WO2022152413A1

WO2022152413A1 - Apparatuses, methods and computer programs for backward compatible discontinuous reception support for sidelink operations

Info

Publication number: WO2022152413A1
Application number: PCT/EP2021/078251
Authority: WO
Inventors: Vinh Van Phan; Ling Yu; Lianghai JI; Nuno Manuel KIILERICH PRATAS
Original assignee: Nokia Technologies Oy
Priority date: 2021-01-18
Filing date: 2021-10-13
Publication date: 2022-07-21

Abstract

Devices, methods and computer programs for discontinuous reception, DRX, support in sidelink, SL, operations are disclosed. An SL operation enabled client device incapable of DRX for SL operations acting as a transmitting client device for an SL service is detected by a service-assisting SL operation enabled client device capable of DRX for SL operations. In response, the service-assisting SL operation enabled client device capable of DRX for SL operations determines to act in an assisting mode for the SL service. An assistance message is transmitted from the service-assisting SL operation enabled client device capable of DRX for SL operations to at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for the at least one service-targeted SL operation enabled client device and/or the SL service. The assistance message indicates assistance information related to the assisting mode.

Description

APPARATUSES, METHODS AND COMPUTER PROGRAMS FOR BACKWARD COMPATIBLE DISCONTINUOUS RECEPTION SUPPORT FOR SIDELINK OPERATIONS

TECHNICAL FIELD

The disclosure relates generally to communica- tions and, more particularly but not exclusively, to discontinuous reception support in sidelink operations.

BACKGROUND

Fifth generation (5G) new radio (NR) wireless networks allow so called sidelink (SL) transmissions that involves direct communications between two nearby user equipments (UEs) without signal relay through a base station.

Starting from 5G NR Release 17, discontinuous reception (DRX) is supported in connection with SL transmissions, while earlier releases of 5G NR do not support DRX in connection with SL transmissions.

Accordingly, at least in some situations it may be desirable to have backwards compatibility in regards to DRX support for SL transmissions. An example of such situations is 5G NR Release 16 compatible services, such as broadcast and groupcast services for road-safety and public-safety .

SUMMARY

The scope of protection sought for various ex- ample embodiments of the invention is set out by the independent claims. The example embodiments and fea- tures, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various example embodiments of the invention.

An example embodiment of a service-assisting sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations com- prises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to at least perform: detecting an SL operation enabled client device incapable of DRX for SL operations acting as a trans- mitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device incapable of DRX for SL operations, determining to act in an assisting mode for the SL service; and transmitting an assistance message to at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the at least one service-targeted SL operation enabled client device or the SL service, the assistance message indicating assistance information related to the assisting mode.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to perform the detecting of the SL operation enabled client device incapable of DRX for SL operations by at least one of: detecting receipt of SL data related to the SL service during an off-period of the DRX cycle; detecting receipt of SL data related to the SL service without DRX support related information during an on-period of the DRX cycle; or detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL operation enabled client device incapable of DRX for SL operations. In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the client device to perform detecting at least one of: an additional service-assisting SL operation enabled client device capable of DRX for SL operations or an SL operation enabled client device capable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to perform the detecting of the at least one of the additional service-assisting SL oper- ation enabled client device capable of DRX for SL oper- ations or the SL operation enabled client device capable of DRX for SL operations based on at least one of: control information related to the SL service received during an on-period of the DRX cycle;

SL data related to the SL service received dur- ing an on-period of the DRX cycle; information related to a capability of the at least one of the additional service-assisting SL oper- ation enabled client device capable of DRX for SL oper- ations or the SL operation enabled client device capable of DRX; or information related to a DRX configuration of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to perform the determining to act in the assisting mode for the SL service further in re- sponse to the result of the detecting of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the client device to perform utilizing an existing unicast SL for transmitting the assistance message.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the assistance information comprises at least one of: information related to at least one of an identity, an SL resource allocation or a transmission pattern of the detected SL operation enabled client de- vice incapable of DRX for SL operations acting as the transmitting client device for the SL service; information related to a duration of the as- sisting mode of the service-assisting SL operation en- abled client device for the SL service; an indication of whether the service-assisting SL operation enabled client device is configured to for- ward SL data related to the SL service received from the SL operation enabled client device incapable of DRX for SL operations; an indication of at least one of monitored time resources or monitored frequency resources for SL oper- ations; or an indication indicating the presence of the detected SL operation enabled client device incapable of DRX for SL operations acting as the transmitting client device for the SL service.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to perform adapting one or more SL operations related to the SL service by: receiving SL data related to the SL service from the SL operation enabled client device incapable of DRX for SL operations during an off-period of the DRX cycle, and forwarding the received SL data to the at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on- period of the DRX cycle.

An example embodiment of a service-assisting sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations comprises means for performing: detecting an SL operation enabled client device incapable of DRX for SL operations acting as a trans- mitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device incapable of DRX for SL operations, determining to act in an assisting mode for the SL service; and causing transmission of an assistance message to at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the at least one service-targeted SL operation ena- bled client device or the SL service, the assistance message indicating assistance information related to the assisting mode.

An example embodiment of a method comprises: detecting, by a service-assisting sidelink, SL, operation enabled client device capable of discon- tinuous reception, DRX, for SL operations, an SL oper- ation enabled client device incapable of DRX for SL operations acting as a transmitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device incapable of DRX for SL operations, determining, by the service-assisting SL operation enabled client device capable of DRX for SL operations, to act in an assisting mode for the SL ser- vice; and transmitting from the service-assisting SL op- eration enabled client device capable of DRX for SL operations an assistance message to at least one ser- vice-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the at least one service-targeted SL operation enabled client device or the SL service, the assistance message indicating as- sistance information related to the assisting mode.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the detecting of the SL operation enabled client device in- capable of DRX for SL operations is performed by at least one of: detecting receipt of SL data related to the SL service during an off-period of the DRX cycle; detecting receipt of SL data related to the SL service without DRX support related information during an on-period of the DRX cycle; or detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL operation enabled client device incapable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the method further comprises detecting at least one of: an additional service-assisting SL operation enabled cli- ent device capable of DRX for SL operations or an SL operation enabled client device capable of DRX for SL operations. In an example embodiment, alternatively or in addition to the above-described example embodiments, the detecting of the at least one of the additional service- assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations is performed based on at least one of: control information related to the SL service received during an on-period of the DRX cycle;

In an example embodiment, alternatively or in addition to the above-described example embodiments, the determining to act in the assisting mode for the SL service is performed further in response to the result of the detecting of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the method further comprises utilizing an existing unicast SL for transmitting the assistance message.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the method further comprises adapting one or more SL oper- ations related to the SL service by: receiving SL data related to the SL service from the SL operation enabled client device incapable of DRX for SL operations during an off-period of the DRX cycle, and forwarding the received SL data to the at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on- period of the DRX cycle.

