WO2025091443A1

WO2025091443A1 - Sounding reference signal resource release

Info

Publication number: WO2025091443A1
Application number: PCT/CN2023/129504
Authority: WO
Inventors: Yan Meng; Tao Tao; Jianguo Liu; Hyun-Su Cha; Sean Kelley; Gilsoo LEE
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: 2023-11-03
Filing date: 2023-11-03
Publication date: 2025-05-08
Anticipated expiration: 2026-05-03
Also published as: CN119946855A

Abstract

Embodiments of the present disclosure relate to sounding reference signal (SRS) resource release. In one aspect, a first network device transmits information to a location management function (LMF), and the information is used for one or more network devices other than the first network device to release at least one SRS resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires. Cells of the first network device and the one or more network devices are in the SRS validity area. In this way, the first network device may indicate the information to other network devices of which cells in the SRS validity area to assist the SRS resource release. Therefore, the resource efficiency is improved.

Description

SOUNDING REFERENCE SIGNAL RESOURCE RELEASE

FIELD

Various example embodiments relate to the field of communication and in particular, to devices, methods, apparatuses and a computer readable storage medium for sounding reference signal (SRS) resource release.

BACKGROUND

With the development of communication technology, low power high accuracy positioning (LPHAP) has been introduced for further enhancement of 3GPP RAN1 new radio (NR) positioning. The enhancements for enabling LPHAP have been defined, e.g., extending extended discontinuous reception (eDRX) cycle beyond 10.24s in RRC_INACTIVE state towards meeting the battery life requirement for LPHAP. The enhancements further include: for uplink (UL) positioning or downlink (DL) and UL positioning for UEs in RRC_INACTIVE state, specifying SRS configuration enhancements based on SRS positioning validity area to avoid frequent radio resource control (RRC) connection for SRS configuration or reconfiguration. However, SRS resource configurations in a communication network can still be optimized and improved, particularly for the LPHAP.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for SRS resource release.

In a first aspect, there is provided a first network device. The first 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 first network device at least to: transmit information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In a second aspect, there is provided a location management function (LMF) . The LMF comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first network device at least to: receive information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and transmit the information to the one or more network devices .

In a third aspect, there is provided a second network device. The second 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 second network device at least to: receive information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and release the at least one SRS resource based on the information.

In a fourth 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 first network device at least to: transmit, to a first network device, a request for an extension of a time alignment timer (TAT) ; and receive, from the first network device, information indicating a time period for which the TAT is extended.

In a fifth aspect, there is provided a method at a first network device. The method comprises transmitting information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In a sixth aspect, there is provided a method at a location management function (LMF) . The method comprises receiving information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and transmitting the information to the one or more network devices.

In a seventh aspect, there is provided a method at a second network device. The method comprises receiving information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and releasing the at least one SRS resource based on the information.

In an eighth aspect, there is provided a method at a terminal device. The method comprises transmitting, to a first network device, a request for an extension of a time alignment timer (TAT) ; and receiving, from the first network device, information indicating a time period for which the TAT is extended.

In a ninth aspect, there is provided an apparatus of first network device. The apparatus comprises means for transmitting information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In a tenth aspect, there is provided an apparatus of location management function (LMF) . The apparatus comprises means for receiving information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and means for transmitting the information to the one or more network devices .

In an eleventh aspect, there is provided an apparatus of second network device. The apparatus comprises means for receiving information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and means for releasing the at least one SRS resource based on the information.

In a twelfth aspect, there is provided an apparatus of terminal device. The apparatus comprises means for transmitting, to a first network device, a request for an extension of a time alignment timer (TAT) ; and means for receiving, from the first network device, information indicating a time period for which the TAT is extended.

In a thirteenth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above fifth to eighth aspect.

In a fourteenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: transmit information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In a fifteenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: receive information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and transmit the information to the one or more network devices .

In a sixteenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: receive information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and release the at least one SRS resource based on the information.

In a seventeenth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: transmit, to a first network device, a request for an extension of a time alignment timer (TAT) ; and receive, from the first network device, information indicating a time period for which the TAT is extended.

In an eighteenth aspect, there is provided a first network device. The first network device comprises transmitting circuitry configured to transmit information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In a nineteenth aspect, there is provided a location management function. The location management function comprises receiving circuitry configured to receive information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and transmitting circuitry configured to transmit the information to the one or more network devices.

In a twentieth aspect, there is provided a second network device. The second network device comprises receiving circuitry configured to receive information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and releasing circuitry configured to release the at least one SRS resource based on the information.

In a twenty-first aspect, there is provided a terminal device. The terminal device comprises transmitting circuitry configured to transmit, to a first network device, a request for an extension of a time alignment timer (TAT) ; and receiving circuitry configured to receive, from the first network device, information indicating a time period for which the TAT is extended.

