WO2023193249A1

WO2023193249A1 - Method, device and computer readable medium for communications

Info

Publication number: WO2023193249A1
Application number: PCT/CN2022/085883
Authority: WO
Inventors: Gang Wang; Zhaobang MIAO
Original assignee: Nec Corporation
Priority date: 2022-04-08
Filing date: 2022-04-08
Publication date: 2023-10-12

Abstract

Embodiments of the present disclosure relate to method, device and computer readable media for communications. A method for communications comprises: determining, at a first terminal device, a first feedback window associated with a physical sidelink feedback channel (PSFCH) transmission occasion, the first feedback window comprising a first set of candidate physical sidelink shared channel (PSSCH) reception occasions; generating sidelink Hybrid Automatic Repeat Request (HARQ) feedback information associated with the candidate PSSCH reception occasions in the first set; and transmitting the sidelink HARQ feedback information in the PSFCH transmission occasion.

Description

METHOD, DEVICE AND COMPUTER READABLE MEDIUM FOR COMMUNICATIONS

TECHNICAL FIELD

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

BACKGROUND

Sidelink in unlicensed spectrum or band (SL-U) and SL Carrier Aggregation (CA) are to be studied in Release 18 sidelink evolution work item of the 3rd Generation Partnership Project (3GPP) . The scheme of SL-U should be based on New Radio (NR) sidelink and NR-U. The scheme of SL CA should be based on NR Uu CA and Long Term Evolution (LTE) sidelink CA. Sidelink Hybrid Automatic Repeat Request (HARQ) feedback scheme in Release 16 is a sequence based scheme, and each feedback channel resource carries one HARQ feedback information bit for one sidelink data transmission.

SUMMARY

In general, example embodiments of the present disclosure provide methods, devices and computer readable media for communications.

In a first aspect, there is provided a method for communications. The method comprises: determining, at a first terminal device, a feedback window associated with a physical sidelink feedback channel (PSFCH) transmission occasion; generating sidelink Hybrid Automatic Repeat Request (HARQ) feedback information associated with candidate physical sidelink shared channel (PSSCH) reception occasions within the feedback window; and transmitting the sidelink HARQ feedback information in the PSFCH transmission occasion.

In a second aspect, there is provided a terminal device. The terminal device comprises a processor and a memory storing instructions. The memory and the instructions are configured, with the processor, to cause the terminal device to perform the method according to the first aspect.

In a third aspect, there is provided a computer readable medium having instructions stored thereon. The instructions, when executed on at least one processor of a device, cause the device to perform the method according to the first aspect.

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

BRIEF DESCRIPTION OF THE DRAWINGS

Through the more detailed description of some 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 network in which implementations of the present disclosure can be implemented;

Fig. 2 illustrates an example of automatic gain control (AGC) symbol and guard period (GP) symbol in accordance with some embodiments of the present disclosure;

Fig. 3 illustrates an example of a sub-channel in accordance with some embodiments of the present disclosure;

Fig. 4 illustrates an example of feedback channel resources in time domain in accordance with some embodiments of the present disclosure;

Fig. 5 illustrates an example of timing line between sidelink data transmissions on PSSCH and a PSFCH resource in prior art;

Fig. 6 illustrates an example of mapping between sidelink data transmissions on PSSCH and a PSFCH resource in accordance with some embodiments of the present disclosure

Fig. 7 illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure;

Fig. 8 illustrates examples of a length of a first feedback window in accordance with some embodiments of the present disclosure;

Figs. 9A to 9D illustrate examples of a time interval in accordance with some embodiments of the present disclosure, respectively;

Fig. 10 illustrates examples of a set of indexes of the candidate PSSCH reception occasions in accordance with some embodiments of the present disclosure;

Figs. 11A to 11I illustrate examples of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure, respectively;

Figs. 12A to 12C illustrate examples of generation of sidelink HARQ feedback information in accordance with some embodiments of the present disclosure, respectively; and

Fig. 13 is a simplified block diagram of a device that is suitable for implementing 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 limitations as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

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

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

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

The terminal or the network device may work on several frequency ranges, e.g. FR1 (410 MHz –7125 MHz) , FR2 (24.25GHz to 71GHz) , frequency band larger than 100GHz 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 network device may have the function of network energy saving, Self-Organizing Networks (SON) /Minimization of Drive Tests (MDT) . The terminal may have the function of power saving.

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

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

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 ‘some embodiments’ and ‘an embodiment’ are to be read as ‘at least some embodiments. ’ 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.

Fig. 1 illustrates a schematic diagram of an example communication network 100 in which embodiments of the present disclosure can be implemented. As shown in Fig. 1, the communication network 100 may include a terminal device 110, a terminal device 120, a terminal device 130,

network devices

140 and 150. The

network devices

140 and 150 may communicate with the terminal device 110, the terminal device 120 and the terminal device 130 via respective wireless communication channels.

In some embodiments, the network device 140 may be a gNB in NR, and the network device 150 may be an eNB in Long Term Evolution (LTE) system.

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

The communications in the communication network 100 may conform to any suitable standards including, but not limited to, Global System for Mobile Communications (GSM) , LTE, LTE-Evolution, LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , Code Division Multiple Access (CDMA) , GSM EDGE Radio Access Network (GERAN) , Machine Type Communication (MTC) and the like. Furthermore, the communications 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.

In some embodiments, the communications in the communication network 100 may comprise sidelink communication. Sidelink communication is a wireless radio communication directly between two or more terminal devices, such as two or more terminal devices among the terminal device 110, the terminal device 120 and the terminal device 130. In this type of communication, the two or more terminal devices that are geographically proximate to each other can directly communicate without going through the

network device

140 or 150 or through a core network. Data transmission in sidelink communication is thus different from typical cellular network communications, in which a terminal device transmits data to the network device 140 or 150 (i.e., uplink transmissions) or receives data from the network device 140 or 150 (i.e., downlink transmissions) . In sidelink communication, data is transmitted directly from a source terminal device (such as the terminal device 110) to a target terminal device (such as the terminal device 120) through the Unified Air Interface, e.g., PC5 interface, (i.e., sidelink transmissions) , as shown in Fig. 1.

Sidelink communication can provide several advantages, including reducing data transmission load on a core network, system resource consumption, transmission power consumption, and network operation costs, saving wireless spectrum resources, and increasing spectrum efficiency of a cellular wireless communication system.

