WO2024216457A1

WO2024216457A1 - Devices, methods, apparatuses and computer-readable medium for communication

Info

Publication number: WO2024216457A1
Application number: PCT/CN2023/088781
Authority: WO
Inventors: Lei Du; Lars Dalsgaard; Naizheng ZHENG; Karri Markus Ranta-Aho
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Priority date: 2023-04-17
Filing date: 2023-04-17
Publication date: 2024-10-24
Anticipated expiration: 2025-10-17

Abstract

Example embodiments of the present disclosure relate to a terminal device, a network device, methods, apparatuses and a computer-readable medium for communication. In an example method, a terminal device receives, from a network device, a secondary cell (SCell) activation command for activating a SCell. The network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells. Then the terminal device determines configuration information for activating the SCell and monitors the SCell based on the configuration information. In this way, communication performance can be improved and the SCell can be activated more reliably.

Description

DEVICES, METHODS, APPARATUSES AND COMPUTER-READABLE MEDIUM FOR COMMUNICATION

FIELD

Example embodiments of the present disclosure generally relate to the field of telecommunication, and in particular, to a terminal device, a network device, methods, apparatuses, and a computer-readable medium for communication.

BACKGROUND

Carrier aggregation (CA) is widely used in communication systems to provide service to a terminal device. CA involves a primary cell (PCell) and at least one secondary cell (SCell) . Usually, the PCell and SCell transmit synchronization signal and physical broadcast channel (PBCH) block (SSB) to the terminal device, respectively.

An SSB-less SCell scenario is proposed for power saving, where the network can benefit from SSB-less operation by not transmitting SSB in the SCell, for example, by reusing the PCell information for the SCell. However, not all inter-band SCells can be activated by reusing the PCell information. Solutions are needed to improve inter-band CA operations.

SUMMARY

In general, example embodiments of the present disclosure provide a terminal device, a network device, methods, devices, and a computer-readable medium for communication, especially for improving inter-band CA operations, for example, to activate an SSB-less SCell more reliably with assisted information.

In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive, from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determine configuration information for activating the SCell; and monitor the SCell based on the configuration information.

In a second aspect, there is provided a network device. The network device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: transmit, to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determine first configuration information for activating the SCell based on information of the PCell; and transmit the first configuration information to the terminal device.

In a third aspect, there is provided a network device. The network device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: obtain configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and transmit, to the terminal device, the at least one RS based on the configuration information.

In a fourth aspect, there is provided a method. The method comprises: receiving, at a terminal device and from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determining configuration information for activating the SCell; and monitoring the SCell based on the configuration information.

In a fifth aspect, there is provided a method. The method comprises: transmitting, at a network device and to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determining first configuration information for activating the SCell based on information of the PCell; and transmitting the first configuration information to the terminal device.

In a sixth aspect, there is provided a method. The method comprises: obtaining, at a network device, configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and transmitting, to the terminal device, the at least one RS based on the configuration information.

In a seventh aspect, there is provided an apparatus. The apparatus comprises: means for receiving, from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; means for determining configuration information for activating the SCell; and means for monitoring the SCell based on the configuration information.

In an eighth aspect, there is provided an apparatus. The apparatus comprises: means for transmitting, to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; means for determining first configuration information for activating the SCell based on information of the PCell; and means for transmitting the first configuration information to the terminal device.

In a ninth aspect, there is provided an apparatus. The apparatus comprises: means for obtaining configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and means for transmitting, to the terminal device, the at least one RS based on the configuration information.

In a tenth aspect, there is provided a non-transitory computer-readable storage medium having instructions stored thereon. The instructions, when executed on at least one processor, cause the at least one processor to perform the method of any of the fourth to sixth aspects.

In an eleventh aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: receive, from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determine configuration information for activating the SCell; and monitor the SCell based on the configuration information.

In a twelfth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: transmit, to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determine first configuration information for activating the SCell based on information of the PCell; and transmit the first configuration information to the terminal device.

In a thirteenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: obtain configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and transmit, to the terminal device, the at least one RS based on the configuration information.

In a fourteenth aspect, there is provided a terminal device. The terminal device comprises: receiving circuitry configured to receive, from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determining circuitry configured to determine configuration information for activating the SCell; and monitoring circuitry configured to monitor the SCell based on the configuration information.

In a fifteenth aspect, there is provided a network device. The network device comprises: transmitting circuitry configured to transmit, to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells; determining circuitry configured to determine first configuration information for activating the SCell based on information of the PCell; and transmitting circuitry configured to transmit the first configuration information to the terminal device.

In a sixteenth aspect, there is provided a network device. The network device comprises: obtaining circuitry configured to obtain configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and transmitting circuitry configured to transmit, to the terminal device, the at least one RS based on the configuration information.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, in which:

FIG. 1 illustrates an example of a network environment in which some example embodiments of the present disclosure may be implemented;

FIG. 2 illustrates a signaling chart illustrating an example communication process in accordance with some example embodiments of the present disclosure;

FIG. 3 illustrates a schematic diagram illustrating SSB-less SCell in accordance with some example embodiments of the present disclosure;

FIG. 4 illustrates a schematic SCell activation procedure for SSB-less SCell in accordance with some example embodiments of the present disclosure;

FIG. 5 illustrates a signaling chart illustrating an example communication process in accordance with some example embodiments of the present disclosure;

FIG. 6 illustrates a flowchart of an example method implemented at a terminal device in accordance with some embodiments of the present disclosure;

FIG. 7 illustrates another flowchart of an example method implemented at a network device in accordance with some embodiments of the present disclosure;

FIG. 8 illustrates another flowchart of another example method implemented at a network device in accordance with some embodiments of the present disclosure;

FIG. 9 illustrates a simplified block diagram of a device that is suitable for implementing some example embodiments of the present disclosure; and

FIG. 10 illustrates a block diagram of an example of a computer-readable medium in accordance with some example embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar elements.

DETAILED DESCRIPTION

Principles of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (for example, firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) , Wireless Fidelity (WiFi) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the fourth generation (4G) , 4.5G, the future fifth generation (5G) , IEEE 802.11 communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a WiFi device, a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology. In the following description, the terms “network device” , “AP device” , “AP” and “access point” may be used interchangeably.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , a station (STA) or station device, or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a VR (virtual reality) device, an XR (eXtended reality) device, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (for example, remote surgery) , an industrial device and applications (for example, a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “station” , “station device” , “STA” , “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

Carrier aggregation is used in communication systems in order to increase the bandwidth, and thereby increase the bitrate. Each aggregated carrier is referred to as a component carrier (CC) . The easiest way to arrange aggregation would be to use contiguous component carriers within the same operating frequency band (as defined for long term evolution (LTE) ) , so called intra-band contiguous. This might not always be possible, due to operator frequency allocation scenarios. For non-contiguous allocation it could either be intra-band, i.e. the component carriers belong to the same operating frequency band, but have a gap in-between, or it could be inter-band, in which case the component carriers belong to different operating frequency bands.

Different component carriers can be planned to provide different coverage, i.e. different cell size. In the case of inter-band carrier aggregation, the component carriers will experience different pathloss, which increases with increasing frequency. When carrier aggregation is used there are a number of serving cells, one for each component carrier. The coverage of the serving cells may differ, for example due to that CCs on different frequency bands will experience different pathloss. The radio resource control (RRC) connection is only handled by one cell, i.e., the primary serving cell, served by the primary component carrier (PCC) . The primary serving cell is also referred to as primary cell (PCell) . It is also on the downlink (DL) PCC that the UE receives non-access stratum (NAS) information, such as security parameters. In idle mode the UE listens to system information on the DL PCC. On the uplink (UL) PCC, physical uplink control channel (PUCCH) is sent. The other component carriers are all referred to as secondary component carriers (SCC) , serving the secondary serving cells. The secondary serving cell is also referred to as secondary cell (SCell) .

SSB usually stands for synchronization signal block and in reality it refers to synchronization and physical broadcast channel (PBCH) block because synchronization signal (SS) and PBCH channel are packed as a single block that always moves together. The components of this block comprise synchronization signal (including PSS (primary synchronization signal) and SSS (secondary synchronization signal) ) and PBCH demodulation reference signal (DMRS) and PBCH data.

In this disclosure, “SSB-less SCell” refers to a SCell without SSB transmission, or when the UE is not provided with SSB configuration (absolute Frequency SSB) nor SSB measurement time configuration (SMTC) configuration for the SCell. Network can benefit from SSB-less operation by not transmitting SSB for power saving. It is different from on-demand SSB scenario where normal SSB transmission may be triggered at some time. In this SSB-less scenario, the SSB-less SCell should be activated without transmitting SSB from the SCell to the terminal device.

In TS 38.133, the SCell activation delay for activating a SSB-less intra-band contiguous SCell is defined by reusing the PCell information. In such a case, only 3ms is needed for activating the SCell as the UE assumes same time/frequency synchronization, beam information and channel propagation conditions with PCell. Hence no dedicated activation steps in terms of AGC, time/frequency/channel tracking, L1-RSRP measurement etc. are needed for activating the SSB-less SCell. UE blindly relies on that the network timing is accurate enough and the UE can reuse the exact same (PCell) information for the SSB-less SCell. And in this manner the UE would start receiving data on the SSB-less SCell.