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 network environment in which example embodiments of the present disclosure may be implemented;

Fig. 2 illustrates an example signaling chart illustrating an example process according to some embodiments of the present disclosure;

Fig. 3 illustrates an example procedure of proposed solution according to some embodiments of the present disclosure;

Fig. 4 illustrates another example procedure of proposed solution according to some embodiments of the present disclosure;

Fig. 5 illustrates a flowchart of a method implemented at a first network device according to some other embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of a method implemented at a LMF according to some other embodiments of the present disclosure;

Fig. 7 illustrates a flowchart of a method implemented at a second network device according to some embodiments of the present disclosure;

Fig. 8 illustrates a flowchart of a method implemented at a terminal device according to some other embodiments of the present disclosure;

Fig. 9 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

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

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

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 only 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 only 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 only 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 (e.g., 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) 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 first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) 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 relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

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) , 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 head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., 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 “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

With the development of communication technology, LPHAP has been introduced for further enhancement of 3GPP RAN1 NR positioning. The enhancements for enabling LPHAP have been defined, e.g., eDRX cycle beyond 10.24s in RRC_INACTIVE state towards meeting the battery life requirement for LPHAP. The enhancements further include: for uplink (UL) positioning or downlink (DL) and UL positioning for UEs in RRC_INACTIVE state, specifying SRS configuration enhancements based on SRS positioning validity area to avoid frequent radio resource control (RRC) connection for SRS configuration or reconfiguration. SRS for positioning configurations in multiple cells, pre-configuration of one or multiple SRS for positioning configurations and SRS for positioning activation/request procedure (s) may be specified. In addition, solutions for DL positioning reference signal (PRS) measurements for a UE in RRC_IDLE state and reporting of the measurements in RRC_CONNECTED state, solutions for alignment between eDRX and PRS configurations, corresponding new core requirements, as well as identifying and specifying the impact on the RAN4 specification (including RRM measurements and procedures) are specified.

In RAN2#121-bis meeting, it was agreed on how to release the SRS needs to be further discussed.

In RAN2#122 meeting, the inactivePosSRS-ValidityArea-TAT was introduced.

It still not clear how to release the SRS configuration at the cells in the validity area when the area-specific time alignment timer (TA timer, TAT) expires. When the area-specific TAT expires, both the UE and serving cell would release the SRS configuration since they both know the information of TAT. However, the other cells in the validity area would not know when the area-specific TAT expires, and then these cells would keep the SRS configuration, which will result to the resource waste.

According to some embodiments of the present disclosure, a solution is provided for SRS resource release. In one aspect of this solution, a first network device transmits information to a location management function (LMF) , and the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires. Cells of the first network device and the one or more network devices are in the SRS validity area. In this way, the first network device may indicate the information to other network devices of which cells in the SRS validity area to assist the SRS resource release. Therefore, the resource efficiency is improved by avoiding unnecessary resource reservation at all the cells in the SRS validity area. Principles and implementations of embodiments of the present disclosure will be described in detail below with reference to Figs. 1-10.

Fig. 1 illustrates an example network environment 100 in which example embodiments of the present disclosure may be implemented. The environment 100, which may be a part of a communication network, comprises terminal devices, network devices. As illustrated in Fig. 1, the network environment 100 may comprise a terminal device 110 (hereinafter may also be referred to as a UE 110) , a first network device 120, a LMF 130 and a second network device 140. The first network device 120 can manage a cell 102, and the second network device 140 can manage a cell 104. The first network device 120 and the terminal device 110 can communicate with each other in the coverage of the cell 102. The first network device 120 can communicate with the second network device 140 via the LMF 130. The first network device 120 and the second network device may be in a validity area of a configuration of the SRS resource. A link from the terminal device 110 to the first network device 120 is referred to as an uplink (UL) , while a link from the first network device 120 to the terminal device 110 is referred to as a downlink (DL) .

It is to be understood that the number of terminal device or network device is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of devices adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices or second network devices may be located in the environment 100.

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: code division multiple access (CDMA) , frequency division multiple access (FDMA) , time division multiple access (TDMA) , frequency division duplex (FDD) , time division duplex (TDD) , multiple-input multiple-output (MIMO) , orthogonal frequency division multiple (OFDM) , discrete Fourier transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

Fig. 2 illustrates a signaling chart illustrating an example process 200 according to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1. The process 200 may involve the terminal device 110, the first network device 120, the LMF 130 and the second network device 140. It would be appreciated that although the process 200 has been described in the communication environment 100 of Fig. 1, this process may be likewise applied to other communication scenarios with similar issues.

In the process 200, the first network device 120 transmits 205 information 210 to the LMF 130. The information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of the terminal device 110 in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires. It is to be understood that the TAT is an area-specific TAT of the SRS validity area. Cells of the first network device 120 and the one or more network devices are in the SRS validity area. The terminal device 110 may be in inactive state, and the first network device 120 configured the SRS resource for the terminal device 110 before the terminal device 110 enters inactive state. For example, when an area-specific TAT expires, the last serving cell (i.e., the serving cell managed by the first network device 120) will trigger all the cells in the validity area (i.e., the cells managed by the one or more network devices) to release the SRS resource.

In some embodiments, the information 210 may comprise a first indication to release the at least one SRS resource, and the first indication is transmitted in the event that the TAT expires. In other words, the first network device 120 may transmit network explicitly indication. For instance, when the area-specific TAT expires, the last serving gNB (corresponding to the first network device 120) will indicate all the cells in the validity area to release the SRS resource.

Additionally or alternatively, if an expired TAT restarts, the first network device 120 may transmit a third indication to the LMF 130 to reserve the at least one SRS resource. For example, when an expired TAT restarts, the last serving gNB will indicate the cells in the validity area to reserve previously released SRS resource again. Additionally, the first network device 120 may reuse at least one released SRS resource valid for multiple cells of the terminal device after the expired TAT restarts. In addition, the terminal device 110 may reuse at least one released SRS resource valid for multiple cells of the terminal device 110 after an expired TAT restarts.

