WO2024092843A1

WO2024092843A1 - Methods, devices and medium for communication

Info

Publication number: WO2024092843A1
Application number: PCT/CN2022/130158
Authority: WO
Inventors: Ying Zhao; Zhaobang MIAO; Jin Yang; Gang Wang
Original assignee: Nec Corporation
Priority date: 2022-11-05
Filing date: 2022-11-05
Publication date: 2024-05-10

Abstract

Example embodiments of the present disclosure relate to a communication method, devices, and computer readable medium. The communication method comprises: performing, at a first communication device, a plurality of data transmissions to at least one second communication device on a plurality of first RB sets on unlicensed spectrum respectively; determining a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; transmitting the resource configuration to the at least one second communication device; and receiving the transmission of the plurality of feedbacks from the second communication device.

Description

METHODS, DEVICES AND MEDIUM FOR COMMUNICATION

FIELDS

Example embodiments of the present disclosure generally relate to the field of communication techniques and in particular, to methods, devices, and medium for feedback transmission in Sidelink-Unlicensed (SL-U) .

BACKGROUND

A sidelink (SL) refers to a communication mode in which a direct link is established between communication devices, e.g., terminal devices, and data or information is directly exchanged between terminal devices without going through a network device.

Channel access mechanisms from New Radio Unlicensed (NR-U) are proposed to be reused for sidelink unlicensed operations. Regarding parallel Physical Sidelink Shared Channel (PSSCH) transmissions based on multiple RB sets for wideband SL transaction in unlicensed or shared spectrum, efficiency of feedback for a single or a group of communication devices is relatively low and LBT failure on Physical Sidelink Feedback Channel (PSFCH) transmission opportunity may be caused. Thus, there is a need to study resource allocation for corresponding PSFCH combining the channel access procedure.

SUMMARY

In general, embodiments of the present disclosure provide methods, devices and computer storage medium for feedback transmission in SL-U.

In a first aspect, there is provided a communication method. The method comprises: performing, at a first communication device, a plurality of data transmissions to at least one second communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively; determining a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; transmitting the resource configuration to the at least one second communication device; and receiving the transmission of the plurality of feedbacks from the second communication device.

In a second aspect, there is provided a communication method. The method comprises: receiving, at a second communication device, a plurality of data transmissions from a first communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively; receiving a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; and performing the transmission of the plurality of feedbacks with the first communication device based on the resource configuration.

In a third aspect, there is provided a first communication device. The first communication device comprises at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the first communication device to perform the method according to the first aspect.

In a fourth aspect, there is provided a second communication device. The second communication device comprises at least one processor; and at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the second communication device to perform the method according to the second aspect.

In a fifth aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to the first or second aspect.

Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some example embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein:

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

FIG. 2 illustrates a signaling flow of feedback transmission in accordance with some embodiments of the present disclosure;

FIGs. 3A to 18 illustrate schematic diagrams of feedback resource allocation in accordance with some embodiments of the present disclosure, respectively;

FIG. 19 illustrates a flowchart of a method implemented at a first communication device according to some example embodiments of the present disclosure;

FIG. 20 illustrates a flowchart of a method implemented at a second communication device according to some example embodiments of the present disclosure; and

FIG. 21 illustrates a simplified block diagram of an apparatus that is suitable for implementing example embodiments of the present disclosure.

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

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some 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. Embodiments described herein can be implemented in various manners other than the ones described below.

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

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

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

The terminal device or the network device may have Artificial intelligence (AI) or Machine learning capability. It generally includes a model which has been trained from numerous collected data for a specific function, and can be used to predict some information.

The terminal or the network device may work on several frequency ranges, e.g., FR1 (e.g., 450 MHz to 6000 MHz) , FR2 (e.g., 24.25GHz to 52.6GHz) , frequency band larger than 100 GHz as well as Tera Hertz (THz) . It can further work on licensed/unlicensed/shared spectrum. The terminal device may have more than one connection with the network devices under Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or the network device can work on full duplex, flexible duplex and cross division duplex modes.

The embodiments of the present disclosure may be performed in test equipment, e.g., signal generator, signal analyzer, spectrum analyzer, network analyzer, test terminal device, test network device, channel emulator. In some embodiments, the terminal device may be connected with a first network device and a second network device. One of the first network device and the second network device may be a master node and the other one may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs) . In some embodiments, the first network device may be a first RAT device and the second network device may be a second RAT device. In some embodiments, the first RAT device is eNB and the second RAT device is gNB. Information related with different RATs may be transmitted to the terminal device from at least one of the first network device or the second network device. In some embodiments, first information may be transmitted to the terminal device from the first network device and second information may be transmitted to the terminal device from the second network device directly or via the first network device. In some embodiments, information related with configuration for the terminal device configured by the second network device may be transmitted from the second network device via the first network device. Information related with reconfiguration for the terminal device configured by the second network device may be transmitted to the terminal device from the second network device directly or via the first network device.

As used herein, the singular forms ‘a’ , ‘an’ and ‘the’ are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term ‘includes’ and its variants are to be read as open terms that mean ‘includes, but is not limited to. ’ The term ‘based on’ is to be read as ‘at least in part based on. ’ The term ‘one embodiment’ and ‘an embodiment’ are to be read as ‘at least one embodiment. ’ The term ‘another embodiment’ is to be read as ‘at least one other embodiment. ’ The terms ‘first, ’ ‘second, ’ and the like may refer to different or same objects. Other definitions, explicit and implicit, may be included below.

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

As used herein, the term “resource, ” “transmission resource, ” “uplink resource, ” or “downlink resource” may refer to any resource for performing a communication, such as a resource in time domain, a resource in frequency domain, a resource in space domain, a resource in code domain, or any other resource enabling a communication, and the like. In the following, unless explicitly stated, a resource in both frequency domain and time domain will be used as an example of a transmission resource for describing some example embodiments of the present disclosure. It is noted that example embodiments of the present disclosure are equally applicable to other resources in other domains.

Embodiments of the present disclosure provide a solution for feedback resource allocation for multi-channel sidelink transmissions. Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

It is noted that any section/subsection headings provided herein are not intended to be limiting. Embodiments are described throughout this document, and any type of embodiment may be included under any section/subsection. Furthermore, embodiments disclosed in any section/subsection may be combined with any other embodiments described in the same section/subsection and/or a different section/subsection in any manner.

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

The communication environment 100 comprises a plurality of communication devices, including, a first communication device 110, a second communication device 120, a third communication device 130, a fourth commination device 140, and a fifth communication device 150. In FIG. 1, the first to

fourth communication devices

110, 120, 130 and 140 are illustrated as terminal devices. The fifth communication device 150 is illustrated as a network device which provides a serving area 102 called a cell.

It is to be understood that the number of devices and their connections in FIG. 1 are given for the purpose of illustration without suggesting any limitations to the present disclosure. The communication environment 100 may include any suitable number of network devices and/or terminal devices adapted for implementations of the present disclosure.

The communications in the communication environment 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , Long Term Evolution (LTE) , LTE-Evolution, LTE-Advanced (LTE-A) , New Radio (NR) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. The embodiments of the present disclosure may be performed according to any generation communication protocols either currently known or to be developed in the future. Examples of the communication protocols include, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or the sixth generation (6G) networks.

In some embodiments, the first communication device 110 and the fifth communication device 150 may communicate with each other via a channel such as a wireless communication channel on an air interface (e.g., Uu interface) . The communication device 110 capable of communicating with the communication device 150 may be in coverage of the serving area 102 of the fifth communication device 150. In the illustrated example of FIG. 1, the first communication device 110 and the second communication device 120 may communicate with the communication device 150. The wireless communication channel may comprise a physical uplink control channel (PUCCH) , a physical uplink shared channel (PUSCH) , a physical random-access channel (PRACH) , a physical downlink control channel (PDCCH) , a physical downlink shared channel (PDSCH) and a physical broadcast channel (PBCH) . Of course, any other suitable channels are also feasible. In the specific example of communication environment 100, a link from the first communication device 110 to the fifth communication device 150 is referred to as uplink, while a link from the fifth communication device 150 to the first communication device 110 is referred to as a downlink.