For intra-band SSB-less operation, this 3ms SCell activation delay is possible under certain side conditions of receive time difference (RTD) , power difference and quasi co-location (QCL) configurations between the PCell and the SSB-less SCell. For intra-band scenario, these conditions can be fulfilled as co-location deployment has been always assumed up to 3GPP Release-17 (R17) and time alignment error (TAE on network side) requirement for intra-band contiguous CA is quite small, i.e. 260ns.

However, directly applying similar requirement for inter-band may not be straight forward as FR1 covers a wide frequency range where the channel characteristics, i.e. propagation delay, reflections and path loss may differ between the carriers used in CA (for example carrier 1 in 900MHz and carrier 2 in 6GHz) . Taking RTD as an example, it shall at least take into account 3us TAE for inter-band network deployment; thus it may be very difficult to achieve RTD < 260ns (nanosecond) for inter-band CA.

This means not all the inter-band SCells can fulfill the currently defined side conditions and only certain SCells can be activated by reusing PCell information. In other words, certain SCells cannot be activated by reusing PCell information. However, it is not discussed or defined how to activate the SCell (for example, the SSB-less SCell) if one or more of the side conditions are not fulfilled. Thus some solution is needed to activate the SCell (for example, the SSB-less SCell) irrespective of the side conditions.

In order to improve the communication performance and reliability of SCell activation (for example, SSB-less SCell activation) , methods for activating a SCell such as an SSB-less SCell with assisted information are proposed in this disclosure. According to this disclosure, a network device transmits, to a terminal device, an SCell activation command for activating a SCell. Here, the network device provides at least a PCell. The network device may further determine first configuration information for activating the SCell based on information of the PCell, and then transmits the first configuration information to the terminal device.

The network device may further transmit, to a further network device providing the SCell, second configuration information for transmitting at least one reference signal (RS) . Here the SCell is provided by the further network device. The second configuration information may be the same as the first configuration information. The second configuration information may comprise beam information of the PCell. Alternatively or additionally, the second configuration information may comprise a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell. The RS configuration may comprise the index of the RS (s) to be transmitted from the SCell, the number of RSs and/or the pattern of the RSs. At the further network device, the further network device obtains configuration information (for example, receives the second configuration information) for transmitting the at least one reference signal (RS) , and transmits, to the terminal device, the at least one RS based on the second configuration information.

At the terminal device, the terminal device receives, from the network device, the SCell activation command for activating the SCell, and obtains/determines (or receives) the first configuration information for activating the SCell. Then, the terminal device monitors the SCell based on the first configuration information. In this way, communication performance can be improved and reliability of SCell activation such as SSB-less SCell activation can be enhanced.

FIG. 1 illustrates an example communication system 100 in which some embodiments of the present disclosure can be implemented. The communication system 100, which is a part of a communication network, includes network devices 110-1 and 110-2 and a terminal device 120. In the following, the network device 110-1 may be referred to as “anetwork device” , and the network device 110-2 may be referred to as “afurther network device” . The network devices 110-1 and 110-2 may be collectively referred to as “network device 110” or individually referred to as “network device 110” .

As illustrated in FIG. 1, network device 110-1 provides a first carrier which has a coverage area of cell 101, and terminal device 120 camps on the cell 101 and is served by the first carrier from the network device 110-1. Network device 110-2 provides a second carrier which has a coverage area of cell 102, and terminal device 12 may also camp on the cell 102 and served by the second carrier from the network device 110-2. In other words, network device 110-1 provides network connection to terminal device 120, as indicated by the two-way arrow between the terminal device 120 and the network device 110-1 in FIG. 1. Meanwhile, the network device 110-2 may also provide network connection to terminal device 120, as indicated by the two-way arrow between the terminal device 120 and the network device 110-2 in FIG. 1. For example, carrier aggregation (CA) with the first carrier and the second carrier can be arranged to serve the terminal device 120. Here, as mentioned above, the first carrier is provided by the network device 110-1 and has a coverage area of cell 101, and the second carrier is provided by the network device 110-2 and has a coverage area of cell 102. Specifically, in such a CA scenario, the first carrier may be the primary component carrier (PCC) , and the second carrier may be the secondary component carrier (SCC) . In other words, the cell 101 may be the primary cell (PCell) and the cell 102 may be the secondary cell (SCell) .

As illustrated in FIG. 1, cell 101 (PCell) is provided by network device 110-1 and cell 102 (SCell) is provided by network device 110-2. It is to be noted that this is for illustrative purpose; in fact, cell 101 and cell 102 may be, instead of being provided by two different network devices 110-1 and 110-2, provided by a single network device.

In the system 100, a link from network device 110 to terminal device 120 is referred to as a downlink (DL) , while a link from terminal device 120 to network device 110 is referred to as an uplink (UL) . In downlink, network device 110 is a transmitting (TX) device (or a transmitter) and terminal device 120 is a receiving (RX) device (or a receiver) . In uplink, terminal device 120 is a transmitting TX device (or a transmitter) and network device 110 is a RX device (or a receiver) . It is to be understood that network device 110 may provide one or more serving cells. In some embodiments, network device 110 can provide multiple cells.

The communications in the communication system 100 may conform to any suitable standards including, but not limited to, Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) and Global System for Mobile Communications (GSM) and the like. Furthermore, the communications may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) , 5.5G, 5G-Advanced networks, or the sixth generation (6G) communication protocols.

It is to be understood that the numbers of devices (including terminal device 120 and network device 110) and their connection relationships and types shown in FIG. 1 are only for illustrative purposes without suggesting any limitation. The communication system 100 may include any suitable numbers of devices adapted for implementing embodiments of the present disclosure.

FIG. 2 illustrates a signaling chart illustrating an example communication process 200 in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the communication process 200 will be described with reference to FIG. 1. The communication process 200 may involve the terminal device 120 and the network device 110 as illustrated in FIG. 1.

In some example embodiments, as illustrated in FIG. 2, the network device 110-1 transmits (210) , to the terminal device 120, a SCell activation command 201 for activating a SCell (for example, cell 102 as illustrated in FIG. 1) . On the other side of communication, the terminal device 120 receives (212) the SCell activation command 201.

Then, at block 220, the network device 110-1 may determine first configuration information for activating the SCell based on information of the PCell (i.e., cell 101) . After that, the network device 110-1 may transmit (230) the first configuration 202 to the terminal device 120. On the other side of communication, the terminal device 120 may receive (232) the first configuration 202. It is to be noted that this step is optional. In one example, the first configuration 202 may comprise beam information of the SCell. Alternatively or additionally, the first configuration 202 may comprise a reference signal (RS) configuration for at least one RS to be transmitted from the SCell to the terminal device. Alternatively or additionally, the first configuration 202 may comprise an offset value to be applied by the terminal device 120 to the information of the PCell for activating the SCell. For example, the terminal device 120 may “add” the offset value to the timing of the PCell to obtain the timing for the SCell.

Then, at block 240, the terminal device 120 determines configuration information for activating the SCell based on the received first configuration 202. Alternatively, for instance if the network device 110-1 does transmit (230) the first configuration 202 to the terminal device 120, the terminal device 120 determines configuration information for activating the SCell based on the information of the PCell. The information of the PCell may comprise beam information of the PCell. Alternatively or additionally, the information of the PCell may comprise an active transmission configuration indicator (TCI) state (s) of the PCell. Alternatively or additionally, the information of the PCell may comprise measurement results of the PCell. Alternatively or additionally, the information of the PCell may comprise quasi-colocation (QCL) relation of the reference signals (RSs) between the PCell and the SCell. In one example, the information of the PCell may be transmitted from the network device 110-1 to the terminal device 120 via the SCell activation command 201. In another example, the information of the PCell may be transmitted from the network device 110-1 to the terminal device 120 via the first configuration 202 (for example, in a TCI activation command) . In another example, the information of the PCell may be determined by the terminal device 120 from current communication parameters and history communication parameters during communication with the network device 110-1 in the PCell (for example, cell 101 as illustrated in FIG. 1) .

After the configuration information for SCell activation is determined by the terminal device 120, at block 250, the terminal device monitors the SCell (i.e., 102) based on the determined configuration information.

Further, the network device 110-1 may transmit (260) , to a further network device, i.e., the network device 110-2, a second configuration 203 for transmitting at least one RS on the SCell. The second configuration information may be the same as the first configuration 202. The second configuration information may comprise beam information of the PCell. Alternatively or additionally, the second configuration information may comprise an RS configuration for at least one RS to be transmitted to the terminal device 120 from the SCell (i.e., cell 102) . The RS configuration may comprise the index of the RS (s) to be transmitted from the SCell, the number of RSs and/or the pattern of the RSs. It is to be noted that, in some example embodiments, this step may happen before or after the transmission of the first configuration 202 or the operation at block 240 and/or block 250, while in some other example embodiments, this step may happen simultaneously with the transmission of the first configuration 202 or the operation at block 240 and/or block 250.

