WO2025014225A1

WO2025014225A1 - Node and user equipment in wireless communication system and method performed by the same

Info

Publication number: WO2025014225A1
Application number: PCT/KR2024/009686
Authority: WO
Inventors: Fanhua Kong; Weiwei Wang; Lixiang Xu; Hong Wang
Original assignee: Beijing Samsung Telecom R&D Center; Samsung Electronics Co Ltd
Current assignee: Beijing Samsung Telecom R&D Center; Samsung Electronics Co Ltd
Priority date: 2023-07-12
Filing date: 2024-07-08
Publication date: 2025-01-16
Anticipated expiration: 2026-01-12
Also published as: CN119316873A

Abstract

The disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. The disclosure provides a centralized unit and a distributed unit in a wireless communication system and methods performed by the same. A method performed by a centralized unit, CU, in a wireless communication system includes: identifying information element associated with a non-integer discontinuous reception, DRX, cycle included in a user equipment, UE, context request message; and transmitting, to a distributed unit, DU, the UE context message including the information element associated with the non-integer DRX cycle.

Description

NODE AND USER EQUIPMENT IN WIRELESS COMMUNICATION SYSTEM AND METHOD PERFORMED BY THE SAME

The disclosure relates to a field of wireless communication technologies, and in particular, to a node and a user equipment in a wireless communication system and methods performed by the same.

5G mobile communication technologies define broad frequency bands such that high transmission rates and new services are possible, and can be implemented not only in "Sub 6GHz" bands such as 3.5GHz, but also in "Above 6GHz" bands referred to as mmWave including 28GHz and 39GHz. In addition, it has been considered to implement 6G mobile communication technologies (referred to as Beyond 5G systems) in terahertz bands (for example, 95GHz to 3THz bands) in order to accomplish transmission rates fifty times faster than 5G mobile communication technologies and ultra-low latencies one-tenth of 5G mobile communication technologies.

At the beginning of the development of 5G mobile communication technologies, in order to support services and to satisfy performance requirements in connection with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), there has been ongoing standardization regarding beamforming and massive MIMO for mitigating radio-wave path loss and increasing radio-wave transmission distances in mmWave, supporting numerologies (for example, operating multiple subcarrier spacings) for efficiently utilizing mmWave resources and dynamic operation of slot formats, initial access technologies for supporting multi-beam transmission and broadbands, definition and operation of BWP (BandWidth Part), new channel coding methods such as a LDPC (Low Density Parity Check) code for large amount of data transmission and a polar code for highly reliable transmission of control information, L2 pre-processing, and network slicing for providing a dedicated network specialized to a specific service.

Currently, there are ongoing discussions regarding improvement and performance enhancement of initial 5G mobile communication technologies in view of services to be supported by 5G mobile communication technologies, and there has been physical layer standardization regarding technologies such as V2X (Vehicle-to-everything) for aiding driving determination by autonomous vehicles based on information regarding positions and states of vehicles transmitted by the vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) aimed at system operations conforming to various regulation-related requirements in unlicensed bands, NR UE Power Saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area in which communication with terrestrial networks is unavailable, and positioning.

Moreover, there has been ongoing standardization in air interface architecture/protocol regarding technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying random access procedures (2-step RACH for NR). There also has been ongoing standardization in system architecture/service regarding a 5G baseline architecture (for example, service based architecture or service based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on UE positions.

As 5G mobile communication systems are commercialized, connected devices that have been exponentially increasing will be connected to communication networks, and it is accordingly expected that enhanced functions and performances of 5G mobile communication systems and integrated operations of connected devices will be necessary. To this end, new research is scheduled in connection with eXtended Reality (XR) for efficiently supporting AR (Augmented Reality), VR (Virtual Reality), MR (Mixed Reality) and the like, 5G performance improvement and complexity reduction by utilizing Artificial Intelligence (AI) and Machine Learning (ML), AI service support, metaverse service support, and drone communication.

Furthermore, such development of 5G mobile communication systems will serve as a basis for developing not only new waveforms for providing coverage in terahertz bands of 6G mobile communication technologies, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), array antennas and large-scale antennas, metamaterial-based lenses and antennas for improving coverage of terahertz band signals, high-dimensional space multiplexing technology using OAM (Orbital Angular Momentum), and RIS (Reconfigurable Intelligent Surface), but also full-duplex technology for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication technology for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing technology for implementing services at levels of complexity exceeding the limit of UE operation capability by utilizing ultra-high-performance communication and computing resources.

Embodiments of the disclosure provide a method performed by centralized unit, CU, in a wireless communication system. The method includes: identifying information element associated with a non-integer discontinuous reception, DRX, cycle included in a user equipment, UE, context request message; and transmitting, to a distributed unit, DU, the UE context message including the information element associated with the non-integer DRX cycle.

Embodiments of the disclosure provide a method performed by distributed unit, DU, in a wireless communication system. The method includes: receiving, from a centralized unit, CU, a user equipment, UE, context message including information element associated with a non-integer discontinuous reception, DRX, cycle; and configuring a DRX configuration based on the information element associated with the non-integer DRX cycle.

Embodiments of the disclosure provide a centralized unit, CU, in a wireless communication, comprising: a transceiver; and at least one processor coupled to the transceiver. The at least one processor configured to: identify information element associated with a non-integer discontinuous reception, DRX, cycle included in a user equipment, UE, context request message, and transmit, to a distributed unit, DU, the UE context message including the information element associated with the non-integer DRX cycle.

Embodiments of the disclosure provide a distributed unit, DU, in a wireless communication, comprising: a transceiver; and at least one processor coupled to the transceiver. The at least one processor configured to: receive, from a centralized unit, CU, a user equipment, UE, context message including information element associated with a non-integer discontinuous reception, DRX, cycle, and configure a DRX configuration based on the information element associated with the non-integer DRX cycle.

The above and other aspects, features and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exemplary system architecture of system architecture evolution (SAE);

FIG. 2 is an exemplary system architecture according to various embodiments of the disclosure;

FIG. 3A illustrates an example structure of a base station according to embodiments of the disclosure;

FIG. 3B illustrates an example structure of a base station according to embodiments of the disclosure;

FIG. 3C illustrates an example structure of a base station according to embodiments of the disclosure;

FIG. 4 illustrates an example scenario of mapping between PDU sets, PSI, and QoS flows according to embodiments of the disclosure;

FIG. 5A illustrates an example flowchart of a CN transmitting indication information to a RAN according to embodiments of the disclosure;

FIG. 5B illustrates an example diagram of a RAN adding a congestion level to a GTP-U header in a per QoS flow manner according to embodiments of the disclosure;

FIG. 5C illustrates an example diagram of a RAN adding a congestion level to a GTP-U header in a per QoS flow manner according to embodiments of the disclosure;

FIG. 6 illustrates an example flowchart of a UE performing cell handover according to embodiments of the disclosure;

FIG. 7 illustrates an example flowchart of a UE performing cell handover according to embodiments of the disclosure;

FIG. 8 illustrates a flowchart of a method performed by a first node in a wireless communication system according to embodiments of the disclosure;

FIG. 9A illustrates a flowchart of a method performed by a second node in a wireless communication system according to embodiments of the disclosure;

FIG. 9B illustrates a flowchart of a method performed by a second node in a wireless communication system according to embodiments of the disclosure;

FIG. 9C illustrates a flowchart of a method performed by a second node in a wireless communication system according to embodiments of the disclosure;

FIG. 10 illustrates a flowchart of a method performed by a user equipment (UE) in a wireless communication system according to embodiments of the disclosure;

FIG. 11 illustrates a schematic diagram of a node in a wireless communication system according to embodiments of the disclosure; and

FIG. 12 illustrates a schematic diagram of a user equipment in a wireless communication system according to embodiments of the disclosure.

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents.

