Feedback for multi-channel sidelink communications

Abstract

The embodiment of the invention relates to equipment, a method, a device and a computer readable storage medium for feedback of multi-channel sidelink communication. A first device performs a plurality of listen-before-talk prior to a plurality of resources for a sidelink feedback channel associated with a first sidelink data channel. If at least two listen-before-talk (LBT) of the plurality of LBTs pass before at least two resources of the plurality of resources, transmitting to the second device, on a first resource of the at least two resources, a first feedback for a transmission from the second device via the first sidelink data channel; the first device also transmits to the second device a second feedback for transmissions from the second device via a previous second sidelink data channel on a second, different, resource of the at least two resources.

Description

Technical Field

[0001] Various example embodiments of the present disclosure relate generally to the field of telecommunications, and in particular, to methods, devices, apparatus, and computer-readable storage media for feedback of multi-channel sidelink communications. Background Art

[0002] Hybrid Automatic Repeat Request (HARQ) feedback is allowed for sidelink communications in licensed spectrum. A Physical Sidelink Feedback Channel (PSFCH) for sidelink communications is defined to carry HARQ feedback to the Physical Sidelink Shared Channel (PSSCH) via a sidelink between user equipments (UEs). To handle Listen Before Talk (LBT) ambiguity in unlicensed spectrum, repeated PSFCH resources can be configured in multiple channels. In some scenarios, repetition of PSFCH transmissions may not be necessary. Summary of the invention

[0003] In a first aspect of the present disclosure, a first device is provided. The first device includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the first device to at least perform: performing multiple listen-before-talk before multiple resources for a side link feedback channel, the side link feedback channel being associated with a first side link data channel; and in response to at least two of the multiple listen-before-talk passing before at least two resources in the multiple resources, transmitting to a second device on a first resource of the at least two resources a first feedback for a transmission from the second device via the first side link data channel; and transmitting to the second device on a different second resource of the at least two resources a second feedback for a transmission from the second device via a previous second side link data channel.

[0004] In a second aspect of the present disclosure, a second device is provided. The second device includes: at least one processor; and at least one memory storing instructions, which when executed by the at least one processor, cause the second device to at least perform: receiving, from the first device, first feedback for a transmission from the second device to the first device via a first side link data channel on a first resource among multiple resources for a side link feedback channel, the side link feedback channel being associated with the first side link data channel; and receiving, from the first device, second feedback for a transmission from the second device to the first device via a previous second side link data channel on a different second resource among the multiple resources, wherein at least two listen-before-talks of the first device pass at least before the first resource and the second resource.

[0005] In a third aspect of the present disclosure, a method is provided. The method includes: at a first device, performing multiple listen-before-talk before multiple resources for a sidelink feedback channel, the sidelink feedback channel being associated with a first sidelink data channel; and in response to at least two of the multiple listen-before-talk passing before at least two resources in the multiple resources, transmitting to a second device, on a first resource in the at least two resources, first feedback for a transmission from the second device via the first sidelink data channel; and transmitting to the second device, on a different second resource in the at least two resources, second feedback for a transmission from the second device via a previous second sidelink data channel.

[0006] In a fourth aspect of the present disclosure, a method is provided. The method includes: receiving, at a second device, first feedback from the first device for a transmission from the second device to the first device via a first sidelink data channel on a first resource among a plurality of resources for a sidelink feedback channel, the sidelink feedback channel being associated with the first sidelink data channel; and receiving, from the first device, second feedback for a transmission from the second device to the first device via a previous second sidelink data channel on a different second resource among the plurality of resources, wherein at least two listen-before-talks of the first device pass at least before the first resource and the second resource.

[0007] In a fifth aspect of the present disclosure, a first device is provided. The first device includes: a component for performing multiple listen-before-talk before multiple resources for a sidelink feedback channel, the sidelink feedback channel being associated with a first sidelink data channel; and a component for transmitting, on a first resource of the at least two resources, first feedback for a transmission from the second device via the first sidelink data channel to a second device in response to at least two of the multiple listen-before-talk passing before at least two of the multiple resources, and a component for transmitting, on a different second resource of the at least two resources, second feedback for a transmission from the second device via a previous second sidelink data channel to the second device.

[0008] In a sixth aspect of the present disclosure, a second device is provided. The second device includes: a component for receiving, from a first device, first feedback for a transmission from a second device to a first device via a first side link data channel on a first resource among a plurality of resources for a side link feedback channel, the side link feedback channel being associated with the first side link data channel; and a component for receiving, from a first device, second feedback for a transmission from a second device to a first device via a previous second side link data channel on a different second resource among the plurality of resources, wherein at least two listen-before-talks of the first device pass at least before the first resource and the second resource.

[0009] In a seventh aspect of the present disclosure, a computer-readable medium is provided, wherein the computer-readable medium includes instructions stored thereon, and the instructions are used to cause a device to at least execute the method according to the third aspect or the fourth aspect.

[0010] It should be understood that the invention summary is not intended to identify the key or essential features of the 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 readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0012] Figure 1 An example communication environment is shown in which example embodiments of the present disclosure may be implemented;

[0013] Figure 2A An example frame structure of a sidelink timeslot having a physical sidelink control channel (PSCCH), a PSSCH, and a PSFCH according to some example embodiments of the present disclosure is shown;

[0014] Figure 2B shows an example mapping between PSSCH and PSFCH according to some example embodiments of the present disclosure;

[0015] Figure 2C shows an example configuration of repeated PSFCH resources according to some example embodiments of the present disclosure;

[0016] Figure 3 An example signaling diagram illustrating a feedback process according to some example embodiments of the present disclosure;

[0017] Figure 4 A flowchart showing a method according to some example embodiments of the present disclosure is shown;

[0018] Figure 5A A schematic diagram showing an example mapping in the case of frequency domain repetition feedback resources according to some example embodiments of the present disclosure;

[0019] Figure 5B A schematic diagram showing an example mapping in the case of repeated feedback resources in the time domain according to some example embodiments of the present disclosure;

[0020] Figure 6 A flowchart showing a method according to some example embodiments of the present disclosure is shown;

[0021] Figure 7 shows a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure; and

[0022] Figure 8A block diagram of an example computer-readable medium is shown according to some example embodiments of the present disclosure.

[0023] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0024] The principle of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only for the purpose of illustrating and helping those skilled in the art to understand and implement the present disclosure, without implying any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in various ways except for the way described below.

[0025] 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 skill in the art to which this disclosure belongs.

[0026] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an example embodiment, whether or not explicitly described, it is considered to be within the knowledge of those skilled in the art to affect the combination of such feature, structure, or characteristic with other embodiments.