In a sidelink communication system, the sidelink resource is used to transmit information between terminal devices. According to application scenarios, service types, etc., a sidelink communication manner includes but is not limited to device to device (D2D) communication, Vehicle-to-Everything (V2X) communication, etc.

V2X communication enables vehicles to communicate with other vehicles (i.e. Vehicle-to-Vehicle (V2V) communication) , with infrastructure (i.e. Vehicle-to-Infrastructure (V2I) , with wireless networks (i.e. Vehicle-to-Network (V2N) communication) , with pedestrians (i.e. Vehicle-to-Pedestrian (V2P) communication) , and even with the owner's home (i.e. Vehicle-to-Home (V2H) ) . Examples of infrastructure include roadside units such as traffic lights, toll gates and the like. V2X communication can be used in a wide range of scenarios, including in accident prevention and safety, convenience, traffic efficiency and clean driving, and ultimately in relation to autonomous or self-driving vehicles.

For sidelink communications, a terminal device uses resources in sidelink resource pools to transmit or receive signals. The sidelink resource pools include resources in time domain and frequency domain, which are dedicated resources of the sidelink communication, or shared by the sidelink communication and a cellular link.

In a sidelink resource pool which may contain multiple slots and resource blocks (RBs) , and all or part of the symbols in a slot can be used for sidelink transmission. Within a resource pool, among all the symbols configured for sidelink in each slot, the first symbol (i.e., the start symbol) is used as the automatic gain control (AGC) symbol, and the last symbol used as a guard period (GP) symbol. AGC symbols and GP symbols can be considered as fixed overheads in sidelink resource. In the description of the following embodiments, AGC symbols and GP symbols are included in the sidelink symbols which are indicated by the sidelink channel resource configuration, and AGC symbols carry redundancy sidelink information while GP symbols are not used for carrying sidelink information, as shown in Fig. 2.

The terminal device 110, the terminal device 120 and the terminal device 130 may use sidelink channels to transmit sidelink signaling or information. The sidelink channels include at least one of the following: a Physical Sidelink Control Channel (PSCCH) resource which is used for carrying sidelink control information (SCI) , a Physical Sidelink Shared Channel (PSSCH) resource which is used for carrying sidelink data service information, a physical sidelink feedback channel (PSFCH) resource which is used for carrying sidelink Hybrid Automatic Repeat Request (HARQ) feedback information, a physical sidelink broadcast channel (PSBCH) resource which is used for carrying sidelink broadcast information, and a physical sidelink discovery channel (PSDCH) resource which is used for carrying a sidelink discovery signal. Hereinafter, a PSFCH resource is also referred to as a feedback channel resource or HARQ feedback opportunity.

Within a resource pool, a PSSCH resource includes all the symbols in a slot that are configured as sidelink available symbols, and one or more sub-channels in frequency domain, where each sub-channel contains an integer number of consecutive RBs. The number m of RBs included in one sub-channel is also called the sub-channel size. Each slot contained in the resource pool contains multiple available sidelink symbols, and the PSSCH resource is located in the time domain from the first available sidelink symbol in this slot to all available symbols. In the frequency domain, the resource pool contains multiple RBs, according to the sub-channel size m, starting from the first RB in the resource pool, each m RBs are divided into one sub-channel, and each PSSCH channel resource is located on one or more sub-channels. When one of the terminal device 110, the terminal device 120 and the terminal device 130 uses the PSSCH resource to send sidelink information, it can use one or more sub-channels to carry corresponding data information. A PSCCH resource includes t symbols in time domain, and l RBs in frequency domain. Each PSCCH channel resource is located at consecutive t symbols starting from the first symbol in the available symbols in the time domain, and located at the position of consecutive l RBs starting from the first RB in the corresponding sub-channel in the frequency domain, as shown in Fig. 3.

Within a resource pool, whether a PSFCH resource is available should be configured or pre-configured. In time domain, according to the configuration or pre-configuration of a resource pool, one of every N slots in the resource pool contains PSFCH resources, N= [0, 1, 2, 4] . In a sidelink resource pool, PSCCH or PSSCH resources are presented in every slot and used for transmitting sidelink data packet. Within a slot containing a PSFCH resource, the last three SL symbols (AGC+PSFCH+GP) are used for PSFCH related, as shown in Fig. 4.

A PSFCH resource may comprises one RB in frequency domain and one symbol in time domain (AGC symbol is repeated) . In addition, the PSFCH resource may carry 1 bit ACK/NACK information. Furthermore, the PSFCH resource may be related to one sub-channel in one slot.

While PSFCH is used for carrying sidelink HARQ feedback information associated with a sidelink data transmission on the assigned slots. Based on that, the time intervals between HARQ feedback information on PSFCH and the associated sidelink data transmission on PSSCH are various. As an example shown in Fig. 5, where N=4, i.e., one out of every four slots in the resource pool contains a PSFCH resource.

There is an N-to-one mapping relationship in time domain between PSSCH and PSFCH. For the data transmission on PSSCH in slot #n, the associated HARQ feedback information should be reported in slot #n+k ₀, k ₀ >=K ₀. K ₀ may be configured or pre-configured through high layer. For example, K ₀ may be configured as K ₀= [2, 3] by sl-MinTimeGapPSFCH. As shown in Fig. 5, K ₀=2 slots. Accordingly, the HARQ feedback information associated with the PSSCH in slots #n and #n+1 should be reported on PSFCH in slot #n+3, and the HARQ feedback information associated with the PSSCH in slots #n+2, #n+3, n+4 and n+5 should be reported on PSFCH in slot #n+7.

In frequency domain, the RBs used as PSFCH resources should be configured by bitmap. Based on that, the assigned RBs for PSFCH resources should be allocated to carry the sidelink HARQ feedback information associated with data transmissions on PSSCH. This will be described with reference to Fig. 6.

Fig. 6 illustrates an example of mapping between sidelink data transmissions on PSSCH and a PSFCH resource. As shown in Fig. 6, a period of PSFCH resources is equal to 1 and K ₀ is equal to 2. Hereinafter, the period of PSFCH resources is also referred to as PSFCH period for brevity. HARQ feedback information associated with a data transmission on PSSCH in slot #n+1 should be reported on PSFCH in slot #n+3.

represents the number of RBs in a resource pool configured for feedback channel resources.

represents the number of RBs for carrying HARQ feedback information associated with a data transmission with a sub-channel in a slot, where

is determined based on the following:

where N _subch represents the number of sub-channels in the resource pool, and

represents a period of PSFCH resources. In the example of Fig. 6,

For SL-U, as a channel access procedure limits sidelink transmission, HARQ feedback information for more than one sidelink data transmission may need to be transmitted in a feedback channel transmission occasion. In addition, For SL CA, more than one carriers may be used for sidelink transmission and corresponding HARQ feedback scheme should be considered.