It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

The term "include" or "may include" refers to the existence of a corresponding disclosed function, operation or component which can be used in various embodiments of the disclosure and does not limit one or more additional functions, operations, or components. Additionally, the terms such as "include" and/or "have" may be construed to denote a certain characteristic, number, step, operation, constituent element, component or a combination thereof, but may not be construed to exclude the existence of or a possibility of addition of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

The term "or" used in various embodiments of the disclosure includes any or all of combinations of listed words. For example, the expression "A or B" may include A, may include B, or may include both A and B.

Unless defined differently, all terms used herein, which include technical terminologies or scientific terminologies, have the same meaning as that understood by a person skilled in the art to which the disclosure belongs. Such terms as those defined in a generally used dictionary are to be interpreted to have the meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the disclosure.

FIGs. 1-12 discussed below and various embodiments for describing the principles of the disclosure in this patent document are only for illustration and should not be interpreted as limiting the scope of the disclosure in any way. Those skilled in the art will understand that the principles of the disclosure can be implemented in any suitably arranged system or device.

In order to meet an increasing demand for wireless data communication services since a deployment of 4G communication system, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called "beyond 4G network" or "post LTE system".

Wireless communication is one of the most successful innovations in modern history. Recently, the number of subscribers of wireless communication services has exceeded 5 billion, and it continues growing rapidly. With the increasing popularity of smart phones and other mobile data devices (such as tablet computers, notebook computers, netbooks, e-book readers and machine-type devices) in consumers and enterprises, a demand for wireless data services is growing rapidly. In order to meet rapid growth of mobile data services and support new applications and deployments, it is very important to improve efficiency and coverage of wireless interfaces.

Compared with 4G, a 5G communication technology has a faster transmission speed, so it can provide users with more kinds of communication services. The extended reality (XR) service is regarded as a key application service to promote the development of the 5G technology, and is the general name of three service types: augmented reality (AR), virtual reality (VR) and mixed reality (MR). The XR service has high requirements on the transmission speed and latency, so it needs more network resources to support a normal operation of the service. At the same time, for the portability of an XR equipment, the size of a battery is greatly limited, and how to reduce energy consumption has become a big challenge. Therefore, in order to improve user experience of XR users, it is necessary to conduct further research on reducing power consumption, improving a network capacity, and improving XR-Awareness.

Embodiments of the disclosure provide a method performed by a first node in a wireless communication system. The method includes: generating a rule for data transmission and/or discard by applying Protocol data unit Set Importance (PSI) when a second node needs to discard data; and transmitting indication information to the second node, where the indication information indicates the rule.

According to embodiments of the disclosure, the rule includes one or more of the following: a protocol data unit (PDU) set with PSI less than or less than or equal to a first threshold is discarded; a protocol data unit (PDU) set with PSI greater than or greater than or equal to the first threshold is transmitted; a PDU set with PSI greater than or greater than or equal to a second threshold has a higher priority, and the PDU set having the higher priority is prioritized for transmission; PDU sets are transmitted based on transmission priorities, where a transmission priority of each PDU set is in direct proportion to PSI of the PDU set; for a plurality of PDU sets with the same PSI, a PDU set with a smaller data amount is prioritized for transmission; when a plurality of PDU sets are mapped to different quality of service (QoS) flows, if different QoS flows have an association, PDU sets having an association are prioritized for transmission; and when a plurality of PDU sets are mapped to different quality of service (QoS) flows, if different QoS flows have an association, when PSI of PDU sets having an association on the different QoS flows is greater than or greater than or equal to a third threshold, the PDU sets having the association are prioritized for transmission.

According to embodiments of the disclosure, the indication information is transmitted in one or more of the following manners: the indication information is carried in a GPRS tunnel protocol user plane (GTP-U) header for transmitting; and the indication information is transmitted through an NG application protocol (NGAP) message.

According to embodiments of the disclosure, the method further includes: transmitting fourth information to the second node, where the fourth information indicates information related to valid time of the rule.

According to embodiments of the disclosure, the method further includes receiving one or more of the following from the second node: first information, where the first information suggests the first node configuring first PSI for protocol data unit (PDU) sets with an association; second information, where the second information suggests the first node not putting data with an association on different PDU sets or suggests the first node putting the data with an association on a same PDU set; and third information, where the third information indicates that congestion occurs to the second node currently.

According to embodiments of the disclosure, the method further includes: transmitting fifth information to the second node, where the fifth information includes a mapping relationship between PSI and a protocol data unit (PDU) set.

Embodiments of the disclosure provide a method performed by a second node in a wireless communication system. The method includes: receiving a scheduling request (SR) and/or a buffer status report (BSR) from a user equipment (UE), where the SR and/or the BSR are received through a first format or a first logical channel or through a second format or a second logical channel based on Protocol data unit Set Importance (PSI) of a protocol data unit (PDU) set corresponding to the SR and/or the BSR; and transmitting an uplink grant to the UE.

According to embodiments of the disclosure, when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is greater than or greater than or equal to a fourth threshold, the SR and/or the BSR are/is received through the first format or the first logical channel; and when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is less than or less than or equal to the fourth threshold, the SR and/or the BSR are/is received through the second format or the second logical channel.

Embodiments of the disclosure provide a method performed by a second node in a wireless communication system. The method includes: receiving indication information from a first node, where the indication information indicates a rule for data transmission and/or discard by applying Protocol data unit Set Importance (PSI) when the second node needs to discard data; and transmitting and/or discarding the data based on the rule.

According to embodiments of the disclosure, the method further includes: receiving fourth information from the first node, where the fourth information indicates information related to valid time of the rule.

According to embodiments of the disclosure, the method further includes transmitting one or more of the following to the first node: first information, where the first information suggests the first node configuring first PSI for protocol data unit (PDU) sets with an association; second information, where the second information suggests the first node not putting data with an association on different PDU sets or suggests the first node putting the data with an association on a same PDU set; and third information, where the third information indicates that congestion occurs to the second node currently.

According to embodiments of the disclosure, the method further includes: receiving fifth information from the first node, where the fifth information includes a mapping relationship between PSI and a protocol data unit (PDU) set; and transmitting the mapping relationship between the PSI and the protocol data unit (PDU) set to a user equipment (UE).

Embodiments of the disclosure provide a method performed by a second node in a wireless communication system. The method includes: transmitting a handover request message to a third node; receiving a handover request acknowledge message from the third node, where the handover request acknowledge message includes a second DRX configuration configured by the third node for a user equipment (UE); and transmitting a handover command to the UE, where the handover command includes the second DRX configuration.

According to embodiments of the disclosure, the handover request acknowledge message further includes a triggering condition for applying the second DRX configuration, and the handover command further includes the triggering condition.

According to embodiments of the disclosure, the triggering condition includes one or more of the following: triggering the second DRX configuration after the UE is handed over to the third node; triggering the second DRX configuration after the UE is handed over to the third node and a first time period is passed; triggering the second DRX configuration after the UE is handed over to the third node and receives triggering information transmitted by the third node.

According to embodiments of the disclosure, the handover request message includes a first DRX configuration configured by the second node for the UE and/or a third DRX configuration expected by the UE.

Embodiments of the disclosure provide a method performed by a user equipment (UE) in a wireless communication system. The method includes: transmitting a scheduling request (SR) and/or a buffer status report (BSR) to a second node; and receiving an uplink grant from the second node, where the SR and/or the BSR are transmitted through a first format or a first logical channel or through a second format or a second logical channel based on Protocol data unit Set Importance (PSI) of a protocol data unit (PDU) set corresponding to the SR and/or the BSR.

According to embodiments of the disclosure, when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is greater than or greater than or equal to a fourth threshold, the SR and/or the BSR are/is transmitted by the UE through the first format or the first logical channel; and when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is less than or less than or equal to the fourth threshold, the SR and/or the BSR are/is transmitted by the UE through the second format or the second logical channel.

According to embodiments of the disclosure, the method further includes: transmitting the fourth threshold to the second node.

According to embodiments of the disclosure, the method further includes: receiving a handover command from the second node, where the handover command includes a second DRX configuration configured for the UE by a third node which serves as a handover target node, where the second DRX configuration is received by the second node from the third node.

According to embodiments of the disclosure, the handover command further includes a triggering condition for applying the second DRX configuration.