[0027] It should be understood that although the terms "first" and "second" 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 element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more listed terms.

[0028] As used herein, “at least one of: ” and “at least one of ” and similar expressions, where a list of two or more elements is combined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0029] As used herein, unless explicitly stated, performing a step "in response to A" does not indicate that the step is performed immediately after "A" occurs, and may include one or more intermediate steps.

[0030] The terms used herein are used only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms "include", "comprise", "have", "contain", "have" and / or "comprising" when used herein specify the presence of stated features, elements and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof.

[0031] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware circuit implementation only (such as implementation only in analog and / or digital circuitry) and (b) a combination of hardware circuitry and software such as (where applicable): (i) a combination of analog and / or digital hardware circuits and software / firmware, and (ii) any portion of hardware processor(s) with software (including digital signal processor(s), software, and memory(s) that work together to enable a device such as a mobile phone or server to perform various functions) and (c) hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when the software is not required.

[0032] This definition of circuitry applies to all uses of the term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. For example, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or network device, if applicable to the particular claim element.

[0033] As used herein, the term "communication network" refers to a network that follows any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), Advanced LTE (LTE-A), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocol and / or any other protocol currently known or developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there will certainly be communication technologies and systems that can embody future types of the present disclosure. It should not be considered that the scope of the present disclosure is limited to the aforementioned system.

[0034] 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 from it. A 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 (eNode B or eNB), a NR NB (also referred to as a gNB), a radio remote unit (RRU), a radio head (RH), a radio remote head (RRH), a relay, an integrated access and backhaul (IAB) node, a low-power node (such as a femto), a micro, a non-terrestrial network (NTN) or a non-terrestrial network device (such as a satellite network device, a low earth orbit (LEO) satellite, and a geosynchronous earth orbit (GEO) satellite), an aircraft network device, etc., depending on the terminology and technology applied. In some example embodiments, a radio access network (RAN) split architecture includes a centralized unit (CU) and a distributed unit (DU) at an IAB donor node. An IAB node includes a mobile terminal (IAB-MT) portion that behaves like a UE, toward a parent node, and the DU portion of the IAB node behaves like a base station, toward a next-hop IAB node.

[0035] The term "terminal device" refers to any end device capable of wireless communication. As an example and not limitation, a terminal device may also be referred to as a communication device, a 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 is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local ring phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device such as a digital camera, a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in the context of an industrial and / or automated processing chain), consumer electronic devices, equipment operating on a commercial and / or industrial wireless network, etc. The terminal device may also correspond to the mobile terminal (MT) part of an integrated access and backhaul (IAB) node (also referred to as a relay node). In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0036] As used herein, the term "resource", "transmission resource", "resource block" (RB) or "physical resource block" (PRB) may refer to any resource used to perform communication (e.g., communication between a terminal device and a network device), such as a time domain resource, a frequency domain resource, a spatial domain resource, a code domain resource, or any other resource that enables communication. In the following, unless explicitly stated, resources in the frequency domain and the time domain will be used as examples of transmission resources for describing some example embodiments of the present disclosure. Note that the example embodiments of the present disclosure are also applicable to other resources in other domains.

[0037] As used herein, the term "side link" (SL) refers to a communication link between end devices. Resources in the side link can be configured by the network. Side link communication in an unlicensed band can be a use case in industrial automation for a private network.

[0038] As mentioned above, HARQ feedback is allowed for sidelink communications in licensed spectrum. In Release 16 (Rel-16), for fifth generation (5G) vehicle-to-everything (V2X) with new radio (NR) sidelink, PSFCH for sidelink communications is defined to carry HARQ feedback over the sidelink (at the physical layer) from a user equipment (UE) that is the intended recipient (hereinafter also referred to as Rx UE) of a transmission over a physical sidelink shared channel (PSSCH) to a transmitting UE (hereinafter also referred to as Tx UE).

[0039] For PSFCH, the sequence is transmitted in one physical resource block (PRB) repeated over two orthogonal frequency division multiplexing (OFDM) symbols near the end of the sidelink resources in the slot, and the first symbol of the two orthogonal frequency division multiplexing (OFDM) symbols can be used for automatic generation control (AGC). The sequence as the base sequence can be (pre)configured for each sidelink resource pool. For PDSCH to HARQ timing, the NR NB (e.g., gNB) can configure the parameter K in units of slots. The timing of the PSFCH is determined from K. For a PSSCH transmission in slot n with the last symbol of this PSSCH transmission, the HARQ feedback is in slot n+a, where a is the smallest integer greater than or equal to K in the case where slot n+a contains PSFCH resources.

[0040] To handle listen-before-talk (LBT) ambiguity in unlicensed spectrum, repeated PSFCH resources can be configured in multiple channels (e.g., two RB sets in two channels). If LBT is over more than one RB set, repetition of PSFCH transmission may not be necessary and thus result in a waste of resources.

[0041] The example embodiments of the present disclosure propose an enhanced scheme for PSFCH transmission for multi-channel sidelink communications in unlicensed spectrum. The scheme can be applied to scenarios with repeated resources of a sidelink feedback channel (e.g., PSFCH) configured on multiple channels to handle LBT uncertainty. The key idea is that when LBT passes through more than one resource of a sidelink feedback channel associated with the latest sidelink data channel (e.g., PSSCH) from a device, then these resources are used to transmit feedback to the latest sidelink data channel and previously unconfirmed sidelink data channels from the same device.

[0042] The proposed scheme can improve the resource efficiency of PSFCH transmission while reducing the PSFCH transmission delay in unlicensed spectrum.

[0043] Figure 1An example communication environment 100 is shown in which example embodiments of the present disclosure may be implemented. In the communication environment 100, a plurality of communication devices including a first device 110 and a second device 120 may communicate with each other.

[0044] Hereinafter, for the purpose of illustration, some example embodiments are described in which the first device 110 and the second device 120 operate as terminal devices and communicate in a side link (SL). In SL communication, one of the first device 110 and the second device 120 is a transmission (TX) device (or transmitter), and the other of the first device 110 and the second device 120 is a reception (RX) device (or receiver). It should be understood that in some example embodiments, either or both of the first device 110 and the second device 120 may operate as a network device or other devices.

[0045] The communication in the communication environment 100 may be implemented according to any appropriate (multiple) communication protocols, including but not limited to cellular communication protocols of the first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), fifth generation (5G), sixth generation (6G), etc., wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocol currently known or developed in the future. In addition, the communication may utilize any appropriate wireless communication technology, including but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiple access (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM) and / or any other technology currently known or developed in the future.