On the other side of communication, the network device 110-2 may receive (262) the second configuration information 203, and then transmit (270) , to the terminal device 120, the at least one RS 204 based on the second configuration information 203. On the other side of communication, the terminal device 120 receives (272) the at least one RS 204.

In some example embodiments, the configuration information determined by the terminal device 120 at block 240 may comprise beam information of the SCell. Alternatively or additionally, the configuration information may comprise a reference signal (RS) configuration for at least one RS to be received from the SCell. Alternatively or additionally, the configuration information may comprise an offset value to be applied to the information of the PCell for activating the SCell.

In some example embodiments, the network device 110-1 may further transmit a TCI activation command for activating the SCell to the terminal device 120. The terminal device 120 may receive the TCI activation command from the network device 110-1, and determine the configuration information based on the received TCI activation command. In some example embodiments, the TCI activation command may be received together with the SCell activation command. Alternatively, the TCI activation command may be received after the SCell activation command.

In some example embodiments, in order to determine the configuration information, the terminal device 120 may, based on receiving the SCell activation command, determine at least one TCI state for monitoring the SCell based on the information of the PCell as the configuration information. In some example embodiments, in order to determine the TCI state for monitoring the SCell, the terminal device 120 may determine, based on determining that a TCI state is active in the PCell, that the TCI state as applicable to the SCell. Alternatively, the terminal device 120 may select, based on determining that a plurality of active TCI states are available in the PCell, a TCI state for activating the SCell from the plurality of active TCI states, as the TCI state for monitoring the SCell. In some example embodiments, the terminal device 120 may determine the TCI state further based on determining that a TCI activation command for the SCell is not received within a predetermined time period after receiving the SCell activation command.

In some example embodiments, in order to determine the configuration information, the terminal device 120 may receive, from the network device 110-1, a reference signal (RS) configuration for at least one RS to be received from the SCell, and determine the configuration information based on the received RS configuration. In some example embodiments, the RS configuration may comprise at least an index of at least one RS to be received from the SCell.

In some example embodiments, in order to determine the configuration information, the terminal device 120 may determine, based on receiving the SCell activation command, a reference signal (RS) configuration for at least one RS to be received from the SCell, and determine the configuration information based on the determined RS configuration.

In some example embodiments, in order to monitor the SCell, the terminal device 120 may use a receive beam pattern for the PCell, and apply a receive beam pattern for the PCell to activate the SCell.

In some example embodiments, after receiving the SCell activation command, the terminal device 120 may receive at least one reference signal (RS) from the SCell, and obtain or refine the time or frequency synchronization on the SCell based on the received at least one RS.

In some example embodiments, in order to determine the configuration information, in the event that an inter-band separation or receive timing difference between the PCell and the SCell is larger than a predetermined threshold, the terminal device 120 may apply an offset value to the information of the PCell as the configuration information. In some example embodiments, the terminal device 120 may apply the offset value to the information of the PCell based on adjusting the timing by offset value for receiving at least one reference signal (RS) from the SCell.

In some example embodiments, in the event that an inter-band separation or receive timing difference between the PCell and the SCell is larger than a predetermined threshold, the terminal device 120 may suspend or stop activation of the SCell.

In some example embodiments, the terminal device 120 may determine a delay for activating the SCell based on a timing for the network device 110-1 to transmit a TCI activation command for SCell to the terminal device 120. Alternatively or additionally, the terminal device 120 may determine the delay based on a fixed timing between receiving at least one of the SCell activation command or the TCI activation command and receiving at least one reference signal (RS) from the SCell. Alternatively or additionally, the terminal device 120 may determine the delay based on the time used to receive a number of RSs from the SCell.

In some example embodiments, an offset value is configured by the network device 110-1 to the terminal device 120 in an SCell configuration or an SCell addition message received prior to the SCell activation command.

In some example embodiments, the first configuration 202 may comprise beam information of the SCell. Alternatively or additionally, the first configuration 202 may comprise a reference signal (RS) configuration for at least one RS to be transmitted from the SCell to the terminal device. The RS configuration may comprise the index of the RS (s) to be transmitted from the SCell, the number of RSs and/or the pattern of the RSs. Alternatively or additionally, the first configuration 202 may comprise an offset value to be applied by the terminal device to the information of the PCell for activating the SCell.

In some example embodiments, in order to transmit the first configuration information, the network device 110-1 may transmit, to the terminal device 120, a TCI activation command for the SCell. In some example embodiments, the network device 110-1 may transmit the TCI activation command together with the SCell activation command. Alternatively, the network device 110-1 may transmit the TCI activation command after the SCell activation command.

In some example embodiments, in order to transmit the first configuration information, the network device 110-1 may transmit, to the terminal device 120, a reference signal (RS) configuration for at least one RS to be received by the terminal device 120 from the SCell. In some example embodiments, the RS configuration may comprise at least an index of at least one RS to be received from the SCell. The RS configuration may further comprise the number of RSs and/or the pattern of the RSs.

In some example embodiments, the network device 110-1 may transmit, to a further network device (for example, network device 110-2 as illustrated in FIG. 1 and FIG. 2) providing the SCell, second configuration information (second configuration 203 as illustrated in FIG. 2) for transmitting at least one reference signal (RS) . Here, the second configuration information may be the same as the first configuration. The second configuration information may comprise beam information of the SCell. Alternatively or additionally, the second configuration information may comprise a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell. Alternatively or additionally, the second configuration information may comprise the number of RS to be transmitted on SCell and/or the pattern of the RSs.

In some example embodiments, the network device 110-1 may further determine the offset value reflecting the time difference between the PCell and the SCell, and transmit the offset value to the terminal device 120.

In some example embodiments, in the event that an inter-band separation between the PCell and the SCell is larger than a predetermined threshold, the network device 110-1 may further deconfigure the carrier aggregation of the PCell and the SCell.

In some example embodiments, the information of the PCell may comprise beam information of the PCell. Alternatively or additionally, the information of the PCell may comprise an active transmission configuration indicator (TCI) state of the PCell. Alternatively or additionally, the information of the PCell may comprise measurement results of the PCell. Alternatively or additionally, the information of the PCell may comprise quasi-colocation (QCL) relation between the PCell and the SCell.

In some example embodiments, the at least one reference signal (RS) 204 may have quasi-colocation (QCL) relation to at least one RS in active TCI state of the PCell.

In some example embodiments, the at least one RS 204 may comprise an aperiodic tracking RS (A-TRS) . Alternatively or additionally, the at least one RS 204 may comprise a periodic tracking RS (P-TRS) . Alternatively or additionally, the at least one RS 204 may comprise a combination of an A-TRS and a P-TRS.

In some example embodiments, the number of the at least one RS 204 may be based on a channel quality of the PCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a timing difference between the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a received time difference (RTD) of the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be based on the frequency separation between the PCell and the SCell.

In some example embodiments, the terminal device 120 may use the at least one RS 204 to perform automatic gain control (AGC) for activating the SCell. Alternatively or additionally, the terminal device 120 may use the at least one RS 204 to perform time synchronization for activating the SCell. Alternatively or additionally, the terminal device 120 may use the at least one RS 204 to perform frequency synchronization for activating the SCell.

In some example embodiments, the SCell may be an SCell without synchronization signal and physical broadcast channel block (SSB) transmission.

FIG. 3 illustrates a schematic diagram illustrating an SSB-less SCell 300 in accordance with some example embodiments of the present disclosure. The SSB-less SCell 300 may be similar to cell 102 as illustrated in FIG. 1.

As illustrated in FIG. 3, for a PCell (for example, cell 101 as illustrated in FIG. 1) , SSB are transmitted from the serving network device (in this case, network device 110-1) to the terminal device 120 to obtain time/frequency synchronization. In contrast, there is no SSB transmission in SCell (for example, cell 102 as illustrated in FIG. 1) ; and that why such an SCell is referred to as “a SSB-less SCell) . Therefore, such an SSB-less SCell needs to be activated in an “no SSB” manner, in other words, the SSB-less SCell should be activated by the terminal device 120 without SSB being transmitted from the network device 110-2 (i.e., the serving network device for the SCell) , as mentioned above.

FIG. 4 illustrates a schematic diagram illustrating an example communication process 400 in accordance with some example embodiments of the present disclosure. The example communication process 400 illustrates SCell activation procedure for SSB-less SCell. The example communication process 400 may involve a network device (like the network device 110 as illustrated in FIG. 1) and a terminal device (like the terminal device 120 as illustrated in FIG. 1) . In the following, the example communication process 400 will be described as executed by the network device 110 and the terminal device 120 as illustrated in FIG. 1. For the purpose of discussion, the example communication process 400 will be described with reference to FIGS. 1-3.

In the example communication process 400 as illustrated in FIG. 4, terminal device (for example, the terminal device 120 as illustrated in FIG. 1) starts activating an SSB-less SCell (for example, cell 102 as illustrated in FIG. 1) blindly based on the PCell information (i.e., information of the PCell, i.e., cell 101) , and then uses additional assistance TRS transmitted on SCell to assist for example AGC and time/frequency synchronization for SSB-less SCell activation. As illustrated in FIG. 4, SSB is transmitted from the PCell to the terminal device; while no SSB is transmitted from the SCell to the terminal device.