Embodiments of the disclosure provide a node in a wireless communication system, including: a transceiver configured to transmit and receive signals; and a controller coupled to the transceiver and configured to perform any method performed by the first node or the second node in the wireless communication system according to embodiments of the disclosure.

Embodiments of the disclosure provide a user equipment (UE) in a wireless communication system, including: a transceiver configured to transmit and receive signals; and a controller coupled to the transceiver and configured to perform any method performed by the user equipment (UE) in the wireless communication system according to embodiments of the disclosure.

Embodiments of the disclosure provide a computer-readable medium on which computer-readable instructions are stored. When executed by a processor, the instructions are used to implement any method performed by the first node or the second node and/or the user equipment (UE) in the wireless communication system according to embodiments of the disclosure.

The methods performed by the first node and/or the second node and/or the user equipment (UE) in the wireless communication system according to embodiments of the disclosure can effectively alleviate or solve network congestion and improve service experience of users.

In an embodiment of the disclosure, a method performed by a first node in a wireless communication system, comprising: generating a rule for data transmission and/or discard by applying Protocol data unit Set Importance (PSI) when a second node needs to discard data; and transmitting indication information to the second node, wherein the indication information indicates the rule.

In an embodiment of the disclosure, wherein the rule comprises one or more of the following: a protocol data unit (PDU) set with PSI less than or less than or equal to a first threshold is discarded; a protocol data unit (PDU) set with PSI greater than or greater than or equal to the first threshold is transmitted; a PDU set with PSI greater than or greater than or equal to a second threshold has a higher priority, and the PDU set having the higher priority is prioritized for transmission; PDU sets are transmitted based on transmission priorities, wherein a transmission priority of each PDU set is in direct proportion to PSI of the PDU set; for a plurality of PDU sets with the same PSI, a PDU set with a smaller data amount is prioritized for transmission; when a plurality of PDU sets are mapped to different quality of service (QoS) flows, if different QoS flows have an association, PDU sets having an association are prioritized for transmission; and when a plurality of PDU sets are mapped to different quality of service (QoS) flows, if different QoS flows have an association, when PSI of PDU sets having an association on the different QoS flows is greater than or greater than or equal to a third threshold, the PDU sets having the association are prioritized for transmission.

In an embodiment of the disclosure, wherein the indication information is transmitted in one or more of the following manners: the indication information is carried in a GPRS tunnel protocol user plane (GTP-U) header for transmitting; and the indication information is transmitted through an NG application protocol (NGAP) message.

In an embodiment of the disclosure, further comprising: transmitting fourth information to the second node, wherein the fourth information indicates information related to valid time of the rule.

In an embodiment of the disclosure, further comprising receiving one or more of the following from the second node: first information, wherein the first information suggests the first node configuring first PSI for protocol data unit (PDU) sets with an association; second information, wherein the second information suggests the first node not putting data with an association on different PDU sets or suggests the first node putting the data with an association on a same PDU set; and third information, wherein the third information indicates that congestion occurs to the second node currently.

In an embodiment of the disclosure, further comprising: transmitting fifth information to the second node, wherein the fifth information comprises a mapping relationship between PSI and a protocol data unit (PDU) set.

In an embodiment of the disclosure, a method performed by a second node in a wireless communication system, comprising: receiving a scheduling request (SR) and/or a buffer status report (BSR) from a user equipment (UE), wherein the SR and/or the BSR are received through a first format or a first logical channel or through a second format or a second logical channel based on Protocol data unit Set Importance (PSI) of a protocol data unit (PDU) set corresponding to the SR and/or the BSR; and transmitting an uplink grant to the UE.

In an embodiment of the disclosure, wherein when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is greater than or greater than or equal to a fourth threshold, the SR and/or the BSR are/is received through the first format or the first logical channel; and when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is less than or less than or equal to the fourth threshold, the SR and/or the BSR are/is received through the second format or the second logical channel.

In an embodiment of the disclosure, a method performed by a second node in a wireless communication system, comprising: receiving indication information from a first node, wherein the indication information indicates a rule for data transmission and/or discard by applying Protocol data unit Set Importance (PSI) when the second node needs to discard data; and transmitting and/or discarding the data based on the rule.

In an embodiment of the disclosure, further comprising: receiving fourth information from the first node, wherein the fourth information indicates information related to valid time of the rule.

In an embodiment of the disclosure, further comprising transmitting one or more of the following to the first node: first information, wherein the first information suggests the first node configuring first PSI for protocol data unit (PDU) sets with an association; second information, wherein the second information suggests the first node not putting data with an association on different PDU sets or suggests the first node putting the data with an association on a same PDU set; and third information, wherein the third information indicates that congestion occurs to the second node currently.

In an embodiment of the disclosure, further comprising: receiving fifth information from the first node, wherein the fifth information comprises a mapping relationship between PSI and a protocol data unit (PDU) set; and transmitting the mapping relationship between the PSI and the protocol data unit (PDU) set to a user equipment (UE).

In an embodiment of the disclosure, a method performed by a second node in a wireless communication system, comprising: transmitting a handover request message to a third node; receiving a handover request acknowledge message from the third node, wherein the handover request acknowledge message comprises a second DRX configuration configured by the third node for a user equipment (UE); and transmitting a handover command to the UE, wherein the handover command comprises the second DRX configuration.

FIG. 1 is an exemplary system architecture 100 of system architecture evolution (SAE). User equipment (UE) 101 is a terminal device for receiving data. An evolved universal terrestrial radio access network (E-UTRAN) 102 is a radio access network, which includes a macro base station (eNodeB/NodeB) that provides UE with interfaces to access the radio network. A mobility management entity (MME) 103 is responsible for managing mobility context, session context and security information of the UE. A serving gateway (SGW) 104 mainly provides functions of user plane, and the MME 103 and the SGW 104 may be in the same physical entity. A packet data network gateway (PGW) 105 is responsible for functions of charging, lawful interception, etc., and may be in the same physical entity as the SGW 104. A policy and charging rules function entity (PCRF) 106 provides quality of service (QoS) policies and charging criteria. A general packet radio service support node (SGSN) 108 is a network node device that provides routing for data transmission in a universal mobile telecommunications system (UMTS). A home subscriber server (HSS) 109 is a home subsystem of the UE, and is responsible for protecting user information including a current location of the user equipment, an address of a serving node, user security information, and packet data context of the user equipment, etc.

FIG. 2 is an exemplary system architecture 200 according to various embodiments of the disclosure. An embodiment of the system architecture 200 can be used without departing from the scope of the disclosure.

User equipment (UE) 201 may be a terminal device for receiving data. A next generation radio access network (NG-RAN) 202 may be a radio access network, which includes a base station (a gNB or an eNB connected to 5G core network 5GC, and the eNB connected to the 5GC is also called ng-eNB) that provides UE with interfaces to access the radio network. An access control and mobility management function entity (AMF) 203 may be responsible for managing mobility context and security information of the UE. A user plane function entity (UPF) 204 mainly provides functions of user plane. A session management function entity SMF 205 is responsible for session management. A data network (DN) 206 may include, for example, services of operators, access of Internet and service of third parties.

