WO2023178694A1

WO2023178694A1 - Method, device and computer readable medium for communciations

Info

Publication number: WO2023178694A1
Application number: PCT/CN2022/083180
Authority: WO
Inventors: Ying Zhao; Zhaobang MIAO; Gang Wang
Original assignee: Nec Corporation
Priority date: 2022-03-25
Filing date: 2022-03-25
Publication date: 2023-09-28

Abstract

Embodiments of the present disclosure relate to methods, devices and computer readable media for communications. According to embodiments of the present disclosure, a first terminal device receives a first cyclic prefix extension, CPE, configuration. The first CPE configuration indicates a first plurality of CPEs. The first terminal device selects or determines a target CPE based on the first plurality of CPEs and a channel access procedure performed by the first terminal device for accessing a sidelink channel associated with a sidelink communication. Then, the first terminal device performs the sidelink transmission to a second terminal device based on the target CPE.

Description

METHOD, DEVICE AND COMPUTER READABLE MEDIUM FOR COMMUNCIATIONS

FIELD

Embodiments of the present disclosure generally relate to the field of communication, and in particular, to a method, device and computer readable medium for sidelink communication.

BACKGROUND

With the development of communication technology, the direct sidelink communication between terminal devices (for example, user equipment, UE) has been proposed to improve communication efficiency. In a wireless communication network, a network device, for example a Base Station (BS) , may communicate with a terminal device, for example user equipment (UE) , in an uplink direction and a downlink direction. Sidelink was introduced in LTE to allow a UE to send data to another UE without tunneling through the BS and/or an associated core network. The LTE sidelink technology had been extended to provision for device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, and/or cellular vehicle-to-everything (C-V2X) communications. Similarly, NR may be extended to support sidelink communications, D2D communications, V2X communications, and/or C-V2X over licensed bands and/or unlicensed bands. Sidelink in shared spectrum, unlicensed spectrum, channel or band (SL-U) is one of the key topics in Release 18 of the 3rd Generation Partnership Project (3GPP) . Before a terminal device initiates channel occupancy on an unlicensed spectrum, the terminal device should perform a channel access procedure for accessing the unlicensed spectrum, for example, a Listen Before Talk (LBT) procedure, to assess the usage of the unlicensed spectrum. Further, once the unlicensed spectrum is determined as idle or clear, the terminal device may occupy the unlicensed spectrum, and starts data transmission from the predefined transmission boundary of the unlicensed spectrum since the sidelink communication system operating on unlicensed spectrum is a synchronization system. However, the duration of the channel access procedure may be a dynamic value which is depending on the radio environment of the unlicensed spectrum. There may be a mismatch between the duration of channel access procedure and the timing of transmission performed by the terminal device. In addition, avoiding the collision between transmissions performed by different terminal devices on the same start boundary is also a key aspect.

SUMMARY

In general, example embodiments of the present disclosure relate to methods, devices and computer readable media for sidelink communication.

In a first aspect, there is provided a method implemented by a first terminal device. In the method, the first terminal device receives a first cyclic prefix extension, CPE, configuration. The first CPE configuration indicates a first plurality of CPEs. The first terminal device selects a target CPE based on the first plurality of CPEs and a channel access procedure performed by the first terminal device for accessing a sidelink channel associated with a sidelink communication. The first terminal device performs the sidelink transmission to a second terminal device based on the target CPE.

In a second aspect, there is provided a method implemented at a second terminal device. In the method, the second terminal device receives a second cyclic prefix extension, CPE, configuration. The second CPE configuration indicates a second plurality of CPEs. The second terminal device selects a target CPE based on the second plurality of CPEs and performs a sidelink reception from a first terminal device based on the target CPE.

In a third aspect, there is provided a method implemented at a network device. In the method, the network device transmits a first cyclic prefix extension, CPE, configuration for a sidelink transmission to a first terminal device. The first CPE configuration indicates a first plurality of CPEs. The network device transmits a second cyclic prefix extension, CPE, configuration for a sidelink reception to a second terminal device. The second CPE configuration indicates a second plurality of CPEs.

In a fourth aspect, there is provided a method implemented at a third terminal device. In the method, the third terminal device transmits a first cyclic prefix extension, CPE, configuration for a sidelink transmission to a first terminal device. The first CPE configuration indicates a first plurality of CPEs. The third terminal device device transmits a second cyclic prefix extension, CPE, configuration for a sidelink reception to a second terminal device. The second CPE configuration indicates a second plurality of CPEs.

In a fifth aspect, there is provided a terminal device. The terminal device comprises a processor and a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the terminal device to perform the method of any one of the first aspect, second aspect or fourth aspect.

In an sixth aspect, there is provided a network device. The network device comprises a processor and a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the network device to perform the method of the third aspect.

In a seventh aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method of any one of the first aspect to the fifth aspect.

It is to be understood that the summary section is not intended to identify key or essential features of example 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, where:

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

FIG. 2 illustrates a signaling process of sidelink communication according to some embodiments of the present disclosure;

FIG. 3 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure;

FIG. 4 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure;

FIG. 5 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure;

FIG. 6 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure;

FIG. 7 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure;

FIG. 8 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure;

FIG. 9 illustrates a flowchart of an example method implemented at a first terminal device in accordance with some embodiments of the present disclosure;

FIG. 10 illustrates a flowchart of an method implemented at a second terminal device in accordance with some embodiments of the present disclosure;

FIG. 11 illustrates a flowchart of an example method implemented at a network device in accordance with some embodiments of the present disclosure;

FIG. 12 illustrates a flowchart of an example method implemented at a third terminal device in accordance with some embodiments of the present disclosure;

FIG. 13 illustrates a simplified block diagram of a device that is suitable for implementing example embodiments of the present disclosure.

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

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some 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 limitations 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.

As used herein, the term ‘terminal device’ refers to any device having wireless or wired communication capabilities. Examples of the terminal device include, but not limited to, user equipment (UE) , personal computers, desktops, mobile phones, cellular phones, smart phones, personal digital assistants (PDAs) , portable computers, tablets, wearable devices, internet of things (IoT) devices, Ultra-reliable and Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, device on vehicle for V2X communication where X means pedestrian, vehicle, or infrastructure/network, devices for Integrated Access and Backhaul (IAB) , Small Data Transmission (SDT) , mobility, Multicast and Broadcast Services (MBS) , positioning, dynamic/flexible duplex in commercial networks, reduced capability (RedCap) , Space borne vehicles or Air borne vehicles in Non-terrestrial networks (NTN) including Satellites and High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) , eXtended Reality (XR) devices including different types of realities such as Augmented Reality (AR) , Mixed Reality (MR) and Virtual Reality (VR) , the unmanned aerial vehicle (UAV) commonly known as a drone which is an aircraft without any human pilot, devices on high speed train (HST) , or image capture devices such as digital cameras, sensors, gaming devices, music storage and playback appliances, or Internet appliances enabling wireless or wired Internet access and browsing and the like. The ‘terminal device’ can further has ‘multicast/broadcast’ feature, to support public safety and mission critical, V2X applications, transparent IPv4/IPv6 multicast delivery, IPTV, smart TV, radio services, software delivery over wireless, group communications and IoT applications. It may also incorporated one or multiple Subscriber Identity Module (SIM) as known as Multi-SIM. The term “terminal device” can be used interchangeably with a UE, a mobile station, a subscriber station, a mobile terminal, a user terminal or a wireless device.