Additionally, the LMF 130 may receive the third indication from the first network device in the event that an expired TAT restarts, then the LMF 130 may transmit the third indication to the one or more network devices. In addition, the second network device 140 may receive a third indication from the LMF to reserve the at least one SRS resource in the event that the expired TAT restarts, then second network device 140 may reserve the at least one SRS resource based on the third indication.

In an example, when the expired TAT restarts, the previously released SRS resource configuration is back to “on. ” The terminal device 110 may use the previously released SRS resource again when the expired TAT is reset or restarted. Thus, the last serving cell will trigger all the cells in the validity area to reserve previously released SRS resource again.

In some embodiments, the information 210 may comprise information of the TAT, a second indication that the terminal device 110 moves out of the SRS validity area, or any combination of two of the above-mentioned items. Additionally or alternatively, the information of the TAT may include: a time point when the TAT starts, a time point when the TAT restarts, an extension of the TAT, a time point when the TAT expires, or any combination of two or more of the above-mentioned items.

On the other side of the communication, the LMF 130 receives 215 the information 210 from the first network device 120. The LMF 130 transmits 220 information 210 to the second network device 140.

Continuing with reference to Fig. 2, the second network device 140 receives 230 information 210 from the LMF 130. Based on the information, the second network device 140 release 265 the at least one SRS resource.

In an example, the TAT can be synchronized at each cell in the validity area, and the cells in the validity area may autonomously release SRS resource. When the TAT started or restarted, the serving cell (corresponding to the first network device 120) may indicate the cells in the validity area to start or restart the TAT. The validity time value of the TAT nay also be indicated to the cells in the validity area when the SRS resource is configured. Thus, the cells in the validity area can know when the TAT expires. The cells in the validity area may autonomously release the SRS resource when the TAT expires.

In some embodiments, the second network device 140 may release the at least one SRS resource upon receiving the first indication. In some other embodiments, the second network device 140 may release the at least one SRS resource upon expiration of the TAT. In some other embodiments, the second network device 140 may release the at least one SRS resource based on determining that the terminal device moves out of the SRS validity area.

Additionally or alternatively, if the information of the TAT includes a time point when the TAT restarts, the second network device 140 may reserve the at least one SRS resource. Additionally, if the information of the TAT includes the extension of the TAT, the second network device 140 may extend a time period for the at least one SRS resource.

Continuing with reference to Fig. 2, the terminal device 110 transmit 235 a request for an extension of a TAT 240 to the first network device 120. After receiving 245 the request for an extension of a TAT 240, the first network device 120 transmits 250 information indicating a time period for which the TAT is extended to the terminal device 110. Correspondingly, the terminal device 110 receives 260 the information indicating the time period 255 from the first network device 120.

In some embodiments, before the TAT expires, the first network device 120 may receive at least one request for an extension of the TAT from at least one terminal device or the LMF 130. For example, the terminal device is allowed to send a request of TAT extension before the area-specific TAT expires.

Additionally or alternatively, if a number of the at least one terminal device is above a threshold, the first network device 120 may determine to extend the TAT for a time period. Then the first network device 120 may extend validity time of the TAT based on the time period.

In an example, a single report is sufficient for an extension. The report may comprise a request for an extension of the TAT. Upon sending a request, the terminal device shall reset the area-specific TAT for an extension. In addition, the first network device 120 will automatically grant an extension of validity area configuration for the reporting terminal device. The decision of the serving cell will be indicated to neighboring cells (i.e., all the cells in the validity area other than the serving cell) .

In another example, multiple reports are required for an extension. If a number of terminal devices send TAT extension requests (e.g., the number of requests is larger than a threshold) before the area-specific timer expires, the triggering of SRS configuration release is delayed by a certain time period.

In addition, upon expiration of the TAT, the first network device 120 may receive a request for an extension of the TAT from at least one of the LMF 130 or the at least one terminal device. In some embodiments, upon expiration of the TAT, the LMF 130 may transmit a request for an extension of the TAT to the first network device.

For instance, the time synchronization could be still valid when the TAT expires. For example, according to the TA validation criterion based on reference signal receiving power (RSRP) , it could be still valid. In order to avoid unnecessary resource re-configuration, the terminal device may send a request of “TAT extension. ” Alternatively, the LMF 130 may send a request of “TAT extension” to the first network device 120.

In some embodiments, the terminal device 110 may determine a time period for which the TAT is extended. In addition, the terminal device 110 may transmit information indicating a time period for which the TAT is extended to the first network device 120. Additionally, the terminal device 110 may extend validity time of the TAT based on the time period.

Additionally or alternatively, the first network device 120 may receive information indicating a time period for which the TAT is extended from the at least one terminal device. Then the first network device 120 may extend validity time of the TAT based on the time period.

Additionally or alternatively, the first network device 120 may transmit information indicating the time period to the at least one terminal device. In some embodiments, the first network device 120 may transmit a fourth indication that the TAT is extended to the LMF 130. In other words, the time period may be determined by at least one terminal device or the first network device 120. The first network device 120 may indicate the time period to the at least one terminal device and the one or more network devices for autonomous extension of the area-specific TAT.

