WO2021081935A1

WO2021081935A1 - Resource mapping for sidelink channel

Info

Publication number: WO2021081935A1
Application number: PCT/CN2019/114855
Authority: WO
Inventors: Yong Liu; Dong Li
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2021-05-06
Also published as: CN114631373A

Abstract

According to embodiments of the present disclosure, a solution to achieve more reliable transmissions of sidelink HARQ feedbacks has been proposed. Embodiments of the present disclosure propose a scheme of HARQ feedback channel resource mapping for sidelink communications so that resources of the feedback channels corresponding to continuous sub-channels in a slot are physically continuous in frequency. In this way, it provides protection to HARQ feedback corresponding to a PSSCH occupying multiple sub-channels. The mutual interference between HARQ feedbacks to different transmitter terminal devices has been reduced.

Description

RESOURCE MAPPING FOR SIDELINK CHANNEL

FIELD

Embodiments of the present disclosure generally relate to communication techniques, and more particularly, to methods, devices and computer readable medium for resource mapping for sidelink channel.

BACKGROUND

With developments of communication systems, new technologies have been proposed. Terminal devices can set up a sidelink with each other to allow direct communications between them. For a group of terminal devices, the sidelink communication may comprise unicast communication, groupcast communication and broadcast communication. Both the unicast and groupcast communication types need to be directly realized at physical layer to improve transmission efficiency of both types. Hence more advanced schemes need to be designed accordingly.

SUMMARY

Generally, embodiments of the present disclosure relate to a method for resource mapping for sidelink channel.

In a first aspect, there is provided a first device. The first device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first device to obtain information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time, resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period being continuous in frequency domain. The first device is also caused to receive from a second device at least one data packet on at least one sidelink channel of the plurality of sidelink channels. The first device is further caused to select at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information. The first device is yet caused to transmit to the second device at least one feedback for the at least one data packet on the at least one feedback channel.

In a second aspect, there is provided a method. The method comprises obtaining, at a first device, information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time, resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period being continuous in frequency domain. The method further comprises receiving from a second device at least one data packet on at least one sidelink channel of the plurality of sidelink channels. The method also comprises selecting at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information. The method yet comprises transmitting to the second device at least one feedback for the at least one data packet on the at least one feedback channel.

In a third aspect, there is provided an apparatus. The apparatus comprises means for obtaining, at a first device, information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time, resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period being continuous in frequency domain. The apparatus also comprises means for receiving from a second device at least one data packet on at least one sidelink channel of the plurality of sidelink channels. The apparatus further comprises means for selecting at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information. The apparatus yet comprises means for transmitting to the second device at least one feedback for the at least one data packet on the at least one feedback channel.

In a fourth aspect, there is provided a computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the above second aspect.

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

BRIEF DESCRIPTION OF THE DRAWINGS

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

Fig. 1 illustrates a schematic diagram of mapping between the physical sidelink shared channel /physical sidelink control channel and the physical sidelink feedback channel according to conventional solutions;

Fig. 2 illustrates a schematic diagram of a communication system;

Fig. 3 illustrates a schematic diagram of a communication system according to embodiments of the present disclosure;

Fig. 4 illustrates a flow chart of a method according to embodiments of the present disclosure;

Fig. 5 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 6 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 7 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 8 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 9 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 10 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 11 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 12 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 13 illustrates a schematic diagram of mapping between the physical sidelink shared channel/physical sidelink control channel and the physical sidelink feedback channel according to embodiments of the present disclosure;

Fig. 14 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 15 illustrates a block diagram of an example computer readable medium in accordance with some example embodiments of the present disclosure.

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

DETAILED DESCRIPTION

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

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

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

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

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

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

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

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

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

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

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

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

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) , New Radio (NR) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.65G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

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

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

In long term evolution (LTE) vehicle to everything (V2X) , only broadcast mode has been specified at physical layer for sidelink communications. The realization of unicast/groupcast modes needs to be carried out at higher layers. On the contrary, new radio (NR) V2X sidelink communication considers the support of unicast/groupcast directly at physical layer.

To achieve hybrid automatic repeat request (HARQ) at the physical layer, acknowledgement/negative acknowledgement (ACK/NACK) needs to be fed back to the device which transmits the data packet. Thus, how to configure relevant sidelink HARQ feedback resources wisely is a critical issue.

Fig. 1 illustrates a schematic diagram of mapping between the physical sidelink shared channel (PSSCH) /physical sidelink control channel (PSCCH) and the physical sidelink feedback channel (PSFCH) . The period shown in Fig. 1 may comprise four time slots, for example, 1000, 1010, 1020 and 1030. There are one or more symbols reserved in each period which are used for feedback channels, for example, 1210 and 1220. NR V2X is required to support data traffic with substantially different packet sizes. With a sub-channel as the minimum granularity, a PSSCH/PSCCH may occupy multiple sub-channels. For this case, the PSFCH resource associated with starting sub-channel is used for HARQ feedback.

As shown in Fig. 1, the sub-channels in the resource pool over each period are indexed orderly, where the indexing is performed first in frequency and then in time. For example, the indices of the sub-channels comprises 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138 and 139. The indices of the feedback channels may comprise 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 21, 32, 33, 34, 35, 36, 37, 38 and 39.