An example embodiment of a computer program comprises instructions for causing a service-assisting sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations to perform at least the following: detecting an SL operation enabled client device incapable of DRX for SL operations acting as a trans- mitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device incapable of DRX for SL operations, determining to act in an assisting mode for the SL service; and transmitting an assistance message to at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the at least one service-targeted SL operation enabled client device or the SL service, the assistance message indicating assistance information related to the assisting mode.

An example embodiment of a service-targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations com- prises at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to at least perform: receiving an assistance message from a service- assisting SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the service-targeted SL operation enabled client device or an SL service, the assistance message indicating assistance information related to an assisting mode in which the service-as- sisting SL operation enabled client device is acting for the SL service; and adapting or maintaining one or more SL opera- tions related to the SL service based on the received assistance information.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to perform the adapting of the one or more SL operations related to the SL service by deactivating the DRX or adjusting at least one of the on-period of the DRX cycle or an off-period of the DRX cycle.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are configured to, with the at least one processor, cause the client device to perform detecting of an SL opera- tion enabled client device incapable of DRX for SL op- erations by at least one of: detecting receipt of SL data related to the SL service during an off-period of the DRX cycle; detecting receipt of SL data related to the SL service without DRX support related information during an on-period of the DRX cycle; or detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL operation enabled client device incapable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the at least one memory and the computer program code are further configured to, with the at least one processor, cause the client device to perform detecting at least one of: an additional service-assisting SL operation enabled client device capable of DRX for SL operations or an SL operation enabled client device capable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the assistance information comprises at least one of: information related to at least one of an identity, an SL resource allocation or a transmission pattern of the detected SL operation enabled client de- vice incapable of DRX for SL operations acting as the transmitting client device for the SL service; information related to a duration of the as- sisting mode of the service-assisting SL operation en- abled client device for the SL service; an indication of whether the service-assisting SL operation enabled client device is configured to for- ward SL data related to the SL service received from the SL operation enabled client device incapable of DRX for SL operations; an indication of at least one of monitored time resources or monitored frequency resources for SL oper- ations; or an indication indicating the presence of the detected SL operation enabled client device incapable of DRX for SL operations acting as the transmitting client device for the SL servic.

An example embodiment of a service-targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations comprises means for performing: receiving an assistance message from a service- assisting SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the service-targeted SL operation enabled client device or an SL service, the assistance message indicating assistance information related to an assisting mode in which the service-as- sisting SL operation enabled client device is acting for the SL service; and adapting or maintaining one or more SL opera- tions related to the SL service based on the received assistance information.

An example embodiment of a method comprises: receiving, at a service-targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations, an assistance message from a service-assisting SL operation enabled client device capable of DRX for SL operations during an on- period of a DRX cycle configured for at least one of the service-targeted SL operation enabled client device or an SL service, the assistance message indicating assis- tance information related to an assisting mode in which the service-assisting SL operation enabled client device is acting for the SL service; and adapting or maintaining, by the service-tar- geted SL operation enabled client device capable of DRX for SL operations, one or more SL operations related to the SL service based on the received assistance infor- mation. In an example embodiment, alternatively or in addition to the above-described example embodiments, the adapting of the one or more SL operations related to the SL service is performed by deactivating the DRX or ad- justing at least one of the on-period of the DRX cycle or an off-period of the DRX cycle.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the method further comprises detecting of an SL operation enabled client device incapable of DRX for SL operations by at least one of: detecting receipt of SL data related to the SL service during an off-period of the DRX cycle; detecting receipt of SL data related to the SL service without DRX support related information during an on-period of the DRX cycle; or detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL operation enabled client device incapable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the method further comprises detecting at least one of: an additional service-assisting SL operation enabled cli- ent device capable of DRX for SL operations or an SL operation enabled client device capable of DRX for SL operations.

In an example embodiment, alternatively or in addition to the above-described example embodiments, the detecting of the at least one of the additional service- assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations is performed based on at least one of: control information related to the SL service received during an on-period of the DRX cycle; SL data related to the SL service received dur- ing an on-period of the DRX cycle; information related to a capability of the at least one of the additional service-assisting SL oper- ation enabled client device capable of DRX for SL oper- ations or the SL operation enabled client device capable of DRX; or information related to a DRX configuration of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX.

An example embodiment of a computer program comprises instructions for causing a service-targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations to perform at least the following: receiving an assistance message from a service- assisting SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the service-targeted SL operation enabled client device or an SL service, the assistance message indicating assistance information related to an assisting mode in which the service-as- sisting SL operation enabled client device is acting for an SL service; and adapting or maintaining one or more SL opera- tions related to the SL service based on the received assistance information.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the embodiments and constitute a part of this specification, illustrate embodiments and together with the description help to explain the principles of the embodiments. In the draw- ings:

FIG. 1 shows an example embodiment of the sub- ject matter described herein illustrating an example system, where various embodiments of the present dis- closure may be implemented;

FIG. 2A shows an example embodiment of the sub- ject matter described herein illustrating a service- assisting sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations;

FIG. 2B shows an example embodiment of the sub- ject matter described herein illustrating a service- targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations; FIG. 3 shows an example embodiment of the sub- ject matter described herein illustrating a method;

FIG. 4 shows an example embodiment of the sub- ject matter described herein illustrating another method; and

FIG. 5 shows an example embodiment of the sub- ject matter described herein illustrating yet another method.

Like reference numerals are used to designate like parts in the accompanying drawings.