In addition, the LMF 130 may receive a fourth indication that the TAT is extended from the first network device 120. Then the LMF 130 may transmit the fourth indication to the one or more network devices. Additionally, the fourth indication may comprise information indicating the time period.

In some embodiments, the second network device 140 may receive information indicating a time period for which the TAT is extended from the LMF 130. Then the second network device 140 may extend validity time of the TAT based on the time period, and run the TAT based on the validity time. In an example, the time period may be proportional to a number of the at least one request. In another example, the time period may be an integer multiple of a duration of the TAT. For instance, the second network device 140 may run the TAT upon receiving the time period from the LMF 130.

For example, a triggering delay period can be proportional to the number of requests. Alternatively, the delay period can be given by an integer time of the area-specific TAT period. The first network device 120 may indicate the integer value to the terminal device and the one or more network devices for autonomous extension of the area-specific TAT.

In some embodiments, if the TAT expires, the first network device 120 may release the at least one SRS resource. Additionally or alternatively, if the terminal device 110 moves out of the SRS validity area, the first network device 120 may release the at least one SRS resource.

In some embodiments, if the TAT expires, the first network device 120 may release a configuration of the at least one SRS resource configured for the SRS validity area. Additionally or alternatively, if the terminal device 110 moves out of the SRS validity area, the first network device 120 may release the configuration of the at least one SRS resource configured for the SRS validity area. It is to be understood that the configuration of the at least one SRS resource may be the area-specific SRS configuration.

In some embodiments, if the TAT expires, the second network device 140 may release a configuration of the at least one SRS resource configured for the SRS validity area. Additionally or alternatively, if the terminal device 110 moves out of the SRS validity area, the second network device 140 may release the configuration of the at least one SRS resource configured for the SRS validity area.

In some embodiments, if the TAT expires, the terminal device 110 may release the at least one SRS resource. Additionally or alternatively, if the terminal device 110 moves out of the SRS validity area, the terminal device 110 may release the at least one SRS resource.

In some embodiments, if the TAT expires, the terminal device 110 may release a configuration of the at least one SRS resource configured for the SRS validity area. Additionally or alternatively, if the terminal device 110 moves out of the SRS validity area, the terminal device 110 may release the configuration of the at least one SRS resource configured for the SRS validity area.

In general, all the cells in the validity area are triggered to release the SRS resource when the area-specific TAT expires. The (last) serving cell may indicate the TAT information (i.e., TAT expiration, the TAT is started/restarted and the validity time of the TAT) to other cells in the validity area to assist the SRS resource release. In this way, the SRS resource release and indication has associated with TAT, and the SRS resource release is efficiently triggered at the cells in the validity area when the TAT expires. This is helpful to improve the resource efficiency by avoiding unnecessary resource reservation at all the cells in the validity area. Thereby, the waste of resource is reduced.

Fig. 3 illustrates an example procedure of proposed solution according to some embodiments of the present disclosure. The procedure 300 may involve a UE 301, a last serving cell 302, a LMF 303, and cells in the validity area 304. It is understood that the process 300 can be considered as a more specific example of the process 200 in Fig. 2. Thus, the UE 301 in Fig. 3 may be an example of the terminal device 110 in Fig. 1 or Fig. 2, the last serving cell 302 in Fig. 3 may correspond to the first network device 120 in Fig. 1 or Fig. 2, the LMF 303 in Fig. 3 may be an example of the LMF 130 in Fig. 1 or Fig. 2, and the cells in the validity area 304 in Fig. 3 may correspond to the second network device 140 in Fig. 1 or Fig. 2.

As shown in Fig. 3, at 310, the UE 301 receive a TA command from the last serving cell 302, then the TAT starts. Prior to receiving the TA command, the UE 301 may transmit a request for starting the TAT. The last serving cell refers to the cell managed by the base station that sets the SRS resource configuration for the UE 301 before UE 301 enters inactive state.

At 315, before the TAT expiration, the UE 301 requests TAT extension from the last serving cell 302. At 320, the last serving cell 302 provides extension time to the UE 301, and the TAT is extended.

At 325, the expiration of the TAT triggers the SRS resource release. At 330, the last serving cell 302 is triggered to release the SRS resource. At 335, the last serving cell 302 transmits a SRS resource release indication to the LMF 303. At 340, the LMF 303 transmits the SRS resource release indication to the cells in the validity area 304. The validity area refers to the validity area of the SRS, and the last serving cell 302 and the cells in the validity area 304 in a same validity area of the SRS. At 345, the cells in the validity area 304 releases the SRS resource.

At 350, the UE 301 receive a TA command from the last serving cell 302, then the expired TAT restarts. The UE 301 reuses previously released SRS resource. Prior to receiving the TA command, the UE 301 may transmit a request for restarting the TAT via random access channel (RACH) . At 355, the last serving cell 302 transmits a SRS resource reservation indication to the LMF 303. At 360, the LMF 303 transmits the SRS resource reservation indication to the cells in the validity area 304. At 365, the cells in the validity area 304 reserves the previously SRS resource.

Fig. 3 shows an example of SRS resource release and reservation by network explicit indication. In procedure 300, the cells in the validity area have no information about the TAT. The SRS resource release and reservation at cells in the validity area could be indicated by the last serving cell via LMF.