In an NR system, in order to support network function virtualization and more efficient resource management and scheduling, a base station (gNB/ng-eNB) that provides wireless network interfaces for terminals (UEs) may be further divided into a centralized unit (for example, gNB-CU/ng-eNB-CU(gNB central unit/ng-eNB central unit)) and a distributed unit (for example, gNB-DU/ng-eNB-DU(gNB distributed unit/ng-eNB distributed unit)) (abbreviated as CU and DU in the disclosure), as shown in FIG. 3A. gNB-CU has radio resource control (RRC), Service Data Adaptation Protocol (SDAP) and Packet Data Convergence Protocol (PDCP) protocol layers, while ng-eNB-CU has RRC and PDCP layers. gNB-DU/ng-eNB-DU has Radio Link Control (RLC) protocol, Media Access Control (MAC) and physical (PHY) layers. There may be a standardized public interface F1 between gNB-CU and gNB-DU, and a standardized public interface W1 between ng-eNB-CU and ng-eNB-DU. The F1 interface may be divided into a control plane F1-C and a user plane F1-U. The transport network layer of F1-C may be based on IP transport. In order to transmit signaling more reliably, stream control transmission protocol (SCTP) protocol may be added onto IP. The protocol of the application layer may be F1 Application Protocol (F1AP). SCTP can provide reliable application layer message transmission. The transport layer of F1-U is UDP/IP, and the GPRS tunneling protocol-user plane (GTP-U) may be used to carry the user plane protocol data unit (PDU) above UDP/IP. Further, for a gNB-CU, as shown in FIG. 3B, the gNB-CU may include a gNB-CU-CP (control plane part of a centralized unit of a base station) and a gNB-CU-UP (user plane part of a centralized unit of a base station), a gNB-CU-CP contains functions of a control plane of a base station and has RRC and SDAP protocol layers, and a gNB-CU-UP contains functions of a user plane of a base station and has SDAP and PDCP protocol layers. There is a standardized public interface E1 between gNB-CU-CP and gNB-CU-UP, and the protocol is E1 Application Protocol (E1AP). The interface between the control plane part of the centralized unit of the base station and the distributed unit of the base station may be an F1-C interface, that is, the control plane interface of F1, and the interface between the user plane part of the centralized unit of the base station and the distributed unit of the base station may be an F1-U interface, that is, the user plane interface of F1. In addition, in the NR system, a base station providing the E-UTRA user plane and control plane which accessed a 5G core network is called ng-eNB. In order to support virtualization, such a base station (ng-eNB) may also be further divided into a centralized unit ng-eNB-CU (gNB central unit/ng-eNB central unit) and a distributed unit ng-eNB-DU (gNB distributed unit/ng-eNB distributed unit) (abbreviated as CU and DU in the disclosure), as shown in FIG. 3C. ng-eNB-CU has RRC and PDCP layers. gNB-DU/ng-eNB-DU has radio link control (RLC) protocol, media access control (MAC) and physical layer. There is a standardized public interface W1 between ng-eNB-CU and ng-eNB-DU. The W1 interface may be divided into a control plane W1-C and a user plane W1-U. The transport network layer of W1-C may be based on IP transport. In order to transmit signaling more reliably, SCTP protocol may be added onto IP. The protocol of the application layer may be W1 Application Protocol (W1AP). The transport layer of W1-U is UDP/IP, and GTP-U may be used to carry user plane protocol data unit (PDU) above UDP/IP.

In order to conduct better research in the XR field, the concept of a PDU set was proposed. The PDU set may be composed of one or more PDUs, and a PDU set may be a frame or a video slice in an XR service. One PDU set can only be mapped to one quality of service flow (QoS flow), and relevant parameters, such as a PDU Set Delay Budget (PSDB), a PDU Set Error Rate (PSER), and a PDU Set Integrated Handling Indication (PSIHI), of all PDU sets on one QoS flow are the same. If network congestion occurs on a RAN side, how to discard and/or transmit a PDU set may be a problem. Thus one of the purposes of the disclosure is to resolve the aforementioned technical issue, and the disclosure proposes a method for using PSI on the RAN side for data transmission (or packet discard).

Different PDU sets may have different degrees of importance, which may be represented by protocol data unit set importance (PDU set importance, PSI) (for example, whose value may be high/medium/low, or 0 to 7, etc., but not limited thereto), and different PDU sets on a same QoS flow may also have different PSI. The PSI may be notified to a radio access network (RAN) by a UPF through a GTP-U header. When network congestion occurs on the RAN side, a corresponding PDU set may be discarded based on a value of the PSI (for example, some PDU sets with low PSI values are discarded), in order to alleviate or solve the network congestion.

Based on a mapping relationship between PDU sets, PSI, and QoS flows, four different scenarios can be summarized as follows:

Scenario 1: a plurality of PDU sets are mapped onto one QoS flow;

Scenario 2: a plurality of PDU sets are mapped to different QoS flows;

Scenario 3: a plurality of PDU sets have different PSI; and

Scenario 4: some PDU sets of a plurality of PDU sets have the same PSI.

FIG. 4 illustrates an example scenario of mapping between PDU sets, PSI, and QoS flows according to embodiments of the disclosure. In FIG. 4, a core network (CN) (e.g., a CN node, which is referred to as a CN hereinafter) transmits a PDU set to a RAN side (e.g., a RAN node, which is referred to as a RAN hereinafter). The RAN side places PDU set1 with PSI=1 and PDU set2 with PSI=3 on QoS flow1 for transmitting to a UE, and places PDU set3 with PSI=3 and PDU set4 with PSI=5 on QoS flow2 for transmitting to the UE. PDU set2 and PDU set3 with the same PSI are mapped to different QoS flows, respectively.

Exemplary embodiments of the disclosure are further described below with reference to the accompanying drawings.

The text and drawings are provided as examples only to help understand the disclosure. They should not be interpreted as limiting the scope of the disclosure in any way. Although certain embodiments and examples have been provided, based on the disclosure herein, it will be apparent to those skilled in the art that changes may be made to the illustrated embodiments and examples without departing from the scope of the disclosure.

Before introducing the specific content, some assumptions and some definitions of the disclosure are given below.

The message names in the disclosure are just examples, and other message names may be used.

The "first" and "second" included in the message names in the disclosure are only examples of messages and are only used to distinguish messages, and they do not rean execution order.

A detailed description of steps irrelevant to the disclosure is omitted in the disclosure.

In an embodiment of the disclosure, steps in various aspects, methods and processes may be combined with each other or performed independently. Execution steps of each process are only examples, and other possible execution orders are not excluded.

In an embodiment of the disclosure, the base station may be a 5G base station (such as gNB, ng-eNB), a 4G base station (such as eNB), a 6G base station, or other types of access nodes.

In an embodiment of the disclosure, the transmission of data refers to the reception and/or transmission of data.

In an embodiment of the disclosure, a core network (CN) node may be referred to as a first node and may include a core network device in any existing or future wireless communication system, such as an access control and mobility management function entity (AMF), a session management function entity (SMF), a user plane function entity (UPF), a policy control function entity (PCF), or the like. A radio access network (RAN) node may be referred to as a second node and may include various base stations, central units of the base stations, distributed units of the base stations, control planes of the central units of the base stations, user planes of the central units of the base stations, various cells (such as a serving cell of the UE, a source cell and a target cell for handover, or the like) as described above.

First aspect: A CN indicates a RAN how to apply PSI for data transmission (or packet discard)

In some implementations, the CN may transmit indication information to the RAN, indicating the RAN to apply PSI for data transmission (or data discard, packet discard, PDU set discard, or the like) according to an indicated rule when the RAN experiences congestion (or needs to discard data). Examples of information carried in the indication information and corresponding rules will be shown below. The CN may indicate one or several rules for the RAN, and the RAN may apply one of these rules or apply a plurality of rules simultaneously to use PSI for data transmission (or packet discard). Herein, packet discard may be referred to as PDU set discard. FIG. 5A illustrates an example flowchart of a CN transmitting indication information to a RAN according to embodiments of the disclosure.

As shown in FIG. 5A, in step 501, the CN may receive or determine one or more rules for data transmission by applying Protocol data unit Set Importance (PSI) through any method, and the specific determining method is not limited herein.

In step 502, the CN may transmit the indication information to the RAN. The indication information may include the one or more rules for data transmission by applying the Protocol data unit Set Importance (PSI) (for example, when network congestion occurs on the RAN side or when data needs to be discarded).

In step 503, after receiving the one or more rules for data transmission by applying the application Protocol data unit Set Importance (PSI), the RAN may apply one or more of the rules for data transmission (or packet discard, PDU set discard, or the like).