DETAILED DESCRIPTION

Reference will now be made in detail to embod- iments, examples of which are illustrated in the accom- panying drawings. The detailed description provided be- low in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the pre- sent example may be constructed or utilized. The de- scription sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

Fig. 1 illustrates an example system 100, where various embodiments of the present disclosure may be implemented. The system 100 may comprise a fifth gener- ation (5G) new radio (NR) network 110 supporting side- link (SL) transmissions and discontinuous reception (DRX) in connection with the SL transmissions. An exam- ple representation of the system 100 is shown depicting a service-assisting SL operation enabled client device 200 that is capable of DRX for SL operations, a service- targeted SL operation enabled client device 210 that is capable of DRX for SL operations, an SL operation enabled client device 220 incapable of DRX for SL operations, and a network node device 230. The client devices 200, 210, and/or 220 may include e.g. a mobile phone, a smartphone, a tablet computer, a smart watch, or any hand-held or portable device. The client device 200, 210, 220 may also be referred to as a user equipment (UE). The network node device 230 may be a base station. The base station may include e.g. a fifth-generation base station (gNB) or any such device suitable for providing an air interface for client devices to connect to a wireless network via wireless transmissions.

As shown in Fig. 1, the network node device 230 and the client device 220 may communicate with each other via uplink (UL) and downlink (DL) transmissions. Even though it is not depicted in Fig. 1 for clarity reasons, the client devices 200 and 210 may also com- municate with the network node device 230 or other net- work node devices (not shown in Fig. 1) via UL and DL transmissions .

In addition, the client devices 200, 210, 220 may communicate with each other via SL transmissions. However, only the client devices 200, 210 support DRX in connection with the SL transmissions.

Generally speaking, SL communications between UEs are based on the principle of transmitter (Tx UE) oriented one-to-many broadcast. On one hand, a Tx UE transmits SL to a receiver (Rx UE) or a group of Rx UEs or all Rx UEs in the proximity of the Tx UE using re- sources from a preconfigured resource pool, at least for transmitting SL control information (SCI) which is used as a scheduling assignment for an SL data transmission. On the other hand, the Rx UE needs to keep monitoring over the preconfigured resource pool to receive SL, at least receiving all SCI instances and determining whether a received SCI and corresponding SL data trans- mission is intended for the Rx UE to receive or not based on source (SRC) and/or destination (DST) identi- fier (s) (IDs) indicated in the received SCI instances. Here, the SRC corresponds to the Tx side, and the DST corresponds to the Rx side. This is applied for casting types, such as unicast, groupcast or broadcast over SL.

There may be at least two modes of resource allocation specified for an SL transmission, referred to as mode 1 and mode 2. Mode 1 is based on using scheduled resources or grants from a serving base sta- tion. This implies that a Tx UE may need to be in a radio resource control (RRC) connected state with the serving base station in order to get mode 1 resources allocated. Mode 2 is based on autonomous allocation or selection of resources from a preconfigured Tx resource pool by a Tx UE. The resource selection in mode 2 may be based on a random selection or sensing-based selec- tion. The latter may be preferred and used for normal operation, while the former may be used for exceptional operations or situations with a particular, preconfig- ured resource pool. Mode 2 can be used for a Tx UE that is in-coverage (IC), or out-of-coverage (OoC), or in an RRC idle state, RRC inactive state, or RRC connected state.

In the following, various example embodiments will be discussed. At least some of these example em- bodiments may allow discontinuous reception support in sidelink operations with backwards compatibility.

Fig. 2A is a block diagram of the service- assisting sidelink, SL, operation enabled client device 200 capable of discontinuous reception, DRX, for SL op- erations, in accordance with an example embodiment.

The client device 200 comprises one or more processors 202 and one or more memories 204 that com- prise computer program code. The client device 200 may also include other elements, such as a transceiver 206, as well as other elements not shown in Fig. 2A.

Although the client device 200 is depicted to include only one processor 202, the client device 200 may include more processors. In an embodiment, the memory 204 is capable of storing instructions, such as an operating system and/or various applications. Fur- thermore, the memory 204 may include a storage that may be used to store e.g. at least some of the information and data used in the disclosed embodiments.

Furthermore, the processor 202 is capable of executing the stored instructions. In an embodiment, the processor 202 may be embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core pro- cessors. For example, the processor 202 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for ex- ample, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a mi- crocontroller unit (MCU), a hardware accelerator, a spe- cial-purpose computer chip, or the like. In an embodi- ment, the processor 202 may be configured to execute hard-coded functionality. In an embodiment, the proces- sor 202 is embodied as an executor of software instruc- tions, wherein the instructions may specifically con- figure the processor 202 to perform the algorithms and/or operations described herein when the instructions are executed.

The memory 204 may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and/or a combination of one or more volatile memory devices and non-volatile memory devices. For ex- ample, the memory 204 may be embodied as semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.).

The client device 200 may be any of various types of devices used directly by an end user entity and capable of communication in a wireless network, such as user equipment (UE). Such devices include but are not limited to smartphones, tablet computers, smart watches, lap top computers, internet-of-things (loT) devices, vehicle-to-everything (V2X) devices, etc.

The at least one memory 204 and the computer program code are configured to, with the at least one processor 202, cause the client device 200 to at least perform detecting (in proximity) an SL operation enabled client device 220 incapable of DRX for SL operations acting as a transmitting client device for an SL ser- vice. Herein, this detection is referred to as a first detection. The SL service may comprise e.g. a broadcast or groupcast service. Herein, the proximity may comprise a direct device-to-device (D2D) communication range be- tween local devices (such as the client devices 200, 210, 220).

For example, the at least one memory 204 and the computer program code may be configured to, with the at least one processor 202, cause the client device 200 to perform the detecting of the SL operation enabled client device 220 incapable of DRX for SL operations by detecting receipt of SL data related to the SL service during an off-period of the DRX cycle.

In other words, the service-assisting client device 200 and the service-targeted client device 210 may be configured to transmit and/or receive SL during the on-period of the configured DRX cycle for the tar- geted backwards compatible SL broadcast/groupcast ser- vice whereas the client device 220 incapable of DRX for SL operations may transmit SL for the targeted service whenever resources can be allocated. Thus, SL reception of data (at least SCI) for the targeted service during the off-period of the configured DRX cycle implies that the transmitting client device for the SL service is a client device incapable of DRX for SL operations. In order to enable an SL operation enabled client device capable of DRX for SL operations to perform this detec- tion, the SL operation enabled client device capable of DRX for SL operations may be configured to wake up during the off-period and perform the detection from time to time, using, for example, a random wake-up mechanism. This mechanism may be tailored for the targeted service such that, from time to time, the SL operation enabled client device capable of DRX for SL operations may be waking up long enough to receive all anticipated SL transmission (s) from transmitting client device (s) in proximity for the targeted service.