As used herein, the term “network device” refers to a device which is capable of providing or hosting a cell or coverage where terminal devices can communicate. Examples of a network device include, but not limited to, a Node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNB) , a transmission reception point (TRP) , a remote radio unit (RRU) , a radio head (RH) , a remote radio head (RRH) , an IAB node, a low power node such as a femto node, a pico node, a reconfigurable intelligent surface (RIS) , Network-controlled Repeaters, and the like.

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information. The terminal or the network device may work on several frequency ranges, e.g. FR1 (410 MHz –7125 MHz) , FR2 (24.25 GHz to 71 GHz) , 71 GHz to 114 GHz, and frequency band larger than 100 GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connections with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The network device may have the function of network energy saving, Self-Organizing Networks (SON) /Minimization of Drive Tests (MDT) . The terminal may have the function of power saving.

The embodiments of the present disclosure may be performed in test equipment, e.g. signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator.

The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

In one embodiment, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In one embodiment, the first network device may be a first RAT device and the second network device may be a second RAT device. In one embodiment, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device and the second network device. In one embodiment, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In one embodiment, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

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. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’ is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’a re to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

In some examples, values, procedures, or apparatus are referred to as ‘best, ’ ‘lowest, ’ ‘highest, ’ ‘minimum, ’ ‘maximum, ’ or the like. It will be appreciated that such descriptions are intended to indicate that a selection among many used functional alternatives can be made, and such selections need not be better, smaller, higher, or otherwise preferable to other selections.

The term “circuitry” used herein may refer to hardware circuits and/or combinations of hardware circuits and software. For example, the circuitry may be a combination of analog and/or digital hardware circuits with software/firmware. As a further example, the circuitry may be any portions of hardware processors with software including digital signal processor (s) , software, and memory (ies) that work together to cause an apparatus, such as a terminal device or a network device, to perform various functions. In a still further example, the circuitry may be hardware circuits and or processors, such as a microprocessor or a portion of a microprocessor, that requires software/firmware for operation, but the software may not be present when it is not needed for operation. As used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (s) or a portion of a hardware circuit or processor (s) and its (or their) accompanying software and/or firmware.

As mentioned above, there may be a mismatch between the duration of channel access procedure and the timing of transmission performed by the terminal device. One solution is that configuring one fixed CPE to a terminal device, the fixed CPE is a repetition of a part of symbols to be transmitted by a terminal device. Once the channel access procedure performed by the terminal device is successful, the terminal device may transmit this fixed CPE before the transmission boundary on the sidelink channel, in order to fill the gap caused by the mismatch. For example, the duration T _ext of this fixed CPE may be determined by the following Equation (1) :

where

is a duration of one symbol with 15kHz Sub-Carrier Spacing (SCS) , and Δ _i can be configured fixedly. In an example, the Δ _i for a terminal devices can be determined by retrieving from the table 1 based on an index for the Δ _i. In this case, the terminal device may be configured with a fixed index for the Δ _i to determine the duration of the CPE.

TABLE 1

However, since the duration of channel access procedure for initiating occupancy on a sidelink channel (for example, Type 1 channel access procedure, Cat 4 LBT) associated with sidelink communication depends on the radio environment, in turn, the gap may be also varied with different radio environment. Therefore, the configured fixed CPE for a terminal device cannot completely adapt to the uncertain sensing duration in the channel access procedure.

The example embodiments of the disclosure propose a mechanism for adaptively filling this gap in the sidelink communication on the shared or unlicensed spectrum. In this mechanism, a plurality of CPEs are configured to a terminal device for selecting a target CPE filling this gap. Specifically, a first terminal device receives a first cyclic prefix extension, CPE, configuration. The first CPE configuration indicates a first plurality of CPEs. Then, based on the first plurality of CPEs and a sensing duration of a channel access procedure performed by the first terminal device for sensing or accessing a sidelink channel associated with a sidelink communication, the first terminal device selects a target CPE. Further, the first terminal device performs the sidelink transmission to a second terminal device based on the target CPE.

In this way, an appropriate CPE may be selected by the terminal device for filling this gap. In addition, different one or more CPEs may be configured to different terminal devices, in order to coordinating the competition of different terminal devices for the same shared or unlicensed spectrum.

FIG. 1 illustrates an example environment 100 in which example embodiments of the present disclosure can be implemented.

The environment 100, which may be a part of a communication network, comprises a first terminal device 110, a second terminal device 120, a third terminal device 130 and a network device 140. The first terminal device 110, the second terminal device 120, the third terminal device 130 may initiate sidelink communication with each other on a sidelink channel. A terminal device in the environment 100 may receive the CPE configuration from a network device or from another terminal device.

It is to be understood that the number of terminal devices and network device is shown in the environment 100 only for the purpose of illustration, without suggesting any limitation to the scope of the present disclosure. In some embodiments, the environment 100 may comprise a further terminal device to communicate information with a further network device.

The communications in the environment 100 may follow any suitable communication standards or protocols, which are already in existence or to be developed in the future, such as Universal Mobile Telecommunications System (UMTS) , long term evolution (LTE) , LTE-Advanced (LTE-A) , the fifth generation (5G) New Radio (NR) , Wireless Fidelity (Wi-Fi) and Worldwide Interoperability for Microwave Access (WiMAX) standards, and employs any suitable communication technologies, including, for example, Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiplexing (OFDM) , time division multiplexing (TDM) , frequency division multiplexing (FDM) , code division multiplexing (CDM) , Bluetooth, ZigBee, and machine type communication (MTC) , enhanced mobile broadband (eMBB) , massive machine type communication (mMTC) , ultra-reliable low latency communication (URLLC) , Carrier Aggregation (CA) , Dual Connection (DC) , and New Radio Unlicensed (NR-U) technologies.

FIG. 2 illustrates a signaling process 200 of sidelink communication according to some embodiments of the present disclosure. For purpose of discussion, the process 200 will be described with reference to FIG. 1.

In the signaling process 200, the first terminal device 110 receives (210) a first CPE configuration. In some embodiments, the first terminal device 110 may receive the first CPE configuration from a network device, for example, the network device 140. In addition or alternatively, the first terminal device may receive the first CPE configuration from another terminal device, for example, the second terminal device 120 or the third terminal device 130, via a PC5-RRC interface. For simplicity of the discussion and without any limitation, the following embodiments are described in the case that the first CPE configuration is transmitted by a network device.