Example implementations of the information carried in the indication information and the corresponding rules may be as follows:

an implementation may be: the indication information carries a first threshold, and indicates that a PDU set with PSI less than or less than or equal to the first threshold may be directly discarded; or indicates to transmit a PDU set with PSI greater than or greater than or equal to the first threshold;

an implementation may be: the indication information carries a second threshold, and indicates that a PDU set with PSI greater than or greater than or equal to the second threshold is prioritized for transmission, for example, the PDU set with PSI greater than or greater than or equal to the second threshold has a higher priority, and the PDU set having the higher priority is prioritized for transmission;

an implementation may be: the indication information indicates that the size of a PSI value is in direct proportion to a transmission priority. In other words, a PDU set with a highest PSI value has a highest transmission priority and may be prioritized for transmission; secondly, a PDU set with a second highest PSI value has a second highest transmission priority, and is transmitted after the PDU set with the highest PSI value is transmitted, and so on. That is, PDU sets are transmitted based on transmission priorities, where a transmission priority of each PDU set is in direct proportion to PSI of the PDU set;

an implementation may be: the indication information indicates that for a plurality of PDU sets with the same PSI, a PDU set with a smallest or smaller size (data amount) is prioritized for transmission;

an implementation may be: the indication information indicates that when a plurality of PDU sets are mapped to different QoS flows, if different QoS flows have an association (for example, the different QoS flows include PDU sets having an association), the PDU sets having the association on the different QoS flows are prioritized for transmission, without considering an impact of PSI values on the transmission priority; and

optionally, the indication information may carry a third threshold, only when a PSI value of a PDU set having an association is greater than (or greater than or equal to) a third threshold, the PDU set having the association will be prioritized for transmission, and in this case, the transmission priority of the PDU set is higher than that of a PDU set with a higher PSI value but having no association.

In some implementations, any threshold described herein (e.g., the first threshold, the second threshold, the third threshold, and the like) may be predetermined, agreed upon through a protocol, or indicated by any other message or signalling, and may not be carried by the indication information.

In some implementations, the priority or the transmission priority of the PDU set as described above may be agreed upon through a protocol, or indicated by any message or signalling.

In some implementations, there may be several ways in which the CN transmits the indication information to the RAN:

the indication information may be carried in a GTP-U header, and in this case, the indication information is only valid for a current PDU set; and

the CN may transmit the indication information to the RAN through an NG interface (e.g. through an NGAP message). It may define a new NG application protocol (NGAP) message, or reuse an existing NGAP message, such as adding the message to a PDU session resource setup request for transmitting, which is not limited herein; and here, the NG interface may be an interface between a base station and a core network;

optionally, the message may carry a timer, indicating the RAN that indication information (or one or more rules indicated by the indication information) is valid within the timer. That is, information (such as a valid time interval or the like) related to valid time of the indication information (or the one or more rules indicated by the indication information) is indicated through a timer; and

optionally, the information related to the valid time of the indication information (or the one or more rules indicated by the indication information) may also be transmitted separately, such as indicating the start and end of the valid time interval of the indication information for the RAN.

Here, the information indicating the valid time of the one or more rules may alternatively be referred to as fourth information. The fourth information and the one or more rules may exist in same information, a same message, or same signalling, or the fourth information and the one or more rules may exist in different information, different messages, or different signalling. The fourth information may include at least one of the following: valid start time (which may be transmitted together with or separately from valid end time), the valid end time, valid time interval, or the like.

Second aspect: The RAN feeds back assistance information to the CN

When congestion occurs to the RAN, if a PDU set that needs to be discarded has an association with one or more other PDU sets, then if one of these PDU sets having an association is discarded, the remaining PDU sets are no longer necessary for transmission, because normal decoding can be performed only after all the PDU sets having an association are successfully transmitted. So if one PDU set is discarded, all PDU sets having an association with the PDU set need to be discarded. This kind of packet discard may have a significant impact on user experience, and there may be serious issues such as a delay, stuttering, or frame loss at an XR device terminal. But at this point, the CN is not aware of whether the congestion occurs to the RAN, and may still set mapping relationship between the PDU set and the corresponding PSI based on original rules. This is not conducive to alleviating and improving the issue.

In some implementations, for example, when congestion occurs to the RAN, the RAN may transmit the assistance information to the CN. Based on the assistance information, the CU may change the mapping relationship between the PDU set and the PSI, or change a correspondence between data packets (or data) and the PDU set, or change a policy and charging control rule (PCC rule) to alleviate a problem of a significant impact on user experience caused by the packet discard. Specific example implementations related to the assistance information may include one or more of the following:

An implementation may be: transmitting the assistance information (such as first information, which may also be referred to as first assistance information) to the CN when congestion occurs to the RAN, to suggest the CN to configure a higher PSI value for a PDU set having an association, such as first PSI. For example, the CN may be suggested to configure PSI of the PDU set having an association to have a higher value than PSI of a PDU set without an association. In this way, when the RAN performs packet discard, the RAN will not easily discard PDU sets with an association (which may also be referred to as correlation). In some implementations, the first PSI may be High, Medium, or greater than a certain threshold. In some implementations, the first PSI may be of a higher value than that of an existing PSI.

An implementation may be: when congestion occurs to the RAN, transmitting the assistance information (such as second information, which may also be referred to as second assistance information) to the CN, to suggest the CN not to place data having an association (which may also be referred to as a packet herein) on different PDU sets, and/or to suggest the CN to place the data having an association on a same PDU set. This will not have an impact on other PDU sets even if a PDU set is discarded.

An implementation may be: transmitting the assistance information (such as third information, which may also be referred to as third assistance information) to the CN when congestion occurs to the RAN, to indicate the CN that congestion occurs to the RAN currently.

The RAN may provide a congestion feedback to the CN at the granularity of a QoS flow, or a UE, or a cell, that is, indicating a congestion status to the CN in a per QoS flow manner, a per UE manner, or a per cell manner. The congestion status may be whether congestion occurs, and/or a congestion degree (congestion level).

Optionally, the RAN may indicate its congestion level or congestion degree (e.g., low/medium/high or 0, 1, 2, 3..., or a percentage of congested packets in total transmitted packets, etc.), and the CN may choose different policies based on the congestion level of the RAN.

It should be noted that the RAN only provides corresponding suggestions and/or information to the CN through feedback of the assistance information, but whether the CN accepts the suggestion of the RAN or adopts relevant policies is determined by the CN itself. The RAN may transmit the assistance information to the CN through an NG interface. It may define a new NG application protocol (NGAP) message, or reuse an existing NGAP message. For example, the assistance information may be added to PDU Session Resource Modification Indication or RAN Configuration Update for transmitting, which is not limited herein. A class 1 procedure may be used to interact with the CN, or a class 2 procedure may be used to interact with the CN, which is not limited herein. For example, when the RAN provides a congestion status feedback to the CN in a per QoS flow manner, that is, reflects a congestion status of data transmission on a certain QoS flow, the assistance information may be added to PDU Session Resource Modification Indication or PDU Session Resource Notification, or to an IP header or a GTP-U header, which is not limited herein. FIG. 5A and FIG. 5B illustrate example diagrams of two different manners of adding a congestion level to a GTP-U header in a per QoS flow manner. In FIG. 5B, in addition to adding an indication of the congestion level to a spare field, a new IE Flag (such as New IE Flag 1) in a New IE Flags Octet is also needed to indicate whether the indication of congestion level exists.

Third aspect: DRX pre-configuration in cell handover

The disclosure considers related schemes for applying a discontinuous reception (DRX) mechanism in an XR service to reduce power consumption.

The application of the DRX mechanism may save power for a user with a periodic service. The XR service has strict periodicity, and in order to make a XR device more lightweight, there are corresponding limitations on a capacity and a size of a battery, resulting in high requirements for energy saving. If the XR device can stay in the DRX mechanism as long as possible, then the DRX mechanism can be maximized for energy saving. FIG. 6 illustrates a general flowchart when a current UE performs cell handover. As shown in FIG. 6, if Cell1 is a serving cell and Cell2 is a target cell (which may also be referred to as a third node herein), when Cell1 determines to hand over the UE to Cell2, the following steps can be taken:

Cell1 transmits a handover request (HO request) to Cell2, to request to hand over the UE to Cell2;

if Cell2 agrees with the handover, it replies a handover request acknowledge (HO request ACK) message to Cell1;

after receiving the ACK message, Cell1 transmits a handover command (HO command) to the UE;

when the UE receives the HO command, if the UE is in the DRX mechanism, the UE exits the DRX mechanism and performs RRC reconfiguration after receiving the HO command, and after the RRC reconfiguration is completed, the UE transmits RRCReconfigComplete to Cell2; and

after Cell2 receives RRCReconfigComplete, which indicates that the UE completes the handover, Cell2 may transmit DRX related configuration information to the UE.