For another example, the at least one memory 204 and the computer program code may be configured to, with the at least one processor 202, cause the client device 200 to perform the detecting of the SL operation enabled client device 220 incapable of DRX for SL oper- ations by detecting receipt of SL data related to the SL service without DRX support related information dur- ing an on-period of the DRX cycle.

In other words, the service-assisting client device 200 and the service-targeted client device 210 may be configured to indicate DRX support or release information (such as standard release compliant infor- mation) when transmitting SL for the targeted SL ser- vice. Thus, an SL operation enabled client device capa- ble of DRX for SL operations may be able to detect a client device incapable of DRX for SL operations upon SL reception of data (at least SCI) without the indica- tion of DRX support or release information from the client device incapable of DRX for SL operations for the targeted service during the on-period of the configured DRX cycle.

SCI comprises a first stage SCI and a second stage SCI. The first stage SCI may be sent on e.g. a physical sidelink control channel (PSCCH) and the second stage SCI may be sent on a physical sidelink shared channel (PSSCH) along with SL data. In an implementation example, when SL operation enabled client devices capa- ble of DRX for SL operations perform SL transmissions they may activate a specific bit (e.g. from 'O' to '1') in the first stage SCI indicating that they are DRX enabled client devices. This information may also be made part on the second stage SCI (e.g. via the intro- duction of a second stage SCI format or by reinterpre- tation of the bits of existing second stage SCI for- mats). When this bit is inactive (i.e. set to '0') then the SL client device is treated as a client device in- capable of DRX for SL operations.

For yet another example, the at least one memory 204 and the computer program code may be config- ured to, with the at least one processor 202, cause the client device 200 to perform the detecting of the SL operation enabled client device 220 incapable of DRX for SL operations by detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL operation enabled cli- ent device 220 incapable of DRX for SL operations.

In other words, the service-assisting client device 200 and the service-targeted client device 210 and/or the client device 220 incapable of DRX for SL operation may be configured to use different exclusive transmit resource pools for SL transmissions for the targeted service. Thus, as long the service-assisting client device 200 and the service-targeted client device 210 are aware of a configuration (i.e. the transmit resource pool of the client device 220 incapable of DRX for SL operation) an SL operation enabled client device capable of DRX for SL operations is able to detect the client device 220 incapable of DRX for SL operations as the transmitting client device of SL transmissions using resources from the transmit resource pool configured for the client device 220 incapable of DRX for SL opera- tions. At least in response to the detecting of the SL operation enabled client device 220 incapable of DRX for SL operations, the at least one memory 204 and the computer program code are further configured to, with the at least one processor 202, cause the client device 200 to at least perform determining to act in an as- sisting mode for the SL service.

The at least one memory 204 and the computer program code are further configured to, with the at least one processor 202, cause the client device 200 to at least perform transmitting an assistance message to at least one service-targeted SL operation enabled cli- ent device 210 capable of DRX for SL operations. The assistance message is transmitted during an on-period of a DRX cycle. The on-period (and off-period) of the DRX cycle is configured for the at least one service- targeted SL operation enabled client device 210 and/or the SL service. The assistance message indicates assis- tance information related to the assisting mode. For example, the assistance message may comprise at least a part of the assistance information. Alternatively or additionally, the assistance message may implicitly or indirectly indicate at least a part of the assistance information. For example, in at least some embodiments, an assistance message without any explicit assistance information may be used to indicate e.g. the presence of the detected SL operation enabled client device 220 incapable of DRX for SL operations acting as the trans- mitting client device for the SL service. The assistance information may be explicit or implicit.

For example, the assistance information may comprise information related to at least one of an iden- tity, an SL resource allocation or a transmission pat- tern of the detected SL operation enabled client device 220 incapable of DRX for SL operations acting as the transmitting client device for the SL service, infor- mation related to a duration of the assisting mode of the service-assisting SL operation enabled client device 200 for the SL service, an indication of whether the service-assisting SL operation enabled client device 200 is configured to forward or relay SL data related to the SL service received from the SL operation enabled client device 220 incapable of DRX for SL operations, an indi- cation of at least one of monitored time resources or monitored frequency resources for SL operations, and/or an indication indicating the presence of the detected SL operation enabled client device 220 incapable of DRX for SL operations acting as the transmitting client device for the SL service.

For example, the information related to the SL resource allocation may indicate the detected client device (s) 220 incapable of DRX for SL operations and its (their) resource reservation (s) either individually or collectively. For example, the information related to the duration of the assisting mode may indicate how long or until when (e.g. as a number of the configured DRX cycles) the client device 200 will be acting as a ser- vice-assisting client device or how long the current assisting mode may last.

In other words, the assistance information may indicate the time and/or frequency resources which the service-assisting client device 200 (which may be oper- ating in SL DRX but with a longer on-period than that of the service-targeted client device 210) monitors for supporting the SL DRX operation of service-targeted cli- ent device (s) 210. This allows the service-assisting client device 200 to monitor only a part of the off- period of the configured SL DRX cycle of the SL operation enabled client device capable of DRX for SL operations. Thus, different service-assisting client devices may monitor different time and/or frequency resources and transmit/relay their assistance message/SL data for the targeted service accordingly. This may be beneficial if different service-assisting client devices have differ- ent SL DRX configurations, e.g., engaged in different SL services with non-overlapping SL DRX configurations. This approach allows the service-assisting client device 200 to simply follow or slightly extend its on-period to support SL DRX operation for service-targeted client devices. In at least some embodiments, based on outcomes of a second detection (described in more detail below) at the service-assisting client device 200, the service- assisting client device 200 may prioritize the time and/or frequency resources (as indicated in the assis- tance message) differently than those of the detected service-assisting client devices in proximity.

In at least some embodiments, the assistance message may be implemented using e.g. physical layer (PHY) signalling (SCI), SL medium access control (MAC) control element (CE), SL-S (sidelink - signalling) or SL-RRC (sidelink - radio resource control) signalling.

In at least some embodiments, the at least one memory 204 and the computer program code may be further configured to, with the at least one processor 202, cause the client device 200 to perform detecting an additional service-assisting SL operation enabled cli- ent device capable of DRX for SL operations and/or an SL operation enabled client device capable of DRX for SL operations.