NR V2X is required to support data traffic with substantially different packet sizes. With a sub-channel as the minimum granularity, a PSSCH/PSCCH may occupy multiple sub-channels. For this case, the PSFCH resource associated with starting sub-channel is used for HARQ feedback. Only as an example, if the data packet is received on the PSSCH/PSCCH which only comprises the sub-channel 113, the feedback of the data packet is to be transmitted on the PSFCH 13. If the data packet is received on the PSSCH/PSCCH which comprises a set of

sub-channels

114, 118, 122, 126 and 130, the feedback of the data packet is to be transmitted on the PSFCH 14 which corresponds to the first sub-channel 114.

With the conventional mapping resource scheme, PSFCH resources associated with a PSSCH are scattered in frequency, which can’t provide good protection to a HARQ feedback transmission, even there are a number of PSFCH resources (corresponding to a PSSCH occupying multiple sub-channels) that the receiving terminal device can use. And it may cause strong in-band emission interference (IBI) between adjacent HARQ feedbacks to different transmitting UEs.

As shown in Fig. 2, there are six terminal devices 210-1, 210-2, 210-3, 210-4, 210-5 and 210-6 forming a platoon. The terminal device 210-1 may groupcast to its member terminal devices 210-2 to 210-6. In the meantime, the terminal device 220-1 and the terminal device 220-2 form a unicast pair with the terminal device 220-1 transmitting packets to the terminal device 220-2. In one PSFCH period, the terminal device 210-1 may groupcast to the terminal devices 210-2 to 210-6 at the PSSCH/PSCCH which comprises the sub-channel 113. The terminal device 220-1 may transmit a data packet to the terminal device 220-2 on the PSSCH that comprises the sub-channels 114, 118, 122, 126 and 130. In the associated PSFCH slot, while the terminal devices 210-2 to 210-6 use the PSFCH 13 for HARQ feedback, the terminal device 220-2 use the PSFCH 14 for its HARQ feedback. Since the terminal device 210-6 is far away from the terminal device 210-1, the terminal device 210-6 may employ large power for its HARQ feedback, which causes substantial IBI interference to signal reception at the terminal device 220-1. Hence, an enhanced resource mapping scheme is needed to alleviate the issue.

Fig. 3 illustrates a schematic diagram of a communication system in which embodiments of the present disclosure can be implemented. The communication system 300, which is a part of a communication network, comprises a device 310-1, a device 310-2, ...., a device 310-N, which can be collectively referred to as “device (s) 310. ” The communication system 300 further comprises a device 330. It is to be understood that the number of devices and cells shown in Fig. 3 is given for the purpose of illustration without suggesting any limitations. It also should be noted that the device 310 and the device 330 can be interchangeable.

In the communication system 300, the device 310 and the device 330 can communicate data and control information to each other. In the case that the device 310 is the terminal device and the device 330 is the network device, a link from the device 330 to the device 310 is referred to as a downlink (DL) , while a link from the device 310 to the device 330 is referred to as an uplink (UL) . A link from the device 310-1 to the device 310-2 is referred to as a sidelink (SL) . The number of devices shown in Fig. 3 is given for the purpose of illustration without suggesting any limitations. For the purpose of illustrations, the device 310-1 is referred to as the first device 310-1 hereinafter, the device 310-2 is referred to as the second device 310-2 hereinafter, the device 330 is referred to as the third device 330 hereinafter. It also should be noted that the device 310-1 and the device 310-2 can be interchangeable.

Communications in the communication system 300 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Divided Multiple Address (CDMA) , Frequency Divided Multiple Address (FDMA) , Time Divided Multiple Address (TDMA) , Frequency Divided Duplexer (FDD) , Time Divided Duplexer (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Divided Multiple Access (OFDMA) and/or any other technologies currently known or to be developed in the future.

Fig. 4 illustrates a flow chart of method 400 according to embodiments of the present disclosure. The method 400 can be implemented at any suitable devices. For example, the method may be implemented at the first device 310-1.

At block 410, the first device 310-1 obtains information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time. Resource mapping from the sidelink channels to corresponding PSFCH resources may be performed in time first manner. In this way, the resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period are continuous in frequency domain, thereby reducing interferences between HARQ feedbacks to different transmitting terminal devices. The sidelink channels may comprise the PSSCHs and/or the PSCCHs. In some embodiments, the information may be preconfigured at the first device 310-1.

Alternatively or in addition, the information may be received from the third device 330. In other embodiments, the third device 330 may transmit configuration related to sidelink HARQ to the first device 310-1. For example, the configuration may indicate the number of time slots in one period of time. Alternatively or in addition, the configuration may indicate the number of feedback channels in the period of time. In other embodiments, the configuration may also indicate that the number of physical resource blocks (PRBs) in one feedback channel.

Now referring to Fig. 5, Fig. 5 illustrates a schematic diagram of mapping between the physical sidelink channels and PSFCH according to embodiments of the present disclosure. As shown in Fig. 5, over each period, all the sub-channels in the resource pool are indexed as

where

denotes number of sub-channels of the resource pool and N is the number of time slots in the period. As an example, in Fig. 5, N=4,

For example, there may be four time slots in one period of time, for example, the

time slots

5000, 5010, 5020 and 5030. The indexing is performed in time first manner, i.e. first in time and then in frequency. For the purpose of illustrations, the feedback channel may be referred to the PSFCH. It should be noted the feedback channel can be other types of channels.

The whole frequency domain (last several symbols) of the PSFCH slot is divided into multiple PSFCH resource groups. PSFCH resource groups are indexed orderly as

Each PSFCH resource group is used for HARQ feedback (s) corresponding to the sub-channel with the same index. PSFCH resource groups are continuous in frequency except guard bands may be inserted between them. There may be one or more symbols at the end of each period for the PSFCH, for example, symbols in the

durations

5110 and 5120. In some embodiments, there may be delay at the receiving terminal device, the sidelink channels in the time slot 5000 may use the corresponding PSFCH in the duration 5120 not the ones in the duration 5110.