Embodiments of the present disclosure provide a solution for sidelink transmission so as to solve the above problems and one or more of other potential problems. According to the solution, there is introduced a feedback window associated with a PSFCH transmission occasion. Sidelink HARQ feedback information associated with a set of candidate PSSCH reception occasions within the feedback window is generated. Hereinafter, principle of the present disclosure will be described with reference to Figs. 7 to 13.

Fig. 7 illustrates a flowchart of an example method in accordance with some embodiments of the present disclosure. In some embodiments, the method 700 can be implemented at a terminal device, such as one of the terminal device 110, the terminal device 120 and the terminal device 130 as shown in Fig. 1. For the purpose of discussion, the method 700 will be described with reference to Fig. 1 as performed by the terminal device 110 without loss of generality.

At block 710, the terminal device 110 determines a first feedback window associated with a PSFCH transmission occasion. The first feedback window comprises a first set of candidate PSSCH reception occasions. At block 720, the terminal device 110 generates HARQ feedback information associated with the candidate PSSCH reception occasions in the first set. At block 730, the terminal device 110 transmits the sidelink HARQ feedback information in the PSFCH transmission occasion.

It should be understood that it is assumed that the sidelink resource structure in Release 16 may be used in embodiments of the present disclosure.

In some embodiments, the terminal device 110 may determine the first feedback window based on at least one of the following:

● a sidelink resource configuration,

● a length of the first feedback window, which is represented by T in the present disclosure, or

● a time interval, which is represented by k in the present disclosure.

In some embodiments, a reception occasion may refer to a time duration for a terminal device to receive a sidelink signal. For example, the reception occasion may comprise a sidelink slot, a number of symbols for a sidelink signal transmission, and so on. A transmission occasion may refer to a time duration for a terminal device to transmit a sidelink signal. For example, the transmission occasion may comprise a sidelink slot, a number of symbols for a sidelink signal transmission, and so on.

It should be understood that in the present disclosure, the terms “PSSCH reception” and “PSFCH transmission” may be used in pair, and the terms “PSSCH transmission” and “PSFCH reception” may be used in pair. These two pairs of terms are described from perspectives of different terminal devices. In particular, PSSCH reception and PSFCH transmission are described from a perspective of a receiving terminal device. The receiving terminal device receives sidelink data on PSSCH and transmits HARQ feedback information associated with the sidelink data on PSFCH. Similarly, PSSCH transmission and PSFCH reception are described from a perspective of a transmitting terminal device. The transmitting terminal device transmits the sidelink data on PSSCH and receives the HARQ feedback information associated with the sidelink data on PSFCH. In this sense, PSSCH reception may be interchangeably used with PSSCH transmission, and PSFCH transmission may be used interchangeably with PSFCH reception.

In some embodiments, the sidelink resource configuration may comprise at least one of the following:

● a sidelink resource pool configuration,

● a sidelink channel configuration, or

● a sidelink HARQ feedback configuration.

In some embodiments, the sidelink resource pool configuration may indicate the allocation of slots and symbols, and RBs comprised in the resource pool. The sidelink channel configuration may indicate the allocation of types of sidelink channels, e.g., PSCCH, PSSCH, and PSFCH, including the symbols and RBs used for each type of the sidelink channels. The sidelink HARQ feedback configuration may indicate the scheme of sidelink HARQ feedback used in a resource pool, e.g., sidelink feedback option 1 or option 2 scheme, the feedback gap between PSSCH and associated PSFCH resource, i.e., K ₀, and mapping relationship between PSSCH and associated PSFCH resource.

In some embodiments, the length of the first feedback window may comprise at least one of the following:

● a first number of physical slots,

● a second number of logical slots in a resource pool,

● a first time interval,

● an integer multiple of a period of PSFCH resources, or

● a third number of interlaces in frequency domain comprised in a sub-channel.

Such some embodiments may provide flexible first feedback window configuration and may be suitable for different requirements or scenarios. This will be described with reference to Fig. 8.

Fig. 8 illustrates examples of a length of a first feedback window in accordance with some embodiments of the present disclosure. As shown in Fig. 8, in an example (a) , the length (T) of the first feedback window comprises a first number of physical slots, where the first number is equal to 5. In an example (b) , the length (T) of the first feedback window comprises a second number of logical slots in a resource pool, where the second number is equal to 5. In an example (c) , the length (T) of the first feedback window comprises a first time interval which is equal to 10ms. In the present disclosure, a logical slot is also referred to as a sidelink (SL) slot.

In an example (d) , the length (T) of the first feedback window comprises an integer multiple of a period of PSFCH resources (also referred to as PSFCH period) . Specifically, the period of PSFCH resources is equal to 2, and the length (T) of the first feedback window comprises 3 PSFCH periods, i.e., comprising a number of SL slots which equals to 3 times of PSFCH period. In an example (e) , the length (T) of the first feedback window comprises a third number of interlaces in frequency domain comprised in a sub-channel. The third number may be represented by C, where C is equal to 2.

In some embodiments, the time interval (k) may be a slot interval. In other words, the time interval (k) may be determined based on slot. The slot interval comprises a plurality of physical consecutive slots or logical consecutive slots in a resource pool. This will be described with reference to Fig. 9A.

In some embodiments, the time interval (k) is determined based on slot. The time interval (k) is a physical slot interval or logical slot interval between a slot comprised PSSCH and a slot comprised PSFCH associated with the PSSCH.

Fig. 9A illustrates examples of the time interval (k) in accordance with some embodiments of the present disclosure. As shown in Fig. 9A, in an example (a1) , the time interval (k) comprises four physical consecutive slots. In an example (a2) , the time interval (k) comprises four logical consecutive slots in a resource pool.

In some other embodiments, the time interval (k) may be a symbol interval. In other words, the time interval (k) may be determined based on symbol. The symbol interval comprises a plurality of symbols within a slot or crossing slots. This will be described with reference to Fig. 9B.

In some embodiments, the time interval (k) is determined based on symbol. The time interval (k) is a symbol interval between a last symbol of PSSCH and a start symbol of PSFCH associated with the PSSCH, or the time interval (k) is a symbol interval between a start symbol of PSSCH and a start symbol of PSFCH associated with the PSSCH.