The received first CPE configuration indicates a plurality of CPEs. In some embodiments, the first CPE configuration may comprise a CPE with the maximum duration or the maximum length, namely the CPE with maximum configured duration or length, for example, “1/14ms” . In this disclosure, the duration of CPE, the length of CPE, CPE duration or CPE length may have the similar meanings and may be used interchangeably. In addition, the CPE with the maximum duration or length may be also referred as “amaximum CPE” corresponding to a CPE group. Then, the first terminal device 110 may derive the plurality of CPEs based on the CPE with the maximum duration. For example, the first terminal device 110 may consider any CPE of which duration is smaller than the maximum duration as a CPE for filling the gap discussed above. In some embodiments, different maximum CPEs may be configured to different terminal devices by the CPE configurations. For example, based on the priority level of a terminal device, a priority level of traffic to be performed by the terminal device or the channel access priority class (CAPC) , a CPE with a certain maximum duration may be configured to the first terminal device 110. In an example, if the first terminal device 110 is configured with the highest priority, the first terminal device 110 may be configured with the CPE with the maximum duration which is larger than respective maximum durations of other CPE groups for other terminal devices, in order to occupying a sidelink channel by the first terminal device 110 in advance. In some embodiments, the first CPE configuration may be determined based on at least one of: a first priority level associated with the first terminal device, a second priority level associated with a traffic to be transmitted by the first terminal device and a channel access priority class in the channel access procedure. For example, the first CPE configuration may be determined based on at least one of: the priority between configured grant based transmission and dynamic grant based transmission, the priority of PSCCH/PSSCH or the service in sidelink operation for the same/different UE, channel access priority class in channel access procedure and the contention window value and so on.

As such, the first terminal device 110 may select an appropriate a CPE and the competition between different terminal devices can be coordinated.

In addition, in some embodiments, the first CPE configuration may comprise a first CPE group index list having one or more group indexes and each CPE group index may correspond to a respective CPE with a maximum duration or a maximum length (as mentioned above, this CPE may be also referred as a maximum CPE) . Then, based on this maximum CPE corresponding to the group index, the first terminal device 110 may derive one or more CPEs of the first plurality of CPEs, and a CPE of the one or more CPEs has a duration smaller than the maximum duration or a length shorter than the maximum length. In this case, the terminal device 110 may be configured with different CPE groups, and derive one or more CPEs associated with a CPE group based on the maximum CPE corresponding to the CPE group. For different requirements, different CPE group indexes may correspond to different maximum CPEs. For example, if a CPE group is assigned for performing the transmission in the case that the occupied sidelink channel for the current transmission is to be occupied continuously for successive transmission (s) , the index of this CPE group may correspond to maximum CPE with 0ms duration.

In addition or alternatively, in some embodiments, the first CPE configuration may comprise a first CPE group index list having one or more group indexes. The group index corresponds to a CPE group which indicates one or more CPEs. For example, the CPE group may comprise one or more CPE related parameter indexes i (namely the index of parameter Δ as listed in Table 1) . Since a duration of a CPE can be defined based on Equation (1) and a given index i c in other words, the CPE related parameter index i can implicitly indicate a respective CPE having a certain duration. Accordingly, once the first CPE configuration is received, the first terminal device may determine the indicated first plurality of CPEs and respective durations of these CPEs autonomously.

In addition or alternatively, the CPE group may also comprise one or more CPE indexes of which each directly corresponds to a CPE with a predefined duration. In this case, without using the equation (1) , the first terminal device 110 may directly retrieve the information on the one or more CPEs and their durations. For example, a Table 2 defining a relation between a CPE index and the duration of this CPE may be preconfigured.

TABLE 2

CPE index j	Duration of CPE j
0	Duration 0
1	Duration 1
2	Duration 2
3	Duration 3
4	Duration 4
5	Duration 5
6	Duration 6

In some embodiments, the value of Duration 0 may be equal to

the value of Duration 1 may be equal to

and so on, where the parameter Δ ₀ and Δ ₁ are the corresponding parameters in the Table 1. In this way, the terminal device may retrieve the CPE with corresponding duration from the Table 2 based on a CPE index in the CPE group.

For discussion simplicity and without any limitation, the following embodiments are discussed with reference to the CPE group comprising CPE related parameter index i as illustrated in Table 1.

In some embodiments, the first CPE configuration may comprise a first CPE group index list having two group indexes, one of the two group indexes corresponds to a first CPE group which is a default CPE group for the sidelink transmission, another of the two group indexes corresponds to a second CPE group which is a CPE group for the sidelink transmission when the channel on sidelink channel is occupied continuously for successive transmissions.

In an example, as discussed above, the first CPE group may comprise the CPE related parameter indexes {4, 5, 6} as listed in the Table 1, the index in turn corresponds to a CPE with a certain duration. For example, the CPE related parameter index {4} corresponds to a CPE with a duration

Further, the second CPE group may comprise the CPE index {6} . In this case, the second CPE group only indicates one CPE with the duration of 0ms

In this way, the first terminal device 110 may be configured with two CPE groups, the first CPE group indirectly indicates three candidate CPEs for being selected to fill the first gap between the ending time of the successful channel access procedure and a transmission boundary and the second CPE group has only one candidate CPE.

In some embodiments, depending on different communication requirements, the first CPE configuration may comprise different CPE group index lists for the first terminal device 110. Similarly, based on the priority level of a terminal device, a priority level of traffic to be performed by the terminal device or the priority level of a channel access procedure, a certain CPE group index list is configured to the first terminal device 110. For example, if the first terminal device 110 is configured with the highest priority, the first terminal device 110 may be configured with a first CPE group comprising the parameter Δindexes {0, 1} . As such, the duration of the candidate CPEs is

which is longer than other CPEs. Therefore, the first terminal device 110 may occupy the sidelink channel in advance.

In some examples, the first CPE group for sidelink transmission may comprise the CPE related parameter indexes: {3, 4, 5, 6} , and the second CPE group for sidelink transmission may comprise the CPE related parameter index: {6} . In some examples, the first CPE group for sidelink transmission may comprise the CPE related parameter index: {0} , and the second CPE group for sidelink transmission may comprise the the CPE related parameter index: {6} . In some examples, the first CPE group for sidelink transmission may comprise the the CPE related parameter index: {3} , and the second CPE group for sidelink transmission may comprise the CPE related parameter index: {6} .

In some embodiments, the first terminal device 110 may receive the first CPE configuration via a first dedicated signaling for the first CPE configuration. For example, the first CPE configuration may be received in a “SLCPE GroupIdlist” signaling.

In some embodiments, the first CPE configuration may be specific to a transmission resource pool. For example, the CPE group corresponding to a CPE group index in the first CPE group index list may be configured for one or more of a plurality of transmission resource pools associated with the sidelink communication.

The network device 140 (or the third terminal device 130) transmits (220) a second CPE configuration to the second terminal device 120. Similarly, in some embodiments, the third terminal device 130 may transmit the second CPE configuration to the second terminal device 120 via PC5 RRC interface.

The second CPE configuration indicates a second plurality of CPEs. In some embodiments, the second CPE configuration may comprise a respective maximum CPE. Then, the second terminal device 120 may derive the second plurality of CPEs based on the second maximum CPE in the similar way as the first terminal device 110.

In addition, the second CPE configuration may comprise a second CPE group index list having one or more group indexes and each CPE group index may correspond to a respective maximum CPE. Then, based on the respective maximum CPE corresponding to the group index, the second terminal device 120 may derive one or more CPEs of the second plurality of CPEs in the similar way as the first terminal device 110. In this case, the second terminal device 120 may be configured with different CPE groups, and derive one or more CPEs associated with a CPE group based on the maximum CPE corresponding to the CPE group. For different requirements, different CPE group indexes may correspond to different maximum CPEs.

