built into the overall operating system or code and so these modules may not be discernible as discrete entities.

In the above embodiments, a number of software modules were described. As those skilled in the art will appreciate, the software modules may be provided in compiled or un-compiled form and may be supplied as a signal over a computer network, or on a recording medium. Further, the functionality performed by part, or all of this software may be performed using one or more dedicated hardware circuits. However, the use of software modules is preferred as it facilitates the updating of the base station or the UE in order to update their functionalities.

Each controller may comprise any suitable form of processing circuitry including (but not limited to), for example: one or more hardware implemented computer processors; microprocessors; central processing units (CPUs); arithmetic logic units (ALUs); input/output (10) circuits; internal memories / caches (program and/or data); processing registers; communication buses (e.g. control, data and/or address buses); direct memory access (DMA) functions; hardware or software implemented counters, pointers and/or timers; and/or the like. Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

The base station may comprise a 'distributed' base station having a central unit 'Cu, and one or more separate distributed units (DUs).

The User Equipment (or "UE", "mobile station", "mobile device" or "wireless device") in the present disclosure is an entity connected to a network via a wireless interface.

It should be noted that the present disclosure is not limited to a dedicated communication device and can be applied to any device having a communication function as explained in the following paragraphs.

The terms "User Equipment" or "UE" (as the term is used by 33PP), "mobile station", "mobile device", and "wireless device" are generally intended to be synonymous with one another, and include standalone mobile stations, such as terminals, cell phones, smart phones, tablets, cellular loT devices, loT devices, and machinery. It will be appreciated that the terms "mobile station" and "mobile device" also encompass devices that remain stationary for a long period of time.

A UE may, for example, be an item of equipment for production or manufacture and/or an item of energy related machinery (for example equipment or machinery such as: boilers; engines; turbines; solar panels; wind turbines; hydroelectric generators; thermal power generators; nuclear electricity generators; batteries; nuclear systems and/or associated equipment; heavy electrical machinery; pumps including vacuum pumps; compressors; fans; blowers; oil hydraulic equipment; pneumatic equipment; metal working machinery; manipulators; robots and/or their application systems; tools; molds or dies; rolls; conveying equipment; elevating equipment; materials handling equipment; textile machinery; sewing machines; printing and/or related machinery; paper converting machinery; chemical machinery; mining and/or construction machinery and/or related equipment; machinery and/or implements for agriculture, forestry and/or fisheries; safety and/or environment preservation equipment; tractors; precision bearings; chains; gears; power transmission equipment; lubricating equipment; valves; pipe fittings; and/or application systems for any of the previously mentioned equipment or machinery etc.).

A UE may, for example, be an item of transport equipment (for example transport equipment such as: rolling stocks; motor vehicles; motorcycles; bicycles; trains; buses; carts; rickshaws; ships and other watercraft; aircraft; rockets; satellites; drones; balloons etc.). A UE may, for example, be an item of information and communication equipment (for example information and communication equipment such as: electronic computer and related equipment; communication and related equipment; electronic components etc.).

A UE may, for example, be a refrigerating machine, a refrigerating machine applied product, an item of trade and/or service industry equipment, a vending machine, an automatic service machine, an office machine or equipment, a consumer electronic and electronic appliance (for example a consumer electronic appliance such as: audio equipment; video equipment; a loud speaker; a radio; a television; a microwave oven; a rice cooker; a coffee machine; a dishwasher; a washing machine; a dryer; an electronic fan or related appliance; a cleaner etc.).

A UE may, for example, be an electrical application system or equipment (for example an electrical application system or equipment such as: an x-ray system; a particle accelerator; radio isotope equipment; sonic equipment; electromagnetic application equipment; electronic power application equipment etc.).

A UE may, for example, be an electronic lamp, a luminaire, a measuring instrument, an analyser, a tester, or a surveying or sensing instrument (for example a surveying or sensing instrument such as: a smoke alarm; a human alarm sensor; a motion sensor; a wireless tag etc.), a watch or clock, a laboratory instrument, optical apparatus, medical equipment and/or system, a weapon, an item of cutlery, a hand tool, or the like.

A UE may, for example, be a wireless-equipped personal digital assistant or related equipment (such as a wireless card or module designed for attachment to or for insertion into another electronic device (for example a personal computer, electrical measuring machine)).

A UE may be a device or a part of a system that provides applications, services, and solutions described below, as to "internet of things (loT)", using a variety of wired and/or wireless communication technologies.