[0046] The first device 110 and the second device 120 may communicate on a sidelink control channel such as a physical sidelink control channel (PSCCH), a sidelink data channel such as a PSSCH, and a sidelink feedback channel such as a PSFCH. Figure 2A An example of the time slot format of PSCCH, PSSCH and PSFCH is shown in FIG.

[0047] The time resources for PSFCH can be (pre)configured to occur once in every 1, 2 or 4 time slots. The HARQ feedback resources (on PSFCH) can be obtained from the resource locations of PSCCH and / or PSSCH. For example, for a PSSCH transmission with the last symbol of this PSSCH transmission in time slot n, the HARQ feedback for the PSSCH with the last symbol in time slot n can be in time slot n+a, where a is the smallest integer greater than or equal to K configured by the network. Figure 2BAn example mapping between PSSCH and PSFCH is shown in , where the period of PSFCH resources is configured as 2 and K is configured as 2.

[0048] To handle LBT uncertainty in unlicensed spectrum, repeated PSFCH resources can be configured in multiple radio channels. For the purpose of discussion, radio channels can be simplified and referred to as channels. Radio channels can typically occupy 20 MHz or 10 MHz. Figure 2C As shown, two sets of RBs 205 and RBs 210 may be configured for PSFCH in two channels 215 and channel 220. The RB sets may be located in a radio channel.

[0049] By using repeated resources, the robustness of HARQ feedback can be improved.To improve resource efficiency, if LBT is over more than one RB set, PSFCH resources in some RB sets can be used for feedback for (multiple) previous PSSCH transmissions.

[0050] Figure 3 An example signaling diagram of a feedback process 300 according to some example embodiments of the present disclosure is shown. For discussion purposes, the process 300 will be discussed in an example scenario where the second device 120 acts as a transmitting device and the first device 110 acts as a receiving device.

[0051] In process 300, second device 120 may transmit (305) data to first device 110 via a sidelink data channel (referred to as a first sidelink data channel). First device 110 may be required to transmit feedback after receiving (310) the transmission from second device 120. Figure 3 As shown in , the first device 110 may perform (315) multiple LBTs before multiple resources for a sidelink feedback channel associated with a first sidelink data channel. If at least two of the LBTs are passed before at least two of the resources, the first device 110 may transmit (320) feedback (referred to as first feedback) for transmission via the first sidelink data channel to the second device 120 on a first resource of the at least two resources. In addition, the first device 110 may transmit (325) feedback (referred to as second feedback) for transmission from the second device 120 via a previous sidelink data channel (referred to as a second sidelink data channel) to the second device 120 on a different second resource of the at least two resources.

[0052] The second device 120 may receive (330) first feedback for a transmission via the first sidelink data channel from the first device 110 on the first resource and receive (335) second feedback for a previous transmission via the second sidelink data channel on the second resource.

[0053] In this way, the resources for the duplication of sidelink feedback can be well utilized, thereby improving resource efficiency and avoiding resource waste. In addition, the sidelink feedback delay in unlicensed spectrum can be reduced and the sidelink (re)transmission can be more efficient.

[0054] Figure 4 A flow chart of an example method 400 implemented at the first device 110 according to some example embodiments of the present disclosure is shown.

[0055] At block 405, the first device 110 performs a plurality of LBTs before a plurality of resources for a sidelink feedback channel (such as PSFCH) associated with a first sidelink data channel (such as PSSCH). The resources may have any suitable granularity, for example, including a number of RBs, a number of OFDM symbols, etc.

[0056] In some example embodiments, repeated PSFCH resources may be (pre)configured in multiple RB sets in multiple channels for reliability of HARQ feedback. For each repeated PSFCH resource, independent LBT may be performed for channel access.

[0057] Resources may be repeated in the time domain and / or frequency domain. For example, multiple radio channels (or channels) in one opportunity may be configured for feedback. As an alternative example, multiple time opportunities may be configured for feedback.

[0058] In response to at least two LBTs passing before at least two resources, at block 410, the first device 110 transmits, on a first resource of the at least two resources, first feedback for a transmission from the second device via the first sidelink data channel to the second device 120. In addition, at block 415, the first device 110 transmits, on a different second resource of the at least two resources, second feedback for a transmission from the second device 120 via a previous second sidelink data channel to the second device 120.

[0059] In some example embodiments, if the resources are repeated in different radio channels in the timing of the sidelink feedback channel, the first resources may include a set of resource blocks in the radio channel in the timing of the sidelink feedback channel, and the second resources may include a set of resource blocks in a different radio channel in the timing.

[0060] In some example embodiments, if the resources are repeated in different radio channels in the timing of the sidelink feedback channel, the first resources may include a set of resource blocks in the timing of the sidelink feedback channel, and the second resources may include a set of resource blocks in different timings of the sidelink feedback channel.

[0061] The following will refer to Figure 5A and Figure 5B to discuss an example mapping of a sidelink feedback channel and a sidelink data channel.

[0062] First, refer to Figure 5A , which shows a diagram 500 of an example mapping in the case of frequency-domain repeated feedback resources according to some example embodiments of the present disclosure.

[0063] In this example, two repeated resources 505 and 510 of a sidelink feedback channel (e.g., PSFCH) are configured in two RB sets 515 and 520 in two radio channels for feedback (e.g., HARQ feedback) of a sidelink data channel (e.g., PSSCH), and the two RB sets 515 and 520 are labeled as RB set 1 and RB set 2. In a time slot 525 labeled as time slot 4, LBT passes through both RB set 1 and RB set 2. In this case, the resource 505 in RB set 1 is used for feedback to the latest sidelink data channel, and the resource 510 in RB set 2 can be used for feedback to a previous unacknowledged PSSCH.

[0064] For example, when LBT is successfully completed in more than one RB set among the configured RB sets, the LBT is associated with different PSFCH symbols within a time slot, and at the repeated PSFCH resources initially configured for HARQ feedback corresponding to a PSSCH (latest PSSCH) transmitted from a Tx UE to an Rx UE, a PSFCH for transmitting HARQ feedback from the same Tx UE to a previous unacknowledged PSSCH can be transmitted by the Rx UE. Therefore, resource efficiency can be improved while feedback latency can be reduced.

[0065] This concept can be similarly applied to the case where multiple occasions (e.g., N occasions, where N represents any positive integer) are configured for a sidelink feedback channel that can be a PSFCH. If LBT passes through before an occasion (e.g., occasion i with 1 <= i < N), resources at the following occasions (e.g., occasion i + 1,..., N) can be used for feedback from the same device to a previous unacknowledged sidelink data channel such as a PSSCH.

[0066] Figure 5B shows a schematic diagram 540 of an example mapping in the case of time-domain repeated feedback resources according to some example embodiments of the present disclosure.