For example, the at least one memory 204 and the computer program code may be configured to, with the at least one processor 202, cause the client device 200 to perform the detecting of the at least one of the additional service-assisting SL operation enabled cli- ent device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations based on control information related to the SL service received during an on-period of the DRX cy- cle, SL data related to the SL service received during an on-period of the DRX cycle, information related to a capability of the at least one of the additional ser- vice-assisting SL operation enabled client device capa- ble of DRX for SL operations or the SL operation enabled client device capable of DRX, and/or information related to a DRX configuration of the at least one of the addi- tional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL oper- ation enabled client device capable of DRX.

In other words, the service-assisting client device 200 and the service-targeted client device 210 may be configured to detect other service-assisting cli- ent device (s) and/or service-targeted client device (s) in proximity. This detection, referred to as a second detection, may be based on SL reception of data (at least SCI) and/or assistance message (s) over SL during the on-period of the configured DRX cycle for the tar- geted service. The detection may further include re- ceiving SL DRX related client device capability and/or DRX configuration from other service-assisting client device (s) and/or service-targeted client device (s).

In at least some embodiments, the at least one memory 204 and the computer program code may be config- ured to, with the at least one processor 202, cause the client device 200 to perform the determining to act in the assisting mode for the SL service further in re- sponse to the result of the detecting of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations.

In other words, an SL operation enabled client device capable of DRX for SL operations, upon detecting a client device incapable of DRX for SL operation acting as a transmitting client device in proximity for the targeted service as an outcome of the first detection, may determine to activate its assisting mode and become a service-assisting client device. This may be further enhanced or optimized based on outcomes of the second detection, in terms of avoiding unnecessary protocol overhead or load caused by operating the assisting mode when there is no other SL operation enabled client de- vice capable of DRX for SL operations in proximity, or by operating the assisting mode for too long, or by having many redundant service-assisting client devices in proximity, for example. In an example, an SL opera- tion enabled client device capable of DRX for SL oper- ations may not activate the assisting mode if there is no other SL operation enabled client device capable of DRX for SL operations in proximity, or if there is at least one service-assisting client device in proximity providing assistance for a time period longer than a configured threshold. In another example, an SL opera- tion enabled client device capable of DRX for SL oper- ations may activate the assisting mode without relaying if the number of detected SL operation enabled client device (s) capable of DRX for SL operations in proximity is under a configured threshold.

In at least some embodiments, the at least one memory 204 and the computer program code may be further configured to, with the at least one processor 202, cause the client device 200 to perform utilizing an existing unicast SL for transmitting the assistance mes- sage.

In other words, a dedicated detection initiated by an SL operation enabled client device capable of DRX for SL operations via an existing unicast SL may be provided, e.g. by using a PC5-RRC procedure. In this case, the SL operation enabled client device capable of DRX for SL operations may indicate the targeted SL broadcast/groupcast service to its SL peer client device which is capable of assisting SL DRX operation for the SL operation enabled client device capable of DRX for SL operations to request the SL peer client device to perform the first and/or second detection and/or to act as a service-assisting client device for at least the SL operation enabled client device capable of DRX for SL operations. Herein, this is referred to as a third detection. In case the SL peer client device decides to act as a service-assisting client device dedicated to the SL operation enabled client device capable of DRX for SL operations, the SL peer client device may send an assistance message and/or relay data for the targeted service to the SL operation enabled client device capa- ble of DRX for SL operations via the existing unicast SL.

In at least some embodiments, the at least one memory 204 and the computer program code may be further configured to, with the at least one processor 202, cause the client device 200 to perform adapting one or more SL operations related to the SL service.

For example, the at least one memory 204 and the computer program code may be configured to, with the at least one processor 202, cause the client device 200 to perform the adapting of the one or more SL operations related to the SL service by receiving SL data related to the SL service from the SL operation enabled client device 220 incapable of DRX for SL operations during an off-period of the DRX cycle, and forwarding the received SL data to the at least one service-targeted SL opera- tion enabled client device 210 capable of DRX for SL operations during an on-period of the DRX cycle.

In other words, in case the service-assisting client device 200 is acting as a relay for service- targeted client devices 210 (i.e. for the targeted ser- vice), the service-assisting client device 200 may per- form adapting the SL operation based on the resolution indicated in the assistance message by:

1 . receiving data from the detected cli- ent device (s) 220 incapable of DRX for SL operations acting as transmitting client device (s) for the targeted service at least during the off-period of a DRX cycle configured for the service-targeted client device (s) 210; and

2 . transmitting the data received from the detected client device (s) 220 incapable of DRX for SL operations to the service-targeted client device (s) 210 during the on-period of a next DRX cycle configured for the service-targeted client device (s) 210.

QoS requirements of data (i.e., the targeted service) may be taken into consideration e.g. as fol- lows:

- the assistance message of the ser- vice-assisting client device 200 may be sent together with data received from the detected client device 220 incapable of DRX for SL operations;

- the service-assisting client device 200 may only forward data of the targeted service within the packet delay budget, e.g. the last received packet (s) of the targeted service (such as a periodic broadcast/groupcast service);

- the service-assisting client device 200 may only forward data generated due to detected event (s); and/or

- to avoid redundancy, the data for- warding or relaying from the service-assisting client device 200 (e.g. UE1) may also depend on a detection of whether the UE1 has received the same data from another service-assisting client device (e.g. UE2). That is, if UE1 detects that UE2 relays the same data received from client device (s) incapable of DRX for SL operations, UE1 may decide not to relay the same data. This detection may be considered as part of the second and/or third detections.

It is to be noted that the data forwarding or relaying described above may be realized e.g. using dif- ferent levels or layers of protocol stacks, from MAC/PHY to application layer (APPL). In at least some embodiments, the service- assisting client device 200 and/or the service-targeted client device 210 may be configured to report outcomes of the first detection and/or the second detection to a serving network (e.g. to a base station). This allows the serving network to identify and configure proper resources (Mode 1) for the detected client device (s) 220 incapable of DRX for SL operation to support SL DRX operation of the service-targeted client device 210.

Fig. 2B is a block diagram of the service- targeted sidelink, SL, operation enabled client device 210 capable of discontinuous reception, DRX, for SL op- erations, in accordance with an example embodiment.

The client device 210 comprises one or more processors 212 and one or more memories 214 that com- prise computer program code. The client device 210 may also include other elements, such as a transceiver 216, as well as other elements not shown in Fig. 2B.

Although the client device 210 is depicted to include only one processor 212, the client device 210 may include more processors. In an embodiment, the memory 214 is capable of storing instructions, such as an operating system and/or various applications. Fur- thermore, the memory 214 may include a storage that may be used to store e.g. at least some of the information and data used in the disclosed embodiments.