From the above process, it can be seen that during a time period from the time when the UE receives the HO command to the time when Cell2 configures the DRX configuration for the UE, the UE cannot be in the DRX mechanism to save power.

Thus an aspect of the disclosure focuses on how XR users can maximize the use of the DRX mechanism to save power during cell handover. FIG. 7 illustrates an example flowchart of a UE performing cell handover according to embodiments of the disclosure. Specific steps are as follows:

when Cell1 determines to hand over the UE from Cell1 to Cell2, Cell1 transmits an HO request to Cell2 and carries a first DRX configuration (such as a configuration for onDuration Timer, Inactivity Timer, DRX cycle, or the like) configured by Cell1 for the UE and/or an expected DRX configuration of the UE (such as drx-Preference, which can be referred to as a third DRX configuration herein), for reference by Cell2; and in some implementations, the first DRX configuration may include one or more DRX configurations configured by Cell1 for the UE, such as a plurality of DRX cycles and/or a plurality of onDuration Timers configured by Cell1 for the UE, or the like;

optionally, if Cell1 can predict a motion trajectory of the UE, Cell1 can know in advance that Cell1 will hand over the UE to Cell2, then Cell1 can interact with Cell2 in advance, and Cell2 can transmit, through an Xn interface in advance, a second DRX configuration configured by Cell2 for the UE to Cell1, so there is no need to perform interaction of the second DRX configuration through an HO preparation process;

if Cell2 determines to accept the handover request and determines to configure DRX for the UE, it transmits an HO request ACK to Cell1 and carry the second DRX configuration configured by Cell2 for the UE, and/or a triggering condition for applying the second DRX configuration, in some implementations, the second DRX configuration may include one or more DRX configurations configured by Cell2 for the UE, such as a plurality of DRX cycles and/or a plurality of onDuration Timers configured by Cell2 for the UE, or the like. In some implementations, the triggering condition may include one or more of the following:

after the UE is handed over to Cell2, the second DRX configuration configured by Cell2 is directly triggered, and in this case, because the UE can immediately apply DRX after handed over to Cell2, a good power consumption gain is obtained;

the second DRX configuration configured by Cell2 is triggered after a first time period (such as after a duration of a timer) after the UE is handed over to Cell2, where this timer configuration may also be determined by Cell2 and added to the HO request ACK message. In this case, it can avoid signalling overheads caused by a need for Cell2 to separately configure DRX for the UE in conventional solutions; and moreover, in addition to using a timer, the first time period may also be indicated by other specific messages or fields, which is not limited herein; and

after the UE is handed over to Cell2, the second DRX configuration configured by Cell2 is triggered after indication information (or triggering message) that is transmitted by Cell2 and that is used to trigger the second DRX configuration is received, where the indication information may further indicate which of the one or more DRX configurations included in the second DRX configuration should be triggered by the UE, for example, it may indicate which DRX cycle of the plurality of DRX cycles configured by Cell2 for the UE and/or which onDuration Timer of the plurality of onDuration Timers configured by Cell2 for the UE should be triggered by the UE;

after receiving the ACK message transmitted by Cell2, Cell1 transmits the HO command to the UE, which carries the second DRX configuration configured by Cell2 and/or the triggering condition for applying the second DRX configuration; and

after the UE completes the RRC reconfiguration, the UE transmits RRCReconfigComplete to Cell2 and executes a corresponding DRX mechanism based on the triggering condition.

In order to better apply DRX technology to XR services, some non-integer DRX cycles (i.e., drx-NonIntegerLongCycle IE and drx-NonIntegerShortCycle IE) are introduced. When the UE is an XR device, the base station may configure a non-integer DRX cycle for the XR UE to match the XR service of a non-integer cycle. However, there is a problem that the non-integer DRX cycle is not added in UE Assistance information (UAI), that is, DRX cycles that the UE prefers (i.e. drx-Preference IE) in the UAI still does not include the non-integer DRX cycle. Therefore, when the base station is of a CU-DU split structure, the DRX cycle IE in the UE Context Setup Request message transmitted by the CU to the DU will not contain the non-integer DRX cycle, because the DRX cycle in the UE Context Setup Request corresponds to the DRX cycle that the UE prefers in the UAI. This will lead to a problem that the DU cannot configure a non-integer DRX cycle for the XR UE either. Therefore, the invention proposes the following several embodiments to solve the configuration problem of non-integer DRX cycle in a CU-DU split structure.

In some implementations, when the DU receives a UE Context Setup Request message and/or a UE Context Modification Request message transmitted by the CU, if the message further contains at least one of the following IEs and/or meets at least one of the following conditions in addition to the DRX cycle IE, the DU can configure a non-integer DRX cycle value for the UE in addition to configure an integer DRX cycle value in the DRX cycle IE for the UE, or the DU can directly ignore the DRX cycle IE and configure a non-integer DRX cycle value for the UE:

PDU Set QoS Parameters IE;

ECN (Explicit Congestion Notification) Marking or Congestion Information Reporting Request IE;

N6 Jitter Information IE;

Periodicity and/or Burst Arrival Time and the like in TSC (Time Sensitive Communication) Assistance information IE conform to the characteristics of XR service cycle, or the Periodicity and/or Burst Arrival Time are non-integer values;

ul-TrafficInfo (uplink traffic information) IE in UAI conforms to the characteristics of XR service cycle;

Other service parameters that can let the DU know that the UE is an XR UE.

When configuring a non-integer DRX cycle for the UE, the DU can refer to Periodicity and/or Burst Arrival Time and the like in TSC Assistance information IE, or other service parameters that can be referred to, which are not limited here.

In some implementations, a new IE may be defined in the UE Context Setup Request message and/or UE Context Modification Request message transmitted by the CU to the DU, and the new IE may be called new DRX cycle IE, extended DRX cycle IE, or other names, which are not limited here. When the UE is an XR UE, or the DRX cycle value that the UE prefers is non-integer, the CU adds the newly defined IE to the UE Context Setup Request message and/or UE Context Modification Request message and transmits it to the DU. The new IE content may include at least one of the following:

All DRX cycle values that can be configured, i.e., including integer DRX cycle values and non-integer DRX cycle values;

Non-integer DRX cycle values;

Non-integer DRX cycle values that the UE prefers;

DRX cycle values that the UE prefers, including desired integer DRX cycle values and desired non-integer DRX cycle values;

Fourth aspect: Mapping relationship between PSI and a PDU set

In some implementations, the CN may determine a priority/importance of a PDU set based on a delay budget, an error rate, or other relevant parameters of the PDU set. The priority/importance may be represented by PSI, and the mapping relationship between the PSI and the PDU set follows a corresponding rule, such as a PDU Priority Mark (PPM) rule or a Policy and Charging Control Rule (PCC rule). The PPM rule may be informed by the CN to the UE through an N1 SM container during a PDU session setup process or modification process, so that the UE can use the PPM rule for transmission of uplink PDU sets. However, if the CN informs the same to the UE in this way, the RAN can not be aware of the PPM rule. The PCC rule is determined by a Policy Control Function (PCF) based on a service requirement provided by an Application Function (AF), etc., and a part of the PCC rule is informed to an SMF. The RAN side also can not be aware of the specific PCC rule. If the RAN can also obtain the PPM rule and/or the PCC rule, it will be more conducive to allocation and scheduling of uplink PDU set resources. Therefore, the disclosure proposes another PPM and/or PCC rule notification method. Specific steps are as follows:

firstly, the CN may inform the RAN of the mapping relationship between the PSI and the PDU set (such as a PPM rule or a PCC rule) through core network assistance information (which may be referred to as fifth information herein), and in this case, the RAN side can be aware of the mapping rule between the PSI and the PDU set, where it should be understood that the mapping relationship between the PSI and the PDU set or the PPM or PCC rule may also be informed to the RAN through another NGAP message (which may also be referred to as the fifth information herein), which is not limited herein;

after receiving the core network assistance information, the RAN will inform the UE of the PPM rule and/or the PCC rule, and in this case, both the RAN and the UE may know the PPM rule and/or the PCC rule; and

the RAN may transmit it to the UE through an RRC message, or may perform broadcast the same through a system information (SI) message, where there is no limitation to the message through which the RAN informs the UE.

