Terminal device and method

Abstract

The embodiments of the present disclosure relate to a method, an apparatus, and a computer-readable medium for communication. According to the embodiments of the present disclosure, a first terminal device transmits a sidelink configuration to a set of terminal devices. The sidelink configuration indicates that one sidelink transmission corresponds to a set of sidelink feedback reception opportunities, and also indicates that a type of sidelink feedback for the sidelink transmission is NACK-only. The first terminal device transmits the set of sidelink transmissions to the set of terminal devices. If no sidelink feedback is detected in a last set of sidelink feedback reception opportunities among the multiple sets of sidelink feedback reception opportunities, the first terminal device transmits an uplink transmission indicating an acknowledgement for the set of sidelink transmissions to a network device. In this way, reporting SL HARQ-ACK on PUCCH / PUSCH is realized when multiple PSFCHs are associated to one PSSCH transmission.

Description

[Technical field]

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to methods, apparatus and computer-readable media for communications. [Background technology]

[0002] To improve communication performance, some techniques have been proposed. For example, device-to-device (D2D) / sidelink communication has been proposed. Sidelink is a special communication mechanism between devices without eNB. In some cases, resources for sidelink communication may be in unlicensed bands. Sidelink in unlicensed spectrum or bands (SL-U) is an important topic in Release 18 of the 3rd Generation Partnership Project (3GPP). The scheme of SL-U should be based on New Radio (NR) sidelink and NR-U. Sidelink Hybrid Automatic Repeat Request (HARQ) feedback information associated with sidelink data communication should be reported in feedback channel resources to the terminal device transmitting the sidelink data transmission. The feedback channel resources are dedicated resources for sidelink HARQ feedback in the sidelink resource pool. To ensure the performance of sidelink HARQ feedback, more feedback channel resources should be provided in SL-U. Summary of the Invention [Problem to be solved by the invention]

[0003] Generally, the exemplary embodiments of the present disclosure provide a solution for communication. [Means for solving the problem]

[0004] In a first aspect, a communication method is provided, comprising: transmitting, in a first terminal device, a sidelink configuration to a set of terminal devices; transmitting a set of sidelink transmissions to the set of terminal devices; and, according to a determination that no sidelink feedback is received in a last set of sidelink feedback reception opportunities of a plurality of sets of sidelink feedback reception opportunities associated with the set of sidelink transmissions, transmitting an uplink transmission to a network device indicating an acknowledgement for the set of sidelink transmissions. The sidelink configuration indicates that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities and also indicates that a type of sidelink feedback for the sidelink transmissions is NACK-only.

[0005] In a second aspect, a method of communication is provided, comprising: receiving, at a second terminal device, a sidelink configuration from a first terminal device; and receiving a set of sidelink transmissions from the first terminal device, the sidelink configuration indicating that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities and also indicating that a type of sidelink feedback for the sidelink transmissions is NACK-only.

[0006] In a third aspect, a terminal device is provided. The terminal device includes a processor unit and a memory, coupled to the processor unit, on which instructions are stored. The instructions, when executed by the processor unit, cause the terminal device to perform operations. The operations include: transmitting a sidelink configuration to a set of terminal devices; transmitting a set of sidelink transmissions to the set of terminal devices; and transmitting, according to a determination that no sidelink feedback is received in a last set of sidelink feedback reception opportunities of a plurality of sets of sidelink feedback reception opportunities associated with the set of sidelink transmissions, an uplink transmission indicating an acknowledgement for the set of sidelink transmissions to a network device. The sidelink configuration indicates that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities and also indicates that a type of sidelink feedback for the sidelink transmission is NACK-only.

[0007] In a fourth aspect, a terminal device is provided. The terminal device includes a processor unit and a memory, coupled to the processor unit, having instructions stored thereon. The instructions, when executed by the processor unit, cause the terminal device to perform operations. The operations include receiving a sidelink configuration from a first terminal device and receiving a set of sidelink transmissions from the first terminal device. The sidelink configuration indicates that a sidelink transmission corresponds to a set of sidelink feedback reception opportunities and also indicates that a type of sidelink feedback for the sidelink transmissions is NACK-only.