[0067] In this example, two opportunities 545 and 550 are configured for a sidelink feedback channel, which may be a PSFCH. If the LBT passes before opportunity 545, the resources at the subsequent opportunity 550 may be used for feedback from the same transmitter to a previously unacknowledged sidelink data channel.

[0068] It should be understood that Figure 5A and Figure 5B The two repeated resources shown in are for illustration purposes only and do not imply any limitation. Multiple repeated resources may be configured, and more than one previous sidelink data channel may be acknowledged using the remaining resources of the repeated resources.

[0069] Still reference Figure 4 In some example embodiments, the first feedback may be transmitted using a first sequence and the second feedback may be transmitted using a different second sequence. The different sequences may be generated from the same base sequence or different base sequences, which may be configured by the network. By using different sequences for feedback for different sidelink data channels, the Tx device may distinguish feedback for a previous unacknowledged sidelink data channel from feedback for the latest sidelink data channel.

[0070] In some example embodiments, if the first feedback is a positive acknowledgement (ACK), the first feedback may be transmitted using a cyclic shift of the first sequence. If the first feedback is a negative acknowledgement (NACK or NAK), the first feedback may be transmitted using a different cyclic shift of the first sequence. If the second feedback is an ACK, the second feedback may be transmitted using a cyclic shift of the second sequence. If the second feedback is a NACK, the second feedback may be transmitted using a different cyclic shift of the second sequence.

[0071] In some example embodiments, the second sequence may be associated with a second sidelink data channel.In some example embodiments, first device 110 may determine the second sequence from a plurality of sequences available for confirmation of a previous sidelink data channel based on the association of the second sequence with the second sidelink data channel.

[0072] For example, a set of M sequences (where M represents any suitable positive integer) may be (pre)configured and may be used for (HARQ) feedback of a previous sidelink data channel (e.g., PSSCH). Each sequence corresponds to a previous sidelink data channel, for example, sequence i (1<=i<=M) corresponds to PSSCH. j-i Correspondingly, the latest PSSCH can be recorded as PSSCH j .

[0073] In some example embodiments, a sequence in the plurality of sequences may be associated with at least one of: a time slot index of a previous sidelink data channel, or an identifier (ID) of a HARQ process associated with a previous sidelink data channel (e.g., a HARQ ID or a HARQ process ID).

[0074] For example, in a slot index-based method, each sequence may correspond to a slot prior to the slot in which the latest PSSCH is transmitted (slot q), for example, sequence i (1 <= i <= M) corresponds to slot qi. Sequence i is used to forward a PSFCH that conveys HARQ feedback to a previously unconfirmed PSSCH transmitted in slot qi.

[0075] As an alternative example, in a HARQ ID-based approach, each sequence may be mapped to a HARQ ID by implying a predetermined ordering. For example, sequence 0 may correspond to the lowest unconfirmed HARQ ID, and sequence 1 may correspond to the second lowest unconfirmed HARQ ID. Alternatively, a reverse ordering may be applied.

[0076] The association of the sequence with the previous side link data channel may be predefined or (pre) configured by the network. Based on the predefined or (pre) configured association, both the first device 110 (as an RX device) and the second device 120 (as a TX device) may know which / which (multiple) previous side link data channels may be confirmed.

[0077] In some example embodiments, the second side link data channel is preconfigured to be confirmed by the first device. For example, the second side link data channel may be (pre)configured: (HARQ) feedback should confirm which previously unconfirmed side link data channel at (multiple) repeated resources. Thus, the first device 110 and the second device 120 may know the second side link data channel to be confirmed.

[0078] In some example embodiments, first device 110 may receive an indication of at least one previous sidelink data channel in sidelink control information (SCI) from second device 120 via the first sidelink data channel. The at least one previous sidelink data channel includes the second sidelink data channel. Thus, first device 110 may determine the second sidelink data channel from the indicated at least one previous sidelink data channel.

[0079] In some example embodiments, the indication of the at least one previous sidelink data channel may include an indication of a time slot index for the at least one previous sidelink data channel. In some example embodiments, the indication of the time slot index for the at least one previous sidelink data channel may include an offset of the time slot index of the at least one previous sidelink data channel relative to the time slot index of the first sidelink data channel.

[0080] For example, in the slot index method, the slot (e.g., slot index) with the previously transmitted unconfirmed sidelink data channel (such as PSSCH) can be indicated in the SCI. The slot index can be an offset relative to the slot with the latest PSSCH transmitted.

[0081] In some example embodiments, the indication of the at least one previous sidelink data channel may include an identification of a HARQ process (also referred to as a HARQ process ID) associated with the at least one previous sidelink data channel.

[0082] In this way, the second device 120 can dynamically indicate to the first device 110 that feedback should confirm which unconfirmed sidelink data channel (such as PSSCH) at (multiple) repeated resources. Which previously unconfirmed PSSCH can be indicated in the SCI of the latest PSSCH or the PSCCH associated with the latest PSSCH, for example, by indicating which / which HARQ process IDs are currently unconfirmed or the (multiple) associated time slots in which the (multiple) unconfirmed PSSCHs were originally transmitted. Thereby, feedback and retransmission efficiency can be further improved while improving resource efficiency.

[0083] In some example embodiments, if multiple previous sidelink data channels need to be confirmed by the first device 110, the first device 110 may determine a second sidelink data channel from the multiple previous sidelink data channels according to an ordering of the multiple previous sidelink data channels based on time slot indices of the multiple previous sidelink data channels and / or HARQ process IDs associated with the multiple previous sidelink data channels.

[0084] For example, in a HARQ process ID-based method, if there is a single (PSFCH) resource available for providing feedback, the first device 110 (as an Rx device) and the second device 120 (as a Tx) may first implicitly assume that the confirmed sidelink data channel (such as PSSCH) (or HARQ process ID) follows a specific sorting rule, such as a lower (or higher) HARQ process ID. If there are multiple resources (e.g., RBs in multiple RB sets or multiple RBs) available for providing feedback, the same sorting principle may be, for example: the lowest RB (or RB in the lowest RB set) of the sidelink feedback channel (e.g., PSFCH) may be used for the lowest HARQ process ID. A similar principle may be applied to a slot index-based method.

[0085] In some example embodiments, if the latest sidelink data channel (such as PSSCH) occupies multiple channels, multiple repeated PRBs of the sidelink feedback channel (e.g., PSFCH) can be used for (HARQ) feedback from the Tx UE (e.g., the second device 120) for multiple previously unconfirmed PSSCHs. The following association rules between repeated PSFCH PRBs and previously unconfirmed PSSCHs can be followed. If multiple previously unconfirmed PSSCHs are in different time slots, the latest previously unconfirmed PSSCH is associated with the lowest PSFCH PRB index. If multiple previously unconfirmed PSSCHs are in the same time slot, the previously unconfirmed PSSCH with the lowest channel index is associated with the lowest PSFCH PRB index.