In some embodiments, the first, second, third and fourth communication devices 110 to 140 may communicate with each other via sidelink (SL) connection (s) . A sidelink is a communication mode that allows direct communications between two or more terminal devices without the communications going through network device. SL communications may be carried out on a wireless interface, e.g., PC5 interface. SL communications may be unicast, groupcast, or broadcast, and may be used for device-to-device (D2D) communications, vehicle-to-everything (V2X) communications, emergency rescue applications, etc.

Depending on whether covered within a serving area of a network device or not, SL communication scenarios may include in-coverage (InC) , partial-coverage, and out-of-coverage (OOC) . For example, in the illustrated example of FIG. 1, SL communications between the first communication device 110 and the second communication device 120 are in-coverage of the fifth communication device 150; SL communications between the third communication device 130 and the fourth communication device 140 are out-of-coverage. Partial-coverage may involve a scenario where a communication device 110 is within the network coverage area while the other communication device is outside the network coverage area. For example, in FIG. 1, SL communications between one of the first and

second communication devices

110 and 120 and one of the third and

fourth communication devices

130 and 140 may be considered as in partial-coverage.

In some cases, a network device (e.g., the fifth communication device 150) facilitates the scheduling of resources for SL communications between the first to fourth communication devices 110 to 140. In other cases, SL communications are carried out between the first to fourth communication devices 110 to 140 without the involvement of a network device (e.g., the fifth communication device 150) .

SL resource allocation schemes may be applied to allocate resources in a SL resource pool for SL communications. There may be two SL resource allocation schemes. In a first SL resource allocation scheme (referred to as Mode1 for SL resource allocation) , the network device may schedule SL resources via the communication interface with the communication devices, for example the first communication device 110. The resource allocation may include dynamic grant, for example, by downlink control information (DCI) , or configured grant (e.g., Type 1 or Type 2 configured grant) . In a second SL resource allocation scheme (referred to as Mode2 for SL resource allocation) , the resources for SL communications may be autonomously selected by the first communication device 110 based on a contention scheme.

Example embodiments of the present disclosure provide a solution for feedback transmission in SL-U. In this solution, a first communication device performs a plurality of data transmissions to at least one second communication device on a plurality of first resource block (RB) sets on unlicensed spectrum, respectively. The first communication device determines a resource configuration and transmits the resource configuration to the at least one second communication device. The resource configuration is determined based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets. The resource configuration indicates at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions. The first communication device receives the transmission of the plurality of feedbacks from the second communication device.

Through this solution, regarding the feedback/PFSCH (s) for multiple RB sets based PSSCH transmission in SL-U, combining with the corresponding channel access procedure (s) for multi-channel sidelink transmission (s) , several enhancements are proposed to facilitate the resource (pre-) configuration, allocation and indication for the feedback channel in SL-U.

Principles and implementations of the present disclosure will be described in detail below with reference to the figures.

Reference is made to FIG. 2, which illustrates a signal flow 200 for feedback transmission according to some example embodiments of the present disclosure. For the purposes of discussion, the signaling flow 200 will be discussed with reference to FIG. 1, for example, by using the first communication device 110 and the second communication device 120. It would be appreciated that the example embodiments may be applicable to any communication devices in SL communications.

The first communication device 110 performs (205) a plurality of data transmissions to at least one second communication device 120 on a plurality of first RB sets on unlicensed spectrum, respectively. The data transmissions across multiple RB sets may be referred to as multi-channel data transmissions, where each RB set may be corresponding to a channel. The second communication device 120 receives (210) these data transmissions from the first communication device 110 on the plurality of first RB sets on unlicensed spectrum, respectively.

The first communication device 110 determines (215) a resource configuration based on one or more factors and transmits (220) the resource configuration to the second communication device 120. The one or more factors include frequency locations of the first plurality of RB sets, channel access states of the plurality of first RB sets, and/or the like. The resource configuration indicates at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions.

In some embodiments, during the determination (215) of the resource configuration, the communication device 110 may determine, based on the channel access states, that a feedback resource immediately follows a data transmission performed in one of the plurality of first RB sets to the second communication device 120. If the feedback resource is available for the plurality of data transmissions, the first communication device 110 may determine the resource configuration to indicate at least the feedback resource.

In some embodiments, if in the slot corresponding to the feedback resource, there is no data transmission (i.e., PSSCH transmission) from the first communication device 110, the first communication device 110 determines (215) that the at least one second RB set indicated by the resource configuration corresponds to all of the plurality of first RB sets.

The second communication device 120 receives (230) the resource configuration from the first communication device 110 and performs (235) , with the first communication device 110, the transmission of the plurality of feedbacks corresponding to the plurality of data transmissions based on the received resource configuration.

In some embodiments, the plurality of data transmissions are of a groupcast type, and the at least one second RB set comprises a first feedback RB set and a second feedback RB set. When transmitting the plurality of feedbacks, in case of a successful channel access procedure on a first feedback resource from the first feedback RB set and a failed channel access procedure on a second feedback resource from the second feedback RB set, the second communication device 120 may transmit at least one of the plurality of feedbacks using the first feedback resource.

In some embodiments, before performing (235) the transmission of the plurality of feedbacks, the second communication device 120 may determine a target feedback resource for the transmission of the plurality of feedbacks from the at least one feedback resource indicated by the resource configuration and at least one candidate feedback resource available to the second communication device. Alternatively, in some embodiments, the target feedback resource may comprise the at least one feedback resource indicated in the resource configuration. Then, the second communication device 120 performs (235) the transmission of the plurality of feedbacks on the target feedback resource.

The first communication device 110 receives (240) the transmission of the plurality of feedbacks from the second communication device 120 and may be aware whether the plurality of data transmissions have been successful based on the received feedbacks.

In some embodiments, the first communication device 110 may receive (240) the transmission of the plurality of feedbacks on at least one candidate frequency resource. The at least one candidate frequency resource may comprise one or more frequency resources, for example, RB set (s) , which are available to the first communication device.

With less impact on the existing specs of SL communication and channel access procedure on unlicensed spectrum, embodiments of the present disclosure propose enhancements on SL PSFCH resource (pre) configuration/allocation/selection and corresponding indication to provide a reasonable and applicable design of the resource for the feedback channel in SL-U.

In some embodiments, within a slot, for example, the slot with a feedback occasion, a resource for the plurality of feedbacks may occupy one or more symbols in the slot. In some examples, the resource for the plurality of feedbacks may include a physical sidelink feedback channel (PSFCH) .

FIGS. 3A and 3B show a schematic diagram of feedback resource allocation in accordance with some embodiments of the present disclosure, respectively. As shown in FIG. 3A, for SL-U operation based on the mode 1 or mode 2 resource allocation scheme, multiple resources locating at different frequency bands may be allocated to the first communication 110 (e.g., a UE) for PSCCH/PSSCH transmission (s) (may or may not IRB-based) . The PSCCH/PSSCH transmission (s) may include a plurality of data transmissions, for example, PSCCH/

PSSCH transmissions

310 and 315, and so on. That is, the first communication 110 may perform a transmission on a set of respective channels, such as one or multiple RB sets (e.g., RB set 1 denoted by 321 in FIG. 3A, RB set 2 denoted by 322 in FIG. 3A, and so on) or LBT sub-bands. The transmission (for example,

PSSCH transmission

310 or 315 as shown in FIG. 3A) on each channel shall satisfy the occupancy channel bandwidth (OCB) requirement according to the NR-U regulations. As shown in FIG. 3A, there illustrate two feedback transmissions (PSFCH transmissions) 301 and 302 on two feedback resources, for example. The feedback transmissions may comprise feedbacks of the PSCCH/PSSCH transmissions transmitted from the second communication device 120. It is to be understood that the number of the feedback transmissions may be one or two or other suitable numbers. Although FIG. 3A illustrates only two feedback transmission, it is just for purpose of illustration, rather than suggesting any limitation.