In addition or alternatively, in some embodiments, the second CPE configuration may comprise a second CPE group index list having one or more group indexes. The group index corresponds to a CPE group which indicates one or more CPEs. For example, similar to the CPE groups in the first CPE group index list, the CPE group in the second CPE index group list may comprise one or more CPE related parameter indexes, and the CPE related parameter index {i} corresponds to a CPE with a certain duration.

In some embodiments, the second CPE configuration may comprise a second CPE group index list having two group indexes, one of the two group indexes corresponds to a first CPE group which is a default CPE group for the sidelink reception, another of the two group indexes corresponds to a second CPE group which is a CPE group for the sidelink reception when the sidelink channel is occupied continuously.

For example, the first CPE group for the sidelink reception may comprise the CPE CPE related indexes: {1, 2, 3} in the Table 1, the CPE index in turn corresponds to a respective CPE with a certain duration in the Table 1. As an example, CPE related parameter index {1} corresponds to a duration

Further, the second CPE group for the sidelink reception may comprise the parameter Δ index {6} . As an example, CPE related parameter index {6} corresponds to a CPE with a duration of 0ms. In this way, the second terminal device 120 may be configured with two CPE groups, a first CPE group for the sidelink transmission inidicates three candidate CPEs of which each has a certain duration, and a second CPE group for the sidelink transmission indicates only one CPE with a duration of 0ms. In some embodiments, if the terminal device 120 determines that the reliability of a traffic on the sidelink channel is necessary, the terminal device 120 may select a CPE with a long duration based on the first CPE group for transmission reception, in order to increase the repetition reception gain.

In some examples, the first CPE group for the sidelink reception may comprise the CPE related parameter indexes {0, 1, 2, 3, 4, 5, 6} , and the second CPE group for sidelink reception may comprise the CPE related parameter indexes {6} . In some examples, the first CPE group for the sidelink reception may comprise the CPE related parameter indexes {4, 6} , and the second CPE group for sidelink transmission may comprise the CPE related parameter indexes {6} . In some examples, the first CPE group for sidelink reception may comprise the CPE related parameter index {2} , and the second CPE group for sidelink transmission may comprise the CPE related parameter index {6} .

In some embodiments, the second terminal device 120 may receive the second CPE configuration via a second dedicated signaling for the first CPE configuration. For example, the first CPE configuration may be received in a “SLCPEGroupIdListCommon” signaling.

In some embodiments, the second CPE configuration may be specific to a reception resource pool. For example, the CPE group corresponding to a CPE group index in the second CPE group index list may be configured for one or more of a plurality of reception resource pools associated with the sidelink communication.

Based on the first plurality of CPEs and a sensing duration of a channel access procedure performed by the first terminal device 110 for sensing or accessing a sidelink channel associated with a sidelink communication, the first terminal device 110 selects (230) a target CPE. In some embodiments, the sidelink channel may be on a shared/unlicensed spectrum associated with the sidelink communication.

The selection of the target CPE by the first terminal device 110 for performing the transmission is further discussed with reference to FIG. 3.

FIG. 3 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure. For purpose of discussion, it will be described with reference to FIG. 1.

In FIG. 3, arrow 301 indicates transmission boundary (for example, start time of a slot or a symbol) in a sidelink channel associated with sidelink communication (in other word, the transmission boundary predefined for the sidelink channel) . After the first terminal device 110 determines that the channel access procedure is successful, the first terminal device 110 should transmit symbols carrying data from the boundary indicated by arrow 301.

In some embodiments, assuming that the first terminal device 110 receives the first CPE configuration comprising the first CPE group index list, the first CPE group index list has two indexes, one index corresponds to a first CPE group {0, 1, 2, 3, 4, 5, 6} , the other one index corresponds to a second CPE group {6} . In some embodiments, the fist CPE group is a default transmission CPE group which may be used after initiating occupancy of the sidelink channel, such as, after performing a successful Type 1 channel access procedure. The second CPE group is a CPE group which may be used in the case that the channel occupied for current transmission on sidelink channel is to be occupied continuously based ona Type 2C channel access procedure.

In some embodiments, the Type 1 channel access procedure (Cat4 LBT) may occasionally require a duration of a whole symbol (for example, LBT 310) , then the first terminal device may select the CPE corresponding to the CPE related parameter index {6} as the a target CPE based on the first CPE configuration. As such, since the channel access procedure ends immediately before the transmission starting boundary, such as a symbol boundary or a slot boundary, there is no gap between the channel access procedure and the transmission boundary, the first terminal device 110 may select the CPE corresponding to the CPE related parameter index {6} as the target CPE, since the duration of this CPE with the index {6} is 0ms.

In some embodiments, if the Type 1 channel access procedure (LBT 320) ends before the intended transmission starting boundary, such as a symbol boundary or a slot boundary, based on the gap between the ending of Type1 channel access procedure and the intended transmission boundary, the first terminal device 110 may select another appropriate CPE as the target CPE for filling the gap between the successful LBT and the transmission boundary on the sidelink channel. For example, assuming that the duration of CPE corresponding to CPE related parameter index {4} is the CPE of which the duration is shorter than the gap and is longer than the durations of other CPEs, then the first terminal device 110 may select the CPE corresponding to the CPE related parameter index {4} (this CPE may be also referred as “CPE 4” ) as the target CPE.

In addition or alternatively, in some embodiments, the first CPE group (or the first index of CPE group) corresponds to a first maximum CPE, the first terminal device 110 may select any CPE of which duration is shorter than the first maximum CPE as the target CPE. For example, the first terminal device 110 may select a CPE which is equal to the gap and smaller than the first maximum CPE as the target CPE.

Upon the first terminal device 110 selects the target CPE, the first terminal device 110 may transmit the target CPE before the transmission boundary and initiate a channel occupancy.

For illustration, FIG. 3 illustrates two example CPE gourps for sidelink transmission, the first CPE group and the second CPE group. The first CPE group (which may be also referred by CPE group index, for example “CPE group 0” ) comprises six CPE related parameters {0, 1, 2, 3, 4, 5, 6} , and the second CPE group (which may be also referred by CPE group index, for example “CPE group 1” ) comprises one CPE related parameter {6} . Further, the rectangle at right side represents an Δ _i corresponding to the CPE related parameter, such as the rectangle 350 represents the Δ ₅ corresponding to the CPE related parameter {5} . In turn, the length of a rectangle represents the duration of the Δ _i, for example, the rectangle 360 represents the duration of Δ ₆ corresponding to the CPE related parameter 6. As discussed above, the duration of a respective CPE may be defined based on Equation (1) and Δ _i. In this way, the CPE group may indicate one or more CPEs with respective durations implicitly. For example, a CPE with CPE related parameter 4, such as “CPE 4” in the FIG. 3, is a CPE with a duration related to Δ ₄, and so on.

Referring back to FIG. 2, the second terminal device 120 selects (240) a target CPE for sidelink reception based on the second plurality CPEs indicated by the second CPE congfiguration.