[0008] In a fifth aspect, there is provided a computer readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to the first or second aspect.

[0009] Other features of the present disclosure will become readily apparent from the following description. [Brief description of the drawings]

[0010] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of some exemplary embodiments of the present disclosure in the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a communication environment in which embodiments of the present disclosure may be implemented. [Diagram 2] FIG. 1 is a schematic diagram of a communication environment in which embodiments of the present disclosure may be implemented. [Diagram 3] 1 illustrates a signaling flow of communication according to some embodiments of the present disclosure. [Figure 4] 1 shows a schematic diagram of a slot structure according to some embodiments of the present disclosure. [Diagram 5] 1 shows a schematic diagram of a slot structure according to some embodiments of the present disclosure. [Figure 6] 1 shows a schematic diagram of a slot structure according to some embodiments of the present disclosure. [Figure 7A] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 7B] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 7C] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 7D] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 7E] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 7F] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 7G] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 8A] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 8B] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 8C] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 8D] 1 illustrates an example of a timing line between sidelink data transmission in a PSSCH and PSFCH resources in accordance with some embodiments of the present disclosure. [Figure 9A] 1 illustrates an example of PSFCH resource allocation according to some embodiments of the present disclosure. [Figure 9B] 1 illustrates an example of PSFCH resource allocation according to some embodiments of the present disclosure. [Figure 9C] 1 illustrates an example of PSFCH resource allocation according to some embodiments of the present disclosure. [Figure 9D] 1 illustrates an example of PSFCH resource allocation according to some embodiments of the present disclosure. [Figure 9E] 1 illustrates an example of PSFCH resource allocation according to some embodiments of the present disclosure. [Figure 10] 1 is a flow chart of an exemplary method according to an embodiment of the present disclosure. [Figure 11] 1 is a flow chart of an exemplary method according to an embodiment of the present disclosure. [Figure 12] FIG. 1 is a schematic block diagram of an apparatus suitable for practicing embodiments of the present disclosure.

[0011] Throughout the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The principles of the present disclosure will be described with reference to some exemplary embodiments. It should be understood that these embodiments are merely described for illustrative purposes to aid those skilled in the art in understanding and implementing the present disclosure, and do not imply any limitations on the scope of the present disclosure. The present disclosure described herein can be implemented in a variety of ways other than those described below.

[0013] In the following description and claims, unless defined otherwise, all technical and scientific terms used have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0014] In this specification, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include user equipment (UE), personal computers, desktops, mobile phones, cell phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, Ultra-Reliable Low Latency Communication (URLLC) devices, Internet of Everything (IoE) devices, Machine Type Communication (MTC) devices, vehicle-mounted devices for V2X communication (where X means pedestrian, vehicle or infrastructure / network), devices for Integrated Access and Backhaul (IAB), spacecraft or aircraft in Non-Terrestrial Networks (NTN) including High Altitude Platforms (HAP) and satellites, including Unmanned Aerial Systems (UAS), and Extended Reality (XR) including different types of reality such as Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR). Examples of such devices include, but are not limited to, a Reality (UE) device, an unmanned aerial vehicle (UAV) that does not require a human pilot, commonly known as a drone, a device on a high speed train (HST), an imaging device such as a digital camera, a sensor, a gaming device, a music storage and playback device, or an Internet device that allows wireless or wired Internet access and browsing. A "terminal device" may also have multicast / broadcast capabilities to support public safety and mission critical, V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, wireless software distribution, group communication, and IoT applications. Also, one or more subscriber identity modules (SIMs) may be incorporated, known as multi-SIM. The term "terminal device" may be used interchangeably with UE, mobile station, subscriber equipment, mobile terminal, user terminal, or wireless device. In the following description, the terms "terminal device", "communication device", "terminal", "user terminal", and "UE" may be used interchangeably.