In embodiments of the present disclosure, different types of channel access procedures may be used. FIG. 3A illustrates a Type 1 channel access procedure 341 and a Type 2 channel access procedure 342. It can be seen that the Type 1 channel access procedure is illustrated as a larger block than the Type 2 channel access procedure. It is to be understood that, similar to FIG. 3A, other figures also illustrate Type 1 channel access procedure and Type 2 channel access procedure in analogous way.

Unlike the uplink resource allocation type 2 in NR where the resource block assignment information indicates to the communication device 110, a set of up to M interlace indices and a set of up to

contiguous RB sets, as per different channel access procedure and resource allocation scheme in sidelink, a set of N channels (e.g., RB set 1 and RB set 2) for transmission may be adjacent to each other in frequency domain (with the gap of a guard band 320) , as shown in FIG. 3A. Alternatively, the set of N channels may be separately distributed with a gap between each other within a resource pool. As shown in FIG. 3B, there is a gap 323 between RB set 1 (denoted by 321) and RB set 2 (denoted by 322) . The gap 323 may comprise one or more RB sets, for example, X RB set (s) , where X is a positive integer.

According to embodiments of the present disclosure, some introductions/enhancements to legacy SCI are proposed. In order to indicate the corresponding information dynamically (may or may not in combination with the resource (pre) configuration) , in some embodiments, one or more new fields with the additional information related to a legacy SCI format (such as SCI format 1-A, SCI format 1-B, SCI format 2-A, SCI format 2-B, SCI format 2-C) may be inserted in sidelink communications. Alternatively, the corresponding field may be replaced by redefined/enhanced information (with the same or different size) .

In some alternative embodiments, one or more new SCI formats (such as SCI format 1-X and/or SCI format 2-D) or media access control-control element (MAC CE) may be introduced to convey the enhanced SCI information for intended transmission on multiple RB sets. In some embodiments, the new SCI format may also include some information as included in the legacy SCI format.

The proposed solutions of the present disclosure may be applied to the dynamically scheduled PSFCH or (pre) configured PSFCH.

Considering the processing capability of the receiving terminal device, for example, the second communication device 120, based on the traffic of PSSCH transmission on multiple RB sets, a threshold T _traffic related to the offset between PSFCH slot and the last associated PSSCH slot may be introduced. If the cumulative traffic on multiple RB sets within a PSFCH period, such as the total number of TB within a PSFCH period, exceeds the T _traffic, then a new larger offset parameter, such as 4 or 6 (slots) may be applied; otherwise, the legacy offset value, namely 2 or 3, may be applied.

In some embodiments of the present disclosure, solutions for feedback resource allocation are discussed by way of example of a unicast type multi-channel transmission (s) in SL-U. In some embodiments, the resource configuration indicates a plurality of feedback resources comprised in a plurality of second RB sets. In such cases, the number of the plurality of second RB sets is the number of the plurality of first RB sets. Thus, there may be a one-to-one mapping between the PSSCH transmission on each RB set and the PSFCH transmission on each RB set.

For the unicast type multi-channel transmission (s) in SL-U, the frequency resource allocation for PFSCH is performed per RB set, namely for a PSSCH (with one or multiple sub-channels) on a RB set, allocates an independent RB set for the corresponding PFSCH. Hence, there is a one-to-one mapping between the PSSCH transmission on each RB set and the corresponding PSFCH transmission on a separate RB set.

In some embodiments, the frequency allocation of each RB set for PFSCH transmission (s) may be independent to that of the PSSCH transmission (s) . Alternatively, for the multi-channel PSSCH transmission (s) on N RB sets, N independent RB sets in the resource pool may be allocated for PFSCH transmission (may or may not be based on interlace resource block, IRB) .

It is to be noted that if adjacent RB sets and related intra-cell guard band (s) are used for PSSCH transmission, the intra-cell guard band (s) of adjacent RB sets (if any) for corresponding PSFCH may or may not be used as resource for feedback transmission, as shown in FIG. 4, which shows a schematic diagram of feedback resource allocation in accordance with the above embodiments of the present disclosure.

In some situations, before the second communication device 120 performs (235) the feedback transmission, it may determine whether a feedback resource from at least one second RB set indicated by the resource configuration immediately follows the resource for any data transmission transmitted to it on the same transmission occasion. If yes, the second communication device 120 may transmit one or more feedbacks using the feedback resource without performing channel access procedure. On the other hand, if the feedback resource does not follow any data transmission within the same transmission occasion, the second communication device 120 performs a channel access procedure on the second RB set. If the channel access procedure is successful, the second communication device 120 transmits the feedback (s) using the feedback resource.

FIG. 5 shows a schematic diagram of feedback resource allocation in accordance with some embodiments of the present disclosure. As shown in FIG. 5, an intended PSFCH transmission 510 immediately follows a PSSCH transmission within the same slot, and occupies a RB set which is overlapped with that of the PSSCH transmission. The PSFCH transmission 510 (within the Maximum Channel Occupancy Time (MCOT) initiated by the PSSCH transmission) on the RB set may be performed without channel access procedure. Otherwise, the PSFCH transmission (s) need to be performed based on certain channel access procedure (s) . As shown in FIG. 5, a Type 1 channel access procedure 501 is performed before the PSFCH transmission 520. The Type 1 channel access procedure 501 is successful and thus the PSFCH transmission 520 is performed by the second communication device 120.

In some embodiments, during the determination of the resource configuration, the first communication device 110 may determine the at least one second RB set based on the frequency locations of the plurality of first RB sets, for example, by requiring that the frequency location of each of the at least one second RB set is one of the frequency locations of the plurality of first RB sets. That is, each second RB set has the same frequency location as one of the first RB sets. For example, assuming that the first RB sets comprise RB set X, RB set Y and RB set Z, the at least one second RB set may comprise only one second RB set for the feedback transmission, for example, RB set X, or may comprise two out of RB set X, RB set Y and RB set Z, or even all these three RB sets.

FIG. 6 shows a schematic diagram of feedback resource allocation in accordance with some embodiments of the present disclosure. As shown in FIG. 6, the frequency resource allocation for PFSCH transmission may be dependent on that of the corresponding PSSCH transmission (s) . For example, each PSSCH transmission and the corresponding PFSCH transmission occupy the same RB set (s) . Similarly, if a PSFCH transmission immediately follows the PSSCH transmission (which may be transmitted from the first communication device 110 or from the other communication device to the second communication device 120) on the same RB set (s) within the same slot, it may be transmitted without performing channel access procedure (depending on the MCOT limit) . Otherwise, the PSFCH transmission should be performed based on certain channel access procedure (s) .

In some embodiments, the plurality of data transmissions may be performed using a plurality of data resources from the plurality of first RB sets. In this case, the first communication device 110 may further determine a first number of the first RB sets, a second number of resource blocks in the at least one second RB set, and a third number of RB sets in the at least one second RB set. Based on the first, second, and third numbers, the first communication device 110 may determine the number of resource blocks in the at least one feedback resource that are mapped to each sub-channel in the plurality of data resources. Thus, it may determine a mapping between sub-channels in the plurality of data resources and RB blocks in the at least one feedback resource. In this way, the number of PRBs for transmitting feedback (s) for data transmission on each sub-channel can be determined.