A PSFCH resource group occupies

PRBs, where

denotes the number of PRBs in a sub-channel (for example, 4 PRBs) . A PSFCH resource group may comprise one or multiple PSFCH resources. A PSFCH resource may comprise K PRBs over M OFDM symbols. Examples of (K, M) = (2, 1) , (2, 2) , (1, 1) and the like. In embodiments of the present disclosure, K=1. The PRBs and symbols are continuous in frequency and time respectively. A PSFCH group consist of

PSFCH resources. PSFCH is sequence based (i.e. NR PUCCH format 0) . Sequence length is 12K, e.g. based on Zadoff-Chu sequence. For simplicity (without loss of generality) , in the following descriptions/examples, a PSFCH resource group may comprise one PSFCH resource which occupies one PRB. It should be noted that the PSFCH resource group may comprise one or more PSFCH resources which occupy one or more PRBs.

As shown in Fig. 5, there may be 40 sub-channels in one period of time and there are 10 sub-channels in each time slot, for example, the sub-channels 50-0, 50-1, 50-2, 50-3, 50-4, 50-5, 50-6, 50-7, 50-8 and 50-9 in the time slot 5000, the sub-channels 51-0, 51-1, 51-2, 51-3, 51-4, 51-5, 51-6, 51-7, 51-8 and 51-9 in the time slot 5010, the sub-channels 52-0, 52-1, 52-2, 52-3, 52-4, 52-5, 52-6, 52-7, 52-8 and 52-9 in the time slot 5020, and the sub-channels 53-0, 53-1, 53-2, 53-3, 53-4, 53-5, 53-6, 53-7, 53-8 and 53-9 in the time slot 5030. Fig. 5 shows that the feedback channels corresponding to one time slot are continuous in frequency domain. The feedback channels 5-0, 5-1, 5-2, 5-3, 5-4, 5-5, 5-6, 5-7, 5-8 and 5-9 are for the sub-channels in the time slot 5000. The feedback channels 5-10, 5-11, 5-12, 5-13, 5-14, 5-15, 5-16, 5-17, 5-18 and 5-19 are for the sub-channels in the time slot 5010. The feedback channels 5-20, 5-21, 5-22, 5-23, 5-24, 5-25, 5-26, 5-27, 5-28 and 5-29 are for the sub-channels in the time slot 5020. The feedback channels 5-30, 5-31, 5-32, 5-33, 5-34, 5-35, 5-36, 5-37, 5-38 and 5-39 are for the sub-channels in the time slot 5030. It should be noted that the number of the sub-channels and the number of the feedback channels shown in Fig. 5 are only examples not limitations. The number of time slots in the one period shown in Fig. 5 is also an example. The number of PRBs allocated to one sub-channels can be any suitable number. Embodiments of the present disclosure are not limited in this aspect.

Referring back to Fig. 4, at block 420, the first device 310-1 receives at least one data packet on at least one sidelink channel from the second device 310-2. In some embodiments, the sidelink channel may comprise only one sub-channel. Alternatively or in addition, the sidelink channel may comprise more than one sub-channel. For example, as show in Figs. 6-13, the sidelink channel 52 may comprise five sub-channels, that is, the sub-channels 52-3, 52-4, 52-5, 52-6 and 52-7. As shown in Fig. 7-11, the sidelink channel 50 may comprise three sub-channels, that is, the sub-channels 50-1, 50-2 and 50-3. The sidelink channel 53 may comprise two sub-channels, that is, the sub-channels 53-8 and 53-9. The numbers of the sub-channels in one sidelink channel shown in the figures are only examples, not limitations. It should be noted that one sidelink channel can comprise any suitable number of sub-channels.

At block 430, the first device 310-1 selects at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information. In some embodiments, if the sidelink channel comprises a plurality of sub-channels, the first device 310-1 may determine a set of candidate feedback channels associated with the plurality of sub-channels based on the information. In this situation, the first device 310-1 may select the feedback channel which is not at the edge in frequency domain in the set of candidate feedback channels. For the example, the selected feedback channel may be in the middle of the set of candidate feedback channels in frequency domain.

At block 440, the first device 310-1 transmits at least one feedback for the at least one data packet on the at least one feedback channel to the second device 310-2. Details of selecting the feedback channel and transmitting the feedback are described with the reference to Figs. 6-13.

For NR V2X, diverse data traffic needs to be supported, including: different magnitudes of packet sizes, e.g. from hundreds of bytes up to tens of thousands of bytes. Hence the number of sub-channels a PSSCH consists of varies greatly. For spectral efficiency, better protection is desired for HARQ feedback of a large packet (occupying a number of continuous sub-channels) . For example, unnecessary retransmission of the large packet is triggered if the ACK feedback is interfered and isn’t successfully received.

It’s assumed the PSCCH/PSSCH occupy the sub-channels [l: l+S-1] in one time slot in one period. Here S is sub-channel number occupied. With the resource mapping, candidate PSFCHs have index [l: l+S-1] occupying physically continuous resources in the PSFCH time slot. The PSFCH in the middle of candidate PSFCHs set (e.g., with index

if S is odd, or with index

or

if S is even) is used for transmitting HARQ feedback for the PSSCH. The other PSFCH resources at two sides or at one side are left unused as guard bands.