[0015] A terminal device or a network device may have artificial intelligence (AI) or machine learning capabilities, typically including models that can be used to learn from a large amount of data collected for a specific function and predict some information.

[0016] The terminal device or network device may function in multiple frequency ranges, e.g., FR1 (410 MHz-7125 MHz), FR2 (24.25 GHz-71 GHz), higher than 100 GHz, Terahertz (THz), etc. Furthermore, it can function in licensed / unlicensed / shared spectrum. The terminal device may have multiple connections with the network device in a multi-radio dual connectivity (MR-DC) application scenario. The terminal device or network device can function in full duplex, flexible duplex, and cross division duplex modes.

[0017] The term "network device" refers to a device capable of providing or hosting a cell or coverage through which terminal devices can communicate. Examples of network devices include, but are not limited to, a Node B (NodeB or NB), an Evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a transmit / receive 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), etc.

[0018] In one embodiment, the terminal device may be connected to 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 may be a secondary node. The first network device and the second network device may use different radio access technologies (RATs). In one embodiment, the first network device may be a first RAT device, and the second network device may be a second RAT device. In one embodiment, the first RAT device is an eNB, and the second RAT device is a gNB. Information related to the different RATs may be transmitted to the terminal device from at least one of the first network device and the second network device. In one embodiment, the first information may be transmitted from the first network device to the terminal device, and the second information may be transmitted from the second network device directly to the terminal device or via the first network device. In one embodiment, information related to the configuration of the terminal device set by the second network device may be transmitted from the second network device via the first network device. Information related to the reconfiguration of the terminal device set by the second network device may be transmitted from the second network device directly to the terminal device or via the first network device.

[0019] Communications discussed herein may conform to any suitable standard, including, but not limited to, New Radio Access (NR), Long Term Evolution (LTE), LTE Evolution (LTE-Evolution), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), cdma2000, Global System for Mobile Communications (GSM), and the like. Furthermore, communications may be performed according to any currently known or future developed generation of communications protocols. Examples of communications protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.85G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G), and sixth generation (6G) communications protocols. The techniques described herein may be used for the above wireless networks and radio technologies as well as other wireless networks and radio technologies. The embodiments of the present disclosure may be performed according to any generation of communication protocols now known or developed in the future. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

[0020] As used herein, the term "circuitry" may refer to hardware circuits and / or combinations of hardware circuits and software. For example, a circuit may be a combination of analog and / or digital hardware circuits and software / firmware. As a further example, a circuit may be any portion of a hardware processor with software, such as a digital signal processor, software, and memory that work together to perform various functions on a device, such as a terminal device or a network device. In yet another example, a circuit may be a hardware circuit and / or processor, such as a microprocessor or a portion of a microprocessor, that requires software / firmware for operation, but the software may not be present when not required for operation. As used herein, the term circuitry also encompasses merely a hardware circuit or processor, or a portion of a hardware circuit or processor, and its (or their) accompanying software and / or firmware implementations.

[0021] 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 "comprising" and variations thereof are intended to be open-ended, meaning "including, but not limited to." The term "based on" is intended to mean "based at least in part on." The terms "one embodiment" and "embodiment" are intended to mean "at least one embodiment." The term "another embodiment" is intended to mean "at least one other embodiment."

[0022] The terms "first", "second", etc. may refer to different objects or the same object. The following content may include other definitions, both explicit and implicit. In some embodiments, the terms "first", "second", etc. may be used to distinguish between different objects, elements, etc. For example, the first number and the second number referred to in the embodiments of the present disclosure may refer to different numbers. It should be understood that in some embodiments, the first number and the second number may have the same value, and in some other embodiments, the first number and the second number may have different values. In some other embodiments, the terms "first", "second", etc. may represent an ordered position of an element or object in a plurality of elements or objects. For example, the term "first sidelink feedback reception opportunity" as used herein refers to a first sidelink feedback reception opportunity in the time domain. A person skilled in the art should understand the exact meaning of the terms "first", "second", etc. according to the context of the description.