In some cases, there may be no guard band used for PSSCH/PSFCH transmission. For example, for a number of N _subch sub-channels for the resource pool including N _RB, _set RB sets in shared spectrum, provided by sl-NumSubchannel, and a number of

sub-channels in RB set k, and a number of PSSCH slots associated with a PSFCH slot that is less than or equal to

the UE allocates the

PRBs from the

PRBs to slot i among the PSSCH slots associated with the PSFCH slot and sub- channel j in RB set k, where

0≤k＜N _RB, _set, and the allocation starts in an ascending order of i and continues in an ascending order of j, and continues in an ascending order of k. The UE expects that

is a multiple of

According to the PSSCH-PSFCH mapping method for legacy SL communication on a continuous frequency band (such as a RB set) , each sub-channel of PSSCH within each slot corresponds to a separate PRB set (e.g. a set including K PRBs, where K represents the second number of PRBs in the at least one second RB set) on a frequency band (such as a RB set) for feedback resource.

Further, for the PSSCH transmission on multiple channels (e.g. Ns RB sets, Ns represents the first number of RB set in the first RB sets, or the number of sub-channels with the same relative frequency location in each RB set of the first RB sets) in shared spectrum within a slot, if single or multiple channels (E. g. Nf RB sets, where Nf represents the third number of RB set in the at least one second RB set, 1<= Nf <= Ns) is identified to be used for corresponding PSFCH transmission, for Ns sub-channels with the same relative frequency location in all Ns RB sets within the slot, the PRB set (s) with the same set index (or with the same relative frequency location) in all Nf RB sets may be identified as corresponding feedback resource (the PRB set in each RB set for PSFCH corresponding to the sub-channel in any RB set for PSSCH may be respectively obtained based on legacy PSSCH-PSFCH mapping method for SL communication on single RB set as described in the last paragraph) . Hence, Nf*K PRBs in Nf RB sets may correspond to the Ns sub-channels with the same relative frequency location in Ns RB sets, and Nf*K/Ns PRBs for feedback transmission corresponding to each sub-channel respectively.

FIG. 7 shows a schematic diagram of an example about the feedback resource mapping between the PSSCH transmission on two RB sets and corresponding PSFCH transmission on single RB set.

In some embodiments, the feedback for an associated PSSCH transmission may be repeatedly transmitted, for example, in the same version or different redundancy versions. In this case, the resource configuration may indicate a first feedback resource for a first version of the plurality of feedbacks, and a second feedback resource for a second version of the plurality of feedbacks.

FIG. 8 shows a schematic diagram of feedback resource allocation in accordance with the embodiments of the present disclosure. As shown in FIG. 8, regarding at least the unicast type multi-channel transmission (s) for PSSCH transmission (s) on N RB sets in SL-U which starts from the starting slot of a PSFCH period and lasts till the ending slot of the PSFCH period, M (1<=M<=N) RB set (s) for corresponding PSFCH transmission may be allocated, the feedback information for the associated PSSCH on all RB sets are combined, and may be repeatedly transmitted (in the same version or different redundancy version) on each RB set for PSFCH (depending on the result of channel access procedure for PSSCH and/or PSFCH transmission) in a manner of frequency division multiplexing (FDM) and/or code division multiplexing (CDM) .

In some embodiments, the first communication device 110 may determine the at least one second RB set based on the frequency locations of the plurality of first RB sets. The determined at least one second RB set has a frequency location which separates from the frequency locations of the plurality of first RB sets in a frequency domain. That is, the frequency allocation of each RB set for PFSCH transmission may be independent of that of the PSSCH transmission (s) .

Alternatively, the frequency allocation of each RB set for PSFCH transmission may be dependent on that of the PSSCH transmission (s) , namely the at least part of RB sets for PSSCH transmission are reused for PSFCH transmission. FIG. 9 shows a schematic diagram of feedback resource allocation in accordance with such embodiments of the present disclosure.

According to embodiments of the present disclosure, the at least one second RB set may comprise one or more second RB sets. In the cases that the at least one second RB set comprises a single second RB set, a frequency location of the single second RB set may be one of frequency locations of the plurality of first RB sets. Assuming that one of the plurality of feedbacks immediately follows a first data transmission in one of the plurality of first RB sets to the second communication device within the same transmission occasion (e.g., a slot) , the frequency location of the single second RB set may be the frequency location of a first RB set of the first data transmission, or may be randomly selected from the frequency locations of the plurality of first RB sets. The first data transmission may be or may not be one of the plurality of data transmissions. For example, the first data transmission may be a data transmission other than the plurality of data transmissions.

Alternative, in such cases, the frequency location of the single second RB set may be the frequency location of a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed, or the frequency location of the lowest one of the plurality of first RB sets.

FIGs. 10A and 10B show schematic diagrams of feedback resource allocation in accordance with the embodiments of the present disclosure, respectively. In these embodiments, only one RB set is independently or dependently allocated for PSFCH transmission related to all associated PSSCH on all RB set (s) . As shown in FIG. 10A, if an intended PSFCH transmission 1001 immediately follows a PSSCH transmission 1020 within the same slot, the RB set for PSFCH transmission 1001 (within the MCOT initiated by the PSSCH transmission) may be the same as that of the PSSCH transmission 1020 on single RB set. Alternatively, the RB set for PSFCH transmission may be randomly selected among multiple RB sets for the PSSCH transmission, as shown in FIG. 10B.

It is to be understood that, in FIG. 10A, the PSSCH transmission 1020 may be one of the plurality of PSSCH transmissions (for example, the PSFCH transmission 1010) associated with the PSFCH transmission 1001, or may be a PSSCH transmission that is different from the plurality of PSSCH transmissions.

FIGs. 11A and 11B show schematic diagrams of feedback resource allocation in accordance with the embodiments of the present disclosure, respectively. The embodiments shown in FIGs. 11A and 11B are alternatives to the embodiments shown with respect to FIGs. 10A and 10B. As shown in FIG. 11A, the RB set for PSFCH transmission (within the MCOT initiated by the PSSCH transmission) may be the same RB set on which at least one Type 1 channel access procedure is performed for the PSSCH transmission on multiple RB sets. FIG. 11B shows alternative embodiments in which the RB set for PSFCH transmission (within the MCOT initiated by the PSSCH transmission) may be the lowest RB set out of multiple RB sets with the PSSCH transmission which is immediately followed by the PSFCH transmission.

It is to be understood that the above examples for determining the single second RB set are discussed for purpose of illustration, rather than suggesting any limitation. The signal second RB set may be determined in several other appropriate ways.

In the cases that the at least one second RB set merely comprises a single second RB set, alternatively, the frequency location of the single second RB set may be randomly selected from frequency locations of a plurality of candidate RB sets. Alternatively, the frequency location of the single second RB set may be a frequency location of a RB set on which at least one successful Type 1 channel access procedure has been performed. As a further alternative, the frequency location of the single second RB set may be the frequency location of a lowest one of RB sets for data transmissions before the feedback on the single second RB set.

FIG. 12 shows a schematic diagram of feedback resource allocation in accordance with the embodiments of the present disclosure. In FIG. 12, the RB set for PSFCH may be randomly selected from M candidate RB sets (it may or may not be the same as that for associated PSSCH transmission) .

FIGs. 13A and 13B show schematic diagrams of feedback resource allocation in accordance with the embodiments of the present disclosure, respectively. As shown in FIG. 13A, the RB set for PSFCH may be the same RB set on which at least one (may be the more the better) successful single Type 1 channel access procedure has been performed for the PSSCH transmission on multiple RB sets in the preceding slots before the PSFCH slot. As shown in FIG. 13B, the RB set for PSFCH may be the lowest RB set out of multiple RB sets with the PSSCH transmission before the PSFCH slot.

Embodiments are also applicable to data transmission of the groupcast type. In some embodiments, the plurality of data transmissions are of a groupcast type, and the at least one second RB set comprises two or more second RB sets. For purpose of discussion, two second RB sets are discussed as a first feedback RB set and a second feedback RB set. It is to be understood that there may be more feedback RB sets (i.e., the second RB sets) in addition to the first feedback RB set and a second feedback RBs. These two feedback RB sets are described just for purpose of example, rather than suggesting any limitations.