Internet of Things devices (or "things") may be equipped with appropriate electronics, software, sensors, network connectivity, and/or the like, which enable these devices to collect and exchange data with each other and with other communication devices. loT devices may comprise automated equipment that follow software instructions stored in an internal memory. loT devices may operate without requiring human supervision or interaction, loT devices might also remain stationary and/or inactive for a long period of time. loT devices may be implemented as a part of a (generally) stationary apparatus. loT devices may also be embedded in non-stationary apparatus (e.g. vehicles) or attached to animals or persons to be monitored/tracked.

It will be appreciated that loT technology can be implemented on any communication devices that can connect to a communications network for sending/receiving data, regardless of whether such communication devices are controlled by human input or software instructions stored in memory.

It will be appreciated that loT devices are sometimes also referred to as Machine-Type Communication (MTC) devices or Machine-to-Machine (M2M) communication devices. It will be appreciated that a UE may support one or more loT or MTC applications. Some examples of MTC applications are listed in the following table. This list is not exhaustive and is intended to be indicative of some examples of machine-type communication applications.

Service Area MTC applications Security Surveillance systems Backup for landline Control of physical access (e.g. to buildings) Car/driver security Tracking & Tracing Fleet Management Order Management Pay as you drive Asset Tracking Navigation Traffic information Road tolling Road traffic optimisation/steering Payment Point of sales Vending machines Gaming machines Health Monitoring vital signs Supporting the aged or handicapped Web Access Telemedicine points Remote diagnostics Remote Maintenance/Control Sensors Lighting Pumps Valves Elevator control Vending machine control Vehicle diagnostics Metering Power Gas Water Heating Grid control Industrial metering Consumer Devices Digital photo frame Digital camera eBook Applications, services, and solutions may be an MVNO (Mobile Virtual Network Operator) service, an emergency radio communication system, a PBX (Private Branch eXchange) system, a PHS/Digital Cordless Telecommunications system, a POS (Point of sale) system, an advertise calling system, an MBMS (Multimedia Broadcast and Multicast Service), a V2X (Vehicle to Everything) system, a train radio system, a location related service, a Disaster/Emergency Wireless Communication Service, a community service, a video streaming service, a femto cell application service, a VoLTE (Voice over LTE) service, a charging service, a radio on demand service, a roaming service, an activity monitoring service, a telecom carrier/communication NW selection service, a functional restriction service, a PoC (Proof of Concept) service, a personal information management service, an ad-hoc network/DTN (Delay Tolerant Networking) service, etc. Further, the above-described UE categories are merely examples of applications of the technical ideas and exemplary embodiments described in the present document.

Needless to say, these technical ideas and embodiments are not limited to the above-described UE and various modifications can be made thereto.

Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

Claims

CLAIMS1. A method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; determining, based on an amount of uplink data in one or more buffers of UE, whether to use the first table to determine a first index that indicates a first range of an amount of uplink data that is in the one or more buffers of UE, or to use the second table to determine a second index that indicates a second range of an amount of uplink data that is in the one or more buffers of UE; determining the first index or the second index based on the amount of uplink data that is in the one or more buffers of UE; transmitting an indication of the first index or the second index to an access network node; transmitting, to the access network node, if the UE transmits an indication of the first index to the access network node, an indication that the first table was used to generate the first index; and transmitting, to the access network node, if the UE transmits an indication of the second index to the access network node, an indication that the second table was used to generate the second index.
2. The method according to claim 1, wherein the method comprises receiving, from the access network node:the second table; orinformation for generating the second table at the UE.
3. The method according to claim 1 or 2, wherein the method comprises: determining to use the first table to determine the first index when the amount of uplink data in one or more buffers of UE falls within a first range; and determining to use the second table to determine the second index when the amount of uplink data in one or more buffers of UE falls within a second range.
4. The method according to claim 1 or 2, wherein the method comprises: determining whether to use the first table to determine the first index or to use the second table to determine the second index based on a comparison of the amount of uplink data in one or more buffers of UE with a threshold value.
5. The method according to any preceding claim, wherein the first index indicates a first range for the amount of uplink data in the one or more buffers of UE; the second index indicates a second range for the amount of uplink data in the one or more buffers of UE; and wherein the method comprises transmitting, to the base station, the indication of the first index when the first range is smaller than the second range, and transmitting, to the base station, the indication of the second index when the second range is smaller than the first range.
6. The method according to any preceding claim, wherein transmitting the indication of the first index or the second index comprises transmitting the indication of the first index or the second index in a buffer status report, BSR.
7. The method according to any preceding claim, wherein the indication that the first table was used to generate the first index or the indication that the second table was used to generate the second index is provided in a medium access control, MAC, control element, CE.
8. The method according to any preceding claim, wherein the method comprises transmitting an indication of a logical channel identity, LCID to the access network node, wherein the LCID indicates a format of a message used to transmit the indication of the first index or the second index to the access network node.
9. The method according to any preceding claim, wherein the indication that the first table was used to generate the first index is provided using a set of one or more bits that are adjacent to a set of one or more bits used to indicate the first index in a transmission to the access network node, 5 or the indication that the second table was used to generate the second index is provided using a set of one or more bits that are adjacent to a set of one or more bits used to indicate the second index in a transmission to the access network node.
10. The method according to any one of claims Ito 6, wherein the indication that the first table was used to generate the first index or the indication that the second table was used to generate the second index is provided using one or more bits of a subheader.
11. The method according to claim 10, wherein the subheader is a subheader associated with a medium access control, MAC, control element, CE.
12. The method according to any preceding claim, wherein the method comprises: determining to use the first table to determine the first index based on a first amount of uplink data in one or more buffers of the UE, and determining the first index based on the first amount of uplink data; determining to use the second table to determine the second index based on a second amount of uplink data in one or more buffers of the UE, and determining the second index based on the second amount of uplink; transmitting an indication of the first index and an indication of the second index to the access network node; transmitting an indication that the first table was used to generate the first index; and transmitting an indication that the second table was used to generate the second index.
13. The method according to claim 12, wherein one or more bits used to indicate that the first table was used to generate the first index are adjacent to one or more bits used to indicate that the second table was used to generate the second index.
14. A method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE; in a first case where the UE has received, from an access network node, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE, or information for generating the second table at the UE, and the second table is stored at the UE: using the first table or the second table to determine, based on an amount of uplink data in the one or more buffers of the UE, an index that indicates a range of the amount of uplink data in the one or more buffers, transmitting an indication of the first index or the second index to the access network node in a buffer status report having a first format that includes an indication of whether the first table or the second table has been used to determine the index; or in a second case where the UE has not received the second table or the information for generating the second table from the access network node, or the second table is not stored at the UE: using the first table to determine, based on the amount of uplink data in the one or more buffers of UE, the index; and transmitting an indication of the index to the access network node in a buffer status report having a second format, wherein the second format is different from the first format.
15. The method according to claim 14, wherein transmitting the indication of the index comprises transmitting, to the access network node the indication of the index in a medium access control, MAC, control element, CE.
16. The method according to claim 15, wherein the first format is a first MAC CE format of the MAC CE, and the second format is a second MAC CE format of the MAC CE.
17. The method according to claim 16, wherein the method further comprises transmitting, to the access network node, a subheader with the MAC CE, wherein a subheader format of the subheader used for the first MAC CE format is the same as a subheader format used for the second MAC CE format.
18. The method according to any one of claims 14 to 17, wherein the UE transmits every buffer status report using the first format in the first case.
19. The method according to any one of claims 14 to 17, wherein, in the first case, use of the first format is based on control signalling received from the access network node.
20. The method according to claim 19, wherein the control signalling comprises an activation signal that indicates that the first format is to be activated, or a setup message for the second table; and wherein the method comprises determining, in the first case, to transmit the indication of the index to the access network node in the buffer status report having the first format based on having received the activation signal or the setup message for the second table.