For example, as illustrated in FIG. 4, at time point T1, the network device 110-1 transmits, to the terminal device 120, an SCell activation command (for example, the SCell activation command 201 as illustrated I FIG. 2) , and the terminal device 120 receives the SCell activation command from the network device 110-1. At time point T2, the terminal device 120 transmits, to the network device 110-1, a HARQ-ACK indicating that the SCell activation command is received successfully by the terminal device 12, and the network device 110-1 receives the HARQ-ACK. The time span from T1 to T2 is denoted as T_HARQ in FIG. 4.

In one aspect, if the terminal device 120 is not configured with an SSB measurement time configuration (SMTC) configuration on the SCell (which means the terminal device 120 does not have the ability to measure an SSB from the SCell) , and it supports SSB-less operation for inter-band CA (which means the terminal device 120 has the ability to activate an inter-band SCell without SSB transmission from the SCell) , the terminal device 120 may blindly use the PCell timing and, if needed, beam information to monitor (reception on) the SCell. In other words, the terminal device 120 may use the same timing (i.e., slot boundary) and the same beam configuration when receiving data from the PCell to monitor (reception on) the SCell.

In another example (especially for FR2, where at least one of the cell 101 or 102 operates on FR2) , the terminal device 120 may monitor the SCell using the same receive (Rx) beam pattern for receiving PCell (here, “receiving PCell” means “receiving data from the PCell” ) . In other words, the terminal device 120 is assumed to use a common beam management for activating the SCell, i.e., the terminal device 120 reuse the same receive beam pattern for obtaining time/frequency synchronization with the PCell (i.e., cell 101) by way of SSB transmission from the PCell to activate the SCell.

The processing time for the network device 110-1 to process the HARQ-ACK is about 3ms. In other words, after 3ms in response to receipt of the HARQ-ACK from the terminal device 120, the network device 110-1 is ready for subsequent operations, like transmission of a TCI activation command. However, it is uncertain to the terminal device 120 at which time point the TCI activation command may be transmitted from the network device 110-1.

At time point T4, the network device 110-1 transmits, to the terminal device 120, a TCI activation command based on the PCell information, and the terminal device 120 receives the TCI activation command. The time span from T3 to T4 is denoted as T_uncertainty in FIG. 4. T_uncertainty is the time period between reception of the last activation command for PDCCH TCI, PDSCH TCI (when applicable) relative to SCell activation command.

In one example, the network device 110-1 may determine and transmit a TCI activation command for the SCell based on the beam information of PCell e.g. the serving cell measurement per SSB index on the PCell. The TCI activation command may be sent together with the SCell activation command. Alternatively, the TCI activation command may be sent separately from the SCell activation command, which is the case as illustrated in FIG. 4. In response to receiving the TCI activation command, the terminal device 120 will monitor SCell on the indicated TCI.

In another example, the terminal device 120 may blindly monitor the SCell assuming the active TCI state in PCell (i.e., cell 101) is applicable to SCell (i.e., cell 102) at least if single TCI is in use in PCell, after receiving the SCell activation command. TCI activation command dedicated for SCell activation is not needed in this case. If multiple TCI states are available in PCell, the terminal device 120 may select one of them for activating the SSB-less SCell. The selected one TCI state may be the TCI state with best RSRP measured according to L1 rules (L1-RSRP) of the PCell. Alternatively or additionally, the selected one TCI state may be the TCI state with best channel state indication (CSI) report of the PCell.

In another aspect, the network device 110-2 may transmit some (one or more) TRSs or TRS bursts to assist the cell activation on the SCell based on the PCell information after the SCell activation command and/or TCI activation command are (is) sent. As the terminal device 120 is monitoring the SCell using the same PCell information, it is able to receive the TRS and acquire the time/frequency synchronization on SCell.

At time point T5, the terminal device 120 receives the first assistance TRS from the network device 110-2. The network device 110-2 may transmit the TRS periodically or aperiodically to the terminal device 120. In other words, the assistance TRS may be an aperiodic TRS (ATRS) , as shown in FIG. 4. Alternatively, the assistance TRS may be a periodic TRS (PTRS) , which is not shown in FIG. 4. Alternatively, the assistance TRS may be a combination of ATRS and PTRS. The time span from T4 to T5 is denoted as “T_1st-ATRS” in FIG. 4. T_1st-ATRS is the time to the end of the first complete ATRS/CSI-RS or ATRS/CSI-RS burst for SCell activation. In response to receiving the ATRS from the network device 110-2, the terminal device 120 measures the ATRS. The network device 110-2 continues to transmit the assistance TRS periodically or aperiodically to the terminal device 120 based on the RS configuration, and the terminal device 120 continues to measure the received TRS based on the RS configuration. After that, a SP-CSI-RS activation command may be received from the network device 110-1 for normal channel measurement.

The assistance TRS may be A-TRS or P-TRS, or a combination of the two, as mentioned above. The assistance TRS is used to compensate the absence of SSB, and facilitate the SCell activation on the SSB-less SCell.

The activation may be solely based on relatively infrequent P-TRS, but this may lead to somewhat long activation delay, so the activation can be expedited by a (set of) A-TRS transmission (s) . The SCell activation can also solely be based on the A-TRS, while the P-TRS is only used for maintaining the cell’s time/frequency synchronization.

A number of TRS transmissions may be needed for the terminal device 120 to complete auto gain control (AGC) and time/frequency synchronization in the SCell before it is ready to receive physical downlink control channel (PDCCH) /physical downlink share channel (PDSCH) transmission over that SCell. The number of TRS transmissions may be determined based on the channel quality of PCell i.e. a less number of TRS is needed in case of higher SNR, or based on the timing difference between the two cells (that is, the PCell and the SCell) , or the frequency/carrier separation between the PCell and the SCell. The timing difference may be estimated by the network device 110 (for example, the network device 110-1) or reported by the terminal device 120. The number of TRS transmissions needed may also depend on the receive time difference (RTD) of the PCell and the SCell being activated, as observed by the terminal device 120.

In the example as illustrated in FIG. 5, it is assumed that the number of TRS transmissions is “3” , which implies the terminal device 120 needs 3 TRS to gain time/frequency synchronization with the network device 110-2. At time point T6, the terminal device 120 receives the third (the last) TRS from the network device 110-2. The time span from T5 to T6 is denoted as T_ATRS, which means the time span from the time point T5 when the terminal device 120 receives the first TRS from the network device 110-2 to the time point T6 when the terminal device 120 receives the last TRS from the network device 110-2.

At time point T7, the network device 110-1 may transmit a SP-CSI-RS activation command to the network device 110-2. In response to receiving the SP-CSI-RS activation command, at time point T8, the network device 110-2 transmits an SP-CSI-RS to the terminal device 120. After receiving the SP-CSI-RS, at time point T9, the terminal device 120 measures the SP-CSI-RS and reports the measured CSI to the network device 110-1, and the network device 110-1 receives a valid CSI reporting. The time span from T6 to T9 is denoted as “T_CSIreporting” in FIG. 4. T_{CSI_reporting} is the delay (in ms) including uncertainty in acquiring the first available downlink CSI reference resource, UE processing time for CSI reporting and uncertainty in acquiring the first available CSI reporting resources.

In some example embodiments, if the CA inter-band separation is larger than a given threshold, the PCell information may not be directly used in SSB-less SCell, such that the time/frequency synchronization cannot be easily compensated even via TRS assistance. In this case, the network device 110 (for example, the network device 110-1 which provides the PCC for CA for the terminal device 120) may configure an offset value for the terminal device 120 to apply on top of PCell information, i.e. (PCell timing information + Offset value) , such that the terminal device 120 may further apply the compensation based on the A-TRS/P-TRS measurements transmitted on the SSB-less SCell. Here, the CA inter-band separation refers to the distance of the center frequency of the carrier provided by the PCell and the center frequency of the carrier provided by the SCell. As an example of the “give threshold” , it may be 3 OFDM symbols.

Specifically, for example, for timing to receive data from the SCell, the terminal device 120 may make use of the PCell timing (that is, the timing to receive data from the PCell) and an offset value configured by the network device 110-1 to obtain the SCell timing (that is, the timing for the terminal device 120 to receive data from the SCell) . In one example, the offset value may be a positive value, for example, 1 OFDM symbol. In this case, it means the SCell timing is “earlier” than the PCell timing by +1 OFDM symbol. In another example, the offset value may be a negative value, for example, -2 OFDM symbol. In this case, it means the SCell timing is “later” than the PCell timing by 2 OFDM symbol. In both cases, the SCell timing is obtained directly based on the PCell timing and the configured offset value, without the need for the network device 110-2 to transmit assistance TRS for the terminal device 120 to obtain time/frequency synchronization with the network device 110-2.