[0023] In some instances, values, procedures, or devices are referred to as "optimum," "lowest," "highest," "minimum," "maximum," etc. It is understood that such descriptions are intended to indicate choices among multiple functional alternatives that may be used, and that such choices are not necessarily better, smaller, higher, or more preferred than other choices.

[0024] As mentioned above, the resources for sidelink communication may be in an unlicensed spectrum. According to some prior art, the resources for sidelink communication may be scheduled by a network device, which is referred to as mode 1. Meanwhile, the resources for sidelink communication may be determined by the UE itself, which is referred to as mode 2. FIG. 1 shows an example schematic diagram of a system in which inter-UE coordination for sidelink UE is performed between a pair of UEs. As shown in FIG. 1, UE 101-1 and UE 101-2 may perform sidelink communication with each other, and each UE may operate as either a transmitting (TX) UE or a receiving (RX) UE. For example, when UE 101-2 operates as a RX UE, UE 101-2 may provide a set of resources to its peer UE, i.e., TX UE 110-1, when performing inter-UE coordination. In this example, UE 101-2 is referred to as an assisting UE, and UE 101-1 is referred to as an assisted UE. As used herein, a "TX UE" may refer to a UE that can transmit data to other UEs when performing sidelink communication with the other UEs. As used herein, a "RX UE" may refer to a UE that can receive data from other UEs when performing sidelink communication with the other UEs.

[0025] According to the prior art, for a physical sidelink shared channel (PSSCH) transmission of SL configuration grant type 1 or type 2 by a UE within a certain period, the UE generates one hybrid automatic repeat request acknowledgement (HARQ-ACK) information bit in response to a physical sidelink feedback channel (PSFCH) reception and multiplexes it in a physical uplink control channel (PUCCH) transmission opportunity that is after the last time resource in a set of time resources. For a PSSCH transmission scheduled by DCI format 3_0, the UE generates HARQ-ACK information in response to a PSFCH reception and multiplexes it in a PUCCH transmission opportunity that is after the last time resource in a set of time resources provided by DCI format 3_0. For one or more PSFCH reception opportunities associated with SCI format 2-B or SCI format 2-A with a cast type indicator field value of "11", the UE generates an ACK if it determines that there is no PSFCH reception for the last PSFCH reception opportunity among several PSFCH reception opportunities corresponding to the PSSCH transmission.

[0026] Furthermore, according to some prior art, one PSSCH can correspond to multiple PSFCH transmissions. However, this may cause some unexpected problems. For example, if multiple PSFCHs are associated with one PSSCH transmission and the UE generates an ACK / NACK based on the last PSFCH reception opportunity, the ACK / NACK may not be accurate because some PSFCH receptions are omitted.

[0027] In an embodiment, a solution regarding sidelink feedback is proposed. According to an embodiment of the present disclosure, a first terminal device transmits a sidelink configuration to a set of terminal devices. The sidelink configuration indicates that one sidelink transmission corresponds to a set of sidelink feedback reception opportunities and also indicates that the type of sidelink feedback for the sidelink transmission is NACK-only. The first terminal device transmits the set of sidelink transmissions to the set of terminal devices. The first terminal device monitors sidelink feedback for the set of sidelink transmissions in a number of sidelink feedback reception opportunities. If no sidelink feedback is detected in the last set of sidelink feedback reception opportunities among the number of sidelink feedback reception opportunities, the first terminal device transmits an uplink transmission indicating an acknowledgement for the set of sidelink transmissions to the network device. In this way, reporting SL HARQ-ACK on PUCCH / PUSCH is realized when multiple PSFCHs are associated to one PSSCH transmission.