In some embodiments, the frequency location of the first feedback RB set is one of frequency locations of the plurality of first RB sets. In some implementations, if one of the plurality of feedbacks immediately follows a first data transmission in one of the plurality of first RB sets to the second communication device within the same transmission occasion, the frequency location of the first feedback RB set may be the frequency location of a first RB set of the first data transmission. The first data transmission may be, for example, one of the plurality of data transmissions, or a data transmission other than the plurality of data transmissions. Alternatively, the frequency location of the first feedback RB set is randomly selected from the frequency locations of the plurality of first RB sets. As a further alternative, the frequency location of the first feedback RB set may be the frequency location of a first RB set of the plurality of first RB sets on which a successful Type 1 channel access procedure has been performed. Furthermore, the frequency location of the first feedback RB set may be the frequency location of a lowest one of the plurality of first RB sets.

For example, for PSFCH involved in groupcast type SL-U communication, if one RB set may meet the requirement of groupcast feedback information on resource allocation, then one RB set may be allocated for PSFCH transmission associated with all PSSCH slot (s) on all RB set (s) , the feedback information for the associated PSSCH on all RB sets are combined and transmitted on the single candidate RB set (may be depending on the result of channel access procedure) .

If an intended PSFCH transmission may immediately follow a PSSCH transmission within the same slot, the RB set for PSFCH transmission (within the MCOT initiated by the PSSCH transmission) may be the same as that of the PSSCH transmission on single RB set. Or, the RB set for PSFCH transmission may be randomly selected among multiple RB sets for the PSSCH transmission. Or, the RB set for PSFCH transmission may be the same RB set on which at least one Type 1 channel access procedure is performed for the PSSCH transmission on multiple RB sets. Or, the RB set for PSFCH transmission may be the lowest RB set out of multiple RB sets with the PSSCH transmission which is immediately followed by the PSFCH transmission.

Alternatively, in the cases that the frequency location of the first feedback RB set is one of frequency locations of the plurality of first RB sets, there are various ways for determining the specific frequency location of the first feedback RB set. For instance, the frequency location of the first feedback RB set may be randomly selected from frequency locations of a plurality of candidate RB sets. Or, the frequency location of the first feedback RB set may be a frequency location of a RB set on which at least one successful Type 1 channel access procedure has been performed. As a further alternative, the frequency location of the first feedback RB set may be the frequency location of a specific RB set of a fifth data transmission. The specific RB set of the fifth data transmission is the lowest one of RB sets for data transmissions before the feedback on the first feedback RB set.

FIG. 14 shows a schematic diagram of feedback resource allocation in accordance with the above embodiments of the present disclosure. As shown in FIG. 14, the RB set for PSFCH may be randomly selected from M candidate RB sets (it may or may not be the same as that for associated PSSCH transmission) . Or, the RB set for PSFCH may be the lowest RB set out of multiple RB sets with the PSSCH transmission before the PSFCH slot. Or, the RB set for PSFCH may be the same RB set on which at least one (the more the best) successful single Type 1 channel access procedure has been performed for the PSSCH transmission on multiple RB sets in the preceding slots before the PSFCH slot. In some alternative embodiments, at least two candidate RB sets for PSFCH may be considered, and according to the result of channel access procedure (such as separated Type 1 with/without same/different CPE) performed on each RB set, one or multiple RB sets (in the same version or different redundancy versions) may be used. The candidate RB sets may be randomly selected from M candidate RB sets, or selected according to the last sub-bullet.

The first and second feedback RB sets may be determined in several ways. In some embodiments, if one of the plurality of feedbacks immediately follows at least two of the plurality of data transmissions on at least two first RB sets, the frequency locations of the first and second feedback RB sets are frequency locations of the at least two first RB sets, respectively, or randomly selected from the frequency locations of the plurality of first RB sets. In a further alternative, the frequency locations of the first and second feedback RB sets may be frequency locations of the lowest two first RB sets of the plurality of first RB sets.

In some implementations, at least two RB sets are required to meet the requirement of groupcast feedback information on resource allocation. If an intended PSFCH transmission may immediately follow a PSSCH transmission within the same slot on at least two RB sets, the RB sets for PSFCH transmission (within the MCOT initiated by the PSSCH transmission) may be the same as that of the PSSCH transmission on two RB sets. Or the RB sets for PSFCH transmission may be randomly selected among multiple (more than 2) RB sets (may be consecutive RB sets along with the gap band included or non-consecutive RB sets) for the PSSCH transmission. Alternatively, the RB sets for PSFCH transmission may be at least the lowest two RB sets for PSSCH transmission. FIG. 15 shows a schematic diagram of feedback resource allocation in accordance with the above embodiments of the present disclosure.

In some embodiments, if one of the plurality of feedbacks immediately follows a data transmission in the plurality of data transmissions on a single first RB set, the frequency location of the first feedback RB set may be a frequency location of the single first RB set. As to the second feedback RB set, its frequency location may be randomly selected from the frequency locations of the plurality of first RB sets, or may be a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed.

In some implementations, if an intended PSFCH transmission may immediately follow a PSSCH transmission within the same slot on single RB set, one of the RB sets for PSFCH may be the same as that of the PSSCH transmission, and the other RB set (s) for PSFCH may be randomly selected among the RB sets for the PSSCH transmission in the preceding slots before the PSFCH slot. Alternatively, they may be the same RB set (s) on which the successful single Type 1 channel access procedure (s) has been performed for the PSSCH transmission on multiple or single RB set in the preceding slots (may be or may not be the associated slot) before the PSFCH slot. FIG. 16 shows a schematic diagram of feedback resource allocation in accordance with the above embodiments of the present disclosure.

In some embodiments, the frequency locations of the first feedback RB set and the second feedback RB set may be randomly selected from the frequency locations of a plurality of candidate RB sets. Alternatively, in some embodiments, the frequency locations of the first feedback RB set and the second feedback RB set are frequency locations of two RB sets in the plurality of candidate RB sets on which at least one successful Type 1 channel access procedure has been performed. In some alternative embodiments, the frequency locations of the first feedback RB set and the second feedback RB set are the frequency locations of the lowest two RB sets of the plurality of candidate RB sets.

Specifically, the RB sets for PSFCH transmission may be randomly selected from M candidate RB sets (it may or may not be the same as that for associated PSSCH transmission) . Alternatively, the RB sets for PSFCH transmission may be the same RB set (s) on which the successful single Type 1 channel access procedure (s) has been performed for the PSSCH transmission on multiple RB sets in the preceding slots (may be or may not be the associated slot) before the PSFCH slot, as shown in FIG. 17A. Or, the RB sets for PSFCH transmission may be the lowest RB set out of multiple RB sets with the PSSCH transmission before the PSFCH slot, as shown in FIG. 17B.

For the groupcast type, the frequency resource for PFSCH may be allocated or indicated so as to simplify the channel access procedure and improves resource utilization efficiently for receiving device (s) , e.g., the second communication device 120. In some embodiments, the first communication device 110 may determine the number of resource blocks per sub-channel per transmission occasion for the plurality of feedbacks. Then, the first communication device 110 may determine a parameter of a capacity of a RB set for the plurality of feedbacks based on the number of resource blocks, the number of orthogonal codes (e.g. the common cyclic shift pair applied in sidelink) for CDM, and the number of slots for the plurality of data transmissions. The number of the at least one second RB set may be determined based on the parameter of the capacity of a RB set and the number of second communication devices in a groupcast.