Fig. 9B illustrates examples of the time interval (k) in accordance with some embodiments of the present disclosure, and the time interval (k) is a symbol interval between a last symbol of PSSCH and a start symbol of PSFCH associated with the PSSCH. As shown in Fig. 9B, in an example (b1) , the time interval (k) comprises four symbols within a slot. In an example (b2) , the time interval (k) comprises six symbols crossing two slots. In an example (b3) , the time interval (k) comprises five symbols within a slot. In an example (b4) , the time interval (k) comprises seven symbols crossing two slots. For example (b1) and (b2) , the last symbol of PSSCH is symbol #n, and the first symbol of associated PSFCH should be symbol #n+k+1. For example (b3) and (b4) , the last symbol of PSSCH is symbol #n, and the first symbol of associated PSFCH should be symbol #n+k.

Hereinafter, some examples of the time interval (k) based on a slot interval will be described with reference to Figs. 9C and 9D. Such examples may provide flexible timing relation between candidate PSSCH reception occasion and PSFCH transmission occasion.

Fig. 9C illustrates examples of the time interval (k) in accordance with some embodiments of the present disclosure. As shown in Fig. 9C, in an example (c1) , the time interval (k) is a first physical slot interval between the PSFCH transmission occasion and a last slot within the first feedback window associated with the PSFCH transmission occasion. Specifically, in the example (c1) , the time interval (k) comprises three physical consecutive slots.

In an example (c2) , the time interval (k) is a minimum physical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions within the first feedback window. In other words, a physical slot interval between the PSFCH transmission occasion and the last candidate PSSCH reception occasion should be equal to or larger than k. Specifically, in the example (c2) , the time interval (k) comprises two physical consecutive slots, and the physical slot interval between the PSFCH transmission occasion and the last candidate PSSCH reception occasion is equal to three physical consecutive slots, which is larger than k.

In an example (c3) , the time interval (k) is a first logical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions within the first feedback window. Specifically, in the example (c3) , the time interval (k) comprises two logical consecutive slots.

Fig. 9D illustrates examples of the time interval (k) in accordance with some embodiments of the present disclosure. As shown in Fig. 9D, in an example (d1) , the time interval (k) is a second physical slot interval between the PSFCH transmission occasion and a starting slot within the first feedback window. Specifically, in the example (d1) , the time interval (k) comprises ten physical consecutive slots.

In an example (d2) , the time interval (k) is a maximum physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions within the first feedback window. In other words, a physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions should be equal to or less than k. Specifically, in the example (d2) , the time interval (k) comprises ten physical consecutive slots, and the physical slot interval between the PSFCH transmission occasion and the starting candidate PSSCH reception occasion is equal to nine physical consecutive slots, which is less than k.

In an example (d3) , the time interval (k) is a second logical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions within the first feedback window. Specifically, in the example (d3) , the time interval (k) comprises six logical consecutive slots.

It will be understood that the time interval (k) based on a slot interval has been described by way of example with reference to Figs. 9C and 9D. The time interval (k) based on a symbol interval may be implemented in a way similar to the examples as shown in Figs. 9C and 9D. Thus, details of the time interval (k) based on the symbol interval are omitted for brevity.

In some embodiments, the time interval (k) may comprise at least one of the following:

● a first physical symbol interval between the PSFCH transmission occasion and a last symbol within the first feedback window,

● a first minimum physical symbol interval between the PSFCH transmission occasion and a starting symbol of a last one of the candidate PSSCH reception occasions within the first feedback window,

● a second minimum physical symbol interval between the PSFCH transmission occasion and a last symbol of the candidate PSSCH reception occasions within the first feedback window,

● a second physical symbol interval between the PSFCH transmission occasion and a starting symbol within the first feedback window,

● a first maximum physical symbol interval between the PSFCH transmission occasion and a starting symbol of the candidate PSSCH reception occasions within the first feedback window, or

● a second maximum physical symbol interval between the PSFCH transmission occasion and a last symbol of a starting one of the candidate PSSCH reception occasions within the first feedback window.

In some embodiments, the time interval (k) between the PSFCH transmission occasion and the associated first feedback window comprises the time interval between a start symbol of the PSFCH transmission occasion and the associated first feedback window, or the time interval between a last symbol of the PSFCH transmission occasion and the associated first feedback window.

In some embodiments, the time interval (k) may be between the PSFCH transmission occasion and a first timing, wherein the first timing comprises at least one of the following:

● a last slot or symbol within the first feedback window,

● a last slot or symbol in a resource pool within the first feedback window,

● a last one of the candidate PSSCH reception occasions within the first feedback window,

● a starting slot or symbol within the first feedback window,

● a starting slot or symbol in a resource pool within the first feedback window, or

● a starting one of the candidate PSSCH reception occasions within the first feedback window.

In some embodiments, the terminal device 110 may further determine, based on the sidelink resource configuration, indexes of the candidate PSSCH reception occasions within the first feedback window. For example, the terminal device 110 may determine the indexes as a set of indexes of the candidate PSSCH reception occasions within the first feedback window. Hereinafter, the set of the indexes may be represented by M _f, and M _f= [0, 1, …, M-1] , where M represents the number of the candidate PSSCH reception occasions within the first feedback window. This will be described with reference to Fig. 10.

Fig. 10 illustrates examples of a set of indexes of the candidate PSSCH reception occasions in accordance with some embodiments of the present disclosure. As shown in Fig. 10, in an example (a) , the length (T) of the first feedback window comprises five physical slots. The terminal device 110 determines, based on an SL slot configuration, that the number of the candidate PSSCH reception occasions within the first feedback window is equal to 4. Thus, a set M _f of indexes of the candidate PSSCH reception occasions may comprise 0, 1, …, 3.

In an example (b) , the length (T) of the first feedback window comprises five logical slots (i.e., five SL slots) . The terminal device 110 determines, based on the SL slot configuration, that the number of the candidate PSSCH reception occasions within the first feedback window is equal to 5. Thus, a set M _f of indexes of the candidate PSSCH reception occasions may comprise 0, 1, …, 4.

In an example (c) , the length (T) of the first feedback window comprises the first time interval of 10ms. The terminal device 110 determines, based on the SL slot configuration, that the number of the candidate PSSCH reception occasions within the first feedback window is equal to 7. Thus, a set M _f of indexes of the candidate PSSCH reception occasions may comprise 0, 1, …, 6.