[0028] 2 shows a schematic diagram of a communication system in which embodiments of the present disclosure can be implemented. The communication system 100, which is part of a communication network, includes terminal devices 110-1, 110-2, ..., 110-N, which may be collectively referred to as "terminal devices 110." The number N may be any suitable integer. The terminal devices 110 may communicate with each other via sidelinks.

[0029] The communication system 100 further includes a network device. In the communication system 100, the network device 120 and the terminal device 110 can communicate data and control information with each other. The number of terminal devices shown in FIG. 1 is provided for illustrative purposes and is not intended to imply any limitation.

[0030] Communications in the communication system 100 may be implemented according to any suitable communication protocol, including, but not limited to, cellular communication protocols such as first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), and fifth generation (5G), wireless local network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, and / or any other protocols now known or developed in the future. Furthermore, communications may utilize any suitable wireless communication technology, including, but not limited to, code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple-input multiple-output (MIMO), orthogonal frequency division multiple access (OFDMA), and / or any other technology now known or developed in the future.

[0031] The embodiments of the present disclosure may be applied to any suitable scenario. For example, the embodiments of the present disclosure may be implemented in a low-capability NR device. Alternatively, the embodiments of the present disclosure may be implemented in any of the following: New Radio (NR) multiple-input and multiple-output (MIMO), NR Sidelink Enhancements, NR systems at frequencies above 52.6 GHz, NR operation extension to 71 GHz, narrow band-Internet of Things (NB-IoT) / enhanced Machine Type Communication (eMTC) in non-terrestrial networks (NTN), NTN, UE power saving enhancements, NR coverage extension, NB-IoT and LTE-MTC, Integrated Access and Backhaul (IAB), NR multicast and broadcast services, or enhanced multi-radio dual connectivity.

[0032] As used herein, the term "slot" refers to a dynamic scheduling unit. A slot contains a predetermined number of symbols. The term "downlink (DL) subslot" may refer to a virtual subslot built on an uplink (UL) subslot. A DL subslot may contain fewer symbols than a DL slot. A slot may refer to a regular slot containing a predetermined number of symbols, or a subslot containing fewer than a predetermined number of symbols.

[0033] In the following, embodiments of the present disclosure will be described in detail. Please refer to FIG. 3 first. FIG. 3 shows a signaling chart illustrating a process 300 between a terminal device and a network device according to some exemplary embodiments of the present disclosure. For discussion purposes only, the process 300 will be described with reference to FIG. 2. The process 300 may involve the terminal device 110-1, the terminal device 110-2, and the network device 120 of FIG. 2.

[0034] In some embodiments, the network device 120 may transmit (3010) a resource configuration for sidelink transmission to the terminal device 110-1. In some embodiments, the resource configuration may indicate a resource pool allocated for sidelink transmission. As used herein, the term "resource pool" may refer to a subset of subframes and resource blocks available for either sidelink transmission or sidelink reception. Sidelink communication is half-duplex and a UE may be configured with multiple transmit resource pools and multiple receive resource pools.

[0035] In some embodiments, the resource configuration may include parameters used to manage resource selection. For example, the resource configuration may indicate resources for the PSCCH value, such as subframes or resource blocks of the PSCCH. Alternatively or additionally, the resource configuration may include a time resource pattern index indicating a PSSCH subframe. In some other embodiments, the resource configuration may include a resource allocation parameter indicating a PSSCH resource block.

[0036] In some embodiments, the resource configuration may indicate a first number of sidelink feedback reception opportunities in a set of sidelink feedback reception opportunities. In other words, the resource configuration may indicate that one sidelink transmission can correspond to a first number of sidelink feedback reception opportunities. For example, if the first number is M, this means that one sidelink transmission is associated with M sidelink feedback reception opportunities. With reference to Figure 4, if PSSCH 420-1 is transmitted, PSFCH reception opportunities 431-1, 431-2, ... and 431-M are associated with PSSCH 420-1.