Herein, the mapping rule and the mapping relationship can be used interchangeably.

In some implementations, the UE may correspond an uplink PDU set to corresponding PSI based on the mapping relationship between the PSI and the PDU set. When transmitting the uplink PDU set, the PSI may be included in the PDU set header, and the base station may perform data transmission, resource scheduling, data discard, or the like based on the PSI.

Fifth aspect: Mapping relationship between an SR/BSR and PSI/LCH

In some implementations, when the UE is to transmit uplink data, the UE will first transmit a scheduling request (SR) or a buffer status report (BSR) to the base station, requesting the base station to allocate an uplink resource for the UE, such as transmitting an uplink grant (UL grant) to the UE, etc. For example, when the UE is to transmit uplink data, the UE may transmit an SR to the base station through a physical uplink control channel (PUCCH). After the base station detects the SR and knows that the UE is to transmit uplink data, the base station transmits an UL grant to the UE to allocate an uplink resource. Subsequently, the UE transmits a BSR on the allocated resource through a physical uplink shared channel (PUSCH) to notify the base station of the amount of uplink data to be transmitted. Based on the BSR, the base station then transmits an uplink grant (UL grant) to the UE to allocate an appropriate uplink resource for the UE to transmit the uplink data. In NR, the UE may skip the process of transmitting SR and may directly transmit the BSR to the base station through the PUCCH to request the resource required for transmitting the uplink data, thereby reducing a transmission latency of the uplink data. After receiving the SR or the BSR transmitted by the UE, the base station may allocate an uplink resource for the UE based on the own situation of the base station. This may result in insufficient uplink resources to transmit all uplink data. If the base station is unaware of the importance of the uplink data, the base station may not promptly configure an uplink resource for the UE. However, latency and the size of uplink resources allocated by the network are very important for the XR service, since if scheduling latency is too large, or uplink data transmission latency increases due to the insufficient uplink resource configured, which exceeds a corresponding packet delay budget (PDB) or PDU set delay budget (PSDB) requirement, the uplink data to be transmitted may be discarded. As a result, the uplink data transmission fails and user experience becomes poor.

An aspect of the disclosure proposes a corresponding solution to resolve this problem. An example implementation may be:

after knowing the PPM rule and/or the PCC rule, the UE may know a mapping relationship between the uplink PDU set and PSI, and when a PSI value corresponding to a PDU set to be transmitted is greater than (or greater than or equal to) a fourth threshold, the UE may use a new SR/BSR format (such as a new format or a specific format, which may be referred to as a first format herein) to transmit the SR/BSR corresponding to the PDU set. In this case, if the RAN receives the SR/BSR in the new format, the RAN may know that the PDU set to be uploaded by the UE is important, and may prioritize uplink resource scheduling for that UE. The format of the BSR may be determined by using a MAC sub-header carrying an LCID. In some implementations, the first format herein may be represented by a spare field of the LCID in the MAC sub-header.

If the fourth threshold is determined by the UE itself, the UE needs to inform the RAN of the fourth threshold after determining it, where the UE may inform the RAN through UE assistance information (UAI) or another existing message, and there is no limitation on what kind of message is used to inform the RAN;

if the fourth threshold is determined by the RAN, the RAN needs to inform the UE of the fourth threshold after determining it, so that the UE can use the fourth threshold. The RAN may inform the UE of the fourth threshold through an RRC message;

if the fourth threshold is determined by the CN, the CN needs to inform the RAN and the UE of the fourth threshold after determining it. The CN may inform the fourth threshold to the RAN through core network assistance information, and the RAN may then inform the same to the UE through an RRC message; or the CN may directly inform the same to the UE through a non-access stratum (NAS) message. There is no limitation on which message the CN may use to inform the RAN and the UE; and

if the PSI value corresponding to the PDU set to be transmitted is less than (or less than or equal to) the fourth threshold, the SR/BSR in an existing format (for example, a general format, which may be referred to as a second format herein) is used for transmitting.

As mentioned above, the first format may be different from the second format, so that the RAN may know the importance of the corresponding PDU sets based on different formats.

In some implementations, the RAN side may determine the importance of the uplink data based on a priority of a logical channel (LCH), thereby determining a priority of uplink packet scheduling. But for the XR service, PDU sets with different PSI values may be mapped to LCHs with a same priority. For example, PDU sets with PSI values of 0, 1, and 2 may be all mapped to an LCH with a priority of 1. If the RAN has insufficient resources, all PDU sets on the LCH with the priority of 1 may be delayed in scheduling, and the primary reason is that the RAN is not aware of PSI corresponding to PDU sets on the LCH. Therefore, the disclosure proposes a method to resolve the problem. An example implementation may be:

when the PSI is greater than (or greater than or equal to) a fifth threshold, the UE may transmit a corresponding SR/BSR through a high priority LCH or a specific LCH (for example, which may be referred to as a first logical channel herein), and in this case, the RAN can prioritize the allocation of uplink resources for the corresponding SR/BSR. In some implementations, a new or specific LCID (logical channel ID) (where the new or specific LCID may be represented by a spare field in the LCID value in an embodiment) may be defined for a PDU set with PSI greater than (or greater than or equal to) the fifth threshold. When the corresponding SR/BSR is transmitted through the LCH corresponding to the new or specific LCID, the RAN side may also be aware of and prioritize the allocation of uplink resources for the corresponding SR/BSR.

If the fifth threshold is determined by the UE, the UE needs to inform the RAN of the fifth threshold after determining it, where the UE may inform the RAN through UAI (UE assistance information) or another existing message, and there is no limitation on what kind of message is used to inform the RAN;

if the fifth threshold is determined by the RAN, the RAN needs to inform the UE of the fifth threshold after determining it, so that the UE can use the fifth threshold, where the RAN may inform the UE of the fifth threshold through an RRC message;

if the fifth threshold is determined by the CN, the CN needs to inform the RAN and the UE of the fifth threshold after determining it, where the CN may inform the RAN through core network assistance information, and the RAN may then inform the UE through the RRC message; or the CN may directly inform the UE through an NAS message, and there is no limitation on which message the CN may use to inform the RAN and the UE; and

if the PSI value corresponding to the PDU set to be transmitted is less than (or less than or equal to) the fifth threshold, the UE may use a general LCH (e.g., which may be referred to as a second logical channel herein) to transmit the corresponding SR/BSR.

In some implementations, the first logical channel as described above may have a higher priority than that of the second logical channel.

Herein, the first format may correspond to the first logical channel, and the second format may correspond to the second logical channel. Herein, the fourth threshold may be the same as or different from the fifth threshold, and they may refer to each other.

It should be understood that any method, aspect, step, or embodiment described herein may be combined with each other.

Next, FIG. 8 illustrates a flowchart of a method 800 performed by a first node in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 8, the method 800 performed by the first node in the wireless communication system according to embodiments of the disclosure may include: in step 801, generating a rule for data transmission and/or discard by applying Protocol data unit Set Importance (PSI) when a second node needs to discard data; and in step 802, transmitting indication information to the second node. As mentioned above, the first node may be any CN node, and the second node may be any RAN node, such as any base station, gNB, eNB, centralized unit of the base station, distributed unit of the base station, control plane part, user plane part, cell, access point, or the like. In some implementations, the indication information may indicate one or more rules for data transmission by applying the Protocol data unit Set Importance (PSI) when network congestion occurs to the second node.