Considering the amount of UEs in groupcast, a parameter Npset about the capacity of a RB set for PSFCH transmission may be introduced and (pre) configured/indicated in a manner of the number of supported UE for certain PSFCH. Npset may be a parameter of a capacity of a RB set for the plurality of feedbacks. It may be determined based on at least the PRB number per sub-channel per slot in PSFCH, the number of orthogonal codes for CDM and the number of the associated slots with multi-RB set transmission.

Given

which indicates the resource needed for PSFCH which is associated with PSSCH in

slots on one RB set, Npset may be determined based on at least the value of

and the number of the orthogonal codes for CDM, e.g. cyclic shift pairs, (such as minimum

and the maximum number of cyclic shift pairs=6) , and then the PSFCH resource allocation method on the basis of UE amount in the groupcast and feedback option (namely

option

1 or 2 groupcast feedback type in sidelink communication) .

In some embodiments, the first communication device 110 may dynamically transmit (220) the resource configuration via a lower layer signaling or a higher layer signaling. For example, the lower layer signaling may be sidelink control information (SCI) , media access control-control element (MAC CE) , and/or the like. The higher layer signaling may be a L3 signaling or other suitable signaling (s) .

In some embodiments, the resource configuration may indicate a channel access state, determined or candidate time-frequency domain resource selection for the transmission of the plurality of feedbacks, a channel access procedure type for the feedback transmission, a channel structure for the feedback transmission, and/or the like. For example, the channel structure may be IRB-based or continuous RB-based. In some implementations, the channel access state may comprise: a Channel Occupancy Time (COT) , a channel access type for a preceding data transmission on each RB set, a resource occupied on each RB set, and/or the like.

In some embodiments, the first communication device 110 may be discussed by example of a transmitting (Tx) UE, the second communication device 120 may be discussed by example of a receiving (Rx) UE, and/or the fifth communication device 150 may be discussed by example of gNB. For example, gNB/Tx UE may (pre) configures or indicates Rx UE (s) the PSFCH resource related information (such as the time-frequency domain (candidate or determined) resource selection and IRB-based or continuous RB-based structure) associated with intended PSSCH transmission (s) on certain RB set (s) .

If lower layer indication (SCI/MAC-CE) or higher layer indication (L3 signaling) from Tx UE is used for a PSFCH in a slot, depending on the traffic on multiple RB sets and corresponding channel access procedure, the indication may be conveyed in any slot from the first PSSCH/PSCCH slot associated with the PSFCH slot till the slot with PSSCH/PSCCH and the PSFCH together.

The indication may be conveyed on any RB set (s) for PSSCH transmission, no matter whether and what type the channel access procedure is performed on the RB set (s) .

The indication may include at least channel (s) access state (such as COT and channel access type for preceding PSSCH on each RB set, and resource occupied on each RB set) , determined/candidate time-frequency domain resource selection for PSFCH, channel access procedure type for PSFCH, channel structure (IRB-based or continuous RB-based) for PSFCH, and so on.

Accordingly, the Rx UE (s) may monitor and decode the indication (lower layer based or high layer based) in above-mentioned slot (s) and RB set (s) , and then perform the channel access procedure on certain resource (s) which may be determined completely based on indication, or be determined jointly combining indication from Tx UE and autonomous choice by Rx UE, and finally transmit the PSFCH based on valid channel occupying. Namely, the Rx UE (s) may identify the RB set (s) for PSFCH transmission based on the RB sets for PSSCH transmission within the associated PSSCH slots (and corresponding channel access procedure outcome (s) ) firstly, and then determine the physical feedback resource in detail for each sub-channel in each RB set for PSSCH transmission.

Further, a Tx UE may monitor PSFCH transmission on identified RB set (s) or on potential/candidate RB sets, the actual PSFCH transmission may be conveyed on certain RB set (s) out of these monitored RB sets only, which may be determined depending on the preceding channel access procedure (s) performed by Rx UE (s) before PSFCH transmission. FIG. 18 shows a schematic diagram of feedback resource allocation in accordance with the above embodiments of the present disclosure.

It would be appreciated that in the example resource allocation in the figures, it is assumed that the period of the feedback resources (PFSCH) is 4 slots and the offset between the PSFCH slot and the last associated PSSCH slot is 2. Other period and offsets of the feedback resources may also be possible.

FIG. 19 illustrates a flowchart of a communication method 1900 implemented at a first communication device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 1900 will be described from the perspective of the first communication device 110 in FIG. 1.

At block 1910, the first communication device 110 performs a plurality of data transmissions to at least one second communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively.

At block 1920, the first communication device 110 determines a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions.

At block 1930, the first communication device 110 transmits the resource configuration to the at least one second communication device.

At block 1940, the first communication device 110 receives the transmission of the plurality of feedbacks from the second communication device 120.

In some example embodiments, the resource configuration indicates a plurality of feedback resources comprised in a plurality of second RB sets, the number of the plurality of second RB sets being the number of the plurality of first RB sets.

In some example embodiments, determining the resource configuration comprises: determining the at least one second RB set based on the frequency locations of the plurality of first RB sets, a frequency location of the at least one second RB set being separate from the frequency locations of the plurality of first RB sets in a frequency domain.

In some example embodiments, determining the resource configuration comprises: determining the at least one second RB set based on the frequency locations of the plurality of first RB sets, a frequency location of each of the at least one second RB set being one of the frequency locations of the plurality of first RB sets.

In some example embodiments, the at least one second RB set comprises a single second RB set, and wherein a frequency location of the single second RB set is one of frequency locations of the plurality of first RB sets.

In some example embodiments, if one of the plurality of feedbacks immediately follows a first data transmission in one of the plurality of first RB sets to the second communication device 120 within the same transmission occasion, the frequency location of the single second RB set is the frequency location of a first RB set of the first data transmission, or the frequency location of the single second RB set is randomly selected from the frequency locations of the plurality of first RB sets, or the frequency location of the single second RB set is the frequency location of a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed, or the frequency location of the single second RB set is the frequency location of the lowest one of the plurality of first RB sets.

In some example embodiments, the at least one second RB set comprises a single second RB set, and wherein a frequency location of the single second RB set is randomly selected from frequency locations of a plurality of candidate RB sets, or the frequency location of the single second RB set is a frequency location of a RB set on which at least one successful Type 1 channel access procedure has been performed, or the frequency location of the single second RB set is the frequency location of a lowest one of RB sets for data transmissions before the feedback on the single second RB set.

In some example embodiments, determining the resource configuration comprises: determining, based on the channel access states, that a feedback resource immediately follows a first data transmission performed in one of the plurality of first RB sets to the second communication device; and in accordance with a determination that the feedback resource is available for the plurality of data transmissions, determining the resource configuration to indicate at least the feedback resource.

In some example embodiments, the resource configuration indicates: a first feedback resource for a first version of the plurality of feedbacks, and a second feedback resource for a second version of the plurality of feedbacks.

In some example embodiments, the plurality of data transmissions are performed using a plurality of data resources from the plurality of first RB sets, the method further comprising: determining a first number of the first RB sets, a second number of resource blocks in the at least one second RB set, and a third number of RB sets in the at least one second RB set; determining, based on the first, second, and third numbers, the number of resource blocks in the at least one feedback resource that are mapped to each sub-channel in the plurality of data resources; and determining a mapping between sub-channels in the plurality of data resources and RB blocks in the at least one feedback resource.

In some example embodiments, the plurality of data transmissions are of a groupcast type, and the at least one second RB set comprises a first feedback RB set and a second feedback RB set.

In some example embodiments, a frequency location of the first feedback RB set is one of frequency locations of the plurality of first RB sets.

In some example embodiments, if one of the plurality of feedbacks immediately follows a first data transmission in one of the plurality of first RB sets to the second communication device within the same transmission occasion, the frequency location of the first feedback RB set is the frequency location of a first RB set of the first data transmission, or the frequency location of the first feedback RB set is randomly selected from the frequency locations of the plurality of first RB sets, or the frequency location of the first feedback RB set is the frequency location of a first RB set of the plurality of first RB sets on which a successful Type 1 channel access procedure has been performed, or the frequency location of the first feedback RB set is the frequency location of a lowest one of the plurality of first RB sets.