In an example (d) , the length (T) of the first feedback window comprises three PSFCH periods. The terminal device 110 determines, based on the SL slot configuration, that the number of the candidate PSSCH reception occasions within the first feedback window is equal to 6. Thus, a set M _f of indexes of the candidate PSSCH reception occasions may comprise 0, 1, …, 5.

In an example (e) , the length (T) of the first feedback window comprises C SL slots (C=2) . The terminal device 110 determines, based on the SL slot configuration, that the number of the candidate PSSCH reception occasions within the first feedback window is equal to 2. Thus, a set M _f of indexes of the candidate PSSCH reception occasions may comprise 0 and 1.

In some embodiments, the terminal device 110 may determine the first feedback window based on the length (T) of the first feedback window and the time interval (k) . In such embodiments, the time interval (k) is a first physical slot interval between the PSFCH transmission occasion and a last slot within the first feedback window, and the length of the first feedback window comprises a first number of physical slots. This will be described with reference to Fig. 11A.

Fig. 11A illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the length (T) of the first feedback window and the time interval (k) are pre-configured per resource pool, and T=8 , k=2. A PSFCH transmission occasion is on slot #n _F. The time interval (k) is a physical slot interval between the PSFCH transmission occasion on slot #n _F and a last slot within the first feedback window.

The terminal device 110 determines the first feedback window based on T and k. The first feedback window comprises slots # [n _F-9, …, n _F-2] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to five, i.e., M=5. In turn, the terminal device 110 determines M _f= [0, 1, …, 4] . This example uses fixed and common configuration for the first feedback window, which makes it more easier to determine the first feedback window

In some embodiments, the terminal device 110 may determine the first feedback window based on the length (T) of the first feedback window and the time interval (k) . In such embodiments, the time interval (k) is a logical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions within the first feedback window, and the length of the first feedback window comprises a first number of physical slots. This will be described with reference to Fig. 11B.

Fig. 11B illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the length (T) of the first feedback window and the time interval (k) are configured by the network device 140 through high layer signaling, and T=8, k=2. A PSFCH transmission occasion is on slot #n _F. The time interval (k) is a logical slot interval between the PSFCH transmission occasion on slot #n _F and a last candidate PSSCH reception occasion within the first feedback window.

The terminal device 110 determines the first feedback window based on T and k. The first feedback window comprises slots # [n _F-10, …, n _F-3] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to six, i.e., M=6. In turn, the terminal device 110 determines M _f= [0, 1, …, 5] . This example uses logical slot interval to determine the first feedback window, which provides more suitable feedback window configuration based on practical sidelink resource configuration.

In some embodiments, the terminal device 110 may determine the first feedback window based on the length (T) of the first feedback window and the time interval (k) . In such embodiments, the time interval (k) is a logical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions within the first feedback window, and the length of the first feedback window comprises a second number of logical slots in a resource pool. This will be described with reference to Fig. 11C.

Fig. 11C illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the length (T) of the first feedback window and the time interval (k) are indicated by a terminal device transmitting PSSCH, such as the terminal device. T=6, and k=2. A PSFCH transmission occasion is on slot #n _F. The time interval (k) is a logical slot interval between the PSFCH transmission occasion on slot #n _F and a last candidate PSSCH reception occasion within the first feedback window.

The terminal device 110 determines the first feedback window based on T and k. The first feedback window comprises slots # [n _F-10, …, n _F-3] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to six, i.e., M=T=6. In turn, the terminal device 110 determines M _f= [0, 1, …, 5] . This example uses logical slot interval to determine the first feedback window, which provides more suitable feedback window configuration based on practical sidelink resource configuration.

In some embodiments, the terminal device 110 may determine the first feedback window based on the length of the first feedback window and the time interval. In such embodiments, the time interval (k) is a minimum physical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions within the first feedback window. In other words, a physical slot interval between the PSFCH transmission occasion and the last one of the candidate PSSCH reception occasions should be equal to or greater than k. The length of the first feedback window is a first time interval. This will be described with reference to Fig. 11D.

Fig. 11D illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the length (T) of the first feedback window and the time interval (k) are pre-configured per resource pool, T=8 ms , and k=2. The PSFCH transmission occasion is on slot #n _F. The time interval (k) is a minimum physical slot interval between the PSFCH transmission occasion on slot #n _F and a last candidate PSSCH reception occasion within the first feedback window.

The terminal device 110 determines the first feedback window based on T and k. The feedback window comprises slots # [n _F-12, …, n _F-5] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to six, i.e., M=6. In turn, the terminal device 110 determines M _f= [0, 1, …, 5] . This example uses k as a minimum physical slot interval, which provides flexible and effective feedback window location based on practical sidelink resource configuration.

In some embodiments, the terminal device 110 may determine an end of the first feedback window. The end of the first feedback window may refer to the last slot within the first feedback window or the last PSSCH reception occasion within the first feedback window. In such embodiments, the end of the first feedback window is a last slot which comprises PSFCH resources before the PSFCH transmission occasion. Alternatively, the end of the first feedback window is a last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion.

In some embodiments, the terminal device 110 may determine the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion based on sidelink HARQ feedback configuration. The sidelink HARQ feedback configuration may indicate a minimum time gap (K ₀) , i.e., the feedback gap, between a candidate PSSCH reception occasion and the associated PSFCH transmission occasion. The terminal device 110 may determine the last candidate PSSCH reception occasion based on K ₀.

In some embodiments, the terminal device 110 may determine the first feedback window based on the time interval and the end of the first feedback window. In such embodiments, the time interval is a maximum physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window. The end of the first feedback window is the last candidate PSSCH reception occasion which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion. Upon determining the first feedback window, the terminal device 110 may determine the last candidate PSSCH reception occasion which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion as the last candidate PSSCH reception occasion within the first feedback window.

Fig. 11E illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the time interval (k) is pre-configured per resource pool, and k=8. The PSFCH transmission occasion is on slot #n _F. The time interval (k) is a maximum physical slot interval between the PSFCH transmission occasion on slot #n _F and a starting one of the candidate PSSCH reception occasions within the first feedback window. The terminal device 110 may determine, based on K ₀, the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion on slot #n _F. In this example, K ₀=2.