21. The method according to claim 19, wherein the control signalling comprises a deactivation signal that indicates that the first format is to be deactivated, or a release message for the second table; and wherein the method comprises: determining, in the first case, to transmit the indication the index to the access network node in the buffer status report having the second format based on having received the deactivation signal or the release message for the secondtable.
22. A method of a user equipment, UE, the method comprising: storing a first table that maps, for an amount of uplink data within a first range, each of a plurality of first indices to a respective sub-range of the first range, storing a second table that maps, for an amount of uplink data within a second range, each of a plurality of second indices to a respective sub-range of the second range; wherein each of the plurality of first indices are different from each of the plurality of second indices; wherein the method further comprises transmitting, to an access network node, when an amount of uplink data in one or more buffers of the UE falls within the second range, the index of the plurality of second indices that indicates the sub-range of the amount of uplink data in the one or more buffers of the UE; and transmitting, to the access network node, when the amount of uplink data in the one or more buffers of the UE falls within the first range but does not fall within the second range, the index of the plurality of first indices that indicates the sub-range of the amount of uplink data in one or more buffers of the UE.
23. The method according to claim 22, wherein the second range is a subset of the first range.
24. The method according to claim 22 or 23 wherein the number of first indices of the first table is different from the number of second indices of the second table.
25. The method according to any one of claims 22 to 24, wherein at least one subrange mapped to an index of the second table is smaller than a subrange mapped to an index of the first table.
26. A method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; receiving, from an access network node, table activation information that indicates whether the second table is to be activated at the UE; determining, if the table activation information indicates that the second table is to be activated at the UE, to use the second table to determine an index of the second plurality of indices that indicates the range of an amount of uplink data in one or more buffers of UE; and transmitting an indication of the index to the access network node
27. The method according to claim 26, wherein the method further comprises: receiving, from the access network node, table activation information that indicates that the second table is to be deactivated at the UE; and determining, based on the indication that the second table is to be deactivated at the UE, to use the first table to determine an index of the first plurality of indices that indicates the range of an amount of uplink data in the one or more buffers of UE; and transmitting an indication of the index to the access network node
28. A method of a user equipment, UE, the method comprising: storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data; receiving, from an access network node, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; determining, based on the table setup information, to use the second table to determine an index of the second plurality of indices that indicates a range of an amount of uplink data in one or more buffers of UE; transmitting an indication of the index to the access network node.
29. The method according to claim 28, wherein the method further comprises: receiving, from an access network node, table release information that indicates that the second table is to be released; and determining, based on the table release information, to use the first table to determine an index of the first plurality of indices that indicates the range of an amount of uplink data in the one or more buffers of UE; and transmitting an indication of the index to the access network node.
30. The method according to claim 28 or 29, wherein the table setup information comprises the second table; or information for generating the second table at the UE.
31. A method of a user equipment, UE, the method comprising: storing a table that maps each of a plurality of indices to a respective range of uplink data; wherein a first index of the plurality of indices is mapped to a first range of uplink data, a second index of the plurality of indices is mapped to a second range of uplink data; a third index of the plurality of indices is mapped to a third range of uplink data, the first range and the third range are smaller than the second range; the upper limit of the first range is smaller than the lower limit of the second range, and the upper limit of the second range is smaller than the lower limit of the third range; and wherein the method further comprises determining, based on an amount of uplink data in one or more buffers of the UE, the index of the table that indicates the range of the amount of uplink data in the one or more buffers of the UE; and transmitting the index to an access network node.
32. A method of an access network node, the method comprising: transmitting, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or information for generating the second table at the UE; receiving, from the UE, an indication of an index that indicates a range of an amount of uplink data in one or more buffers of the UE; receiving, from the UE, if the index is an index determined using a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, an indication that the first table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the first table; and receiving, from the UE, if the index is an index determined using the second table, an indication that the second table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.
33. A method of an access network node, the method comprising: in a first case where the access network node has transmitted, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or the access network node has transmitted information for generating the second table at the UE, and the second table is stored at the UE: receiving, from the UE, an indication of an index in a buffer status report, wherein the buffer status report has a first format that includes an indication of whether a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE or the second table has been used to determine the index; or in a second case where the base station has not transmitted the second table or the information for generating the second table to the UE, or the second table is not stored at the UE: receiving, from the UE, an indication of the index in a buffer status report having a second format, wherein the second format is different from the first format.
34. A method of an access network node, the method comprising: transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table activation information that indicates whether a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE is to be activated at the UE; receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.
35. The method according to 34, wherein the method further comprises: transmitting, to the UE, table activation information that indicates that the second table is to be deactivated at the UE; and receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the first table.
36. A method of an access network node, the method comprising: transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE; receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.
37. The method according to claim 36, wherein the method further comprises: transmitting, to the UE, table release information that indicates that the second table is to be released; and receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the first table.