In some example embodiments, a frequency location of the first feedback RB set is randomly selected from frequency locations of a plurality of candidate RB sets, or wherein the frequency location of the first feedback RB set is a frequency location of a RB set on which at least one successful Type 1 channel access procedure has been performed, or wherein the frequency location of the first feedback RB set is the frequency location of a RB set of a fifth data transmission, the RB set of the fifth data transmission being the lowest one of RB sets for data transmissions before the feedback on the first feedback RB set.

In some example embodiments, if one of the plurality of feedbacks immediately follows at least two of the plurality of data transmissions on at least two first RB sets, the frequency locations of the first and second feedback RB sets are frequency locations of the at least two first RB sets, respectively, or the frequency locations of the first and second feedback RB sets are randomly selected from the frequency locations of the plurality of first RB sets, or the frequency locations of the first and second feedback RB sets are frequency locations of the lowest two first RB sets of the plurality of first RB sets.

In some example embodiments, if one of the plurality of feedbacks immediately follows a data transmission in the plurality of data transmissions on a single first RB set, the frequency location of the first feedback RB set is a frequency location of the single first RB set, and the frequency location of the second feedback RB set is randomly selected from the frequency locations of the plurality of first RB sets, or the frequency location of the second feedback RB set is a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed.

In some example embodiments, the frequency locations of the first feedback RB set and the second feedback RB set are randomly selected from the frequency locations of a plurality of candidate RB sets.

In some example embodiments, the frequency locations of the first feedback RB set and the second feedback RB set are frequency locations of two RB sets in the plurality of candidate RB sets on which at least one successful Type 1 channel access procedure has been performed.

In some example embodiments, the frequency locations of the first feedback RB set and the second feedback RB set are the frequency locations of the lowest two RB sets of the plurality of candidate RB sets.

In some example embodiments, the method further comprises: determining the number of resource blocks per sub-channel per transmission occasion for the plurality of feedbacks; determining a parameter of a capacity of a RB set for the plurality of feedbacks based on the number of resource blocks, the number of orthogonal codes for CDM, and the number of transmission occasions (for example, slots) for the plurality of data transmissions; and determining the number of the at least one second RB set based on the parameter of the capacity of a RB set and the number of second communication devices in a groupcast.

In some example embodiments, transmitting the resource configuration comprises: transmitting the resource configuration via a lower layer signaling or a higher layer signaling.

In some example embodiments, the lower layer signaling comprises at least one of sidelink control information (SCI) or media access control-control element (MAC CE) , or wherein the higher layer signaling comprises a L3 signaling.

In some example embodiments, the resource configuration indicates at least one of the following: a channel access state, determined or candidate time-frequency domain resource selection for the transmission of the plurality of feedbacks, a channel access procedure type for the feedback transmission, or a channel structure for the feedback transmission.

In some example embodiments, the channel access state at least one of the following: a Channel Occupancy Time (COT) , a channel access type for a preceding data transmission on each RB set, or a resource occupied on each RB set.

In some example embodiments, the first data transmission is one of the plurality of data transmissions, or a data transmission other than the plurality of data transmissions.

In some example embodiments, receiving the transmission of the plurality of feedbacks comprises: receiving the transmission of the plurality of feedbacks on at least one candidate frequency resource available to the first communication device.

FIG. 20 illustrates a flowchart of a communication method 2000 implemented at a second communication device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 2000 will be described from the perspective of the second communication device 120 in FIG. 1.

At block 2010, the second communication device 120 receives a plurality of data transmissions from a first communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively.

At block 2020, the second communication device 120 receives a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions.

At block 2030, the second communication device 120 performs the transmission of the plurality of feedbacks with the first communication device based on the resource configuration.

In some example embodiments, performing the transmission of the plurality of feedbacks comprises: in accordance with a determination that there is no data transmission (i.e. PSSCH transmission) performed on the same transmission occasion immediately before a feedback resource from a second RB set indicated by the resource configuration, performing a channel access procedure on the second RB set; in accordance with a successful result of the channel access procedure, transmitting at least one of the plurality of feedbacks using the feedback resource.

In some example embodiments, a frequency location of the at least one second RB set is separate from the frequency locations of the plurality of first RB sets in a frequency domain.

In some example embodiments, a frequency location of each of the at least one second RB set is one of the frequency locations of the plurality of first RB sets.

In some example embodiments, if one of the plurality of feedbacks immediately follows a first data transmission in one of the plurality of first RB sets to the second communication device within the same transmission occasion, the frequency location of the single second RB set is the frequency location of a first RB set of the first data transmission, or the frequency location of the single second RB set is randomly selected from the frequency locations of the plurality of first RB sets, or the frequency location of the single second RB set is the frequency location of a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed, or the frequency location of the single second RB set is the frequency location of the lowest one of the plurality of first RB sets.

In some example embodiments, the resource configuration indicates a feedback resource immediately following a data transmission performed in one of the plurality of first RB sets to the second communication device, the feedback resource being available for the plurality of data transmissions.

In some example embodiments, transmitting the plurality of feedbacks comprises: in accordance with a successful channel access procedure on a first feedback resource from the first feedback RB set and a failed channel access procedure on a second feedback resource from the second feedback RB set, transmitting at least one of the plurality of feedbacks using the first feedback resource.

In some example embodiments, receiving the resource configuration comprises: receiving the resource configuration via a lower layer signaling or a higher layer signaling.

In some example embodiments, performing the transmission of the plurality of feedbacks with the first communication device based on the resource configuration comprises: determining a target feedback resource for the transmission of the plurality of feedbacks from the at least one feedback resource indicated by the resource configuration and at least one candidate feedback resource available to the second communication device; and performing the transmission of the plurality of feedbacks on the target feedback resource.

FIG. 21 is a simplified block diagram of a device 2100 that is suitable for implementing embodiments of the present disclosure. The device 2100 can be considered as a further example implementation of any of the devices as shown in FIG. 1. Accordingly, the device 2100 can be implemented at or as at least a part of the first communication device 110 or the second communication device 120.

As shown, the device 2100 includes a processor 2110, a memory 2120 coupled to the processor 2110, a suitable transmitter (TX) /receiver (RX) 2140 coupled to the processor 2110, and a communication interface coupled to the TX/RX 2140. The memory 2110 stores at least a part of a program 2130. The TX/RX 2140 is for bidirectional communications. The TX/RX 2140 has at least one antenna to facilitate communication, though in practice an Access Node mentioned in this application may have several ones. The communication interface may represent any interface that is necessary for communication with other network elements, such as X2/Xn interface for bidirectional communications between eNBs/gNBs, S1/NG interface for communication between a Mobility Management Entity (MME) /Access and Mobility Management Function (AMF) /SGW/UPF and the eNB/gNB, Un interface for communication between the eNB/gNB and a relay node (RN) , or Uu interface for communication between the eNB/gNB and a terminal device.

The program 2130 is assumed to include program instructions that, when executed by the associated processor 2110, enable the device 2100 to operate in accordance with the embodiments of the present disclosure, as discussed herein with reference to FIGS. 1 to 20. The embodiments herein may be implemented by computer software executable by the processor 2110 of the device 2100, or by hardware, or by a combination of software and hardware. The processor 2110 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 2110 and memory 2120 may form processing means 2150 adapted to implement various embodiments of the present disclosure.