Fig. 4 illustrates another example procedure of proposed solution according to some embodiments of the present disclosure. The procedure 400 may involve a UE 401, a last serving cell 402, a LMF 403, and cells in the validity area 404. It is understood that the process 400 can be considered as a more specific example of the process 200 in Fig. 2. Thus, the UE 401 in Fig. 4 may be an example of the terminal device 110 in Fig. 1 or Fig. 2, the last serving cell 402 in Fig. 4 may correspond to the first network device 120 in Fig. 1 or Fig. 2, the LMF 403 in Fig. 4 may be an example of the LMF 130 in Fig. 1 or Fig. 2, and the cells in the validity area 404 in Fig. 4 may correspond to the second network device 140 in Fig. 1 or Fig. 2.

As shown in Fig. 4, at 410, the UE 401 receive a TA command from the last serving cell 402, then the TAT starts. Prior to receiving the TA command, the UE 401 may transmit a request for starting the TAT. The last serving cell refers to the cell managed by the base station that sets the SRS resource configuration for the UE 401 before UE 401 enters inactive state.

At 415, the last serving cell 402 indicates to the LMF 403 that the TAT starts. At 420, the LMF 403 indicates to the cells in the validity area 404 that the TAT starts. At 425, before the TAT expiration, the UE 401 requests TAT extension from the last serving cell 402. At 430, the last serving cell 402 provides extension time to the UE 401, and the TAT is extended. At 435, the last serving cell 402 indicates to the LMF 403 that the extension of the TAT. At 440, the LMF 403 indicates to the cells in the validity area 404 that the extension of the TAT. At 445, the expiration of the TAT triggers the SRS resource release. At 450, the last serving cell 402 is triggered to release the SRS resource. At 455, the cells in the validity area 404 is triggered to release the SRS resource.

At 460, the UE 401 receive a TA command from the last serving cell 402, then the expired TAT restarts. The UE 401 reuses previously released SRS resource. Prior to receiving the TA command, the UE 401 may transmit a request for restarting the TAT via random access channel (RACH) . At 465, the last serving cell 402 indicates to the LMF 403 that the expired TAT restarts. At 470, the LMF 403 indicates to the cells in the validity area 404 that the expired TAT restarts. At 475, the cells in the validity area 404 reserves the previously SRS resource.

Fig. 4 shows an example of SRS resource release and reservation by TAT synchronization between cells in the validity area. In procedure 400, the cells in the validity area have known information about the TAT, such as when the TAT starts, restarts, TAT extension and TAT expires, etc. Thus, cells in the validity area can release or reserve the SRS resource autonomously based on the TAT.

It is to be understood that in procedures 300 and 400, the TAT extension is performed before the TAT expiration. Additionally or alternatively, the TAT extension may also be performed after the TAT expiration. For example, according to the TA validation criterion based on RSRP, it could be still valid. To avoid the SRS resource re-configuration, the UE or LMF may send request to “TAT extension. ” It is assumed that the validity time of the TAT is pre-configured before the last serving cell sends the TA commands.

Fig. 5 shows a flowchart of an example method 500 implemented at a first network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 500 will be described from the perspective of the first network device 120 with reference to Fig. 1.

At block 510, the first network device 120 transmits information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In some embodiments, the information may comprise a first indication to release the at least one SRS resource, and wherein the first indication is transmitted based on determining that the TAT expires. In some embodiments, the information may comprise information of the TAT, a second indication that the terminal device moves out of the SRS validity area, or any combination of two of the above-mentioned items.

In some embodiments, information of the TAT may include a time point when the TAT starts, a time point when the TAT restarts, an extension of the TAT, a time point when the TAT expires, or any combination of two or more of the above-mentioned items.

In some embodiments, the first network device 120 may further transmit, to the LMF, a third indication to reserve the at least one SRS resource based on determining that an expired TAT restarts. In some embodiments, the first network device 120 may further reuse at least one released SRS resource valid for multiple cells of the terminal device after the expired TAT restarts.

In some embodiments, the first network device 120 may further receive, from at least one terminal device or the LMF, at least one request for an extension of the TAT before the TAT expires.

In some embodiments, the first network device 120 may further determine to extend the TAT for a time period based on determining that a number of the at least one terminal device is above a threshold, and extend validity time of the TAT based on the time period.

In some embodiments, the first network device 120 may further receive a request for an extension of the TAT from the at least one terminal device or the LMF upon expiration of the TAT.

In some embodiments, the first network device may further receive, from the at least one terminal device, information indicating a time period for which the TAT is extended, and extend validity time of the TAT based on the time period.

In some embodiments, the time period may be proportional to a number of the at least one request, or the time period may be an integer multiple of a duration of the TAT.

In some embodiments, the first network device 120 may further transmit, to the at least one terminal device, information indicating the time period.

In some embodiments, the first network device 120 may further transmit, to the LMF, a fourth indication that the TAT is extended. In some embodiments, the fourth indication may comprise information indicating the time period. In some embodiments, the first network device may further release the at least one SRS resource based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

In some embodiments, the first network device 120 may further release a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

Fig. 6 shows a flowchart of an example method 600 implemented at a LMF in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the LMF 130 with reference to Fig. 1.

At block 610, the LMF 130 receives information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area. At block 620, the LMF 130 transmits the information to the one or more network devices.