After the first terminal device 110 selects the target CPE (for example, the CPE corresponding to parameter Δ index 4) , the first terminal device 110 performs (250) the sidelink transmission to the second terminal device 120 based on the target CPE. For example, the first terminal device 110 may transmit the target CPE before the transmission boundary on the sidelink channel, and further start transmitting at transmission boundary.

Accordingly, the second device 120 performs (250) the sidelink reception from the first terminal device 120 based on the target CPE selected by the second device 120 for the sidelink reception.

Alternatively, in some embodiments, the second device 120 may directly receive the sidelink transmission at the conventional symbol boundary or slot boundary without receiving a selected target CPE for sidelink transmission in advance. In some embodiments, due to the importance of PSFCH, the second terminal device 120 may monitor PSFCH based on a target CPE selected from a CPE group which is corresponding to one or more candidate CPEs. In this way, based on the reception of CPE, the reliability of reception PSFCH may be increased since the repetition gain as discussed above.

In some embodiments, upon performing the sidelink transmission, for selecting the target CPE, the first terminal device 110 may switch (260) between the first CPE group and the second CPE group based on whether the channel on sidelink channel will be continuously occupied for sidelink transmission from the first terminal device. If the first terminal device 110 reserves the sidelink resources/channel for intending sidelink transmission and will continuously occupy the resources/channel for the data transmission in next slot (s) subsequent to the slot currently occupied by the first terminal device 110, then, it is not necessary to select the target CPE based on a plurality of candidate CPEs, for example, the CPEs corresponding to the CPE related parameter indexes in the first CPE group.

In turn, if the first terminal device 110 shares a sidelink channel occupancy from other terminal device for the intending sidelink transmission (s) from the first terminal device 110 based on a Type 2 channel access procedure, the first terminal device 110 may select (260) a target CPE based on the second CPE group which may comprise only one parameter Δ index for the subsequent sidelink transmission (s) . In this way, the operations at the terminal devices can be simplified when the first terminal device 110 performs the sidelink transmission in a next slot.

In some embodiments, if the first terminal device 110 determines to select the target CPE based on the second CPE group, the first terminal device 110 may transmit (270) to the second terminal device 120 a group switching flag indicating the subsequent channel occupancy status on the sidelink channel. Accordingly, the second terminal device 120 may switch (280) from the first CPE group for sidelink reception to the second CPE group for sidelink reception. Then, the second device 120 may perform the sidelink reception from the first terminal device 110 based on the target CPE further selected from the second CPE group for sidelink transmission.

With reference to FIGs. 4-8, some embodiments will be discussed related to selecting the target CPE and performing the sidelink transmission or reception after initiating a sidelink channel occupancy for sidelink transmission.

FIG. 4 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure.

In FIG. 4, assuming that the first terminal device 110 receives the first CPE configuration comprising the first CPE group index list, the first CPE group index list has two indexes, one index corresponds to a first CPE group {3, 4, 5, 6} , the other one index corresponds to a second CPE group (which may be also referred as “CPE group 1” ) {6} . At the second terminal device 120, assuming that the second terminal device 120 receives the second CPE configuration comprising the second CPE group index list, and the second CPE group index list has only two indexes. One index in the second CPE group index list corresponds to a first CPE group (which may be also referred as “CPE group 0” ) {3, 4, 5, 6} , the other one index in the second CPE group index list corresponds to a second CPE group (which may be also referred as “CPE group 0” ) {6} .

If the first terminal device 110 transmitted a Physical Sidelink Control Channel (PSCCH) , Physical Sidelink Shared Channel (PSSCH) or Physical Sidelink Feedback Channel (PSFCH) transmission with a group switching flag having a second value on a slot after a successful channel access procedure and initiated a channel occupancy, the first terminal device 110 may continue to transmit a PSCCH/PSSCH or PSFCH transmission (s) without long gap (e.g. larger than 16us) on a successive slot (s) based on the second CPE group for the sidelink transmission within the MCOT (maximum channel occupancy time) . The first terminal device 110 may transmit a group switching flag having a second value 401 (for example, “1” ) , the second value indicates the sidelink channel being used is to be continuously occupied. In addition, the first terminal device 110 may select the CPE corresponding to parameter Δ index 6 (that is, the duration of the target CPE is 0ms) in the second CPE group to perform the sidelink transmission on the next slot 410.

Upon detecting the received group switching flag having the second value 401, the second terminal device 120 may select the target CPE based on the second CPE group for sidelink reception to perform the sidelink reception on the next slot 410, as illustrated by the arrow 420. In this way, in the case that the sidelink channel will be occupied continuously, the second terminal device 120 may select the target CPE for performing the sidelink reception in a more efficiency way.

FIG. 5 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure.

Assuming that the second terminal device 120 receives the second CPE configuration comprising the second CPE group index list, and the second CPE group index list has only two indexes. One index in the second CPE group index list corresponds to a CPE group (which may be also referred as “CPE group 0” ) {3, 4, 5, 6} , the other one index in the second CPE group index list corresponds to a second CPE group (which may be also referred as “CPE group 1” ) {6} .

In some embodiments, if the first terminal device 110 transmitted a PSCCH, PSSCH or PSFCH transmission with group switching flag having the second value (for example, “1” ) in a slot within a shared channel occupancy initiated by another terminal device using the Type 2 channel access procedures on a channel, the first terminal device 110 may continue to transmit a PSCCH, PSSCH or PSFCH transmission (s) on a successive slot (s) according to second CPE group within the shared COT without a long gap (e.g. larger than 16us) , as illustrated by the slot 501. Similarly, upon detecting the received group switching flag having the second value (flag = 1) , the second terminal device 120 may select the target CPE based on the second CPE group for sidelink reception to perform the sidelink reception on the next slot, as illustrated by the arrow 510.

FIG. 6 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure.

Assuming that the second terminal device 120 receives the second CPE configuration comprising the second CPE group index list, and the second CPE group index list has only two indexes. One index in the second CPE group index list corresponds to a first CPE group (which may be also referred as “CPE group 0” ) {3, 4, 5, 6} , the other one index in the second CPE group index list corresponds to a second CPE group (which may be also referred as “CPE group 1” ) {6} .

If the second terminal device 120 detects a Sidelink Control Information (SCI) /PSFCH in a slot and a value of group switching flag is a first value (for example, the flag = 0) , the first value indicates that the first terminal device 110 selects a CPE based on a default CPE group for sidelink transmission. Then, the second terminal device 120 starts monitoring PSCCH/PSSCH (or PSFCH) based on the default CPE group in the next slot (or the current slot) .

In some embodiments, upon the second terminal device 120 detects that a channel occupancy has been initiated for the sidelink transmission on a shared or unlicensed spectrum by a terminal device (for example, the first terminal device 110) , the second terminal device 120 may set a timer for the MCOT on the sidelink channel since the maximum duration of the COT is predefined. Once the MCOT is reached, a Type 1 channel access procedure should be performed to initiate a new channel occupancy on sidelink channel. In turn, once the timer expires or the second terminal device 110 receives a group switching flag having the first value within a slot, the second terminal device 110 may select the target CPE based on the default CPE group for the sidelink reception, and perform the sidelink reception based on this target CPE on the next slot.