In this way, it introduces guard bands around HARQ feedback transmissions. This provides protection to HARQ feedback corresponding to one sidelink channel occupying multiple sub-channels and it reduces mutual interference (IBI in-band emission interference) between HARQ feedbacks to different transmitting terminal devices.

Now referring to Fig. 6, the first device 310-1 receives the data packet from the second device 310-2 on the sidelink channel 52. The sidelink channel 52 may comprise the sub-channels 52-3, 52-4, 52-5, 52-6 and 52-7. According to the information, the sub-channel 52-3 corresponds to the feedback channel 5-23, the sub-channel 52-4 corresponds to the feedback channel 5-24, the sub-channel 52-5 corresponds to the feedback channel 5-25, the sub-channel 52-6 corresponds to the feedback channel 5-26, and the sub-channel 52-7 corresponds to the feedback channel 5-27. The first device 310-1 may determine the set of candidate feedback channels 5-23, 5-24, 5-25, 5-26 and 5-27. The first device 310-1 may select the feedback channel5-25 from the set of candidate feedback channels since the feedback channel 5-25 is in the middle in frequency domain.

In some embodiments, the first device 310-1 may receive multiple data packets from the second device 310-2. Now referring to Fig. 7, the first device 310-1 may receive a first data packet on the sidelink channel 52, a second data packet on the sidelink channel 50 and a third data packet on the sidelink channel 53 from the second device 310-2. It should be noted that the number of data packets the first device 310-1 received is only an example. It should be noted that the terms “first” , “second” , and “third” do not indicate the order of receiving the data packets and they are only used to distinguish the data packets.

The first device 310-1 may determine the first set of candidate feedback channels for the sidelink channel 52 comprising the sub-channel 5-23, 5-24, 5-25, 5-26 and 5-27. The first device 310-1 may determine the second set of candidate feedback channels for the sidelink channel 50 comprising the sub-channels 5-1, 5-2 and 5-3. The first device 310-1 may determine the second set of candidate feedback channels for the sidelink channel 53 comprising the sub-channels 5-38 and 5-39.

In some embodiments, the first device 310-1 may select the first feedback channel 5-25 from the first set of candidate feedback channels, the second feedback channel 5-2 from the second set of candidate feedback channels, and the third feedback channel 5-38 from the third set of candidate feedback channels. The first device 310-1 may transmit the first feedback to the first data packet on the first feedback channel 5-25. The first device 310-1 may also transmit the second feedback to the second data packet on the second feedback channel 5-2. The first device 310-1 may further transmit the third feedback to the third data packet on the third feedback channel 5-38.

Alternatively or in addition, the first device 310-1 may identify the feedback set with largest size based on decoded sidelink channels and transmit the feedbacks of different data packets on the feedback channels in the identified feedback set which corresponds to the sidelink channel with the most number of sub-channels. In this way, it introduces guard bands around HARQ feedback transmissions. For example, since the first set of candidate feedback channels has more channels than the second and third sets, the first device 310-1 may select the first feedback channel 5-25 from the first set of candidate channels and transmit the first, second and third feedbacks on the first feedback channel 5-25 to the second device 310-2. The first, second and third feedbacks can be frequency division multiplexed (FDMed) or code division multiplexed (CDMed) . In some embodiments, for CDM, the first device 310-1 may employ different cyclic shifts of a Zadoff-Chu sequence for the multiple feedbacks.

In some embodiments, the first device 310-1 may fail to receive PSCCH (s) for one or more data packets from the second device 310-2. As shown in Fig. 8, the first device 310-1 may fail to receive the PSCCH for the first data packet on the sidelink channel 52 and succeed in receiving the PSCCH for the second data packet on the sidelink channel 50 and the PSCCH for the third data packet on the sidelink channel 53 from the second device 310-2. In this situation, the first device 310-1 cannot obtain the information of the first set of feedback channels associated with the sidelink channel 52. The first device 310-1 may transmit the second feedback to the second data packet on the feedback channel 5-2 and transmit the third feedback to the third data packet on the feedback channel 5-38. Alternatively, since the second set of candidate feedback channels has more feedback channels than the third set of candidate feedback channels, the first device 310-1 may select the second feedback channel 5-2 and transmit the second feedback and the third feedback on the second feedback channel 5-2 to the second device 310-2.

Alternatively or in addition, the second device 310-2 may transmit control information on a selected sidelink channel (for example, the selected sidelink channel occupying largest number of sub-channels) in this period. The control information may comprise one or more of: starting sub-channel index of the sidelink channel, the number of sub-channels occupied by the sidelink channel. For example, as shown in Fig 9, even though the first device 310-1 fails in receiving the PSCCH for the first data packet on the first sidelink channel 52, the first device 310-1 may determine that the first set of candidate feedback channels can be used for transmitting the feedback based on the control information. The first device 310-1 may select the first feedback channel 5-25 and transmit the second feedback and the third feedback (or the first feedback, the second feedback and the third feedback) on the first feedback channel 5-25 to the second device 310-2. In this way, the transmission of HARQ feedbacks has been protected.

In some embodiments, the first device 310-1 may determine the number of time slots in the period and select the set of feedback channels corresponding to the number of the time slots. As shown in Fig. 10, the first device 310-1 may assume there are data packets transmitted in all four time slots. Accordingly, four feedback channel resources 5-25-1, 5-25-2, 5-25-3 and the 5-24-1 (for example, code resources) are allocated orderly for the feedbacks corresponding to data packets in four time slots.