In some embodiments, the information of the TAT may include a time point when the TAT starts, a time point when the TAT restarts, an extension of the TAT, a time point when the TAT expires, or any combination of two or more of the above-mentioned items.

In some embodiments, the first network device may further receive, from the first network device, a third indication to reserve the at least one SRS resource in the event that an expired TAT restarts, and transmit the third indication to the one or more network devices.

In some embodiments, the LMF may further transmit, to the first network device, a request for an extension of the TAT upon expiration of the TAT. In some embodiments, the LMF may further receive, from the first network device, a fourth indication that the TAT is extended, and transmit the fourth indication to the one or more network devices.

In some embodiments, the fourth indication may comprise information indicating a time period of the TAT is extended. In some embodiments, the time period may be proportional to a number of at least one request for an extension of the TAT transmitted by at least one terminal device, or the time period may be an integer multiple of a duration of the TAT.

Fig. 7 shows a flowchart of an example method 700 implemented at a second network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the second network device 140 with reference to Fig. 1.

At block 710, the second network device 140 receives information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices. At block 720, the second network device 140 releases the at least one SRS resource based on the information.

In some embodiments, in order to release the at least one SRS resource based on the information, the second network device may release the at least one SRS resource upon receiving the first indication, release the at least one SRS resource based on determining that the terminal device moves out of the SRS validity area, or release the at least one SRS resource upon expiration of the TAT.

In some embodiments, the second network device may further receive, from the LMF, a third indication to reserve the at least one SRS resource in the event that an expired TAT restarts, and reserve the at least one SRS resource based on the third indication.

In some embodiments, the second network device may further reserve the at least one SRS resource based on determining that the information of the TAT includes a time point when the TAT restarts, or extend a time period for the at least one SRS resource based on determining that the information of the TAT includes the extension of the TAT.

In some embodiments, the second network device may further receive, from the LMF, information indicating a time period for which the TAT is extended, and extend validity time of the TAT based on the time period.

In some embodiments, the time period may be proportional to a number of the at least one request for an extension of the TAT transmitted by at least one terminal device, or the time period may be an integer multiple of a duration of the TAT.

In some embodiments, the second network device may further release a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

Fig. 8 shows a flowchart of an example method 800 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 800 will be described from the perspective of the terminal device 110 with reference to Fig. 1.

At block 810, the terminal device 110 transmits, to a first network device, a request for an extension of a time alignment timer (TAT) . At block 820, the terminal device 110 receives, from the first network device, information indicating a time period for which the TAT is extended.

In some embodiments, the terminal device 110 may further determine a time period for which the TAT is extended. In some embodiments, the terminal device may further extend validity time of the TAT based on the time period. In some embodiments, the terminal device may further reuse at least one released SRS resource valid for multiple cells of the terminal device after an expired TAT restarts. In some embodiments, the terminal device may further release the at least one SRS resource based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

In some embodiments, the terminal device 110 may further release a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

In some embodiments, an apparatus capable of performing any of the method 500 (for example, the first network device 120) is provided. The apparatus may comprise means for performing the respective steps of the method 500. 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 transmitting information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.

In some embodiments, the apparatus may further comprise means for transmitting, to the LMF, a third indication to reserve the at least one SRS resource based on determining that an expired TAT restarts.

In some embodiments, the apparatus may further comprise means for reusing at least one released SRS resource valid for multiple cells of the terminal device after the expired TAT restarts. In some embodiments, the apparatus may further comprise means for receiving, from at least one terminal device or the LMF, at least one request for an extension of the TAT before the TAT expires.

In some embodiments, the apparatus may further comprise means for determining to extend the TAT for a time period based on determining that a number of the at least one terminal device is above a threshold and means for extending validity time of the TAT based on the time period.

In some embodiments, the apparatus may further comprise means for receiving a request for an extension of the TAT from the at least one terminal device or the LMF upon expiration of the TAT. In some embodiments, the apparatus may further comprise means for receiving, from the at least one terminal device, information indicating a time period for which the TAT is extended, and means for extending validity time of the TAT based on the time period.

In some embodiments, the apparatus may further comprise means for transmitting, to the at least one terminal device, information indicating the time period. In some embodiments, the apparatus may further comprise means for transmitting, to the LMF, a fourth indication that the TAT is extended.

In some embodiments, the fourth indication may comprise information indicating the time period. In some embodiments, the apparatus may further comprise means for releasing the at least one SRS resource based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

In some embodiments, the apparatus may further comprise means for releasing a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 500. 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 any of the method 600 (for example, the LMF 130) is provided. The apparatus 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 embodiments, the apparatus comprises means for receiving information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and means for transmitting the information to the one or more network devices.

In some embodiments, the apparatus may further comprise means for receiving, from the first network device, a third indication to reserve the at least one SRS resource in the event that an expired TAT restarts, and means for transmitting the third indication to the one or more network devices.

In some embodiments, the apparatus may further comprise means for transmitting, to the first network device, a request for an extension of the TAT upon expiration of the TAT. In some embodiments, t the apparatus may further comprise means for receiving, from the first network device, a fourth indication that the TAT is extended, and means for transmitting the fourth indication to the one or more network devices.

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 device.

In some embodiments, an apparatus capable of performing any of the method 700 (for example, the second network device 140) is provided. The apparatus 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 embodiments, the apparatus comprises means for receiving information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and means for releasing the at least one SRS resource based on the information.