FIG. 7 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure.

Assuming that the second terminal device 120 receives the second CPE configuration comprising the second CPE group index list, and the second CPE group index list has only two indexes. One index in the second CPE group index list corresponds to a first CPE group (which may be also referred as “CPE group 0” ) {4} , the other one index in the second CPE group index list corresponds to a second CPE group (which may be also referred as “CPE group 1” ) {6} .

If the second terminal device 120 sets a timer (as illustrated by arrow 701) for the MCOT on the shared or unlicensed spectrum and monitors PSCCH/PSSCH or PSFCH based on the second CPE group for the sidelink reception (as illustrated by arrow 710) , once the timer expires (as illustrated by arrow 720) , the second terminal device 120 stops monitoring PSCCH/PSSCH based on the second CPE group for the sidelink reception (as illustrated by arrow 730) . Then, the second terminal device 120 monitors PSCCH/PSSCH or PSFCH based on the default CPE group (for example, the first CPE group) for the sidelink reception.

In some embodiments, if one terminal device initiates a channel occupancy for sidelink transmission on shared or unlicensed spectrum by Type 1 channel access procedure and the channel occupancy is shared with another terminal device, then this one terminal device may confirm that the channel will be occupied continuously within the MCOT. Accordingly, the one terminal device may directly perform the sidelink reception on the shared channel based on the second CP group for the sidelink reception in a slot within the COT.

FIG. 8 illustrates a schematic showing a CPE selection according to some embodiments of the present disclosure.

If the first terminal device 110 initiated a channel occupancy for a PSCCH/PSSCH or PSFCH transmission by the Type 1 channel access procedure. The first terminal device 110 may set the value of the group switching flag to the second value, then the first terminal device 110 may share the channel occupancy with other terminal device (s) and starts to monitoring PSCCH/PSSCH or PSFCH based on the second CPE group.

FIG. 9 illustrates a flowchart of a method 900 of communication implemented at a fourth network device in accordance with some embodiments of the present disclosure. The method 900 can be implemented at the first terminal device 110 shown in FIG. 1. For the purpose of discussion, the method 900 will be described with reference to FIG. 1. It is to be understood that the method 900 may include additional acts not shown and/or may omit some shown acts, and the scope of the present disclosure is not limited in this regard.

At block 910, the first terminal device 110 receives a first CPE configuration. The first CPE configuration indicates a first plurality of CPEs.

At block 920, the first terminal device 110 selects a target CPE based on the first plurality of CPEs and a sensing duration of a channel access procedure performed by the first terminal device for accesing a sidelink channel associated with a sidelink communication.

At block 930, the first terminal device 110 performs the sidelink transmission to a second terminal device based on the target CPE.

In some embodiments, the first CPE configuration comprises a first CPE group index list having one or more group indexes, each group index in the first CPE group index list corresponding to a respective CPE with a maximum CPE duration or a maximum CPE length, the method further comprising: , the method further comprising: deriving one or more CPEs of the first plurality of CPEs based on the maximum CPE duration or the maximum CPE length, a CPE of the one or more CPEs having a duration smaller than the maximum CPE duration or a length shorter than the maximum CPE length.

In some embodiments, the first CPE configuration comprises a first CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs.

In some embodiments, the CPE group comprises one or more related parameter indexes, a CPE related parameter index in the CPE group corresponding to a CPE.

In some embodiments, the CPE group is configured for one or more of a plurality of transmission resource pools associated with the sidelink communication.

In some embodiments, receiving the first CPE configuration comprises: receiving a first dedicated signaling for the first CPE configuration.

In some embodiments, the first CPE configuration is determined based on at least one of: a first priority level associated with the first terminal device; a second priority level associated with a traffic to be transmitted by the first terminal device; and a channel access priority class in the channel access procedure.

In some embodiments, selecting the target CPE comprises: in accordance with a determination that the channel access procedure is successful, selecting the target CPE for filling a first gap between the successful channel access procedure and a transmission starting boundary based on one or more CPEs indicated by a first CPE group, the first CPE group corresponding to a first group index in the first CPE group index list, the first CPE group being a default CPE group for the sidelink transmission.

In some embodiments, performing the sidelink transmission comprises: transmitting, to the second terminal device, a group switching flag having a first value, the first value indicating that the first terminal device has selected the target CPE based on the first CPE group.

In some embodiments, selecting the target CPE comprises: in accordance with a determination that the sidelink channel is to be continuously occupied, selecting the target CPE based on one or more CPEs indicated by a second CPE group, the second CPE group corresponding to a second group index in the first CPE group index list.

In some embodiments, performing the sidelink transmission comprises: transmitting, to the second terminal device, a group switching flag having a second value, the second value indicating that the sidelink channel is to be continuously occupied; and performing, based on the target CPE, the sidelink transmission in a next slot subsequent to the slot currently occupied by the first terminal device.

In some embodiments, determining that the sidelink channel is to be continuously occupied comprises: in accordance with a determination that a second gap between a slot currently occupied by the first terminal device and a next slot subsequent to the slot is below a predetermined threshold, determining that the sidelink channel is to be continuously occupied.

FIG. 10 illustrates a flowchart of a method 1000 of communication implemented at a first terminal device in accordance with some embodiments of the present disclosure. The method 1000 can be implemented at the second terminal device 120 shown in FIG. 1. For the purpose of discussion, the method 1000 will be described with reference to FIG. 1. It is to be understood that the method 1000 may include additional acts not shown and/or may omit some shown acts, and the scope of the present disclosure is not limited in this regard.

At block 1010, the second terminal device 120 receives a second CPE configuration, the second CPE configuration indicating a second plurality of CPEs.

At block 1020, the second terminal device 120 selects a target CPE based on the second plurality of CPEs.

At block 1030, the second terminal device 120 performs a sidelink reception from a first terminal device based on the target CPE.

In some embodiments, the second CPE configuration comprises a second CPE group index list having one or more group indexes, each group index in the second CPE group index list corresponding to a respective CPE with a maximum CPE duration , the method further comprising: deriving one or more CPEs of the second plurality of CPEs based on the maximum CPE duration, a CPE of the one or more CPEs having a duration smaller than the maximum CPE duration .

In some embodiments, the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the second CPE group index list corresponding to a CPE group indicating one or more CPEs.

In some embodiments, the CPE group comprises one or more CPE related parameter indexes, a CPE related parameter index in the CPE group corresponding to a CPE.

In some embodiments, the CPE group is configured for one or more of a plurality of reception resource pools associated with a sidelink communication.

In some embodiments, receiving the second CPE configuration comprises: receiving a second dedicated signaling for the second CPE configuration.

In some embodiments, selecting the target CPE comprises: in response to receiving a group switching flag having a first value indicating that the first terminal device selects a CPE based on a default CPE group for sidelink transmission, selecting the target CPE based on a first CPE group corresponding to a first group index in the second CPE group index list, the first CPE group being a default CPE group for the sidelink reception.