It is to be noted that, for assisting the network device 110 to setup this offset value, the terminal device 120 may be required to report, e.g. RTD value to the network device 110. Alternatively, some defined value in the specification for a given band combination based on simulation evaluations or field test may be used.

In some example embodiments, the above proposed solution may apply only if the receive time difference (RTD) is within a band separation threshold, e.g. 2 OFDM symbols. If the CA inter-band separation is quite large, the terminal device 120 may suspend the SCell activation and the network device 110 may deconfigure the inter-band CA. For example, the network device 110-1 may deconfigure the cell 102 (in other words, the network device 110-1 may “remove” the second carrier provided by the network device 110-2 from the operating carrier aggregation) .

In some example embodiments, the SCell activation delay for a SSB-less SCell is defined considering at least one of the time uncertainty to transmit TCI activation command for SCell, the timing to transmit the first TRS, or the number of TRS to be transmitted. The time uncertainty refers to the time span from end of HARQ-ACK processing to the reception of the TCI activation command as illustrated in FIG. 4. If the terminal device 120 blindly assumes the active TCI state of PCell for activating the SCell, the time uncertainty is zero. For the timing to transmit the first TRS, a fixed timing can be defined/ (pre-) configured between when the terminal device 120 receives the SCell/TCI activation command from the network device 110-1 and when the terminal device receives the first TRS from the network device 110-2.

Regarding the number of TRS to be transmitted, since TRS is applied for AGC and time/frequency synchronization adjustment, the number of TRS may be based on the channel quality of PCell. Alternatively or additionally, the number of TRS may be based on the RTD between the inter-band carriers (that is, the PCC serving cell 101 (the PCell) and the SCC serving cell 102 (the SCell) ) . Alternatively or additionally, the number of TRS may be based on the CA inter-band frequency or carrier separation. For example, it may be predefined that the number of TRS to be transmitted to the terminal device 120 is M when the RTD between the PCell and the SCell is equal to or less than N OFDM symbols, where M, N is an integer. For example, if the RTD between the PCell and the SCell is around 2 OFDM symbols (i.e., N ≈ 2) , then the network device 110-2 may determine that the number of TRS to be transmitted to the terminal device 120 is “2” (i.e., M = 2) , and then transmits 2 TRSs to the terminal device 120 accordingly.

It is to be noted that, although the 3GPP Release-18 (R-18) Network Energy Saving WI targets only FR1 inter-band collocated scenarios, the proposed solution in this disclosure can be applied to both FR1 and FR2, both co-located and non-colocated SSB-less SCell activation. The PCell provides the rough information to start the SCell activation, and the terminal device 120 uses the TRS on SCell for refined measurement so that the SSB-less SCell can be activated more reliably and communication performance can be improved.

FIG. 5 illustrates a signaling chart illustrating an example communication process 500 in accordance with some example embodiments of the present disclosure. For the purpose of discussion, the communication process 500 will be described with reference to FIGS. 1 and 2. The communication process 500 may involve a UE 510, a PCell 520 and a Cell1 530. The UE 510 is an example of the terminal device 120 as illustrated in FIG. 1, the PCell 520 is an example of cell 101 which is a PCell provided by the network device 110-1 as illustrated in FIG. 1, and Cell1 520 is an example of cell 102 which is a SCell provided by the network device 110-2 as illustrated in FIG. 1.

In the example as illustrated in FIG. 5, UE 510 is already connected with PCell 520 and Cell1 530 is to be added as SCell for inter-band CA operation. UE 510 is not configured with any SMTC configuration on Cell1 530 i.e. the Cell1 530 is assumed without SSB transmission. Specifically, PCell 520 transmits (540) , to UE 510, an SCell configuration /addition message. In other words, PCell 520 may transmit (540) an SCell configuration message to UE 510. Alternatively or additionally, PCell 520 may transmit (540) an SCell addition message to UE 510. On the other side of communication, UE 510 receives (542) the SCell configuration /addition message

Then, the PCell 520 transmits (545) a SCell activation command 501 for activating a the Cell1 530 as an SCell in CA with PCell 520. On the other side of communication, UE 510 receives (547) the SCell activation command 501.

When the PCell 520 transmits (545) the SCell activation command 501, it may transmit simultaneously a TCI activation command indicating the TCI state the UE 510 shall monitor in Cell1 530. This may be based on the layer-3 (L3) measurement reporting for PCell 520 or based on the active TCI state in the PCell 520. Alternatively, the PCell 520 may not explicitly transmit the TCI activation command. In such a case, UE 510 may assume reusing the same TCI state of PCell 520 for Cell1 530, and monitor the Cell1 530 accordingly. The TCI activation command, if to be transmitted by the PCell 520, shall be transmitted within a time period after the SCell activation command 501. Otherwise, UE 510 may determine the TCI state for monitoring Cell1 530 implicitly. For example, UE 510 may determine a TCI state as applicable to the Cell1 530 based on determining that the TCI state is active in the PCell 520. Alternatively, UE 510 may select a TCI state for activating the Cell1 530 from a plurality of active TCI states which are available in the PCell 520.

Then, at block 550, UE 510 evaluates whether PCell information (i.e., information of the PCell 520) can be fully reused, in other words, whether activation of Cell1 530 can be performed without assistance information (for example, TRS as illustrated in FIG. 4) . In one example, UE 510 may evaluate the side conditions of RTD, power difference etc., if available. Here, “side conditions” means conditions at the UE side, i.e., at UE 510 to determine if the SCell can be activated by completely reusing PCell information. If any of the conditions is not fulfilled, UE 510 understands it cannot completely reuse PCell information for Cell1 530; in other words, UE 510 needs additional TRS assistance from the Cell1 530 in order to activate Cell1 530. In another example, the evaluation of side condition at block 550 may be skipped. In such a case, UE 510 may always monitor for the TRS on the Cell1 530 to assist activation of the Cell1 530. In still another example, one or more “offset value” as mentioned above may be configured in the SCell configuration /addition message (for example, one or more “offset value” may be comprised in the SCell configuration /addition message transmitted (540) from the PCell 520 to the UE 510) , and the UE 510 may evaluate the side conditions (in other words, the UE 510 determines whether PCell information can be fully reused at block 550) , i.e. RTD, power different, etc., having “offset values” considered/included in the side conditions.

At block 555, the UE 510 determines that PCell information cannot be used. In other words, the SCell activation cannot be performed without assistance information, i.e., the information of the PCell 520 cannot be fully used for SCell activation of Cell1 530. Therefore, UE 510 waits for assistance information from Cell1 530.

Then, PCell 520 transmits (560) a TCI activation command 502 to the UE 510. In one example, the TCI activation command 502 may be determined based on the information of the PCell 520 (for example, serving cell (i.e., PCell) measurement (s) ) . In another example, the TCI activation command 502 may comprise the identifier (ID) of the SCell and/or the TCI states to indicate to the UE 510 which SCell should be activated. On the other side of communication, UE 510 receives (562) the TCI activation command 502. From then on, UE 510 monitors the Cell1 530.

PCell 520 transmits (565) TCI state (and/or TRS ID) 503 to Cell1 530. On the other side of communication, Cell1 530 receives (567) TCI state (and/or TRS ID) 503 from the PCell 520. It is to be noted that this step is optional and may be omitted when the PCell 520 and Cell1 530 are co-located, for example, when the network device providing PCell 520 and the network device providing Cell1 530 are positioned on a same panel, as in such a case transmission between the two network devices is “transparent” . However, if the two network devices are positioned on separate panels, they may not be able to be regarded as co-located (i.e., the PCell 520 and Cell1 530 cannot be regarded as co-located) , the RTD between the PCell 520 and the Cell1 530 as seen by the UE 510 may not be neglected. In such a case, this step is necessary as the UE 510 needs the TRS from the Cell1 530 to adjust its timing to receive data from the Cell1 530 based on the PCell timing (i.e., timing of the PCell 520) .

After receiving (567) the TCI state (and/or TRS ID) 503, for example, after some fixed timing from receipt of the TCI state (and/or TRS ID) 503 (the fixed timing can be predefined/preconfigured) , Cell1 530 transmits (570) TRS 504 to UE 510. On the other side of communication, UE 510 receives (572) the TRS 504 from Cell1 530. UE 510 then measures the TRS 504.

Cell1 530 may transmit a number of TRSs on the Cell1 530 on the same beams corresponding to the TCI state (s) in PCell 520. The transmission can start a time period following SCell activation command 501 or HARQ-ACK in response to SCell activation command 501. UE 510 detects the TRS on the Cell1 530 which can assist at least AGC and time/frequency synchronization for SCell activation.

In some example embodiments, if the number of TRSs is determined as two ( “2” ) , Cell1 530 further transmits (575) TRS 505 to UE 510. On the other side of communication, UE 510 receives (577) the TRS 505 from Cell1 530. UE 510 then measures the TRS 505. With these assistance TRSs, the UE acquires time/frequency synchronization to the SCell.