In some embodiments, means for releasing the at least one SRS resource based on the information may comprise means for releasing the at least one SRS resource upon receiving the first indication, means for releasing the at least one SRS resource based on determining that the terminal device moves out of the SRS validity area, or means for releasing the at least one SRS resource upon expiration of the TAT.

In some embodiments, the apparatus may further comprise means for receiving, from the LMF, a third indication to reserve the at least one SRS resource in the event that an expired TAT restarts, and means for reserving the at least one SRS resource based on the third indication.

In some embodiments, the apparatus may further comprise means for reserving the at least one SRS resource based on determining that the information of the TAT includes a time point when the TAT restarts, or means for extending a time period for the at least one SRS resource based on determining that the information of the TAT includes the extension of the TAT.

In some embodiments, the apparatus may further comprise means for receiving, from the LMF, information indicating a time period for which the TAT is extended, and means for extending validity time of the TAT based on the time period.

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 device.

In some embodiments, an apparatus capable of performing any of the method 800 (for example, the terminal device 110) is provided. The apparatus 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 transmitting, to a first network device, a request for an extension of a time alignment timer (TAT) ; and means for receiving, from the first network device, information indicating a time period for which the TAT is extended.

In some embodiments, the apparatus may further comprise means for determining a time period for which the TAT is extended. In some embodiments, the apparatus may further comprise means for extending validity time of the TAT based on the time period.

In some embodiments, the apparatus may further comprise means for reusing at least one released SRS resource valid for multiple cells of the terminal device after an expired TAT restarts. In some embodiments, the apparatus may further comprise means for releasing the at least one SRS resource based on determining at least one of the following: the TAT expires; or the terminal device moves out of the SRS validity area.

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 device.

FIG. 9 is a simplified block diagram of a device 900 that is suitable for implementing embodiments of the present disclosure. The device 900 may be provided to implement the communication device, for example the terminal device 110, a first network device 120, a LMF 130 or a second network device 140 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 modules 940 is for bidirectional communications. The communication modules 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 930 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 Figs. 2 to 8. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some 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 shows an example of the computer readable medium 1000 in form of CD or DVD. The computer readable medium has the program 930 stored thereon.

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 500, 600, 700, and 800 as described above with reference to Figs. 5-8. 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.

Claims

A first 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 first network device at least to:

transmit information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.
The first network device of claim 1, wherein the information comprises a first indication to release the at least one SRS resource, and wherein the first indication is transmitted based on determining that the TAT expires.
The first network device of claim 1, wherein the information comprises at least one of the following:

information of the TAT; or

a second indication that the terminal device moves out of the SRS validity area.
The first network device of claim 3, wherein the information of the TAT includes at least one of the following:

a time point when the TAT starts;

a time point when the TAT restarts;

an extension of the TAT; or

a time point when the TAT expires.
The first network device of claim 1 or 2, wherein the first network device is further caused to:

transmit, to the LMF, a third indication to reserve the at least one SRS resource based on determining that an expired TAT restarts.
The first network device of claim 5, wherein the first network device is further caused to:

reuse at least one released SRS resource valid for multiple cells of the terminal device after the expired TAT restarts.
The first network device any of claims 1-6, wherein the first network device is further caused to:

receive, from at least one terminal device or the LMF, at least one request for an extension of the TAT before the TAT expires.
The first network device of claim 7, wherein the first network device is further caused to:

determine to extend the TAT for a time period based on determining that a number of the at least one terminal device is above a threshold; and

extend validity time of the TAT based on the time period.
The first network device of any of claims 1-6, wherein the first network device is further caused to:

receive a request for an extension of the TAT from the at least one terminal device or the LMF upon expiration of the TAT.
The first network device of claim 7, wherein the first network device is further caused to:

receive, from the at least one terminal device, information indicating a time period for which the TAT is extended; and

extend validity time of the TAT based on the time period.
The first network device of any of claims 8-10, wherein one of the following:

the time period is proportional to a number of the at least one request; or

the time period is an integer multiple of a duration of the TAT.
The first network device of claim 8 or 11, wherein the first network device is further caused to:

transmit, to the at least one terminal device, information indicating the time period.
The first network device of any of claims 7-12, wherein the first network device is further caused to:

transmit, to the LMF, a fourth indication that the TAT is extended.
The first network device of claim 13, wherein the fourth indication comprises information indicating the time period.
The first network device of any of claims 1-14, wherein the first network device is further caused to:

release the at least one SRS resource based on determining at least one of the following:

the TAT expires; or

the terminal device moves out of the SRS validity area.
The first network device of any of claims 1-15, wherein the first network device is further caused to:

release a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following:

the TAT expires; or

the terminal device moves out of the SRS validity area.
A location management function (LMF) comprising:

at least one processor; and

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

receive information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and

transmit the information to the one or more network devices.
The LMF of claim 17, wherein the information comprises a first indication to release the at least one SRS resource, and wherein the first indication is transmitted based on determining that the TAT expires.
The LMF of claim 17, wherein the information comprises at least one of the following:

information of the TAT; or

a second indication that the terminal device moves out of the SRS validity area.
The LMF of claim 19, wherein the information of the TAT includes at least one of the following:

a time point when the TAT starts;

a time point when the TAT restarts;