38. A user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; means for determining configured for: determining, based on an amount of uplink data in one or more buffers of UE, whether to use the first table to determine a first index that indicates a first range of an amount of uplink data that is in the one or more buffers of UE, or to use the second table to determine a second index that indicates a second range of an amount of uplink data that is in the one or more buffers of UE; and determining the first index or the second index based on the amount of uplink data that is in the one or more buffers of UE and means for transmitting configured for: transmitting an indication of the first index or the second index to an access network node; transmitting, to the access network node, if the UE transmits an indication of the first index to the access network node, an indication that the first table was used to generate the first index; and transmitting, to the access network node, if the UE transmits an indication of the second index to the access network node, an indication that the second table was used to generate the second index.
39. A user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE; wherein the UE is configured for: in a first case where the UE has received, from an access network node, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE, or information for generating the second table at the UE, and the second table is stored at the UE: using the first table or the second table to determine, based on an amount of uplink data in the one or more buffers of the UE, an index that indicates a range of the amount of uplink data in the one or more buffers, transmitting an indication of the first index or the second index to the access network node in a buffer status report having a first format that includes an indication of whether the first table or the second table has been used to determine the index; or in a second case where the UE has not received the second table or the information for generating the second table from the access network node, or the second table is not stored at the UE: using the first table to determine, based on the amount of uplink data in the one or more buffers of UE, the index; and transmitting an indication of the index to the access network node in a buffer status report having a second format, wherein the second format is different from the first format.
40. A user equipment, UE, comprising: means for storing configured for: storing a first table that maps, for an amount of uplink data within a first range, each of a plurality of first indices to a respective sub-range of the first range; and storing a second table that maps, for an amount of uplink data within a second range, each of a plurality of second indices to a respective sub-range of the second range; wherein each of the plurality of first indices are different from each of the plurality of second indices; and wherein the UE further comprises means for transmitting configured for: transmitting, to an access network node, when an amount of uplink data in one or more buffers of the UE falls within the second range, the index of the plurality of second indices that indicates the sub-range of the amount of uplink data in the one or more buffers of the UE; and transmitting, to the access network node, when the amount of uplink data in the one or more buffers of the UE falls within the first range but does not fall within the second range, the index of the plurality of first indices that indicates the sub-range of the amount of uplink data in one or more buffers of the UE.
41. A user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data, and a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; means for receiving, from an access network node, table activation information that indicates whether the second table is to be activated at the UE; means for determining, if the table activation information indicates that the second table is to be activated at the UE, to use the second table to determine an index of the second plurality of indices that indicates the range of an amount of uplink data in one or more buffers of UE; and means for transmitting an indication of the index to the access network node
42. A user equipment, UE, comprising: means for storing a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data; means for receiving, from an access network node, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data; means for determining, based on the table setup information, to use the second table to determine an index of the second plurality of indices that indicates a range of an amount of uplink data in one or more buffers of UE; means for transmitting an indication of the index to the access network node.
43. A user equipment, UE, comprising: means for storing a table that maps each of a plurality of indices to a respective range of uplink data; wherein a first index of the plurality of indices is mapped to a first range of uplink data a second index of the plurality of indices is mapped to a second range of uplink data; a third index of the plurality of indices is mapped to a third range of uplink data; the first range and the third range are smaller than the second range; the upper limit of the first range is smaller than the lower limit of the second range, and the upper limit of the second range is smaller than the lower limit of the third range; and wherein the UE further comprises means for determining, based on an amount of uplink data in one or more buffers of the UE, the index of the table that indicates the range of the amount of uplink data in the one or more buffers of the UE; and means for transmitting the index to an access network node.
44. An access network node comprising: means for transmitting, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or information for generating the second table at the UE; and means for receiving configured for: receiving, from the UE, an indication of an index that indicates a range of an amount of uplink data in one or more buffers of the UE; receiving, from the UE, if the index is an index determined using a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, an indication that the first table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the first table; and receiving, from the UE, if the index is an index determined using the second table, an indication that the second table was used to generate the index, and determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.
45. An access network node, wherein the access network node is configured for: in a first case where the access network node has transmitted, to a user equipment, UE, a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in one or more buffers of the UE, or the access network node has transmitted information for generating the second table at the UE, and the second table is stored at the UE: receiving, from the UE, an indication of an index in a buffer status report, wherein the buffer status report has a first format that includes an indication of whether a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE or the second table has been used to determine the index; or in a second case where the base station has not transmitted the second table or the information for generating the second table to the UE, or the second table is not stored at the UE: receiving, from the UE, an indication of the index in a buffer status report having a second format, wherein the second format is different from the first format.
46. An access network node comprising: means for transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table activation information that indicates whether a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE is to be activated at the UE; means for receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE; and means for determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table.
47. An access network node comprising: means for transmitting, to a user equipment, UE, that stores a first table that maps each of a plurality of first indices to a respective first range of an amount of uplink data in one or more buffers of the UE, table setup information for a second table that maps each of a plurality of second indices to a respective second range of an amount of uplink data in the one or more buffers of the UE; means for receiving, from the UE, an indication of an index that indicates the range of an amount of uplink data in the one or more buffers of UE, and means for determining the range of the amount of uplink data in the one or more buffers of the UE using the index and the second table