[0086] In some example embodiments, if the first device 110 (which may be an Rx UE) does not receive an indication of which unconfirmed sidelink data channel (which may be a PSSCH), the HARQ feedback should be confirmed at repeated resources of the sidelink feedback channel (which may be a PSFCH), and the second device 120 may choose not to transmit to reduce mutual interference of transmissions of the sidelink feedback channel, or transmit a sidelink feedback channel that conveys feedback corresponding to the latest sidelink data channel transmitted from the second device 120 (which may be a Tx UE) to improve the link-level transmission reliability of the sidelink feedback channel.

[0087] Figure 6 A flow chart of an example method 600 implemented at the second device 120 according to some example embodiments of the present disclosure is shown.

[0088] At box 610, the second device 120 receives, from the first device 110, first feedback for a transmission from the second device to the first device via a first sidelink data channel, on a first resource among multiple resources for a sidelink feedback channel, which is associated with the first sidelink data channel.

[0089] At block 620, the second device 120 receives second feedback from the first device 110 for transmission from the second device to the first device via the previous second sidelink data channel on a different second resource of the plurality of resources. At least two LBTs of the first device 110 pass before the first resource and the second resource.

[0090] In some example embodiments, the first feedback is received using a first sequence and the second feedback is received using a different second sequence. In this way, the second device 120 can distinguish feedback for a previous unacknowledged sidelink data channel from feedback for the latest sidelink data channel.

[0091] In some example embodiments, the second device 120 may also identify the second sidelink data channel based on an association of the second sequence with the second sidelink data channel.

[0092] In some example embodiments, the second sequence may be associated with at least one of: a time slot index of the second sidelink data channel, or an identification of a hybrid automatic repeat request process associated with the second sidelink data channel.

[0093] In some example embodiments, if the first feedback is a positive acknowledgment, the first feedback is received using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgment, the first feedback is received using a different cyclic shift of the first sequence, and / or if the second feedback is a positive acknowledgment, the second feedback is received using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgment, the second feedback is received using a different cyclic shift of the second sequence.

[0094] In some example embodiments, second device 120 may also transmit, via the first sidelink data channel or via a sidelink control channel associated with the first sidelink data channel, an indication of at least one previous sidelink data channel in the sidelink control information to first device 110, the at least one previous sidelink data channel including the second sidelink data channel. In this manner, second device 120 may dynamically indicate to first device 110 the unacknowledged sidelink data channel(s) to be acknowledged.

[0095] In some example embodiments, the indication of the at least one previous sidelink data channel may include an indication of a time slot index for the at least one previous sidelink data channel.

[0096] In some example embodiments, the indication of a time slot index for at least one previous sidelink data channel may include an offset of the time slot index of the at least one previous sidelink data channel relative to a time slot index of the first sidelink data channel.

[0097] In some example embodiments, the indication of the at least one previous sidelink data channel may include an identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

[0098] In some example embodiments, the second device 120 may also identify a second side link data channel from the plurality of previous side link data channels according to an ordering of the plurality of previous side link data channels based on time slot indices of the plurality of previous side link data channels, and / or an identifier of a hybrid automatic repeat request process associated with the plurality of previous side link data channels.

[0099] In some example embodiments, the second sidelink data channel may be preconfigured to be acknowledged by the first device.

[0100] In some example embodiments, the first resources may comprise a set of resource blocks in a radio channel in an opportunity of the sidelink feedback channel, and the second resources may comprise a set of resource blocks in a different radio channel in the opportunity.

[0101] In some example embodiments, the first resources may comprise a set of resource blocks in an occasion of a sidelink feedback channel, and the second resources may comprise a set of resource blocks in a different occasion of the sidelink feedback channel.

[0102] As mentioned above Figures 1 to 5B All operations and features described for the second device 120 or TX device or UE or transmitter are also applicable to the method 600 and have similar effects. For the purpose of simplicity, the details will be omitted.

[0103] In some example embodiments, a first device (eg, Figure 1 The first device 110 in the method 400 may include a component for performing the corresponding operation of the method 400). The component may be implemented in any suitable form. For example, the component may be implemented in a circuit system or a software module. The first device may be implemented as or included in Figure 1 In the first device 110.

[0104] In some example embodiments, the first device includes: a component for performing a plurality of listen-before-talk operations before a plurality of resources for a sidelink feedback channel associated with a first sidelink data channel; and a component for transmitting, to a second device, on a first resource of the at least two resources, first feedback for a transmission from the second device via the first sidelink data channel, and transmitting, to the second device, on a different second resource of the at least two resources, second feedback for a transmission from the second device via a previous second sidelink data channel, in response to at least two of the plurality of listen-before-talk operations passing before at least two of the plurality of resources.

[0105] In some example embodiments, the first feedback is received using a first sequence and the second feedback is received using a second, different sequence.

[0106] In some example embodiments, the second sequence is associated with a second sidelink data channel.

[0107] In some example embodiments, the first apparatus further comprises means for determining the second sequence from a plurality of sequences available for acknowledgment to a previous sidelink data channel based on an association of the second sequence with the second sidelink data channel.

[0108] In some example embodiments, a sequence in the plurality of sequences is associated with at least one of: a time slot index of a previous sidelink data channel, or an identification of a hybrid automatic repeat request process associated with the previous sidelink data channel.

[0109] In some example embodiments, if the first feedback is a positive acknowledgment, the first feedback is transmitted using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgment, the first feedback is transmitted using a different cyclic shift of the first sequence, and / or if the second feedback is a positive acknowledgment, the second feedback is transmitted using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgment, the second feedback is transmitted using a different cyclic shift of the second sequence.

[0110] In some example embodiments, the first apparatus further comprises means for receiving, from the second device via the first side link data channel or via a side link control channel associated with the first side link data channel, an indication of at least one previous side link data channel in side link control information, the at least one previous side link data channel comprising the second side link data channel.

[0111] In some example embodiments, the indication of the at least one previous sidelink data channel comprises an indication of a time slot index for the at least one previous sidelink data channel.

[0112] In some example embodiments, the indication of a time slot index for at least one previous sidelink data channel comprises an offset of the time slot index of the at least one previous sidelink data channel relative to a time slot index of the first sidelink data channel.