Alternatively or in addition, the first device 310-1 may receive control information indicating the number of time slots in which the at least one data packet is transmitted and select the set of feedback channels corresponding to the number of the time slots in which the at least one data packet is transmitted. For example, as shown in Fig. 11, there are data packets transmitted on the

time slots

5000, 5020 and 5030 and there is no data packet transmitted on the time slot 5010. The second device 310-2 may transmit the control information comprising a bitmap, for example, “1 0 1 1. ” The bitmap indicates that the data packets are transmitted on the first, third and fourth time slots. Accordingly, three feedback channel resources 5-25-1, 5-25-2 and 5-25-3 (for example, code resources) are allocated orderly for the feedbacks corresponding to data packets in the three time slots. In this way, there is more feedback channel resources left as guard bands and hence better protection to transmissions of HARQ feedbacks.

In an example embodiment, the first device 310-1 may be in a group of devices 310. The first device 310-1 may select the at least one feedback channel based on the identity of the first device 310-1 and identities of other devices in the group of devices.

The identities of the devices in the group are ordered. Within the candidate feedback channel resource set, each device may determine its feedback channel resource based on its identity. As shown in Fig. 12, if there are four devices in the group, the first device 310-1 may select the middle feedback channel 5-25, the second device 310-2 may select the adjacent feedback channel 5-24, the third device in the group may select the feedback channel 5-26, and the fourth device in the group may select the feedback channel 5-23. In this way, the feedback channel resources in the middle are used for HARQ feedbacks. The unused feedback channel resources at two sides are left as guard bands.

As another example, there are three code resources in a feedback channel resource. The devices 310 may select code resources in the middle feedback channel resources first and then move to adjacent frequency feedback channel resources. Each terminal device may need two code resources for ACK/NACK separately. For example, as shown in Fig. 12, the first device 310-1 may select the feedback channel resources 5-25-1 and 5-25-2, the second device 310-2 may select the feedback channel resources 5-25-3 and 5-24-1, the third device in the group may select the feedback channel resources 5-24-2 and 5-24-3, and the fourth device in the group may select the feedback channel resources 5-26-1 and 5-26-2.

In some embodiments, the second device 310-2 may include its identity in the control information. In this way, the consumption of the feedback channel resources has been reduced. The first device 310-1 may select the feedback channel based on the identity of the first device 310-1 and the second identity of the second device 310-2. As shown in Fig. 13, if there are four devices in the group, the first identity of the first device 310-1 is “1” , the second identity of the second device 310-2 is “2” , the third identity of the third device in the group is “3” , the fourth identity of the fourth device in the group is “4. ” In this situation, if an identity of one receiving device is larger than the transmitting device, the relative identity of the receiving device is calculated as its local identity minus 1. Otherwise, its relative ID is equal to its local ID. The receiving device may determine its feedback channel based on relative ID.

For example, since the first identity of the first device 310-1 is smaller than the second identity of the second device 310-2, the first device 310-1 may still select the middle feedback channel 5-25. Since the third identity of the third device in the group is larger than the second device of the second device 310-2, the third device in the group may select the feedback channel 5-24. Similarly, the fourth device in the group may select the feedback channel 5-26.

As another example, there are three code resources in a feedback channel resource. The devices 110 may select code resources in the middle feedback channel resources first and then move to adjacent frequency feedback channel resources. Each terminal device may need two code resources for ACK/NACK separately. As shown in Fig. 13, since the first identity of the first device 310-1 is smaller than the second identity of the second device 310-2, the first device 310-1 may still select the feedback channel resources 5-25-1 and 5-25-2. Since the third identity of the third device in the group is larger than the second identity of the second device 310-2, the third device in the group may select the feedback channel resources 5-25-3 and 5-24-1. Similarly, the fourth device in the group may select the feedback channel resources 5-24-2 and 5-24-3. In this way, overall feedback resource consumption is reduced and more feedback resources can be left unused as guard bands.

In some embodiments, an apparatus for performing the method 400 (for example, the first device 310-1) may comprise respective means for performing the corresponding steps in the method 400. These means may be implemented in any suitable manners. For example, it can be implemented by circuitry or software modules.

In some embodiments, the apparatus comprises means for obtaining, at a first device, information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time, resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period being continuous in frequency domain; means for receiving from a second device at least one data packet on at least one sidelink channel of the plurality of sidelink channels; means for selecting at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information; and means for transmitting to the second device at least one feedback for the at least one data packet on the at least one feedback channel.

In some embodiments, the means for selecting the at least one feedback channel comprises: means for in accordance with a determination that the at least one sidelink channel comprises a plurality of sub-channels, determining a set of candidate feedback channels associated with the plurality of sub-channels based on the information; and means for selecting the at least one feedback channel from the set of candidate feedback channels, such that the at least one feedback channel is non-edge in frequency domain in the set of candidate feedback channels.

In some embodiments, the at least one data packet comprises a first data packet and a second data packet, and at least one sidelink channel comprises a first sidelink channel for transmitting the first data packet and a second sidelink channel for transmitting the second data packet, and wherein the means for receiving the at least one data packet comprises: means for receiving the first data packet on the first sidelink channel from the second device during a first time slot; and means for receiving the second data packet on the second sidelink channel from the second device during a second time slot.

In some embodiments, the means for selecting the at least one feedback channel comprises: means for determining a first set of candidate feedback channels associated with the first sidelink channel based on the information; means for determining a second set of candidate feedback channels associated with the second sidelink channel based on the information; and means for in accordance with a determination that the first set of candidate feedback channels is longer than the second set of candidate feedback channels, selecting the at least one feedback channel from the first set of candidate feedback channels such that the at least one feedback channel is non-edge in frequency domain in the first set of candidate feedback channels.