Furthermore, the processor 212 is capable of executing the stored instructions. In an embodiment, the processor 212 may be embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core pro- cessors. For example, the processor 212 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for ex- ample, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a mi- crocontroller unit (MCU), a hardware accelerator, a spe- cial-purpose computer chip, or the like. In an embodi- ment, the processor 212 may be configured to execute hard-coded functionality. In an embodiment, the proces- sor 212 is embodied as an executor of software instruc- tions, wherein the instructions may specifically con- figure the processor 212 to perform the algorithms and/or operations described herein when the instructions are executed.

The memory 214 may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and/or a combination of one or more volatile memory devices and non-volatile memory devices. For ex- ample, the memory 214 may be embodied as semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.).

The client device 210 may be any of various types of devices used directly by an end user entity and capable of communication in a wireless network, such as user equipment (UE). Such devices include but are not limited to smartphones, tablet computers, smart watches, lap top computers, internet-of-things (loT) devices, vehicle-to-everything (V2X) devices, etc.

The at least one memory 214 and the computer program code are configured to, with the at least one processor 212, cause the client device 210 to at least perform receiving the assistance message from a service- assisting SL operation enabled client device 200 capable of DRX for SL operations during an on-period of a DRX cycle configured for the service-targeted SL operation enabled client device 210 and/or the SL service. The assistance message indicates assistance information re- lated to an assisting mode in which the service-assist- ing SL operation enabled client device 200 is acting for an SL service.

The at least one memory 214 and the computer program code are configured to, with the at least one processor 212, cause the client device 210 to at least perform maintaining or adapting one or more SL opera- tions related to the SL service based on the received assistance information.

For example, the at least one memory 214 and the computer program code may be configured to, with the at least one processor 212, cause the client device 210 to perform the adapting of the one or more SL operations related to the SL service by deactivating the DRX or by adjusting the on-period of the DRX cycle and/or an off- period of the DRX cycle. For enabling this deactivating of the DRX, the assistance information in the assistance message may include an indication or notification that there is a SL UE incapable of DRX acting as a transmit- ting (Tx) UE for the SL service in proximity, as de- scribed above in connection with Fig. 2A.

In other words, the adaptation of a DRX SL operation at an SL operation enabled client device ca- pable of DRX for SL operation based on outcome (s) of at least one of the first, second and third detections and/or the resolution indicated in received assistance message (s) from one or more service-assisting client devices 20 may comprise e.g.:

- in case a client device 220 incapable of DRX for SL operations acting as a transmitting client device for the targeted service is detected and there is no service-assisting client device (i.e. no assis- tance message is received over SL), the SL operation enabled client device capable of DRX for SL operations may deactivate its SL DRX to become a service-assisting client device, as described above. In an option, the SL operation enabled client device capable of DRX for SL operations may adjust its SL DRX, e.g., by extending its current SL DRX on-period, while acting as the service- assisting client device, instead of staying awake all the time. In this option, the assistance message and/or the relayed data may only carry the information received during its extended on-period, as described above. This option allows the SL operation enabled client device in question capable of DRX for SL operations to partially assist other SL operation enabled client devices capable of DRX for SL operations;

- in case a service-assisting client device acting as a relay is detected (as indicated in the assistance message received from the service-as- sisting client device), the SL operation enabled client device capable of DRX for SL operations may keep or maintain its current DRX operation;

- in case assistance message (s) is (are) received and no resolution with relay is indicated in the received assistance message (s) (i.e. no relaying service-assisting client device is detected), the SL operation enabled client device capable of DRX for SL operations may adjust its DRX operation with e.g. the following options: o deactivating or adjusting its DRX op- eration by extending the on-period of its SL DRX cycle to become a service-assisting client device, optionally with a configured probability of P, if the SL DRX as- sistance provided by the detected service-assisting cli- ent device (s) is lasting for less than a preconfigured time interval, starting from the instance that assis- tance message (s) from the detected service-assisting client device (s) are received, as the received assis- tance message (s) indicate (s) how long the provided SL DRX assistance may last. The probability P may be used for an optimization purpose which can be set by a con- figured function of the number of detected SL operation enabled client device (s) capable of DRX for SL opera- tions of the targeted service and/or the timing infor- mation of the resource reservation of the client de- vice (s) incapable of DRX for SL operations acting as transmitting client device (s) for the targeted service, as detected or indicated in the received assistance mes- sage (s). o adjusting the on-off periods of the DRX cycle based on the timing information of the re- source reservation of the client device (s) 220 incapable of DRX for SL operations acting as transmitting client device (s) for the targeted service, as detected or in- dicated in the received assistance message (s).

Similar to the service-assisting client device 200, in at least some embodiments, the at least one memory 214 and the computer program code may be config- ured to, with the at least one processor 212, cause the client device 210 to perform detecting of an SL opera- tion enabled client device 220 incapable of DRX for SL operations by detecting receipt of SL data related to the SL service during an off-period of the DRX cycle, by detecting receipt of SL data related to the SL service without DRX support related information during an on- period of the DRX cycle, and/or by detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL opera- tion enabled client device incapable of DRX for SL op- erations.

Similar to the service-assisting client device 200, in at least some embodiments, the at least one memory 214 and the computer program code may be config- ured to, with the at least one processor 212, cause the client device 210 to perform detecting an additional service-assisting SL operation enabled client device capable of DRX for SL operations and/or an SL operation enabled client device capable of DRX for SL operations. For example, the at least one memory 214 and the computer program code may be configured to, with the at least one processor 212, cause the client device 210 to perform the detecting of the additional service-as- sisting SL operation enabled client device capable of DRX for SL operations and/or the SL operation enabled client device capable of DRX for SL operations based on control information related to the SL service received during an on-period of the DRX cycle, SL data related to the SL service received during an on-period of the DRX cycle, information related to a capability of the at least one of the additional service-assisting SL op- eration enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX, and/or information related to a DRX configuration of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX.

Further features of the service-targeted cli- ent device 210 directly result from the functionalities and parameters of the service-assisting client device 200 and thus are not repeated here.

Fig. 3 illustrates an example flow chart 300 of a method, in accordance with an example embodiment.

At operation 301, the service-assisting SL op- eration enabled client device 200 capable of DRX for SL operations detects the SL operation enabled client de- vice 220 incapable of DRX for SL operations acting as a transmitting client device for an SL service.