[0113] In some example embodiments, the indication of the at least one previous sidelink data channel comprises an identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

[0114] In some example embodiments, the first device also includes: a component for determining a second side link data channel from a plurality of previous side link data channels according to an ordering of the plurality of previous side link data channels based on time slot indices of the plurality of previous side link data channels, and / or an identifier of a hybrid automatic repeat request process associated with the plurality of previous side link data channels.

[0115] In some example embodiments, the second sidelink data channel is preconfigured to be acknowledged by the first device.

[0116] In some example embodiments, the first resources comprise a set of resource blocks in a radio channel in an opportunity of the sidelink feedback channel, and the second resources comprise a set of resource blocks in a different radio channel in an opportunity.

[0117] In some example embodiments, the first resources comprise a set of resource blocks in an occasion of a sidelink feedback channel, and the second resources comprise a set of resource blocks in a different occasion of the sidelink feedback channel.

[0118] In some example embodiments, the first apparatus further comprises means for performing the method 400 or other operations in some example embodiments of the first device 110. In some example embodiments, the means comprises: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the execution of the first apparatus.

[0119] In some example embodiments, a second device (eg, Figure 1 The second device 120 in the method 600 may include a component for performing the corresponding operation of the method 600). The component may be implemented in any suitable form. For example, the device may be implemented in a circuit system or a software module. The second device may be implemented as or included in Figure 1 In the second device 120.

[0120] In some example embodiments, the second apparatus includes: a component for receiving, from the first device on a first resource among a plurality of resources for a side link feedback channel, first feedback for a transmission from the second device to the first device via a first side link data channel, the side link feedback channel being associated with the first side link data channel; and a component for receiving, from the first device on a different second resource among the plurality of resources, second feedback for a transmission from the second device to the first device via a previous second side link data channel, wherein at least two listen-before-talk of the first device pass through at least the first resource and the second resource.

[0121] In some example embodiments, the first feedback is received using a first sequence and the second feedback is received using a second, different sequence.

[0122] In some example embodiments, the second apparatus further comprises means for identifying the second sidelink data channel based on an association of the second sequence with the second sidelink data channel.

[0123] In some example embodiments, the second sequence is associated with at least one of: a time slot index of the second sidelink data channel, or an identification of a hybrid automatic repeat request process associated with the second sidelink data channel.

[0124] In some example embodiments, if the first feedback is a positive acknowledgment, the first feedback is received using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgment, the first feedback is received using a different cyclic shift of the first sequence, and / or if the second feedback is a positive acknowledgment, the second feedback is received using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgment, the second feedback is received using a different cyclic shift of the second sequence.

[0125] In some example embodiments, the second apparatus further comprises means for transmitting, to the first device via the first side link data channel or via a side link control channel associated with the first side link data channel, an indication of at least one previous side link data channel in the side link control information, the at least one previous side link data channel comprising the second side link data channel.

[0126] In some example embodiments, the indication of the at least one previous sidelink data channel comprises an indication of a time slot index for the at least one previous sidelink data channel.

[0127] In some example embodiments, the indication of a time slot index for at least one previous sidelink data channel comprises an offset of the time slot index of the at least one previous sidelink data channel relative to a time slot index of the first sidelink data channel.

[0128] In some example embodiments, the indication of the at least one previous sidelink data channel comprises an identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

[0129] In some example embodiments, the second device also includes: a component for identifying a second side link data channel from a plurality of previous side link data channels according to an ordering of the plurality of previous side link data channels based on time slot indices of the plurality of previous side link data channels and / or an identifier of a hybrid automatic repeat request process associated with the plurality of previous side link data channels.

[0130] In some example embodiments, the second sidelink data channel is preconfigured to be acknowledged by the first device.

[0131] In some example embodiments, the first resources comprise a set of resource blocks in a radio channel in an opportunity of the sidelink feedback channel, and the second resources comprise a set of resource blocks in a different radio channel in an opportunity.

[0132] In some example embodiments, the first resources comprise a set of resource blocks in an occasion of a sidelink feedback channel, and the second resources comprise a set of resource blocks in a different occasion of the sidelink feedback channel.

[0133] In some example embodiments, the second apparatus further comprises means for performing the method 600 or other operations in some example embodiments of the second device 120. In some example embodiments, the means comprises: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the execution of the second apparatus.

[0134] Figure 7 700 is a simplified block diagram of a device 700 suitable for implementing an example embodiment of the present disclosure. The device 700 may be provided to implement a communication device, such as Figure 1 The first device 110 or the second device 120 shown in FIG. As shown in the figure, the device 700 includes one or more processors 710, one or more memories 720 that can be coupled to the processor 710, and one or more communication modules 740 that can be coupled to the processor 710.

[0135] The communication module 740 may be used for two-way communication. The communication module 740 may have one or more communication interfaces that facilitate communication with one or more other modules or devices. The communication interface may represent any interface necessary for communication with other network elements. In some example embodiments, the communication module 740 may include at least one antenna.

[0136] As non-limiting examples, processor 710 may be of any type suitable for a local technology network, and may include one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 700 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock of a synchronized main processor.

[0137] The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 724, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), and other magnetic and / or optical memories. Examples of volatile memories include, but are not limited to, random access memory (RAM) 722 and other volatile memories that are not retained during power failure.

[0138] The computer program 730 includes computer executable instructions executed by the associated processor 710. The instructions of the program 730 may include instructions for performing the operations / actions of some example embodiments of the present disclosure. The program 730 may be stored in a memory, such as ROM 724. The processor 710 may perform any suitable actions and processes by loading the program 730 into the RAM 722.

[0139] The embodiments of the present disclosure may be implemented with the aid of program 730, so that device 700 may execute the following steps: Figures 1 to 6 Any process of the present disclosure discussed. The embodiments of the present disclosure may also be implemented by hardware, or by a combination of software and hardware.

[0140] In some embodiments, the program 730 may be tangibly contained in a computer-readable medium, which may be included in the device 700 (e.g., memory 720) or other storage device accessible by the device 800. The device 700 may load the program 730 from the computer-readable medium to the RAM 722 for execution. In some embodiments, the computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. The term "non-transitory" as used herein is a limitation of the medium itself (i.e., tangible, not a signal), not a limitation on data storage persistence (e.g., RAM versus ROM).

[0141] Figure 8 An example of a computer readable medium 800 in the form of a CD or DVD or other optical storage disk is shown. The computer readable medium 800 has a program 730 stored thereon.

[0142] In general, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof.

[0143] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a non-transient computer-readable storage medium. The computer program product includes computer executable instructions, such as those included in a program module, which are executed in a device on a target real or virtual processor to implement any of the methods described above. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of the program modules can be combined or split between program modules as needed. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in both local and remote storage media.