In some embodiments, the means for transmitting the at least one feedback of the at least one data packet comprises: means for transmitting a first feedback of the first data packet and a second feedback of the second data packet on the at least one feedback channel to the second device.

In some embodiments, the means for selecting the at least one feedback channel comprises: means for determining a first set of candidate feedback channels associated with the first sidelink channel based on the information; means for determining a second set of candidate feedback channels associated with the second sidelink channel based on the information; means for selecting a first feedback channel from the first set of candidate feedback channels, the first feedback channel being non-edge in frequency domain in the first set of candidate feedback channels; and means for selecting a second feedback channel from the second set of candidate feedback channels, such that the second feedback channel is non-edge in frequency domain in the second set of candidate feedback channels.

In some embodiments, the means for transmitting the at least one feedback of the at least one data packet comprises: means for transmitting a first feedback of the first data packet on the first feedback channel to the second device; and means for transmitting a second feedback of the second data packet on the second feedback channel to the second device.

In some embodiments, the at least one data packet comprises a first data packet and a second data packet, and at least one sidelink channel comprises a first sidelink channel for transmitting the first data packet and a second sidelink channel for transmitting the second data packet, and wherein the means for selecting the at least one feedback channel comprises: means for in accordance the first sidelink channel comprising more sub-channels than the second sidelink channel, receiving, from the second device, control information indicating the sub-channels in the first sidelink channel; means for determining a first set of candidate feedback channels associated with the sub-channels in the first sidelink channel based on the information; and means for selecting the at least one feedback channel from the first set of candidate feedback channels, such that the at least one feedback channel is non-edge in frequency domain in the first set of candidate feedback channels.

In some embodiments, the means for selecting the at least one feedback channel comprises: means for determining the number of time slots in the period; and means for selecting a set of feedback channels, the number of feedback channels in the set of feedback channels corresponding to the number of time slots.

In some embodiments, the means for selecting the at least one feedback channel comprises: means for receiving, from the second device, control information indicating the number of time slots in which the at least one data packet is transmitted; and means for selecting a set of feedback channels, the number of feedback channels in the set of feedback channels corresponding to the number of time slots in which the at least one data packet is transmitted.

In some embodiments, a group of devices comprises the first device, and wherein the means for selecting the at least one feedback channel comprises: means for selecting the at least one feedback channel based on a first identity of the first device and identities of other devices in the group of devices.

In some embodiments, the group of devices further comprises the second device, and wherein the means for selecting the at least one feedback channel comprises: means for receiving an indication of a second identity of the second device from the second device; and means for selecting the at least one feedback channel by excluding the second identity from the identities of other devices in the group of devices.

In some embodiments, the apparatus further comprises means for transmitting at least one further data packet on at least one further sidelink channel in the plurality of sidelink channels to the second device.

In some embodiments, the apparatus further comprises means for receiving further configuration from a third device, the further configuration indicating at least one of: the number of time slots in the period of time, the number of the plurality of the feedback channels in the period of time, or the number of physical resource blocks in one feedback channel.

In some embodiments, the first device comprises a terminal device, the second device comprises a further terminal device, and the third device comprises a network device.

Fig. 14 is a simplified block diagram of a device 1400 that is suitable for implementing embodiments of the present disclosure. The device 1400 may be provided to implement the communication device, for example the first device 310-1, the second device 310-2, or the third device 330 as shown in Fig. 3. As shown, the device 1400 includes one or more processors 1410, one or more memories 1420 coupled to the processor 1410, and one or more communication modules 1440 coupled to the processor 1410.

The communication module 1440 is for bidirectional communications. The communication module 1440 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 1410 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 1400 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 1420 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 1424, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 1422 and other volatile memories that will not last in the power-down duration.

A computer program 1430 includes computer executable instructions that are executed by the associated processor 1410. The program 1430 may be stored in the ROM 1424. The processor 1410 may perform any suitable actions and processing by loading the program 1430 into the RAM 1422.

Embodiments of the present disclosure may be implemented by means of the program 1420 so that the device 1400 may perform any process of the disclosure as discussed with reference to Figs. 4 to 13. Embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some example embodiments, the program 1430 may be tangibly contained in a computer readable medium which may be included in the device 1400 (such as in the memory 1420) or other storage devices that are accessible by the device 1400. The device 1400 may load the program 1430 from the computer readable medium to the RAM 1422 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 15 shows an example of the computer readable medium 1500 in form of CD or DVD. The computer readable medium has the program 1430 stored thereon.

It should be appreciated that future networks may utilize network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into “building blocks” or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications, this may mean node operations to be carried out, at least partly, in a central/centralized unit, CU, (e.g. server, host or node) operationally coupled to distributed unit, DU, (e.g. a radio head/node) . It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may vary depending on implementation.

In an embodiment, the server may generate a virtual network through which the server communicates with the distributed unit. In general, virtual networking may involve a process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Such virtual network may provide flexible distribution of operations between the server and the radio head/node. In practice, any digital signal processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation.