Further, Cell1 530 transmits (580) SP/P CSI-RS 506 to UE 510. In one example, the Cell1 530 may transmit (580) a semi-persistent (SP) channel state information reference signal (CSI-RS) 506 to UE 510. Alternatively, in another example, the Cell1 530 may transmit (580) a persistent (P) CSI-RS 506 to UE 510. Alternatively, in another example, the Cell1 530 may transmit (580) a combination of SP CSI-RS and persistent (P) CSI-RS to UE 510. On the other side of communication, UE 510 receives (582) the SP/P CSI-RS 506. UE 510 then measures the SP/P CSI-RS 506.

UE 510 transmits (585) a CSI report 507 for Cell1 530 to the PCell 520. On the other side of communication, PCell 520 receives (587) the CSI report 507.

FIG. 6 illustrates a flowchart of an example method 600 implemented at a terminal device 120 in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 120 with reference to FIGS. 1, 2 and 5.

At block 610, the terminal device 120 receives, from a network device (for example, network device 110-1 as illustrated in FIG. 1) , a SCell activation command (for example, SCell activation command 201 as illustrated in FIG. 2, or SCell activation command 501 as illustrated in FIG. 5) for activating a SCell (for example, cell 102 as illustrated in FIG. 1, or Cell1 530 as illustrated in FIG. 5) . Here, the network device 110-1 provides a primary cell (PCell, for example, cell 101 as illustrated in FIG. 1, or PCell 520 as illustrated in FIG. 5) of the terminal device 120, and the PCell and the SCell are inter-band cells. At block 620, the terminal device 120 determines configuration information for activating the SCell. At block 630, the terminal device 120 monitors the SCell based on the configuration information.

In some example embodiments, if the network device 110-1 does transmit for example the first configuration 202 as illustrated in FIG. 1 to the terminal device 120, the terminal device 120 may determines configuration information for activating the SCell based on the information of the PCell. In one example, the information of the PCell may be transmitted from the network device 110-1 to the terminal device 120 via the SCell activation command 201. In another example, the information of the PCell may be determined by the terminal device 120 from current communication parameters and history communication parameters during communication with the network device 110-1 in the PCell (for example, cell 101 as illustrated in FIG. 1) . The information of the PCell may comprise beam information of the PCell. Alternatively or additionally, the information of the PCell may comprise an active transmission configuration indicator (TCI) state (s) of the PCell. Alternatively or additionally, the information of the PCell may comprise measurement results of the PCell. Alternatively or additionally, the information of the PCell may comprise quasi-colocation (QCL) relation of the reference signals (RSs) between the PCell and the SCell.

In some example embodiments, the configuration information may comprise beam information of the SCell. Alternatively or additionally, the configuration information may comprise a reference signal (RS) configuration for at least one RS to be received from the SCell. Alternatively or additionally, the configuration information may comprise an offset value to be applied to the information of the PCell for activating the SCell.

In some example embodiments, the terminal device 120 may receive a TCI activation command (for example, the TCI activation command as illustrated in FIG. 4, or the TCI activation command 502 as illustrated in FIG. 5) from the network device 110-1, and determine the configuration information based on the received TCI activation command. In some example embodiments, the TCI activation command may be received together with the SCell activation command. Alternatively, the TCI activation command may be received after the SCell activation command.

In some example embodiments, after receiving the SCell activation command, the terminal device 120 may receive at least one reference signal (RS) from the SCell, and obtain time or frequency synchronization on the SCell based on the received at least one RS.

In some example embodiments, in order to determine the configuration information, in the event that an inter-band separation or receive timing difference (RTD) between the PCell and the SCell is larger than a predetermined threshold, the terminal device 120 may apply an offset value to the information of the PCell as the configuration information. In some example embodiments, the terminal device 120 may apply the offset value to the information of the PCell based on adjusting the timing for receiving at least one reference signal (RS) from the SCell. For example, the terminal device 120 may “add” the offset value to the timing of the PCell to obtain the timing for the SCell.

In some example embodiments, in the event that an inter-band separation or receive timing difference (RTD) between the PCell and the SCell is larger than a predetermined threshold, the terminal device 120 may suspend activation of the SCell. If such a condition continue for a predefined/preconfigured time period, the terminal device 120 may quit the activation of the SCell.

In some example embodiments, the terminal device 120 may determine a delay for activating the SCell based on a timing for the network device 110-1 to transmit a TCI activation command for SCell to the terminal device 120. Alternatively or additionally, the terminal device 120 may determine the delay based on a fixed timing between receiving at least one of the SCell activation command or the TCI activation command and receiving at least one reference signal (RS) from the SCell.

In some example embodiments, an offset value is configured by the network device 110-1 to the terminal device 120 in an SCell configuration message or an SCell addition message received prior to the SCell activation command.

In some example embodiments, the number of the at least one RS 204 may be based on a channel quality of the PCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a timing difference between the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a received time difference (RTD) of the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be configured, by the network device 110-1 providing the PCell, to the network device 110-2 providing the SCell.

In some example embodiments, the SCell may be an SCell without SSB transmission.

FIG. 7 illustrates another flowchart of an example method 700 implemented at a network device in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the network device 110-1 with reference to FIGS. 1, 2 and 5.

At block 710, the network device 110-1 transmits, to a terminal device (for example, the terminal device 120 as illustrated in FIG. 1) , a SCell activation command (for example, SCell activation command 201 as illustrated in FIG. 2, or SCell activation command 501 as illustrated in FIG. 5) for activating a SCell (for example, cell 102 as illustrated in FIG. 1, or Cell1 530 as illustrated in FIG. 5) . Here, the network device 110-1 provides a primary cell (PCell, for example, cell 101 as illustrated in the FIG. 1, or PCell 520 as illustrated in FIG. 5) of the terminal device 120, and the PCell and the SCell are inter-band cells. At block 720, the terminal device 110-1 determines first configuration information (for example, the first configuration 202 as illustrated in FIG. 2) for activating the SCell based on information of the PCell. At block 730, the network device 110-1 transmits the first configuration information to the terminal device 120.

In some example embodiments, the first configuration information may comprise beam information of the SCell. Alternatively or additionally, the first configuration information may comprise a reference signal (RS) configuration for at least one RS to be transmitted from the SCell to the terminal device. Alternatively or additionally, the first configuration information may comprise an offset value to be applied by the terminal device to the information of the PCell for activating the SCell.

In some example embodiments, in order to transmit the first configuration information, the network device 110-1 may transmit, to the terminal device 120, a reference signal (RS) configuration for at least one RS to be received by the terminal device 120 from the SCell. In some example embodiments, the RS configuration may comprise at least an index of at least one RS to be received from the SCell.

In some example embodiments, the network device 110-1 may transmit, to a further network device (for example, network device 110-2 as illustrated in FIG. 1 and FIG. 2) providing the SCell, second configuration information (second configuration 203 as illustrated in FIG. 2) for transmitting at least one reference signal (RS) . Here, the second configuration information may comprise beam information of the SCell. Alternatively or additionally, the second configuration information may comprise a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell. Alternatively or additionally, the second configuration information may comprise the number of RS to be transmitted on SCell.

In some example embodiments, the number of the at least one RS 204 may be based on a channel quality of the PCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a timing difference between the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a received time difference (RTD) of the PCell and the SCell.

In some example embodiments, the at least one RS 204 may be used by the terminal device 120 to perform automatic gain control (AGC) for activating the SCell. Alternatively or additionally, the at least one RS 204 may be used by the terminal device 120 to perform time synchronization for activating the SCell. Alternatively or additionally, the at least one RS 204 may be used by the terminal device 120 to perform frequency synchronization for activating the SCell.

FIG. 8 illustrates another flowchart of an example method 800 implemented at a network device in accordance with some other embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the network device 110-2 with reference to FIGS. 1, 2 and 5.

At block 810, the network device 110-2 obtains configuration information (for example, the second configuration 203 as illustrated in FIG. 2, or TCI state (and/or TRS ID) 503 as illustrated in FIG. 5) for transmitting at least one reference signal (RS) . Here, the network device 110-2 provides a secondary cell (SCell, for example, cell 102 as illustrated in FIG. 1, or Cell1 530 as illustrated in FIG. 5) to be activated by a terminal device (for example, terminal device 120 as illustrated in FIG. 1) , and a primary cell (PCell, for example, cell 101 as illustrated in FIG. 1, or PCell 520 as illustrated in FIG. 5) of the terminal device and the SCell are inter-band cells. At block 820, the network device 110-2 transmits, to the terminal device, the at least one RS based on the configuration information.

In some example embodiments, the configuration information may comprise beam information of the SCell. Alternatively or additionally, the configuration information may comprise a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell. Alternatively or additionally, the configuration information may comprise the number of RS to be transmitted on SCell.

In some example embodiments, the number of the at least one RS 204 may be based on a channel quality of the PCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a timing difference between the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a received time difference (RTD) of the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be configured in the configuration information (for example, the second configuration 203 as illustrated in FIG. 2) .