Further, the terminal device 110 may determine the first feedback window based on the time interval (k) and the last candidate PSSCH reception occasion. The first feedback window comprises slots # [n _F-7, …, n _F-3] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to four, i.e., M=4. In turn, the terminal device 110 determines M _f= [0, 1, …, 3] . This example uses k as a maximum slot interval, which provides as much as possible feedback information for an associated PSFCH occasion.

In some embodiments, the terminal device 110 may determine the first feedback window based on the time interval and the end of the first feedback window. In such embodiments, the time interval is a physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window. The end of the first feedback window is the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion. This will be described with reference to Fig. 11F.

Fig. 11F illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the time interval (k) is a system pre-defined value, and k=10. The PSFCH transmission occasion is on slot #n _F. The time interval (k) is a physical slot interval between the PSFCH transmission occasion and a starting candidate PSSCH reception occasion within the first feedback window. The terminal device 110 may determine, based on K ₀, the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion on slot #n _F. In this example, K ₀=2 or 3.

In turn, the terminal device 110 may determine the first feedback window based on the time interval (k) and the last candidate PSSCH reception occasion. The first feedback window comprises slots # [n _F-10, …, n _F-2] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f. This example uses fixed configuration for feedback window, which makes it more easier to determine the feedback window. In addition, this example benefits Type 1 codebook size determining.

In some embodiments, the time interval comprises a first logical slot interval (k ₁) between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions within the first feedback window, and a second logical slot interval (k ₂) between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions within the first feedback window. The terminal device 110 may determine the first feedback window based on the first logical slot interval and the second logical slot interval. This will be described with reference to Fig. 11G.

Fig. 11G illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the first logical slot interval (k ₁) and the second logical slot interval (k ₂) are pre-configured per resource pool, k ₁=2, and k ₂=6. The PSFCH transmission occasion is on slot #n _F. The first logical slot interval (k ₁) is between the PSFCH transmission occasion on slot #n _F and a last candidate PSSCH reception occasion within the first feedback window. The second logical slot interval (k ₂) is between the PSFCH transmission occasion on slot #n _F and a starting candidate PSSCH reception occasion within the first feedback window.

The terminal device 110 determines the first feedback window based on the first logical slot interval (k ₁) and the second logical slot interval (k ₂) . The feedback window comprises slots # [n _F-9, …, n _F-3] . The terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to five, i.e., M=k ₂-k ₁+1=5. In turn, Based on the sidelink resource configuration, the terminal device 110 determines M _f. This example uses logical slot interval to determine the feedback window, which provides more suitable feedback window configuration based on practical sidelink resource configuration. In addition, this example benefits Type 1 codebook size determining.

In some embodiments, the terminal device 110 may determine the first feedback window based on the length of the first feedback window and the end of the first feedback window. In such embodiments, the length of the first feedback window comprises an integer multiple of a period of PSFCH resources. The end of the first feedback window is the last slot which comprises PSFCH resources before the PSFCH transmission occasion. This will be described with reference to Fig. 11H.

Fig. 11H illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the length (T) of the first feedback window is pre-configured per resource pool, and T=2 PSFCH periods. The PSFCH transmission occasion is on slot #n _F. The end of the first feedback window is a last slot 110 which comprises PSFCH resources before the PSFCH transmission occasion on slot #n _F.

The terminal device 110 determines the first feedback window based on the length (T) of the first feedback window and the last slot 110. The feedback window comprises slots # [n _F-7, …, n _F-3] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to 4, i.e., M=T*PSFCH period = 4. In turn, the terminal device 110 determines M _f based on the sidelink resource configuration. In this example, the feedback window is determined according to sidelink resource configuration, which benefits Type 1 codebook size determining.

In some embodiments, the terminal device 110 may determine the first feedback window based on the length of the first feedback window and the end of the first feedback window. In such embodiments, the length of the first feedback window comprises an integer multiple of a period of PSFCH resources. The end of the first feedback window is the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion. This will be described with reference to Fig. 11I.

Fig. 11I illustrates an example of a first feedback window and associated PSFCH transmission occasion in accordance with some embodiments of the present disclosure. In this example, the length (T) of the first feedback window is pre-configured per resource pool, and T=2 PSFCH periods. The PSFCH transmission occasion is on slot #n _F. The end of the first feedback window is the last candidate PSSCH reception occasion 120 for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion on slot #n _F. The terminal device 110 may determine the last candidate PSSCH reception occasion 120 based on K ₀. In this example, K ₀=3 slots.

The terminal device 110 determines the first feedback window based on the length (T) of the first feedback window and the last candidate PSSCH reception occasion 120. The feedback window comprises slots # [n _F-10, …, n _F-5] . Based on the sidelink resource configuration, the terminal device 110 determines that the number of candidate PSSCH reception occasions in M _f is equal to 4, i.e., M=T*PSFCH period = 4. In turn, the terminal device 110 determines M _f based on the sidelink resource configuration. In this example, the feedback window is determined according to sidelink resource configuration, which benefits Type 1 codebook size determining.

In some embodiments, the terminal device 110 may generate, in an order of the indexes of the candidate PSSCH reception occasions in the first set, the sidelink HARQ feedback information associated with the candidate PSSCH reception occasions in the first set. In some embodiments, the terminal device 110 may generate the sidelink HARQ feedback information as a Type 1 codebook.

In some embodiments, the terminal device 110 may determine the indexes in timing order of the candidate PSSCH reception occasions in the first set. In such embodiments, the terminal device 110 may generate, in an order of the indexes of the candidate PSSCH reception occasions in the first set, one or more sidelink HARQ feedback bits associated with each of the candidate PSSCH reception occasions.

For example, within the M _f, the terminal device 110 may determine sidelink HARQ feedback information for each candidate PSSCH transmission occasion in sequence as below:

● for a PSSCH reception, generating ACK or NACK according to the result of the PSSCH reception;

● for a candidate PSSCH reception occasion without PSSCH reception, generating NACK.

Fig. 12A illustrates an example of generation of sidelink HARQ feedback information in accordance with some embodiments of the present disclosure. In this example, for each candidate PSSCH reception occasion, at most one transmission block (TB) is received on each sub-channel and one sidelink HARQ feedback bit for each TB. In other words, TB based feedback is generated. In addition, for each candidate PSSCH reception occasion, the terminal device 110 generates A/N in Type 1 codebook according to PSSCH reception result in slots #n, n+3. For other PSSCH reception occasions, NACK is generated in Type 1 codebook. In this example, based on the feedback window, HARQ information of more PSSCH reception occasions is multiplexed.