[0037] In some embodiments, the first number of sidelink feedback reception opportunities may be configured per carrier. Alternatively, the first number of sidelink feedback reception opportunities may be configured per bandwidth portion (BWP). In some other embodiments, the first number of sidelink feedback reception opportunities may be configured per resource pool. Alternatively, the first number of sidelink feedback reception opportunities may be predefined in the terminal device 110-1.

[0038] Alternatively, the terminal device 110-1 may determine (3020) a second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. For example, the terminal device 110-1 may determine the second number of sidelink feedback reception opportunities based on a traffic packet delay budget (PDB). The packet delay budget can be described as an upper limit of the time a packet may be delayed between the UE and a Policy and Charging Enforcement Function (PCEF). In this case, the second number can be reduced if the PDB is increased. In other words, a larger PDB can be associated with a smaller second number.

[0039] In another embodiment, the terminal device 110-1 may determine the second number of sidelink feedback reception opportunities based on a priority of the set of sidelink transmissions. In this case, the second number of sidelink feedback reception opportunities may be large if the set of sidelink transmissions has a high priority. In other words, a higher priority may be associated with a larger second number.

[0040] The terminal device 110-1 transmits (3030) a sidelink configuration to the terminal device 110-2. The sidelink configuration also indicates that the type of sidelink feedback for the sidelink transmission is negative acknowledgement only (NACK-only).

[0041] The sidelink configuration may indicate that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities. In some embodiments, the sidelink configuration may indicate a first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. As mentioned above, the terminal device 110-1 may determine a second number of sidelink feedback reception opportunities. In this case, the sidelink configuration may indicate the second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. For example, the sidelink configuration may indicate that there are M sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. With reference to FIG. 4, the set of PSFCH reception opportunities 431 may include PSFCH reception opportunities 431-1, 431-2, ..., and 431-M. The set of PSFCH reception opportunities 432 may include PSFCH reception opportunities 432-1, 432-2, ..., and 432-M. The set of PSFCH reception opportunities 433 may include PSFCH reception opportunities 433-1, 433-2, ..., and 433-M.

[0042] Returning to FIG. 3, the terminal device 110-1 transmits (3040) a set of sidelink transmissions to a set of terminal devices (e.g., the terminal device 110-2 shown in FIG. 3). For example, as shown in FIG. 4, the network device 120 may transmit downlink control information (DCI) 410 to the terminal device 110-1. The DCI 410 may schedule the sidelink transmissions. As shown in FIG. 4, the terminal device 110-1 may transmit PSSCHs 420-1, 420-2, 420-3. The PSSCHs 420-2, 420-3 may be repetitions of the PSSCH 420-1. It should be noted that the number of PSSCHs is merely an example.

[0043] In some embodiments, the time gap between two adjacent sidelink transmissions in the set of sidelink transmissions may include a first time gap between the end of the last symbol of a first sidelink transmission in the set of sidelink transmissions and the start of the first symbol of a first sidelink feedback reception in the set of sidelink feedback reception opportunities, a second time gap between the first symbol of the first sidelink feedback reception opportunity and the first symbol of a last sidelink feedback reception opportunity in the set of sidelink feedback reception opportunities, and a third time gap required for the reception and processing of the last sidelink feedback and preparation of a sidelink retransmission. With reference to Figure 5, the time gap between PSSCH 420-1 and 420-2 may include a time gap 510, a time gap 520, and a time gap 530. The time gap 510 may be the time gap between the end of the last symbol of the PSSCH transmission 420-1 on the first resource and the start of the first symbol of the corresponding first PSFCH reception 431-1 as determined by sl-MinTimeGapPSFCH and sl-PSFCH-Period for the pool of resources within the M PSFCH reception opportunities. The time gap 520 may be the time gap between the first symbol of the first PSFCH receiving opportunity 431-1 and the first symbol of the last PSFCH receiving opportunity 431-M. The time gap 530 may be the time required for the last PSFCH receiving opportunity 431-M and processing and sidelink retransmission preparation, including the required physical channel multiplexing and any TX-RX / RX-TX switching time.