an extension of the TAT; or

a time point when the TAT expires.
The LMF of claim 17 or 18, wherein the first network device is further caused to:

receive, from the first network device, a third indication to reserve the at least one SRS resource in the event that an expired TAT restarts; and

transmit the third indication to the one or more network devices.
The LMF of any of claims 17-21, wherein the LMF is further caused to:

transmit, to the first network device, a request for an extension of the TAT upon expiration of the TAT.
The LMF of any of claims 17-22, wherein the LMF is further caused to:

receive, from the first network device, a fourth indication that the TAT is extended; and

transmit the fourth indication to the one or more network devices.
The LMF of claim 23, wherein the fourth indication comprises information indicating a time period of the TAT is extended.
The LMF of claim 24, wherein one of the following:

the time period is proportional to a number of at least one request for an extension of the TAT transmitted by at least one terminal device; or

the time period is an integer multiple of a duration of the TAT.
A second 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 second network device at least to:

receive information from a location management function (LMF) , wherein the information is used for one or more network devices other than a first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and

release the at least one SRS resource based on the information.
The second network device of claim 26, wherein the information comprises a first indication to release the at least one SRS resource, and wherein the first indication is transmitted based on determining that the TAT expires.
The second network device of claim 26, wherein the information comprises at least one of the following:

information of the TAT; or

a second indication that the terminal device moves out of the SRS validity area.
The second network device of claim 28, wherein the information of the TAT includes at least one of the following:

a time point when the TAT starts;

a time point when the TAT restarts;

an extension of the TAT; or

a time point when the TAT expires.
The second network device of any of claims 26-29, wherein the second network device is caused to release the at least one SRS resource based on the information by at least one of the following:

release the at least one SRS resource upon receiving the first indication;

release the at least one SRS resource based on determining that the terminal device moves out of the SRS validity area; or

release the at least one SRS resource upon expiration of the TAT.
The second network device of claim 26 or 27, wherein the second network device is further caused to:

receive, from the LMF, a third indication to reserve the at least one SRS resource in the event that an expired TAT restarts; and

reserve the at least one SRS resource based on the third indication.
The second network device of claim 29, wherein the second network device is further caused to:

reserve the at least one SRS resource based on determining that the information of the TAT includes a time point when the TAT restarts; or

extend a time period for the at least one SRS resource based on determining that the information of the TAT includes the extension of the TAT.
The second network device of any of claims 26-32, wherein the second network device is further caused to:

receive, from the LMF, information indicating a time period for which the TAT is extended;

extend validity time of the TAT based on the time period; and

run the TAT based on the validity time.
The second network device of any of claims 26-33, wherein one of the following:

the time period is proportional to a number of the at least one request for an extension of the TAT transmitted by at least one terminal device; or

the time period is an integer multiple of a duration of the TAT.
The second network device of any of claims 26-34, wherein the second network device is further caused to:

release a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following:

the TAT expires; or

the terminal device moves out of the SRS validity area.
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:

transmit, to a first network device, a request for an extension of a time alignment timer (TAT) ; and

receive, from the first network device, information indicating a time period for which the TAT is extended.
The terminal device of claim 36, wherein the terminal device is further caused to:

determine a time period for which the TAT is extended.
The terminal device of claim 36 or 37, wherein the terminal device is further caused to:

extend validity time of the TAT based on the time period.
The terminal device of any of claims 36-38, wherein the terminal device is further caused to:

reuse at least one released SRS resource valid for multiple cells of the terminal device after an expired TAT restarts.
The terminal device of any of claims 36-39, wherein the terminal device is further caused to:

release the at least one SRS resource based on determining at least one of the following:

the TAT expires; or

the terminal device moves out of the SRS validity area.
The terminal device of any of claims 36-40, wherein the terminal device is further caused to:

release a configuration of the at least one SRS resource configured for the SRS validity area based on determining at least one of the following:

the TAT expires; or

the terminal device moves out of the SRS validity area.
A method comprising:

transmitting, at a first network device, information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.
A method comprising:

receiving, at a location management function (LMF) , information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and

transmitting the information to the one or more network devices.
A method comprising:

receiving, at a second network device, information from a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and

releasing the at least one SRS resource based on the information.
A method comprising:

transmitting, at a terminal device to a first network device, a request for an extension of a time alignment timer (TAT) ; and

receiving, from the first network device, information indicating a time period for which the TAT is extended.
An apparatus comprising:

means for transmitting, at a first network device, information to a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area.
An apparatus comprising:

means for receiving, at a location management function (LMF) , information from a first network device, wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area; and

means for transmitting the information to the one or more network devices.
An apparatus comprising:

means for receiving, at a second network device, information from a location management function (LMF) , wherein the information is used for one or more network devices other than the first network device to release at least one sounding reference signal (SRS) resource valid for multiple cells of a terminal device in the event that a time alignment timer (TAT) configured for a SRS validity area of the terminal device expires, wherein cells of the first network device and the one or more network devices are in the SRS validity area, wherein the second network device is one of the one or more network devices; and

means for releasing the at least one SRS resource based on the information.
An apparatus comprising:

means for transmitting, at a terminal device to a first network device, a request for an extension of a time alignment timer (TAT) ; and

means for receiving, from the first network device, information indicating a time period for which the TAT is extended.
A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of any of claims 42-45.