In some embodiments, an apparatus capable of performing the method 600 (for example, the terminal device 120) may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises: means for receiving, from a network device (for example, network device 110-1 as illustrated in FIG. 1) , a SCell activation command (for example, SCell activation command 201 as illustrated in FIG. 2 or SCell activation command 501 as illustrated in FIG. 5) for activating a SCell (for example, cell 102 as illustrated in FIG. 1, or Cell1 530 as illustrated in FIG. 5) , and the network device provides a primary cell (PCell, for example, cell 101 as illustrated in FIG. 1, or PCell 520 as illustrated in FIG. 5) of the terminal device, and the PCell and the SCell are inter-band cells; means for determining configuration information for activating the SCell; and means for monitoring the SCell based on the configuration information.

In some example embodiments, the means for determining configuration information may further comprise means for receiving a TCI activation command from the network device, and means for determining the configuration information based on the received TCI activation command. In some example embodiments, the TCI activation command may be received together with the SCell activation command. Alternatively, the TCI activation command may be received after the SCell activation command.

In some example embodiments, the means for determining configuration information may comprise means for based on receiving the SCell activation command, determining at least one TCI state for monitoring the SCell based on the information of the PCell as the configuration information. In some example embodiments, the means for determining at least one TCI state may comprise means for determining, based on determining that a TCI state is active in the PCell, that the TCI state as applicable to the SCell. Alternatively, the means for determining at least one TCI state may comprise means for based on determining that a plurality of active TCI states are available in the PCell, selecting a TCI state for activating the SCell from the plurality of active TCI states, as the TCI state for monitoring the SCell. In some example embodiments, the means for determining at least one TCI state may also comprise means for determining that a TCI activation command for the SCell is not received within a predetermined time period after receiving the SCell activation command.

In some example embodiments, the means for determining configuration information may comprise means for receiving, from the network device 110-1, a reference signal (RS) configuration for at least one RS to be received from the SCell, and means for determining the configuration information based on the received RS configuration. In some example embodiments, the RS configuration may comprise at least an index of at least one RS to be received from the SCell.

In some example embodiments, the means for determining configuration information may comprise means for determining, based on receiving the SCell activation command, a reference signal (RS) configuration for at least one RS to be received from the SCell, and means for determining the configuration information based on the determined RS configuration.

In some example embodiments, the means for monitoring may comprise means for using a receive beam pattern for the PCell, and means for applying a receive beam pattern for the PCell to activate the SCell.

In some example embodiments, the apparatus may comprise means for, after receiving the SCell activation command, receiving at least one reference signal (RS) from the SCell, and means for obtaining time or frequency synchronization on the SCell based on the received at least one RS.

In some example embodiments, in the event that an inter-band separation or receive timing difference between the PCell and the SCell is larger than a predetermined threshold, the means for determining configuration information may comprise means for applying an offset value to the information of the PCell as the configuration information. In some example embodiments, the means for applying an offset value may comprise means for adjusting the timing for receiving at least one reference signal (RS) from the SCell.

In some example embodiments, in the event that an inter-band separation or receive timing difference between the PCell and the SCell is larger than a predetermined threshold, the apparatus may comprise means for suspending activation of the SCell.

In some example embodiments, the apparatus may comprise means for determining a delay for activating the SCell based on a timing for the network device 110-1 to transmit a TCI activation command for SCell to the terminal device 120. Alternatively or additionally, the means for determining a delay may determine the delay based on a fixed timing between receiving at least one of the SCell activation command or the TCI activation command and receiving at least one reference signal (RS) from the SCell.

In some example embodiments, the apparatus may comprise means for performing automatic gain control (AGC) for activating the SCell by using the at least one RS 204. Alternatively or additionally, the apparatus may comprise means for performing time synchronization for activating the SCell by using the at least one RS 204. Alternatively or additionally, the apparatus may comprise means for performing frequency synchronization for activating the SCell by using the at least one RS 204.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing the method 700 (for example, the network device 110-1) may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises: means for transmitting, to a terminal device, a secondary cell (SCell) activation command (for example, the SCell activation command 201 as illustrated in FIG. 1, or the SCell activation command 501 as illustrated in FIG. 5) for activating a SCell (for example, cell 102 as illustrated in FIG. 1, or Cell1 530 as illustrated in FIG. 5) , wherein the network device provides a primary cell (PCell, for example, cell 101 as illustrated in FIG. 1, or PCell 520 as illustrated in FIG. 5) of the terminal device, and the PCell and the SCell are inter-band cells; means for determining first configuration information (for example, first configuration 202 as illustrated in FIG. 2, or TCI state (and/or TRS ID) 503 as illustrated in FIG. 5) . for activating the SCell based on information of the PCell; and means for transmitting the first configuration information to the terminal device.

In some example embodiments, the means for transmitting the first configuration information may comprise means for transmitting, to the terminal device 120, a TCI activation command for the SCell. In some example embodiments, the means for transmitting the TCI activation command may transmit the TCI activation command together with the SCell activation command. Alternatively, the means for transmitting the TCI activation command may transmit the TCI activation command after the SCell activation command.

In some example embodiments, the means for transmitting the first configuration information may comprise means for transmitting, to the terminal device 120, a reference signal (RS) configuration for at least one RS to be received by the terminal device 120 from the SCell. In some example embodiments, the RS configuration may comprise at least an index of at least one RS to be received from the SCell.

In some example embodiments, the apparatus may comprise means for transmitting, to a further network device (for example, network device 110-2 as illustrated in FIG. 1 and FIG. 2) providing the SCell, second configuration information (second configuration 203 as illustrated in FIG. 2) for transmitting at least one reference signal (RS) . Here, the second configuration information may comprise beam information of the SCell. Alternatively or additionally, the second configuration information may comprise a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell. For example, the RS configuration may comprise the index of the RS (s) to be transmitted from the SCell, the number of RSs and/or the pattern of the RSs. Alternatively or additionally, the second configuration information may comprise the number of RS to be transmitted on SCell.

In some example embodiments, the apparatus may comprise means for determining the offset value reflecting the time difference between the PCell and the SCell, and means for transmitting the offset value to the terminal device 120.

In some example embodiments, in the event that an inter-band separation between the PCell and the SCell is larger than a predetermined threshold, the apparatus may comprise means for deconfiguring the carrier aggregation of the PCell and the SCell.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing the method 800 (for example, the network device 110-2) may comprise means for performing the respective steps of the method 800. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises: means for obtaining configuration information (for example, second configuration 203 as illustrated in FIG. 2, or TCI state (and/or TRS ID) 503 as illustrated in FIG. 5) for transmitting at least one reference signal (RS) . Here, the network device provides a secondary cell (SCell, for example, cell 102 as illustrated in FIG. 1) to be activated by a terminal device (for example, terminal device 120) , and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and means for transmitting, to the terminal device, the at least one RS based on the configuration information.

In some example embodiments, the at least one reference signal (RS) 204 may have quasi-colocation (QCL) relation to at least one RS (for example, reference signal (RS) 204 as illustrated in FIG. 2) in active TCI state of the PCell.

In some example embodiments, the number of the at least one RS 204 may be based on a channel quality of the PCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a timing difference between the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be based on a received time difference (RTD) of the PCell and the SCell. Alternatively or additionally, the number of the at least one RS 204 may be configured to the network device 110-2 in the configuration information (for example, the second configuration 203 as illustrated in FIG. 2) .

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 800. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

FIG. 9 illustrates a simplified block diagram of a device 900 that is suitable for implementing some example embodiments of the present disclosure. The device 900 may be provided to implement a communication device, for example, the terminal device 120 or the network device 110 as shown in FIG. 1. As shown, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processor 910, and one or more communication modules 940 coupled to the processor 910.

The communication module 940 is for bidirectional communications. The communication module 940 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 910 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 900 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 920 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 924, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 922 and other volatile memories that will not last in the power-down duration.

A computer program 930 includes computer executable instructions that are executed by the associated processor 910. The program 1130 may be stored in the ROM 924. The processor 910 may perform any suitable actions and processing by loading the program 930 into the RAM 922.

The embodiments of the present disclosure may be implemented by means of the program 930 so that the device 900 may perform any process of the disclosure as discussed with reference to FIG. 2 and 4-6. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments, the program 930 may be tangibly contained in a computer-readable medium which may be included in the device 900 (such as in the memory 920) or other storage devices that are accessible by the device 900. The device 900 may load the program 930 from the computer-readable medium to the RAM 922 for execution. The computer-readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like.

FIG. 10 illustrates a block diagram of an example of a computer-readable medium 1000 in accordance with some example embodiments of the present disclosure. The computer-readable medium 1000 has the program 930 stored thereon. It is noted that although the computer-readable medium 1000 is depicted in form of CD or DVD in FIG. 10, the computer-readable medium 1000 may be in any other form suitable for carry or hold the program 930.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 600 or 700 or 800 as described above with reference to FIG. 6, 7 or 8. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer-readable medium, and the like.

The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer-readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) .

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Through this document, the terms defined below may be referenced.