At operation 302, at least in response to the detecting of the SL operation enabled client device 220 incapable of DRX for SL operations, the service-assist- ing SL operation enabled client device 200 capable of DRX for SL operations determines to act in an assisting mode for the SL service. At operation 303, an assistance message is transmitted from the service-assisting SL operation en- abled client device 200 capable of DRX for SL operations to at least one service-targeted SL operation enabled client device 210 capable of DRX for SL operations dur- ing an on-period of a DRX cycle configured for the at least one service-targeted SL operation enabled client device 210 and/or for the SL service, the assistance message indicating assistance information related to the assisting mode.

At optional operation 304, one or more SL op- erations related to the SL service may be adapted. For example, SL data related to the SL service may be re- ceived from the SL operation enabled client device 220 incapable of DRX for SL operations during an off-period of the DRX cycle, and forwarded to the at least one service-targeted SL operation enabled client device 210 capable of DRX for SL operations during an on-period of the DRX cycle.

The method of flow chart 300 may be performed by the service-assisting client device 200 of Fig. 2A. The operations 301, 302, 303, 304 can, for example, be performed by the at least one processor 202 and the at least one memory 204. Further features of the method of flow chart 300 directly result from the functionalities and parameters of the service-assisting client device 200, and thus are not repeated here. The method of flow chart 300 can be performed by computer program (s).

Fig. 4 illustrates an example flow chart 400 of another method, in accordance with an example embod- iment.

At operation 401, the assistance message is received at the service-targeted SL operation enabled client device 210 capable of DRX for SL operations from the service-assisting SL operation enabled client device 200 capable of DRX for SL operations during an on-period of the DRX cycle configured for the service-targeted SL operation enabled client device 200 and/or for the SL service. The assistance message indicates assistance information related to the assisting mode in which the service-assisting SL operation enabled client device 200 is acting for an SL service.

At operation 402, the service-targeted SL op- eration enabled client device 210 capable of DRX for SL operations adapts one or more SL operations related to the SL service based on the received assistance infor- mation. For example, the on-period of the DRX cycle and/or an off-period of the DRX cycle may be adjusted.

The method of flow chart 400 may be performed by the service-targeted client device 210 of Fig. 2B. The operations 401, 402 can, for example, be performed by the at least one processor 212 and the at least one memory 214. Further features of the method of flow chart 400 directly result from the functionalities and parameters of the service-targeted client device 210, and thus are not repeated here. The method of flow chart 400 can be performed by computer program (s).

Fig. 5 illustrates a signaling diagram 500 of a method, in accordance with an example embodiment.

At operation 501, the service-assisting client device 200 detects the SL operation enabled client de- vice 220 incapable of DRX for SL operations acting as a transmitting client device for an SL service.

At operation 502, at least in response to the detecting of the SL operation enabled client device 220 incapable of DRX for SL operations, the service-assist- ing client device 200 determines to act in an assisting mode for the SL service.

At operation 503, an assistance message is transmitted from the service-assisting client device 200 to the service-targeted client device 210 during an on- period of a DRX cycle configured for the service-tar- geted client device 210 and/or for the SL service, the assistance message indicating assistance information related to the assisting mode. In this embodiment, the assistance information comprises an indication that the service-assisting client device 200 is configured to relay or forward SL data related to the SL service received from the client device 220 incapable of DRX for SL operations.

At operation 504, the assistance message is received at the service-targeted client device 210 from the service-assisting client device 200 during an on- period of the DRX cycle configured for the service- targeted client device 200.

At operation 505, the service-targeted client device 210 maintains one or more SL operations related to the SL service based on the received assistance in- formation (i.e., the indication that the service- assisting client device 200 is configured to relay or forward SL data related to the SL service received from the client device 220 incapable of DRX for SL operations).

At operation 506, SL data related to the SL service is received at the service-assisting client de- vice 200 from the SL operation enabled client device 220 incapable of DRX for SL operations during an off-period of the DRX cycle.

At operation 507, the received SL data is forwarded by the service-assisting client device 200 to the service-targeted client device 210 during an on- period of the DRX cycle.

The method of diagram 500 may be performed by the service-assisting client device 200 of Fig. 2A and the service-targeted client device 210 of Fig. 2B. The operations 501, 502, 503, 506, 507 can, for example, be performed by the at least one processor 202 and the at least one memory 204. The operations 504, 505 can, for example, be performed by the at least one processor 212 and the at least one memory 214. Further features of the method of diagram 500 directly result from the functionalities and parameters of the service-assisting client device 200 and the service-targeted client device 210, and thus are not repeated here. The method of diagram 500 can be performed by computer program (s).

The functionality described herein can be per- formed, at least in part, by one or more computer program product components such as software components. Accord- ing to an embodiment, the service-assisting client de- vice 200 and/or the service-targeted client device 210 may comprise a processor configured by the program code when executed to execute the embodiments of the opera- tions and functionality described. Alternatively, or in addition, the functionality described herein can be per- formed, at least in part, by one or more hardware logic components. For example, and without limitation, illus- trative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Program-specific Integrated Circuits (ASICs), Program- specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), and Graphics Processing Units (GPUs).

Any range or device value given herein may be extended or altered without losing the effect sought. Also, any embodiment may be combined with another em- bodiment unless explicitly disallowed.

Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter 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 examples of implementing the claims and other equiv- alent features and acts are intended to be within the scope of the claims.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be un- derstood that reference to 'an' item may refer to one or more of those items.

The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter de- scribed herein. Aspects of any of the embodiments de- scribed above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought.

The term 'comprising' is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclu- sive list and a method or apparatus may contain addi- tional blocks or elements.

It will be understood that the above descrip- tion is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exem- plary embodiments. Although various embodiments have been described above with a certain degree of particu- larity, or with reference to one or more individual embodiments, those skilled in the art could make numer- ous alterations to the disclosed embodiments without departing from the spirit or scope of this specifica- tion.

Claims

CLAIMS:

1. A service-assisting sidelink, SL, operation enabled client device (200) capable of discontinuous reception, DRX, for SL operations, comprising: at least one processor (202); and at least one memory (204) including computer program code; the at least one memory (204) and the computer program code configured to, with the at least one processor (202), cause the client device (200) to at least perform: detecting an SL operation enabled client device (220) incapable of DRX for SL operations acting as a transmitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device (220) incapable of DRX for SL operations, determining to act in an assisting mode for the SL service; and transmitting an assistance message to at least one service-targeted SL operation enabled client device (210) capable of DRX for SL operations during an on- period of a DRX cycle configured for at least one of the at least one service-targeted SL operation enabled client device (210) or the SL service, the assistance message indicating assistance information related to the assisting mode.

2. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to claim 1, wherein the at least one memory (204) and the computer program code are configured to, with the at least one processor (202), cause the client device (200) to perform the detecting of the SL operation enabled client device (220) incapable of DRX for SL operations by at least one of: detecting receipt of SL data related to the SL service during an off-period of the DRX cycle; detecting receipt of SL data related to the SL service without DRX support related information during an on-period of the DRX cycle; or detecting receipt of SL data related to the SL service based on a transmit resource pool exclusively configured for the SL operation enabled client device (220) incapable of DRX for SL operations.

3. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to claim 1 or 2, wherein the at least one memory (204) and the computer program code are further configured to, with the at least one processor (202), cause the client device (200) to perform detecting at least one of: an additional service-assisting SL operation enabled client device capable of DRX for SL operations or an SL operation enabled client device capable of DRX for SL operations.

4. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to claim 3, wherein the at least one memory (204) and the computer program code are configured to, with the at least one processor (202), cause the client device (200) to perform the detecting of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations based on at least one of: control information related to the SL service received during an on-period of the DRX cycle;

SL data related to the SL service received during an on-period of the DRX cycle; information related to a capability of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX; or information related to a DRX configuration of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX.

5. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to claim 3 or 4, wherein the at least one memory (204) and the computer program code are configured to, with the at least one processor (202), cause the client device (200) to perform the determining to act in the assisting mode for the SL service further in response to the result of the detecting of the at least one of the additional service-assisting SL operation enabled client device capable of DRX for SL operations or the SL operation enabled client device capable of DRX for SL operations.

6. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to any of claims 1 to 5, wherein the at least one memory (204) and the computer program code are further configured to, with the at least one processor (202), cause the client device (200) to perform utilizing an existing unicast SL for transmitting the assistance message.

7. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to any of claims 1 to 6, wherein the assistance information comprises at least one of: information related to at least one of an identity, an SL resource allocation or a transmission pattern of the detected SL operation enabled client device (220) incapable of DRX for SL operations acting as the transmitting client device for the SL service; information related to a duration of the assisting mode of the service-assisting SL operation enabled client device (200) for the SL service; an indication of whether the service-assisting SL operation enabled client device (200) is configured to forward SL data related to the SL service received from the SL operation enabled client device (220) incapable of DRX for SL operations; an indication of at least one of monitored time resources or monitored frequency resources for SL operations; or an indication indicating the presence of the detected SL operation enabled client device (220) incapable of DRX for SL operations acting as the transmitting client device for the SL service.

8. The service-assisting SL operation enabled client device (200) capable of DRX for SL operations according to any of claims 1 to 7, wherein the at least one memory (204) and the computer program code are configured to, with the at least one processor (202), cause the client device (200) to perform adapting one or more SL operations related to the SL service by: receiving SL data related to the SL service from the SL operation enabled client device (220) incapable of DRX for SL operations during an off-period of the DRX cycle, and forwarding the received SL data to the at least one service-targeted SL operation enabled client device (210) capable of DRX for SL operations during an on-period of the DRX cycle.

9. A method, comprising: detecting (301, 501), by a service-assisting sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations, an SL operation enabled client device incapable of DRX for SL operations acting as a transmitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device incapable of DRX for SL operations, determining (302, 502), by the service- assisting SL operation enabled client device capable of DRX for SL operations, to act in an assisting mode for the SL service; and transmitting (303, 503) from the service- assisting SL operation enabled client device capable of DRX for SL operations an assistance message to at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the at least one service-targeted SL operation enabled client device or the SL service, the assistance message indicating assistance information related to the assisting mode.

10. A computer program comprising instructions for causing a service-assisting sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations to perform at least the following: detecting an SL operation enabled client device incapable of DRX for SL operations acting as a transmitting client device for an SL service; at least in response to the detecting of the SL operation enabled client device incapable of DRX for SL operations, determining to act in an assisting mode for the SL service; and transmitting an assistance message to at least one service-targeted SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the at least one service-targeted SL operation enabled client device or the SL service, the assistance message indicating assistance information related to the assisting mode.

11. A service-targeted sidelink, SL, operation enabled client device (210) capable of discontinuous reception, DRX, for SL operations, comprising: at least one processor (212); and at least one memory (214) including computer program code; the at least one memory (214) and the computer program code configured to, with the at least one processor (212), cause the client device (210) to at least perform: receiving an assistance message from a service- assisting SL operation enabled client device (200) capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the service- targeted SL operation enabled client device (210) or an SL service, the assistance message indicating assistance information related to an assisting mode in which the service-assisting SL operation enabled client device (200) is acting for the SL service; and adapting or maintaining one or more SL operations related to the SL service based on the received assistance information.

12. The service-targeted SL operation enabled client device (210) capable of DRX for SL operations according to claim 11, wherein the at least one memory (214) and the computer program code are configured to, with the at least one processor (212), cause the client device (210) to perform the adapting of the one or more SL operations related to the SL service by deactivating the DRX or adjusting at least one of the on-period of the DRX cycle or an off-period of the DRX cycle.

13. A method, comprising: receiving (401, 504), at a service-targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations, an assistance message from a service-assisting SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the service-targeted SL operation enabled client device or an SL service, the assistance message indicating assistance information related to an assisting mode in which the service-assisting SL operation enabled client device is acting for the SL service; and adapting (402) or maintaining (505), by the service-targeted SL operation enabled client device capable of DRX for SL operations, one or more SL operations related to the SL service based on the received assistance information.

14. A computer program comprising instructions for causing a service-targeted sidelink, SL, operation enabled client device capable of discontinuous reception, DRX, for SL operations to perform at least the following: receiving an assistance message from a service- assisting SL operation enabled client device capable of DRX for SL operations during an on-period of a DRX cycle configured for at least one of the service-targeted SL operation enabled client device or an SL service, the assistance message indicating assistance information related to an assisting mode in which the service- assisting SL operation enabled client device is acting for the SL service; and adapting or maintaining one or more SL operations related to the SL service based on the received assistance information.