[0144] The program code for implementing the disclosed method 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, a special-purpose computer, or other programmable data processing device so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code may be executed entirely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0145] In the context of the present disclosure, computer program codes or related data may be implemented by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0146] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. More specific examples of computer readable storage media will include an electrical connection with one or more wires, a portable computer disk, 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 disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0147] In addition, although operations are depicted in a particular order, this should not be understood as requiring such operations to be performed in the particular order shown or in order, or performing all operations shown to achieve the desired result. In certain cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but should be interpreted as descriptions of features that may be specific to a particular embodiment. Unless explicitly stated, the specific features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. On the contrary, unless explicitly stated, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0148] Although the disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the 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

1. A first device, include: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the first device to at least perform: performing a plurality of listen-before-talk prior to a plurality of resources for a sidelink feedback channel associated with a first sidelink data channel; as well as In response to at least two of the plurality of listen-before-talk resources passing before at least two of the plurality of resources, transmitting, to a second device, on a first resource of the at least two resources, first feedback for a transmission from the second device via the first sidelink data channel; as well as Second feedback for a transmission from the second device via a previous second sidelink data channel is transmitted to the second device on a different second resource of the at least two resources. 2 . The first device of claim 1 , wherein the first feedback is transmitted using a first sequence and the second feedback is transmitted using a different second sequence.

3. The first device of claim 2, wherein the second sequence is associated with the second sidelink data channel.

4. The first device according to claim 3, wherein the first device is further configured to perform: Based on the association of the second sequence with the second sidelink data channel, the second sequence is determined from a plurality of sequences available for acknowledgment to a previous sidelink data channel.

5. The first device of claim 4, wherein a sequence in the plurality of sequences is associated with at least one of: The slot index of the previous sidelink data channel, or Identification of the hybrid automatic repeat request process associated with the previous sidelink data channel.

6. The first device according to any one of claims 2 to 4, wherein If the first feedback is a positive acknowledgement, the first feedback is transmitted using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgement, the first feedback is transmitted using a different cyclic shift of the first sequence, and / or If the second feedback is a positive acknowledgement, the second feedback is transmitted using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgement, the second feedback is transmitted using a different cyclic shift of the second sequence.

7. The first device according to any one of claims 1 to 6, wherein the first device is further configured to execute: An indication of at least one previous side link data channel in side link control information is received from the second device via the first side link data channel or via a side link control channel associated with the first side link data channel, the at least one previous side link data channel including the second side link data channel.

8. The first device of claim 7, wherein the indication of the at least one previous sidelink data channel include: An indication of a time slot index for the at least one previous sidelink data channel.

9. The first device of claim 8, wherein the indication of the time slot index for the at least one previous sidelink data channel include: An offset of the time slot index of the at least one previous sidelink data channel relative to the time slot index of the first sidelink data channel.

10. The first device of claim 7, wherein the indication of the at least one previous sidelink data channel include: An identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

11. The first device according to any one of claims 7 to 10, wherein the at least one previous sidelink data channel comprises a plurality of previous sidelink data channels, and the first device is further caused to perform: Based on the time slot indexes of the multiple previous side link data channels and / or the identifier of the hybrid automatic repeat request process associated with the multiple previous side link data channels, the second side link data channel is determined from the multiple previous side link data channels according to the order of the multiple previous side link data channels.

12. The first device of any one of claims 1-6, wherein the second sidelink data channel is preconfigured to be acknowledged by the first device.

13. The first device according to any one of claims 1-12, wherein the first resources include a set of resource blocks in a radio channel in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different radio channel in the timing.

14. The first device according to any one of claims 1-12, wherein the first resources include a set of resource blocks in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different timing of the sidelink feedback channel.

15. A second device, include: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the second device to at least perform: receiving, from a first device, first feedback for a transmission from the second device to the first device via a first sidelink data channel on a first resource of a plurality of resources for a sidelink feedback channel, the sidelink feedback channel being associated with the first sidelink data channel; as well as receiving, from the first device, on a different second resource of the plurality of resources, second feedback for a transmission from the second device to the first device via a previous second sidelink data channel, Wherein at least two listen-before-talk operations of the first device are passed at least before the first resource and the second resource. 16 . The second device of claim 15 , wherein the first feedback is received using a first sequence and the second feedback is received using a second, different sequence.

17. The second device according to claim 16, wherein the second device is further configured to perform: The second sidelink data channel is identified based on an association of the second sequence with the second sidelink data channel.

18. The second device of claim 17, wherein the second sequence is associated with at least one of: a timeslot index of the second sidelink data channel, or An identification of a hybrid automatic repeat request process associated with the second sidelink data channel.

19. The second device according to any one of claims 16 to 18, wherein If the first feedback is a positive acknowledgement, the first feedback is received using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgement, the first feedback is received using a different cyclic shift of the first sequence, and / or If the second feedback is a positive acknowledgement, the second feedback is received using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgement, the second feedback is received using a different cyclic shift of the second sequence.

20. The second device according to any one of claims 15-19, wherein the second device is further configured to perform: An indication of at least one previous sidelink data channel in sidelink control information is transmitted to the first device via the first sidelink data channel or via a sidelink control channel associated with the first sidelink data channel, the at least one previous sidelink data channel including the second sidelink data channel.

21. The second device of claim 20, wherein the indication of the at least one previous sidelink data channel include: An indication of a time slot index for the at least one previous sidelink data channel.

22. The second device of claim 21, wherein the indication of the time slot index for the at least one previous sidelink data channel include: An offset of the time slot index of the at least one previous sidelink data channel relative to the time slot index of the first sidelink data channel.

23. The second device of claim 20, wherein the indication of the at least one previous sidelink data channel include: An identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

24. The second device according to any one of claims 20-23, wherein the at least one previous sidelink data channel comprises a plurality of previous sidelink data channels, and the second device is further caused to perform: Based on time slot indices of the multiple previous side link data channels and / or identification of a hybrid automatic repeat request process associated with the multiple previous side link data channels, the second side link data channel is identified from the multiple previous side link data channels according to the order of the multiple previous side link data channels.

25. The second device of any one of claims 15-19, wherein the second sidelink data channel is preconfigured to be acknowledged by the first device.

26. The second device according to any one of claims 15-25, wherein the first resources include a set of resource blocks in a radio channel in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different radio channel in the timing.

27. The second device according to any one of claims 15-25, wherein the first resources include a set of resource blocks in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different timing of the sidelink feedback channel.

28. A method, include: At the first device, performing a plurality of listen-before-talk prior to a plurality of resources for a sidelink feedback channel associated with a first sidelink data channel; as well as In response to at least two of the plurality of listen-before-talk resources passing before at least two of the plurality of resources, transmitting, to a second device, on a first resource of the at least two resources, first feedback for a transmission from the second device via the first sidelink data channel; as well as Second feedback for a transmission from the second device via a previous second sidelink data channel is transmitted to the second device on a different second resource of the at least two resources.