Fig. 12B illustrates another example of generation of sidelink HARQ feedback information in accordance with some embodiments of the present disclosure. In this example, for each candidate PSSCH reception occasion, at most two TBs are received, i.e., there are 2 bits for each PSSCH reception occasion in M _f. In addition, for each candidate PSSCH reception occasion, more than one bit HARQ information for each TB. In other words, CBG based feedback is generated. In this example, one TB comprises m+1 CBGs.

In some embodiments, the terminal device 110 may determine a second feedback window associated with the PSFCH transmission occasion. The second feedback window comprises a second set of candidate PSSCH reception occasions. The first and second sets of candidate PSSCH reception occasions are in different sidelink resource pools, resources block (RB) sets, sidelink bandwidth parts (BWPs) or sidelink carriers.

In some embodiments, the terminal device 110 may determine, based on the sidelink resource configuration, indexes of the candidate PSSCH reception occasions in the second set. In addition, the terminal device 110 may generate, in an order of the indexes, sidelink HARQ feedback information associated with the candidate PSSCH reception occasions in the second set.

In some embodiments, the terminal device 110 may generate sidelink HARQ feedback information associated with the candidate PSSCH reception occasions in the first and second sets in an order of indexes of at least one of the following: the sidelink resource pools, the RB sets, the BWPs or the sidelink carriers. This will be described with reference to Fig. 12C.

Fig. 12C illustrates a further example of generation of sidelink HARQ feedback information in accordance with some embodiments of the present disclosure. In this example, the terminal device 110 determines feedback windows #1 and #2 associated with the PSFCH transmission occasion on slot #n _F. The feedback window #1 comprises a first set of candidate PSSCH reception occasions in a sidelink resource pool #1 of an SL BWP. The feedback window #2 comprises a second set of candidate PSSCH reception occasions in a sidelink resource pool #2 of the SL BWP.

The terminal device 110 determines M _f1 for the sidelink resource pool #1 and M _f2 for the sidelink resource pool #2. For a same SL slot belongs to M _f1 and M _f2, the associated HARQ feedback information is generated in an order of indexes of the sidelink resource pools #1 and #2. In other words, the terminal device 110 generates HARQ feedback information for the sidelink resource pool #1 first, and then HARQ feedback information for the sidelink resource pool #2.

For example, for slot #0, the terminal device 110 generates HARQ feedback information a0 for the sidelink resource pool #1 first, and then HARQ feedback information a1 for the sidelink resource pool #2. For another example, for slot #1, the terminal device 110 generates HARQ feedback information a2 for the sidelink resource pool #1 first, and then HARQ feedback information a3 for the sidelink resource pool #2. For another example, for slot #2, because there is no candidate PSSCH reception occasion in the sidelink resource pool #1, the terminal device 110 only generates HARQ feedback information a4 for the sidelink resource pool #2.

It is to be understood that the number of sidelink resource pools is only for the purpose of illustration without suggesting any limitations. More than two sidelink resource pools may be adapted for implementing embodiments of the present disclosure.

In addition, it is to be understood that the two sidelink resource pools of the same SL BWP are described by way of example. In other embodiments, the two sidelink resource pools may belong to different SL BWPs. Alternatively, the two sidelink resource pools may belong to the same or different RB sets, the same or different SL carriers.

In some embodiments, for multiple RB sets of an SL BWP, the terminal device 110 may determine M _f for each RB set respectively. For a same slot belonging to M _f of different RB sets, the associated HARQ feedback information may be generated in an order of indexes of RB sets.

In some embodiments, for multiple SL BWPs in a SL carrier, the terminal device 110 may determine M _ffor each resource pool, each RB set of each SL BWP, respectively. For a same slot belonging to different M _f, the associated HARQ feedback information may be generated in an order of: indexes of SL BWPs first, then indexes of resource pools or indexes of RB sets.

In some embodiments, for multiple SL carriers, the terminal device 110 may determine M _ffor each resource pool, RB set of each SL BWP of each SL carrier, respectively. For a same slot belonging to different M _f, the associated HARQ feedback information may be generated in an order of: indexes of SL carriers first, then indexes of SL BWPs, and then indexes of resource pools or indexes of RB sets.

In some embodiments, the terminal device 110 may determine the length of the first feedback window and the time interval based on at least one of the following:

● pre-definition,

● configuration,

● pre-configuration,

● an indication received from a second terminal device transmitting PSSCH, or

● the sidelink resource configuration.

For example, the terminal device 110 may receive sidelink HARQ feedback configuration in high layer signaling, including at least one of the following:

● SL-HARQ-Config :

- sl-Timeinterval-dataToPSFCH (K ₀) ;

● SL-Type1codebookConfig:

- sl-feedbackwindow (T) .

In this way, relevant high layer information element (IE) content for PSCCH may be provided.

Fig. 13 is a simplified block diagram of a device 1300 that is suitable for implementing some embodiments of the present disclosure. The device 1300 can be considered as a further example embodiment of the terminal device 110 as shown in Fig. 1. Accordingly, the device 1300 can be implemented at or as at least a part of the terminal device 110.

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

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

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

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

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, apparatus, systems, 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 any of Figs. 1 to 12. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

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

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

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

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

Claims

A method for communications, comprising:

determining, at a first terminal device, a first feedback window associated with a physical sidelink feedback channel (PSFCH) transmission occasion, the first feedback window comprising a first set of candidate physical sidelink shared channel (PSSCH) reception occasions;

generating sidelink Hybrid Automatic Repeat Request (HARQ) feedback information associated with the candidate PSSCH reception occasions in the first set; and

transmitting the sidelink HARQ feedback information in the PSFCH transmission occasion.
The method of claim 1, wherein determining the first feedback window comprises:

determining the first feedback window based on at least one of the following:

a sidelink resource configuration,

a length of the first feedback window, or

a time interval.
The method of claim 2, wherein the length of the first feedback window comprises at least one of the following:

a first number of physical slots,

a second number of logical slots in a resource pool,

a first time interval,

an integer multiple of a period of PSFCH resources, or

a third number of interlaces in frequency domain comprised in a sub-channel.
The method of claim 2, wherein the time interval is a slot interval, the slot interval comprises a plurality of physical consecutive slots or logical consecutive slots in a resource pool.
The method of claim 2, wherein the time interval is a symbol interval, the symbol interval comprises a plurality of symbols within a slot or crossing slots.
The method of claim 2, wherein the time interval comprises at least one of the following:

a first physical slot interval between the PSFCH transmission occasion and a last slot within the first feedback window,

a minimum physical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions in the first set within the first feedback window,

a first logical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions in the first set within the first feedback window,

a second physical slot interval between the PSFCH transmission occasion and a starting slot within the first feedback window,

a maximum physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window, or

a second logical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window.
The method of claim 2, wherein the time interval comprises at least one of the following:

a first physical symbol interval between the PSFCH transmission occasion and a last symbol within the first feedback window,

a first minimum physical symbol interval between the PSFCH transmission occasion and a starting symbol of a last one of the candidate PSSCH reception occasions in the first set within the first feedback window,

a second minimum physical symbol interval between the PSFCH transmission occasion and a last symbol of the candidate PSSCH reception occasions in the first set within the first feedback window,

a second physical symbol interval between the PSFCH transmission occasion and a starting symbol within the first feedback window,

a first maximum physical symbol interval between the PSFCH transmission occasion and a starting symbol of the candidate PSSCH reception occasions in the first set within the first feedback window, or

a second maximum physical symbol interval between the PSFCH transmission occasion and a last symbol of a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window.
The method of claim 2, wherein the time interval is between the PSFCH transmission occasion and a first timing, wherein the first timing comprises at least one of the following:

a last slot or symbol within the first feedback window,

a last slot or symbol in a resource pool within the first feedback window,

a last one of the candidate PSSCH reception occasions in the first set within the first feedback window,

a starting slot or symbol within the first feedback window,

a starting slot or symbol in a resource pool within the first feedback window, or

a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window.
The method of claim 2, wherein the sidelink resource configuration comprises at least one of the following:

a sidelink resource pool configuration,

a sidelink channel configuration, or

a sidelink HARQ feedback configuration.
The method of claim 2, wherein determining the first feedback window comprises:

determining the first feedback window based on the length of the first feedback window and the time interval,

wherein the time interval is a first physical slot interval between the PSFCH transmission occasion and a last slot within the first feedback window, and the length of the first feedback window is a first number of physical slots.
The method of claim 2, wherein determining the first feedback window comprises:

determining the first feedback window based on the length of the first feedback window and the time interval,

wherein the time interval is a logical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions in the first set within the first feedback window, and

the length of the first feedback window is a first number of physical slots or a second number of logical slots in a resource pool.
The method of claim 2, wherein determining the first feedback window comprises:

determining the first feedback window based on the length of the first feedback window and the time interval,

wherein the time interval is a minimum physical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions in the first set within the first feedback window, and

the length of the first feedback window is a first time interval.
The method of claim 2, wherein determining the first feedback window further comprises:

determining an end of the first feedback window, wherein the end of the first feedback window comprises:

a last slot which comprises PSFCH resources before the PSFCH transmission occasion, or

a last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion.
The method of claim 13, wherein determining the first feedback window comprises:

determining the first feedback window based on the time interval and the end of the first feedback window,

wherein the time interval is a maximum physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window, and

the end of the first feedback window is the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion.
The method of claim 13, wherein determining the first feedback window comprises:

determining the first feedback window based on the time interval and the end of the first feedback window, and

wherein the time interval is a physical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window, and

the end of the first feedback window is the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion.
The method of claim 2, wherein determining the first feedback window comprises:

determining the first feedback window based on the time interval, and

wherein the time interval comprises:

a first logical slot interval between the PSFCH transmission occasion and a last one of the candidate PSSCH reception occasions in the first set within the first feedback window, and

a second logical slot interval between the PSFCH transmission occasion and a starting one of the candidate PSSCH reception occasions in the first set within the first feedback window.
The method of claim 13, wherein determining the first feedback window comprises:

determining the first feedback window based on the length of the first feedback window and the end of the first feedback window, and

wherein the length of the first feedback window is an integer multiple of a period of PSFCH resources, and

the end of the first feedback window is the last candidate PSSCH reception occasion for which corresponding sidelink HARQ feedback information can be transmitted in the PSFCH transmission occasion.
The method of claim 13, wherein determining the end of the first feedback window comprises:

determining the first feedback window based on the length of the first feedback window and the end of the first feedback window, and

wherein the length of the first feedback window is an integer multiple of a period of PSFCH resources, and

the end of the first feedback window is the last slot which comprises PSFCH resources before the PSFCH transmission occasion.
The method of any of claims 2 to 18, further comprising:

determining, based on the sidelink resource configuration, indexes of the candidate PSSCH reception occasions in the first set.
The method of claim 19, wherein generating the sidelink HARQ feedback information comprises:

generating, in an order of the indexes, the sidelink HARQ feedback information.
The method of claim 20, wherein:

determining the indexes of the candidate PSSCH reception occasions comprises:

determining the indexes in timing order of the candidate PSSCH reception occasions in the first set; and

generating the sidelink HARQ feedback information comprises:

generating, in an order of the indexes, one or more sidelink HARQ feedback bits associated with each of the candidate PSSCH reception occasions.
The method of any of claims 2 to 21, further comprising:

determining a second feedback window associated with the PSFCH transmission occasion, the second feedback window comprising a second set of candidate PSSCH reception occasions, the first and second sets of candidate PSSCH reception occasions being in different sidelink resource pools, resources block (RB) sets, sidelink bandwidth parts (BWPs) or sidelink carriers.
The method of claim 22, further comprising:

determining, based on the sidelink resource configuration, indexes of the candidate PSSCH reception occasions in the second set, and

generating, in an order of the indexes, sidelink HARQ feedback information associated with the candidate PSSCH reception occasions in the second set.
The method of claim 22, wherein generating the sidelink HARQ feedback information comprises:

generating sidelink HARQ feedback information associated with the candidate PSSCH reception occasions in the first and second sets in an order of indexes of at least one of the following: the sidelink resource pools, the RB sets, the BWPs or the sidelink carriers.
The method of claim 2, further comprising:

determining the length of the first feedback window and the time interval based on at least one of the following:

pre-definition,

configuration,

pre-configuration,

an indication received from a second terminal device transmitting PSSCH, or

the sidelink resource configuration.
A terminal device, comprising:

a processor; and

a memory coupled to the processor and storing instructions thereon, the instructions, when executed by the processor, causing the terminal device to perform the method according to any of claims 1-25.
A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor of a device, causing the device to carry out the method according to any of claims 1-25.