TRS Tracking Reference Signal (CSI-RS for tracking)

A-TRS Aperiodic TRS

AGC Automatic Gain Control

CA Carrier Aggregation

CBM Common Beam Management

CP Cyclic Prefix

CSI Channel State Indication

CSI-RS CSI Reference Signal

RRM Radio Resource Management

eFeRRM even Further enhanced RRM

FR1 Frequency Range 1

FR2 Frequency Range 2

IBM Independent Beam Management

RSRP Reference Signal Received Power

L1-RSRP RSRP measured according to L1 rules

MRTD Maximum Receive Time Difference

P-TRS Periodic TRS

QCL Quasi-collocation

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

RF Radio Frequency

RRH Remote Radio Head

RTD Receive Time Difference

SMTC SSB Measurement Time Configuration

SS-RSRP RSRP based on SSB

SSB Synchronization Signal and PBCH block

TAE Time Alignment Error

TRP Transmission Point

UE User Equipment

Claims

A terminal device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:

receive, from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells;

determine configuration information for activating the SCell; and

monitor the SCell based on the configuration information.
The terminal device of claim 1, wherein the configuration information comprises at least one of the following:

beam information of the SCell;

a reference signal (RS) configuration for at least one RS to be received from the SCell; or

an offset value to be applied to the information of the PCell for activating the SCell.
The terminal device of any of claims 1 to 2, wherein the terminal device is caused to determine the configuration information by:

receiving, from the network device, a transmission configuration indicator (TCI) activation command for the SCell; and

determine the configuration information based on the received TCI activation command.
The terminal device of claim 3, wherein the TCI activation command is received together with or after the SCell activation command.
The terminal device of any of claims 1 to 2, wherein the terminal device is caused to determine the configuration information by:

based on receiving the SCell activation command, determining, as the configuration information, at least one TCI state for monitoring the SCell based on the information of the PCell.
The terminal device of claim 5, wherein the terminal device is caused to determine the TCI state for monitoring the SCell by:

based on determining that a TCI state is active in the PCell, determining the TCI state as applicable to the SCell, or

based on determining that a plurality of active TCI states are available in the PCell, selecting, from the plurality of active TCI states, a TCI state for activating the SCell.
The terminal device of claim 5 or 6, wherein the TCI state is determined further based on determining that a TCI activation command for the SCell is not received within a predetermined time period after receiving the SCell activation command.
The terminal device of any of claims 1 to 2, wherein the terminal device is caused to determine the configuration information by:

receiving, from the network device, a reference signal (RS) configuration for at least one RS to be received from the SCell, and

determine the configuration information based on the received RS configuration.
The terminal device of claim 8, wherein the RS configuration comprises at least an index of at least one RS to be received from the SCell.
The terminal device of any of claims 1 to 2, wherein the terminal device is caused to determine the configuration information by:

based on receiving the SCell activation command, determining a reference signal (RS) configuration for at least one RS to be received from the SCell; and

determine the configuration information based on the determined RS configuration.
The terminal device of any of claims 1 to 10, wherein the terminal device is caused to monitor the SCell by:

using a receive beam pattern for the PCell, and

applying a receive beam pattern for the PCell to activate the SCell.
The terminal device of any of claims 1 to 11, wherein the terminal device is further caused to:

after receiving the SCell activation command, receive at least one reference signal (RS) from the SCell; and

obtain time or frequency synchronization on the SCell based on the received at least one RS.
The terminal device of any of claims 1 to 2, wherein the terminal device is caused to determine the configuration information by:

in the event that an inter-band separation or receive timing difference between the PCell and the SCell is larger than a predetermined threshold, applying an offset value to the information of the PCell as the configuration information.
The terminal device of claim 13, wherein the applying the offset value to the information of the PCell is based on adjusting the timing for receiving at least one reference signal (RS) from the SCell.
The terminal device of any of claims 1 to 14, wherein the terminal device is further caused to:

in the event that an inter-band separation or receive timing difference between the PCell and the SCell is larger than a predetermined threshold, suspend activation of the SCell.
The terminal device of any of claims 1 to 15, wherein a delay for activating the SCell is determined based on at least one of the following:

a timing for the network device to transmit a transmission configuration indicator (TCI) activation command for SCell to the terminal device; or

a fixed timing between receiving at least one of the SCell activation command or the TCI activation command and receiving at least one reference signal (RS) from the SCell.
The terminal device of any of claims 1 to 16, wherein an offset value is configured in an SCell configuration message or an SCell addition message received prior to the SCell activation command.
A network device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:

transmit, to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells;

determine first configuration information for activating the SCell based on information of the PCell; and

transmit the first configuration information to the terminal device.
The network device of claim 18, wherein the first configuration information comprises at least one of the following:

beam information of the SCell;

a reference signal (RS) configuration for at least one RS to be transmitted from the SCell to the terminal device; or

an offset value to be applied by the terminal device to the information of the PCell for activating the SCell.
The network device of any of claims 18 to 19, wherein the network device is caused to transmit the first configuration information by:

transmitting, to the terminal device, a transmission configuration indicator (TCI) activation command for the SCell.
The network device of claim 20, wherein the TCI activation command is transmitted together with or after the SCell activation command.
The network device of any of claims 18 to 21, wherein the network device is caused to transmit the first configuration information by:

transmitting, to the terminal device, a reference signal (RS) configuration for at least one RS to be received by the terminal device from the SCell.
The network device of claim 22, wherein the RS configuration comprises at least an index of at least one RS to be received from the SCell.
The network device of any of claims 18 to 23, wherein the network device is further caused to:

transmit, to a further network device providing the SCell, second configuration information for transmitting at least one reference signal (RS) ,

wherein the second configuration information comprises at least one of the following:

beam information of the SCell;

a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell; or

the number of RS to be transmitted on SCell.
The network device of claim 19, wherein the network device is further caused to:

determine the offset value reflecting the time difference between the PCell and the SCell, and

transmit the offset value to the terminal device.
The network device of any of claims 18 to 25, wherein the network device is further caused to:

in the event that an inter-band separation between the PCell and the SCell is larger than a predetermined threshold, deconfigure the carrier aggregation of the PCell and the SCell.
The terminal device of any of claims 1 to 17, or the network device of any of claims 18 to 26, wherein the information of the PCell comprises at least one of the following:

beam information of the PCell,

an active transmission configuration indicator (TCI) state of the PCell;

measurement results of the PCell; or

quasi-colocation (QCL) relation between the PCell and the SCell.
A network device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:

obtain configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and

transmit, to the terminal device, the at least one RS based on the configuration information.
The network device of claim 28, wherein the configuration information comprises at least one of the following:

beam information of the SCell;

a reference signal (RS) configuration for at least one RS to be transmitted to the terminal device from the SCell; or

the number of RS to be transmitted on SCell.
The terminal device of any of claims 1 to 17, or the network device of any of claims 18 to 30, wherein the at least one reference signal (RS) has quasi-colocation (QCL) relation to at least one RS in active transmission configuration indicator (TCI) state of the PCell.
The terminal device of any of claims 1 to 17, or the network device of any of claims 18 to 30, wherein the at least one RS comprises at least one of the following:

an aperiodic tracking RS (A-TRS) ;

a periodic tracking RS (P-TRS) ; or

a combination of an A-TRS and a P-TRS.
The terminal device of any of claims 1 to 17, or the network device of any of claims 18 to 31, wherein the number of the at least one RS is based on at least one of the following:

a channel quality of the PCell;

a timing difference between the PCell and the SCell; or

a received time difference (RTD) of the PCell and the SCell.
The terminal device of any of claims 1 to 17, or the network device of any of claims 18 to 32, wherein the at least one RS is used by the terminal device to perform at least one of the following:

automatic gain control (AGC) for activating the SCell;

time synchronization for activating the SCell; or

frequency synchronization for activating the SCell.
The terminal device of any of claims 1 to 17, or the network device of any of claims 18 to 33, wherein the SCell is an SCell without synchronization signal and physical broadcast channel block (SSB) transmission.
A method comprising:

receiving, at a terminal device and from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells;

determining configuration information for activating the SCell; and

monitoring the SCell based on the configuration information.
A method comprising:

transmitting, at a network device and to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells;

determining first configuration information for activating the SCell based on information of the PCell; and

transmitting the first configuration information to the terminal device.
A method comprising:

obtaining, at a network device, configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and

transmitting, to the terminal device, the at least one RS based on the configuration information.
An apparatus comprising:

means for receiving, from a network device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells;

means for determining configuration information for activating the SCell; and

means for monitoring the SCell based on the configuration information.
An apparatus comprising:

means for transmitting, to a terminal device, a secondary cell (SCell) activation command for activating a SCell, wherein the network device provides a primary cell (PCell) of the terminal device, and the PCell and the SCell are inter-band cells;

means for determining first configuration information for activating the SCell based on information of the PCell; and

means for transmitting the first configuration information to the terminal device.
An apparatus comprising:

means for obtaining configuration information for transmitting at least one reference signal (RS) , wherein the network device provides a secondary cell (SCell) to be activated by a terminal device, and a primary cell (PCell) of the terminal device and the SCell are inter-band cells; and

means for transmitting, to the terminal device, the at least one RS based on the configuration information.
A non-transitory computer readable medium comprising program instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method of any of claims 35 to 37.