FIG. 9A illustrates a flowchart of a method 900 performed by a second node in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 9A, the method 900 performed by the second node in the wireless communication system according to embodiments of the disclosure may include: in step S901, receiving a scheduling request (SR) and/or a buffer status report (BSR) from a user equipment (UE); and in step S902, transmitting an uplink grant to the UE. In some implementations, the SR and/or the BSR may be received through a first format or a first logical channel or through a second format or a second logical channel based on Protocol data unit Set Importance (PSI) of a protocol data unit (PDU) set corresponding to the SR and/or the BSR.

In some implementations, when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is greater than or greater than or equal to a fourth threshold, the SR and/or the BSR are/is received through the first format or the first logical channel; and when the PSI of the protocol data unit (PDU) set corresponding to the SR and/or the BSR is less than or less than or equal to the fourth threshold, the SR and/or the BSR are/is received through the second format or the second logical channel.

FIG. 9B illustrates a flowchart of a method 910 performed by a second node in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 9B, the method 910 performed by the second node in the wireless communication system according to embodiments of the disclosure may include: in step S911, receiving indication information from a first node; and in step S912, transmitting and/or discarding data based on the indication information or a rule included in the indication information. As mentioned above, the first node may be any CN node, and the second node may be any RAN node. In some implementations, the indication information may indicate one or more rules for data transmission by applying the Protocol data unit Set Importance (PSI) when network congestion occurs to the second node.

FIG. 9C illustrates a flowchart of a method 920 performed by a second node in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 9C, the method 920 performed by the second node in the wireless communication system according to embodiments of the disclosure may include: in step S921, transmitting a handover request message to a third node; in step S922, receiving a handover request acknowledge message from the third node; and in step S923, transmitting a handover command to the UE. In some implementations, the handover request acknowledge message may include a second DRX configuration configured by the third node for a user equipment (UE). In some implementations, the handover command may include the second DRX configuration. As mentioned above, the first node may be any CN node, and the second node may be any RAN node. The third node may be any node that can serve as a handover target node.

FIG. 10 illustrates a flowchart of a method 1000 performed by a user equipment (UE) in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 10, the method 1000 performed by the user equipment (UE) in the wireless communication system according to embodiments of the disclosure may include: in step S1001, transmitting a scheduling request (SR) and/or a buffer status report (BSR) to a second node; and in step S1002, receiving an uplink grant from the second node. As mentioned above, the second node may be any RAN node. In some implementations, the SR and/or the BSR may be transmitted through a first format or a first logical channel or through a second format or a second logical channel based on Protocol data unit Set Importance (PSI) of a protocol data unit (PDU) set corresponding to the SR and/or the BSR.

It should be understood that

methods

800, 900, 910, 920, and 1000 according to embodiments of the disclosure may further include one or more of the methods or steps described above in conjunction with any examples or drawings. Details will not be repeatedly described here.

Next, FIG. 11 illustrates a schematic diagram of a node 1100 in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 11, the node 1100 (for example, which may be a first node (for example, a CN node), a second node (for example, a RAN node), or any other network node as described above) according to embodiments of the disclosure may include a transceiver 1110 and a processor 1120. The transceiver 1110 may be configured to transmit and receive signals. The processor 1120 may be coupled to the transceiver 1110 and may be configured to (e.g., control the transceiver 1110 to) perform any method performed by the node in the wireless communication system according to embodiments of the disclosure.

FIG. 12 illustrates a schematic diagram of a user equipment 1200 in a wireless communication system according to embodiments of the disclosure.

As shown in FIG. 12, the user equipment 1200 according to embodiments of the disclosure may include a transceiver 1210 and a processor 1220. The transceiver 1210 may be configured to transmit and receive signals. The processor 1220 may be coupled to the transceiver 1210 and may be configured to (e.g., control the transceiver 1210 to) perform any method performed by the user equipment according to embodiments of the disclosure. Herein, a processor may also be referred to as a controller.

Various embodiments of the disclosure may be implemented as computer-readable codes embodied on a computer-readable recording medium from a specific perspective. A computer-readable recording medium is any data storage device that can store data readable by a computer system. Examples of computer-readable recording media may include read-only memory (ROM), random access memory (RAM), compact disk read-only memory (CD-ROM), magnetic tape, floppy disk, optical data storage device, carrier wave (e.g., data transmission via the Internet), etc. Computer-readable recording media can be distributed by computer systems connected via a network, and thus computer-readable codes can be stored and executed in a distributed manner. Furthermore, functional programs, codes and code segments for implementing various embodiments of the disclosure can be easily explained by those skilled in the art to which embodiments of the disclosure are applied.

It will be understood that embodiments of the disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. The software may be stored as program indications or computer-readable codes executable on a processor on a non-transitory computer-readable medium. Examples of non-transitory computer-readable recording media include magnetic storage media (such as ROM, floppy disk, hard disk, etc.) and optical recording media (such as CD-ROM, digital video disk (DVD), etc.). Non-transitory computer-readable recording media may also be distributed on computer systems coupled to a network, so that computer-readable codes are stored and executed in a distributed manner. The medium can be read by a computer, stored in a memory, and executed by a processor. Various embodiments may be implemented by a computer or a portable terminal including a controller and a memory, and the memory may be an example of a non-transitory computer-readable recording medium suitable for storing program (s) with indications for implementing embodiments of the disclosure. The disclosure may be realized by a program with code for concretely implementing the apparatus and method described in the claims, which is stored in a machine (or computer)-readable storage medium. The program may be electronically carried on any medium, such as a communication signal transmitted via a wired or wireless connection, and the disclosure suitably includes its equivalents.

What has been described above is only the specific implementation of the disclosure, but the scope of protection of the disclosure is not limited thereto. Anyone who is familiar with this technical field may make various changes or substitutions within the technical scope disclosed in the disclosure, and these changes or substitutions should be covered within the scope of protection of the disclosure. Therefore, the scope of protection of the disclosure should be based on the scope of protection of the claims.

Claims

A method performed by centralized unit, CU, in a wireless communication system, the method comprising:

identifying information element associated with a non-integer discontinuous reception, DRX, cycle included in a user equipment, UE, context request message; and

transmitting, to a distributed unit, DU, the UE context message including the information element associated with the non-integer DRX cycle.
The method of claim 1, wherein the UE context request message is a UE context setup message.
The method of claim 1, wherein the UE context request message is a UE context modification message.
The method of claim 1, wherein the information element comprises a long non-integer DRX cycle or a short non-integer DRX cycle.
A method performed by distributed unit, DU, in a wireless communication system, the method comprising:

receiving, from a centralized unit, CU, a user equipment, UE, context message including information element associated with a non-integer discontinuous reception, DRX, cycle; and

configuring a DRX configuration based on the information element associated with the non-integer DRX cycle.
The method of claim 5, wherein the UE context request message is a UE context setup message.
The method of claim 5, wherein the UE context request message is a UE context modification message.
The method of claim 5, wherein the information element comprises a long non-integer DRX cycle or a short non-integer DRX cycle.
A centralized unit, CU, in a wireless communication, comprising:

a transceiver; and

at least one processor coupled to the transceiver, configured to:

identify information element associated with a non-integer discontinuous reception, DRX, cycle included in a user equipment, UE, context request message, and

transmit, to a distributed unit, DU, the UE context message including the information element associated with the non-integer DRX cycle.
The CU of claim 9, wherein the UE context request message is a UE context setup message.
The CU of claim 9, wherein the UE context request message is a UE context modification message.
The CU of claim 9, wherein the information element comprises a long non-integer DRX cycle or a short non-integer DRX cycle.
A centralized unit, CU, in a wireless communication, comprising:

a transceiver; and

at least one processor coupled to the transceiver, configured to:

receive, from a centralized unit, CU, a user equipment, UE, context message including information element associated with a non-integer discontinuous reception, DRX, cycle, and

configure a DRX configuration based on the information element associated with the non-integer DRX cycle.
The DU of claim 13, wherein the UE context request message is a UE context setup message.
The DU of claim 13, wherein the information element comprises a long non-integer DRX cycle or a short non-integer DRX cycle.