Therefore, in an embodiment, a CU-DU architecture is implemented. In such case the device 1400 may be comprised in a central unit (e.g. a control unit, an edge cloud server, a server) operatively coupled (e.g. via a wireless or wired network) to a distributed unit (e.g. a remote radio head/node) . That is, the central unit (e.g. an edge cloud server) and the distributed unit may be stand-alone apparatuses communicating with each other via a radio path or via a wired connection. Alternatively, they may be in a same entity communicating via a wired connection, etc. The edge cloud or edge cloud server may serve a plurality of distributed units or a radio access networks. In an embodiment, at least some of the described processes may be performed by the central unit. In another embodiment, the device 1400 may be instead comprised in the distributed unit, and at least some of the described processes may be performed by the distributed unit.

In an embodiment, the execution of at least some of the functionalities of the device 600 may be shared between two physically separate devices (DU and CU) forming one operational entity. Therefore, the apparatus may be seen to depict the operational entity comprising one or more physically separate devices for executing at least some of the described processes. In an embodiment, such CU-DU architecture may provide flexible distribution of operations between the CU and the DU. In practice, any digital signal processing task may be performed in either the CU or the DU and the boundary where the responsibility is shifted between the CU and the DU may be selected according to implementation. In an embodiment, the device 1400 controls the execution of the processes, regardless of the location of the apparatus and regardless of where the processes/functions are carried out.

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

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 400 as described above with reference to Fig. 4. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

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

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

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

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

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

Claims

A device comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the device to:

obtain information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time, resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period being continuous in frequency domain;

receive from a further device at least one data packet on at least one sidelink channel of the plurality of sidelink channels;

select at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information; and

transmit to the further device at least one feedback for the at least one data packet on the at least one feedback channel.
The device of claim 1, wherein the device is caused to select the at least one feedback channel by:

in accordance with a determination that the at least one sidelink channel comprises a plurality of sub-channels, determining a set of candidate feedback channels associated with the plurality of sub-channels based on the information; and

selecting the at least one feedback channel from the set of candidate feedback channels, such that the at least one feedback channel is non-edge in frequency domain in the set of candidate feedback channels.
The device of claim 1, wherein the at least one data packet comprises a first data packet and a second data packet, and at least one sidelink channel comprises a first sidelink channel for transmitting the first data packet and a second sidelink channel for transmitting the second data packet, and wherein the device is caused to receive the at least one data packet by:

receiving the first data packet on the first sidelink channel from the further device during a first time slot; and

receiving the second data packet on the second sidelink channel from the further device during a second time slot.
The device of claim 3, wherein the device is caused to select the at least one feedback channel by:

determining a first set of candidate feedback channels associated with the first sidelink channel based on the information;

determining a second set of candidate feedback channels associated with the second sidelink channel based on the information; and

in accordance with a determination that the first set of candidate feedback channels is longer than the second set of candidate feedback channels, selecting the at least one feedback channel from the first set of candidate feedback channels such that the at least one feedback channel is non-edge in frequency domain in the first set of candidate feedback channels.
The device of claim 4, wherein the device is caused to transmit the at least one feedback of the at least one data packet by:

transmitting a first feedback of the first data packet and a second feedback of the second data packet on the at least one feedback channel to the further device.
The device of claim 3, wherein the device is caused to select the at least one feedback channel by:

determining a first set of candidate feedback channels associated with the first sidelink channel based on the information;

determining a second set of candidate feedback channels associated with the second sidelink channel based on the information;

selecting a first feedback channel from the first set of candidate feedback channels, the first feedback channel being non-edge in frequency domain in the first set of candidate feedback channels; and

selecting a second feedback channel from the second set of candidate feedback channels, such that the second feedback channel is non-edge in frequency domain in the second set of candidate feedback channels.
The device of claim 6, wherein the device is caused to transmit the at least one feedback of the at least one data packet by:

transmitting a first feedback of the first data packet on the first feedback channel to the further device; and

transmitting a second feedback of the second data packet on the second feedback channel to the further device.
The device of claim 3, wherein the at least one data packet comprises a first data packet and a second data packet, and at least one sidelink channel comprises a first sidelink channel for transmitting the first data packet and a second sidelink channel for transmitting the second data packet, and wherein the device is caused to select the at least one feedback channel by:

in accordance the first sidelink channel comprising more sub-channels than the second sidelink channel, receiving, from the further device, control information indicating the sub-channels in the first sidelink channel;

determining a first set of candidate feedback channels associated with the sub-channels in the first sidelink channel based on the information; and

selecting the at least one feedback channel from the first set of candidate feedback channels, such that the at least one feedback channel is non-edge in frequency domain in the first set of candidate feedback channels.
The device of claim 1, wherein the device is caused to select the at least one feedback channel by:

determining the number of time slots in the period; and

selecting a set of feedback channels, the number of feedback channels in the set of feedback channels corresponding to the number of time slots.
The device of claim 1, wherein the device is caused to select the at least one feedback channel by:

receiving, from the further device, control information indicating the number of time slots in which the at least one data packet is transmitted; and

selecting a set of feedback channels, the number of feedback channels in the set of feedback channels corresponding to the number of time slots in which the at least one data packet is transmitted.
The device of claim 1, wherein a group of devices comprises the first device, and wherein the device is caused to select the at least one feedback channel by:

selecting the at least one feedback channel based on a first identity of the first device and identities of other devices in the group of devices.
The device of claim 11, wherein the group of devices further comprises the further device, and wherein the device is caused to select the at least one feedback channel by:

receiving an indication of a second identity of the further device from the further device; and

selecting the at least one feedback channel by excluding the second identity from the identities of other devices in the group of devices.
The device of claim 1, wherein the device is further caused to:

transmit at least one further data packet on at least one further sidelink channel in the plurality of sidelink channels to the further device.
The device of claim 1, wherein the device is further caused to:

receive further configuration from another device, the further configuration indicating at least one of:

the number of time slots in the period of time,

the number of the plurality of the feedback channels in the period of time, or

the number of physical resource blocks in one feedback channel.
The device of claim 14, wherein the device comprises a terminal device, the further device comprises a further terminal device, and the other device comprises a network device.
A method comprising:

obtaining, at a first device, information indicating mapping between a plurality of sidelink channels and a plurality of feedback channels within a period of time, resources allocated to feedback channels which correspond to sidelink channels in one time slot in the period being continuous in frequency domain;

receiving from a second device at least one data packet on at least one sidelink channel of the plurality of sidelink channels;

selecting at least one feedback channel associated with the at least one sidelink channel from the plurality of feedback channels based on the information; and

transmitting to the second device at least one feedback for the at least one data packet on the at least one feedback channel.
The method of claim 16, wherein selecting the at least one feedback channel comprises:

in accordance with a determination that the at least one sidelink channel comprises a plurality of sub-channels, determining a set of candidate feedback channels associated with the plurality of sub-channels based on the information; and

selecting the at least one feedback channel from the set of candidate feedback channels, such that the at least one feedback channel is non-edge in frequency domain in the set of candidate feedback channels.
The method of claim 16, wherein the at least one data packet comprises a first data packet and a second data packet, and at least one sidelink channel comprises a first sidelink channel for transmitting the first data packet and a second sidelink channel for transmitting the second data packet, and wherein receiving the at least one data packet comprises:

receiving the first data packet on the first sidelink channel from the second device during a first time slot; and

receiving the second data packet on the second sidelink channel from the second device during a second time slot.
The method of claim 18, wherein selecting the at least one feedback channel comprises:

determining a first set of candidate feedback channels associated with the first sidelink channel based on the information;

determining a second set of candidate feedback channels associated with the second sidelink channel based on the information; and

in accordance with a determination that the first set of candidate feedback channels is longer than the second set of candidate feedback channels, selecting the at least one feedback channel from the first set of candidate feedback channels such that the at least one feedback channel is non-edge in frequency domain in the first set of candidate feedback channels.
The method of claim 19, wherein transmitting the at least one feedback of the at least one data packet comprises:

transmitting a first feedback of the first data packet and a second feedback of the second data packet on the at least one feedback channel to the second device.
The method of claim 18, wherein selecting the at least one feedback channel comprises:

determining a first set of candidate feedback channels associated with the first sidelink channel based on the information;

determining a second set of candidate feedback channels associated with the second sidelink channel based on the information;

selecting a first feedback channel from the first set of candidate feedback channels, the first feedback channel being non-edge in frequency domain in the first set of candidate feedback channels; and

selecting a second feedback channel from the second set of candidate feedback channels, such that the second feedback channel is non-edge in frequency domain in the second set of candidate feedback channels.
The method of claim 21, wherein transmitting the at least one feedback of the at least one data packet comprises:

transmitting a first feedback of the first data packet on the first feedback channel to the second device; and

transmitting a second feedback of the second data packet on the second feedback channel to the second device.
The method of claim 18, wherein the at least one data packet comprises a first data packet and a second data packet, and at least one sidelink channel comprises a first sidelink channel for transmitting the first data packet and a second sidelink channel for transmitting the second data packet, and wherein selecting the at least one feedback channel comprises:

in accordance the first sidelink channel comprising more sub-channels than the second sidelink channel, receiving, from the second device, control information indicating the sub-channels in the first sidelink channel;

determining a first set of candidate feedback channels associated with the sub-channels in the first sidelink channel based on the information; and

selecting the at least one feedback channel from the first set of candidate feedback channels, such that the at least one feedback channel is non-edge in frequency domain in the first set of candidate feedback channels.
The method of claim 16, wherein selecting the at least one feedback channel comprises:

determining the number of time slots in the period; and

selecting a set of feedback channels, the number of feedback channels in the set of feedback channels corresponding to the number of time slots.
The method of claim 16, wherein selecting the at least one feedback channel comprises:

receiving, from the second device, control information indicating the number of time slots in which the at least one data packet is transmitted; and

selecting a set of feedback channels, the number of feedback channels in the set of feedback channels corresponding to the number of time slots in which the at least one data packet is transmitted.
The method of claim 16, wherein a group of devices comprises the first device, and wherein selecting the at least one feedback channel comprises:

selecting the at least one feedback channel based on a first identity of the first device and identities of other devices in the group of devices.
The method of claim 26, wherein the group of devices further comprises the second device, and wherein selecting the at least one feedback channel comprises:

receiving an indication of a second identity of the second device from the second device; and

selecting the at least one feedback channel by excluding the second identity from the identities of other devices in the group of devices.
The method of claim 16, further comprising:

transmitting at least one further data packet on at least one further sidelink channel in the plurality of sidelink channels to the second device.
The method of claim 16, further comprising:

receiving further configuration from a third device, the further configuration indicating at least one of:

the number of time slots in the period of time,

the number of the plurality of the feedback channels in the period of time, or

the number of physical resource blocks in one feedback channel.
The method of claim 29, wherein the first device comprises a terminal device, the second device comprises a further terminal device, and the third device comprises a network device.
A computer readable storage medium comprising program instructions stored thereon, the instructions, when executed by an apparatus, causing the apparatus to perform the method of any one of claims 16-30.
An apparatus comprising means for performing a process according to any of claims 16-30.