In some embodiments, selecting the target CPE comprises: in response to receiving a group switching flag having a second value indicating that the sidelink channel being used is to be continuously occupied, selecting the target CPE based on one or more CPEs indicated by a second CPE group, the second CPE group corresponding to a second group index in the second CPE group index list.

In some embodiments, performing the sidelink reception comprises: in response to receiving the group switching flag having the second value, initializing a timer for a channel occupancy being used; and in accordance with a determination that the timer expires, selecting the target CPE based on a first CPE group corresponding to a first group index in the second CPE group index list, the first CPE group being a default CPE group for the sidelink reception.

In some embodiments, based on the target CPE, the second terminal device 120 performs the sidelink reception in a next slot subsequent to the slot currently occupied by the first terminal device.

FIG. 11 illustrates a flowchart of a method 1100 of communication implemented at a network device in accordance with some embodiments of the present disclosure. The method 1100 can be implemented at the network device 140 shown in FIG. 1. For the purpose of discussion, the method 1100 will be described with reference to FIG. 1. It is to be understood that the method 1100 may include additional acts not shown and/or may omit some shown acts, and the scope of the present disclosure is not limited in this regard.

At bock 1110, a network device 140 transmits, to the first terminal device 110, a first CPE configuration for a sidelink transmission, the first CPE configuration indicating a first plurality of CPEs.

At bock 1120, the network device 140 transmits, to the second terminal device 120, a second CPE configuration for a sidelink reception, the second CPE configuration indicating a second plurality of CPEs.

In some embodiments, the first CPE configuration comprises a first CPE group index list having one or more group indexes, each group index in the first CPE group index list corresponding to a respective first CPE with a first maximum CPE duration, and the second CPE configuration comprises a second CPE group index list having one or more group indexes, each group index in the second CPE group index list corresponding to a respective second CPE with a second maximum CPE duration.

In some embodiments, the first CPE configuration comprises a first CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs for the sidelink transmission.

In some embodiments, the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs for the sidelink reception.

In some embodiments, the CPE group comprises one or more CPE related parameter, a CPE related parameter in the CPE group corresponding to a CPE.

In some embodiments, the CPE group is configured for one or more of a plurality of resource pools associated with the sidelink communication.

In some embodiments, transmitting the first CPE configuration comprises transmitting a first dedicated signaling for the first CPE configuration to the first terminal device, and transmitting the second CPE configuration comprises transmitting a second dedicated signaling for the second CPE configuration to the second terminal device.

FIG. 12 illustrates a flowchart of a method 1200 of communication implemented at a network device in accordance with some embodiments of the present disclosure. The method 1100 can be implemented at the third terminal device 130 shown in FIG. 1. For the purpose of discussion, the method 1200 will be described with reference to FIG. 1. It is to be understood that the method 1200 may include additional acts not shown and/or may omit some shown acts, and the scope of the present disclosure is not limited in this regard.

At block 1210, a third terminal device 130 transmits, to the first terminal device 110, a first CPE configuration for a sidelink transmission, the first CPE configuration indicating a first plurality of CPEs.

At bock 1120, the network device 130 transmits, to the second terminal device 120, a second CPE configuration for a sidelink reception, the second CPE configuration indicating a second plurality of CPEs.

Fig. 13 is a simplified block diagram of a device 1300 that is suitable for implementing some embodiments of the present disclosure. The device 1200 can be considered as a further example embodiment of the

terminal devices

110, 120 and 130 as shown in FIG. 1, or network devices 140 as shown in FIG. 1. Accordingly, the device 1300 can be implemented at or as at least a part of the above network devices or terminal devices.

As shown, the device 1300 includes a processor 1310, a memory 1320 coupled to the processor 1310, a suitable transmitter (TX) and receiver (RX) 1340 coupled to the processor 1310, and a communication interface coupled to the TX/RX 1340. The memory 1320 stores at least a part of a program 1330. The TX/RX 1340 is for bidirectional communications. The TX/RX 1340 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2 interface for bidirectional communications between gNBs or eNBs, S1 interface for communication between a Mobility Management Entity (MME) /Serving Gateway (S-GW) and the gNB or eNB, Un interface for communication between the gNB or eNB and a relay node (RN) , or Uu interface for communication between the gNB or eNB and a terminal device.

The program 1330 is assumed to include program instructions that, when executed by the associated processor 1310, enable the device 1300 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGs. 1-12. The embodiments herein may be implemented by computer software executable by the processor 1310 of the device 1300, or by hardware, or by a combination of software and hardware. The processor 1310 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 1310 and memory 1320 may form processing means 1350 adapted to implement various embodiments of the present disclosure.

The memory 1320 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 1320 is shown in the device 1300, there may be several physically distinct memory modules in the device 1300. The processor 1310 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1200 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.

In some embodiments, a terminal device comprises circuitry configured to perform method 900 and/or 1100.

In some embodiments, a network device comprises circuitry configured to perform method 1000.

The components included in the apparatuses and/or devices of the present disclosure may be implemented in various manners, including software, hardware, firmware, or any combination thereof. In one embodiment, one or more units may be implemented using software and/or firmware, for example, machine-executable instructions stored on the storage medium. In addition to or instead of machine-executable instructions, parts or all of the units in the apparatuses and/or devices may be implemented, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs) , Application-specific Integrated Circuits (ASICs) , Application-specific Standard Products (ASSPs) , System-on-a-chip systems (SOCs) , Complex Programmable Logic Devices (CPLDs) , and the like.

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 representation, it will be appreciated that the blocks, apparatus, systems, technique terminal devices or methods 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 process or method as described above with reference to any of Figs. 3 to 11. 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.

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine 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 machine 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.

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 embodiment 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 language 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 communication method implemented at a first terminal device, comprising:

receiving a first cyclic prefix extension, CPE, configuration, the first CPE configuration indicating a first plurality of CPEs;

selecting a target CPE based on the first plurality of CPEs and a sensing duration of a channel access procedure performed by the first terminal device for accessing a sidelink channel associated with a sidelink communication; and

performing a sidelink transmission to a second terminal device based on the target CPE.
The method of claim 1, wherein the first CPE configuration comprises a first CPE group index list having one or more group indexes, each group index in the first CPE group index list corresponding to a respective CPE with a maximum CPE duration, the method further comprising:

deriving one or more CPEs of the first plurality of CPEs based on the maximum CPE duration, a CPE of the one or more CPEs having a duration smaller than the maximum CPE duration.
The method of claim 1, wherein the first CPE configuration comprises a first CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs.
The method of claim 3, wherein the CPE group comprises one or more CPE related parameter indexes, a CPE related parameter index in the CPE group corresponding to a CPE.
The method of claim 3, wherein the CPE group is configured for one or more of a plurality of transmission resource pools associated with the sidelink communication.
The method of claim 1, wherein receiving the first CPE configuration comprises:

receiving a first dedicated signaling for the first CPE configuration.
The method of claim 1, wherein the first CPE configuration is determined based on at least one of:

a first priority level associated with the first terminal device;

a second priority level associated with a traffic to be transmitted by the first terminal device; and

a channel access priority class in the channel access procedure.
The method of claim 3, wherein selecting the target CPE comprises:

in accordance with a determination that the channel access procedure is successful, selecting the target CPE for filling a first gap between ending time of the successful channel access procedure and a transmission boundary of the sidelink transmission based on one or more CPEs indicated by a first CPE group, the first CPE group corresponding to a first group index in the first CPE group index list, the first CPE group being a default CPE group for the sidelink transmission.
The method of claim 8, wherein performing the sidelink transmission comprises:

transmitting, to the second terminal device, a group switching flag having a first value, the first value indicating that the first terminal device has selected the target CPE based on the first CPE group.
The method of claim 3, wherein selecting the target CPE comprises:

in accordance with a determination that the sidelink channel is to be continuously occupied, selecting the target CPE based on one or more CPEs indicated by a second CPE group, the second CPE group corresponding to a second group index in the first CPE group index list.
The method of claim 10, wherein performing the sidelink transmission comprises:

transmitting, to the second terminal device, a group switching flag having a second value, the second value indicating that the sidelink channel is to be continuously occupied; and

performing, based on the target CPE, the sidelink transmission in a next slot subsequent to the slot currently occupied by the first terminal device.
The method of claim 10, wherein determining that the sidelink channel is to be continuously occupied comprises:

in accordance with a determination that a second gap between a slot occupied currently by the first terminal device and a next slot subsequent to the slot is below a predetermined threshold, determining that the sidelink channel is to be continuously occupied.
A method implemented at a second terminal device, comprising:

receiving a second cyclic prefix extension, CPE, configuration, the second CPE configuration indicating a second plurality of CPEs;

selecting a target CPE based on the second plurality of CPEs; and

performing a sidelink reception from a first terminal device based on the target CPE.
The method of claim 13, wherein the second CPE configuration comprises a second CPE group index list having one or more group indexes, each group index in the second CPE group index list corresponding to a respective CPE with a maximum CPE duration, the method further comprising:

deriving one or more CPEs of the second plurality of CPEs based on the maximum CPE duration, a CPE of the one or more CPEs having a duration smaller than the maximum CPE duration.
The method of claim 13, wherein the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the second CPE group index list corresponding to a CPE group indicating one or more CPEs.
The method of claim 15, wherein the CPE group comprises one or more CPE related parameter indexes, a CPE related parameter index in the CPE group corresponding to a CPE.
The method of claim 15, wherein the CPE group is configured for one or more of a plurality of reception resource pools associated with a sidelink communication.
The method of claim 13, wherein receiving the second CPE configuration comprises:

receiving a second dedicated signaling for the second CPE configuration.
The method of claim 15, wherein selecting the target CPE comprises:

in response to receiving a group switching flag having a first value indicating that the first terminal device selects a CPE based on a default CPE group for sidelink transmission, selecting the target CPE based on a first CPE group corresponding to a first group index in the second CPE group index list, the first CPE group being a default CPE group for the sidelink reception.
The method of claim 15, wherein selecting the target CPE comprises:

in response to receiving a group switching flag having a second value indicating that a sidelink channel being used is to be continuously occupied, selecting the target CPE based on one or more CPEs indicated by a second CPE group, the second CPE group corresponding to a second group index in the second CPE group index list.
The method of claim 20, wherein performing the sidelink reception comprises:

in response to receiving the group switching flag having the second value, initializing a timer for occupancy of the spectrum being used; and

in accordance with a determination that the timer expires, selecting the target CPE based on a first CPE group corresponding to a first group index in the second CPE group index list, the first CPE group being a default CPE group for the sidelink reception.
The method of any of claims 19-21, wherein performing the sidelink reception comprising:

performing, based on the target CPE, the sidelink reception in a next slot subsequent to the slot currently occupied by the first terminal device.
A method implemented at a network device, comprising:

transmitting, to a first terminal device, a first cyclic prefix extension, CPE, configuration for a sidelink transmission, the first CPE configuration indicating a first plurality of CPEs; and

transmitting, to a second terminal device, a second cyclic prefix extension, CPE, configuration for a sidelink reception, the second CPE configuration indicating a second plurality of CPEs.
The method of claim 23, wherein the first CPE configuration comprises a first CPE group index list having one or more group indexes, each group index in the first CPE group index list corresponding to a respective first CPE with a first maximum CPE duration, and the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the second CPE group index list corresponding to a respective second CPE with a second maximum CPE duration.
The method of claim 23, wherein the first CPE configuration comprises a first CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs for the sidelink transmission.
The method of claim 25, wherein the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs for the sidelink reception.
The method of claim 25 or 26, wherein the CPE group comprises one or more CPE related parameter indexes, a CPE related parameter index in the CPE group corresponding to a CPE.
The method of claim 25 or 26, wherein the CPE group is configured for one or more of a plurality of resource pools associated with the sidelink communication.
The method of claim 23, wherein transmitting the first CPE configuration comprises transmitting a first dedicated signaling for the first CPE configuration to the first terminal device, and transmitting the second CPE configuration comprises transmitting a second dedicated signaling for the second CPE configuration to the second terminal device.
The method of claim 23, wherein the first CPE configuration is determined based on at least one of:

a first priority level associated with the first terminal device;

a second priority level associated with a traffic to be transmitted by the first terminal device; and

a channel access priority class in the channel access procedure.
A method implemented at a third terminal device, comprising:

transmitting, to a first terminal device, a first cyclic prefix extension, CPE, configuration for a sidelink transmission, the first CPE configuration indicating a first plurality of CPEs; and

transmitting, to a second terminal device, a second cyclic prefix extension, CPE, configuration for a sidelink reception, the second CPE configuration indicating a second plurality of CPEs.
The method of claim 31, wherein the first CPE configuration comprises a first CPE group index list having one or more group indexes, each group index in the first CPE group index list corresponding to a respective first CPE with a first maximum CPE duration, and the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the second CPE group index list corresponding to a respective second CPE with a second maximum CPE duration.
The method of claim 31, wherein the first CPE configuration comprises a first CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs for the sidelink transmission.
The method of claim 33, wherein the second CPE configuration comprises a second CPE group index list having one or more group indexes, a group index in the first CPE group index list corresponding to a CPE group indicating one or more CPEs for the sidelink reception.
The method of claim 33 or 34, wherein the CPE group comprises one or more CPE related parameter indexes, a CPE related parameter index in the CPE group corresponding to a CPE.
The method of claim 33 or 34, wherein the CPE group is configured for one or more of a plurality of resource pools associated with the sidelink communication.
The method of claim 31, wherein transmitting the first CPE configuration comprises transmitting a first dedicated signaling for the first CPE configuration to the first terminal device, and transmitting the second CPE configuration comprises transmitting a second dedicated signaling for the second CPE configuration to the second terminal device.
The method of claim 31, wherein the first CPE configuration is determined based on at least one of:

a first priority level associated with the first terminal device;

a second priority level associated with a traffic to be transmitted by the first terminal device; and

a channel access priority class in the channel access procedure.
A terminal device comprising:

a processor; and

a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the terminal device to perform the method according to any of claims 1-12, claims 13-22 or claims 31-38.
A network device comprising:

a processor; and

a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the network device to perform the method according to any of claims 23-30.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method according to any of claims 1-12, claims 13-22, claims 31-38 or claims 23-30.