The memory 2120 may be of any type suitable to the local technical network and may be implemented using any suitable data storage technology, such as a non-transitory computer readable storage medium, semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. While only one memory 2120 is shown in the device 2100, there may be several physically distinct memory modules in the device 2100. The processor 2110 may be of any type suitable to the local technical network, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 2100 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

In some embodiments, a first communication device comprises a circuitry which is configured to: perform a plurality of data transmissions to at least one second communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively; determine a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; and transmit the resource configuration to the at least one second communication device. According to embodiments of the present disclosure, the circuitry may be configured to perform any of the method implemented by the first communication device as discussed above.

In some embodiments, a second communication device comprises a circuitry configured to: receive a plurality of data transmissions from a first communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively; receive a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; and perform the transmission of the plurality of feedbacks with the first communication device based on the resource configuration. According to embodiments of the present disclosure, the circuitry may be configured to perform any of the method implemented by the second communication device as discussed above.

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

In summary, embodiments of the present disclosure provide the following aspects.

In a first aspect, there is provided a communication method. The method comprises: performing, at a first communication device, a plurality of data transmissions to at least one second communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively; determining a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; and transmitting the resource configuration to the at least one second communication device.

In a fifth aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first communication device discussed above.

In a sixth aspect, there is provided a computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the second communication device discussed above.

In a seventh aspect, a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the first communication device discussed above.

In an eighth aspect, a computer program comprising instructions, the instructions, when executed on at least one processor, causing the at least one processor to perform the method implemented by the second communication device discussed above.

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

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the process or method as described above with reference to FIGS. 1 to 21. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

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

The above program code may be embodied on a machine readable medium, which may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific 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 language specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A communication method comprising:

performing, at a first communication device, a plurality of data transmissions to at least one second communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively;

determining a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions;

transmitting the resource configuration to the at least one second communication device; and

receiving the transmission of the plurality of feedbacks from the second communication device.
The method of claim 1, wherein the resource configuration indicates a plurality of feedback resources comprised in a plurality of second RB sets, the number of the plurality of second RB sets being the number of the plurality of first RB sets.
The method of claim 1, wherein determining the resource configuration comprises at least one of the following:

determining the at least one second RB set based on the frequency locations of the plurality of first RB sets, a frequency location of the at least one second RB set being separate from the frequency locations of the plurality of first RB sets in a frequency domain; or

determining the at least one second RB set based on the frequency locations of the plurality of first RB sets, a frequency location of each of the at least one second RB set being one of the frequency locations of the plurality of first RB sets.
The method of claim 1, wherein the at least one second RB set comprises a single second RB set, and wherein a frequency location of the single second RB set is one of frequency locations of the plurality of first RB sets.
The method of claim 4, wherein if one of the plurality of feedbacks immediately follows a first data transmission in one of the plurality of first RB sets to the second communication device within the same transmission occasion,

the frequency location of the single second RB set is the frequency location of a first RB set of the first data transmission, or

the frequency location of the single second RB set is randomly selected from the frequency locations of the plurality of first RB sets, or

the frequency location of the single second RB set is the frequency location of a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed, or

the frequency location of the single second RB set is the frequency location of the lowest one of the plurality of first RB sets.
The method of claim 1, wherein the at least one second RB set comprises a single second RB set, and wherein

a frequency location of the single second RB set is randomly selected from frequency locations of a plurality of candidate RB sets, or

the frequency location of the single second RB set is a frequency location of a RB set on which at least one successful Type 1 channel access procedure has been performed, or

the frequency location of the single second RB set is the frequency location of a lowest one of RB sets for data transmissions before the feedback on the single second RB set.
The method of claim 1, wherein determining the resource configuration comprises:

determining, based on the channel access states, that a feedback resource immediately follows a first data transmission performed in one of the plurality of first RB sets to the second communication device; and

in accordance with a determination that the feedback resource is available for the plurality of data transmissions, determining the resource configuration to indicate at least the feedback resource.
The method of claim 1, wherein the resource configuration indicates:

a first feedback resource for a first version of the plurality of feedbacks, and

a second feedback resource for a second version of the plurality of feedbacks.
The method of claim 1, wherein the plurality of data transmissions are performed using a plurality of data resources from the plurality of first RB sets, the method further comprising:

determining a first number of the first RB sets, a second number of resource blocks in the at least one second RB set, and a third number of RB sets in the at least one second RB set;

determining, based on the first, second, and third numbers, the number of resource blocks in the at least one feedback resource that are mapped to each sub-channel in the plurality of data resources; and

determining a mapping between sub-channels in the plurality of data resources and RB blocks in the at least one feedback resource.
The method of claim 1, wherein the plurality of data transmissions are of a groupcast type, and the at least one second RB sets comprises a first feedback RB set and a second feedback RB set.
The method of claim 10, wherein a frequency location of the first feedback RB set is one of frequency locations of the plurality of first RB sets.
The method of claim 10, wherein if one of the plurality of feedbacks immediately follows at least two of the plurality of data transmissions on at least two first RB sets,

the frequency locations of the first and second feedback RB sets are frequency locations of the at least two first RB sets, respectively, or

the frequency locations of the first and second feedback RB sets are randomly selected from the frequency locations of the plurality of first RB sets, or

the frequency locations of the first and second feedback RB sets are frequency locations of the lowest two first RB sets of the plurality of first RB sets.
The method of claim 10, wherein if one of the plurality of feedbacks immediately follows a data transmission in the plurality of data transmissions on a single first RB set,

the frequency location of the first feedback RB set is a frequency location of the single first RB set, and

the frequency location of the first feedback RB set is randomly selected from the frequency locations of the plurality of first RB sets, or the frequency location of the first feedback RB set is a first RB set of the plurality of the first RB sets on which a Type 1 channel access procedure having been performed.
The method of claim 10, wherein the frequency locations of the first feedback RB set and the second feedback RB set are randomly selected from the frequency locations of a plurality of candidate RB sets, or

wherein the frequency locations of the first feedback RB set and the second feedback RB set are frequency locations of two RB sets in the plurality of candidate RB sets on which at least one successful Type 1 channel access procedure has been performed, or

wherein the frequency locations of the first feedback RB set and the second feedback RB set are the frequency locations of the lowest two RB sets of the plurality of candidate RB sets.
The method of claim 10, further comprising:

determining the number of resource blocks per sub-channel per transmission occasion for the plurality of feedbacks;

determining a parameter of a capacity of a RB set for the plurality of feedbacks based on the number of resource blocks, the number of orthogonal codes for code division multiplexing (CDM) , and the number of transmission occasions for the plurality of data transmissions; and

determining the number of the at least one second RB set based on the parameter of the capacity of a RB set and the number of second communication devices in a groupcast.
The method of claim 1, wherein receiving the transmission of the plurality of feedbacks comprises:

receiving the transmission of the plurality of feedbacks on at least one candidate frequency resource available to the first communication device.
A communication method comprising:

receiving, at a second communication device, a plurality of data transmissions from a first communication device on a plurality of first resource block (RB) sets on unlicensed spectrum respectively;

receiving a resource configuration based on at least one of the following: frequency locations of the first plurality of RB sets, or channel access states of the plurality of first RB sets, the resource configuration indicating at least one feedback resource from at least one second RB set for transmission of a plurality of feedbacks corresponding to the plurality of data transmissions; and

performing the transmission of the plurality of feedbacks with the first communication device based on the resource configuration.
The method of claim 17, wherein performing the transmission of the plurality of feedbacks comprises:

in accordance with a determination that no data transmission that is to be performed on the same transmission occasion is immediately preceding a feedback resource from a second RB set indicated by the resource configuration, performing a channel access procedure on the second RB set;

in accordance with a successful result of the channel access procedure, transmitting at least one of the plurality of feedbacks using the feedback resource.
A communication device comprising:

at least one processor; and

at least one memory coupled to the at least one processor and storing instructions thereon, the instructions, when executed by the at least one processor, causing the communication device to perform the method according to any of claims 1-16 or the method according to any of claims 17-18.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to perform the method according to any of claims 1-16 or the method according to any of claims 17-18.