29. The method of claim 28, wherein the first feedback is transmitted using a first sequence and the second feedback is transmitted using a different second sequence.

30. The method of claim 29, wherein the second sequence is associated with the second sidelink data channel.

31. The method according to claim 30, further comprising: include: Based on the association of the second sequence with the second sidelink data channel, the second sequence is determined from a plurality of sequences available for acknowledgment to a previous sidelink data channel.

32. The method of claim 31 , wherein a sequence in the plurality of sequences is associated with at least one of: The slot index of the previous sidelink data channel, or Identification of the hybrid automatic repeat request process associated with the previous sidelink data channel.

33. The method according to any one of claims 29 to 32, wherein If the first feedback is a positive acknowledgement, the first feedback is transmitted using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgement, the first feedback is transmitted using a different cyclic shift of the first sequence, and / or If the second feedback is a positive acknowledgement, the second feedback is transmitted using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgement, the second feedback is transmitted using a different cyclic shift of the second sequence.

34. The method according to any one of claims 28 to 33, further comprising: include: An indication of at least one previous side link data channel in side link control information is received from the second device via the first side link data channel or via a side link control channel associated with the first side link data channel, the at least one previous side link data channel including the second side link data channel.

35. The method of claim 34, wherein the indication of the at least one previous sidelink data channel include: An indication of a time slot index for the at least one previous sidelink data channel.

36. The method of claim 35, wherein the indication of the time slot index for the at least one previous sidelink data channel include: An offset of the time slot index of the at least one previous sidelink data channel relative to the time slot index of the first sidelink data channel.

37. The method of claim 34, wherein the indication of the at least one previous sidelink data channel include: An identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

38. The method according to any one of claims 34-37, further comprising: include: Based on the time slot indexes of the multiple previous side link data channels and / or the identifier of the hybrid automatic repeat request process associated with the multiple previous side link data channels, the second side link data channel is determined from the multiple previous side link data channels according to the order of the multiple previous side link data channels.

39. The method of any one of claims 28-33, wherein the second sidelink data channel is preconfigured to be acknowledged by the first device.

40. The method according to any one of claims 28-39, wherein the first resources include a set of resource blocks in a radio channel in an opportunity of the sidelink feedback channel, and the second resources include a set of resource blocks in a different radio channel in the opportunity.

41. The method according to any one of claims 28-39, wherein the first resources include a set of resource blocks in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different timing of the sidelink feedback channel.

42. A method, include: At the second device, receiving, from a first device, first feedback for a transmission from the second device to the first device via a first sidelink data channel on a first resource of a plurality of resources for a sidelink feedback channel, the sidelink feedback channel being associated with the first sidelink data channel; as well as receiving, from the first device, on a different second resource of the plurality of resources, second feedback for a transmission from the second device to the first device via a previous second sidelink data channel, Wherein at least two listen-before-talk operations of the first device are passed at least before the first resource and the second resource.

43. The method of claim 42, wherein the first feedback is received using a first sequence and the second feedback is received using a different second sequence.

44. The method according to claim 43, further comprising: include: The second sidelink data channel is identified based on an association of the second sequence with the second sidelink data channel.

45. The method of claim 44, wherein the second sequence is associated with at least one of: a timeslot index of the second sidelink data channel, or An identification of a hybrid automatic repeat request process associated with the second sidelink data channel.

46. ​​The method according to any one of claims 43 to 45, wherein If the first feedback is a positive acknowledgement, the first feedback is received using a cyclic shift of the first sequence, and if the first feedback is a negative acknowledgement, the first feedback is received using a different cyclic shift of the first sequence, and / or If the second feedback is a positive acknowledgement, the second feedback is received using a cyclic shift of the second sequence, and if the second feedback is a negative acknowledgement, the second feedback is received using a different cyclic shift of the second sequence.

47. The method according to any one of claims 42-46, further comprising: include: An indication of at least one previous sidelink data channel in sidelink control information is transmitted to the first device via the first sidelink data channel or via a sidelink control channel associated with the first sidelink data channel, the at least one previous sidelink data channel including the second sidelink data channel.

48. The method of claim 47, wherein the indication of the at least one previous sidelink data channel include: An indication of a time slot index for the at least one previous sidelink data channel.

49. A method according to claim 48, wherein the indication of the time slot index of the at least one previous side link data channel comprises an offset of the time slot index of the at least one previous side link data channel relative to the time slot index of the first side link data channel.

50. The method of claim 47, wherein the indication of the at least one previous sidelink data channel include: An identification of a hybrid automatic repeat request process associated with the at least one previous sidelink data channel.

51. The method according to any one of claims 47-50, further comprising: include: Based on time slot indices of the multiple previous side link data channels and / or identification of a hybrid automatic repeat request process associated with the multiple previous side link data channels, the second side link data channel is identified from the multiple previous side link data channels according to the order of the multiple previous side link data channels.

52. The method of any one of claims 42-46, wherein the second sidelink data channel is preconfigured to be acknowledged by the first device.

53. A method according to any one of claims 42-52, wherein the first resources include a set of resource blocks in a radio channel in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different radio channel in the timing.

54. The method according to any one of claims 42-52, wherein the first resources include a set of resource blocks in a timing of the sidelink feedback channel, and the second resources include a set of resource blocks in a different timing of the sidelink feedback channel.

55. A first device, include: means for performing a plurality of listen-before-talk means before a plurality of resources for a sidelink feedback channel associated with a first sidelink data channel; as well as In response to at least two of the plurality of listen-before-talk resources passing before at least two of the plurality of resources, means for transmitting, to a second device, first feedback on a first resource of the at least two resources for a transmission from the second device via the first sidelink data channel, and means for transmitting, to the second device, second feedback for a transmission from the second device via a previous second sidelink data channel, on a different second resource of the at least two resources.

56. A second device, include: means for receiving, from a first device, first feedback for a transmission from a second device to the first device via a first sidelink data channel on a first resource of a plurality of resources for a sidelink feedback channel, the sidelink feedback channel being associated with the first sidelink data channel; as well as means for receiving, from the first device, on a different second resource of the plurality of resources, second feedback for a transmission from the second device to the first device via a previous second sidelink data channel, Wherein at least two listen-before-talk operations of the first device are passed at least before the first resource and the second resource.

57. A computer-readable medium comprising instructions stored thereon, the instructions being used to cause an apparatus to at least perform the method according to any one of claims 28-41 or the method according to any one of claims 42-54.

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