[0044] In some embodiments, the time gap between the start of a PSCCH / PSSCH slot and the start symbol of the last PSFCH associated with the preceding PSCCH / PSSCH slot in the same CG or in the set of resources indicated by one DCI must be greater than a predefined duration T_m (e.g., time gap 530). T_m may include reception of the PSFCH and processing including the required physical channel multiplexing and any TX-RX / RX-TX switching time and sidelink retransmission preparation.

[0045] As mentioned above, the sidelink configuration indicates that the type of sidelink feedback is only NACK. In this case, if the terminal device 110-2 cannot decode or receive the sidelink transmission from the terminal device 110-1, the terminal device 110-2 may transmit a NACK (3050). Alternatively, if the terminal device 110-2 successfully decodes or receives the sidelink transmission from the terminal device 110-1, the terminal device 110-2 may not transmit feedback to the terminal device 110-1.

[0046] 4, if the terminal device 110-2 cannot decode or receive the PSSCH 420-1, the terminal device 110-2 may transmit a NACK on any one of the PSFCH reception opportunities 431-1, 431-2, ..., and 431-M. In some embodiments, the sidelink configuration may further indicate a scheme for reporting ACK / NACK on multiple resources. For example, the sidelink configuration may indicate that sidelink feedback for a sidelink transmission needs to be transmitted on each set of sidelink feedback reception opportunities. In this case, if the terminal device 110-2 cannot decode or receive the PSSCH 420-1, the terminal device 110-2 may transmit a NACK on all of the PSFCH reception opportunities 431-1, 431-2, ..., and 431-M. Similarly, if the terminal device 110-2 cannot decode or receive the PSSCH 420-2, the terminal device 110-2 may transmit a NACK in any one or all of the PSFCH reception opportunities 432-1, 432-2, ..., and 432-M. If the terminal device 110-2 cannot decode or receive the PSSCH 420-3, the terminal device 110-2 may transmit a NACK in any one or all of the PSFCH reception opportunities 433-1, 433-2, ..., and 433-M. Schemes for reporting ACK / NACK on multiple resources are described in more detail below.

[0047] In some embodiments, the terminal device 110-2 may perform listen-before-talk (LBT) or clear channel assessment (CCA) before transmitting the NACK. As used herein, the term "listen-before-talk (LBT)" may refer to a technique used in wireless communication where a wireless transmitter senses its wireless environment before starting transmission. A wireless device may use LBT to find a network in which it can operate or to find a free wireless channel to operate on. As used herein, the term "clear channel assessment (CCA)" refers to a technique to evaluate the RF medium. CCA involves listening to RF transmissions in the physical layer radio. A CCA threshold is used when listening to the RF medium. For example, energy detection may be used in CCA. An energy detection (ED) threshold is used to detect other types of RF transmissions during CCA. If the energy detected on the channel is less than the energy detection threshold, the channel may be considered available for performing transmission. If the energy detected on the channel is greater than the energy detection threshold, the channel may be considered busy. For example, the terminal device 110-2 may determine the result of the LBT (or CCA) in the unlicensed spectrum band based on the difference between the energy of the sidelink transmission in the unlicensed spectrum band and the measured energy of the LBT (or CCA). For example, if the difference is within a threshold difference, the terminal device 310-1 may be deemed to have successfully acquired the COT in the LBT. In other words, if the energy detection in the LBT is similar to the calculated energy level of the monitored SL-U transmission, the COT initiator may be deemed to have successfully acquired the COT in the LBT. Alternatively, if the energy detection value of the LBT is higher than the calculated energy level of the monitored SL-U transmission by more than a set threshold, the LBT may be deemed to have failed.

[0048] If the LBT is successful, the terminal device 110-2 may transmit a NACK to the terminal device 110-1 (3050). Alternatively, if the LBT is unsuccessful, the terminal device 110-2 may transmit an indication of LBT failure to the terminal device 110-1 (3060). For example, in some embodiments, the terminal device 110-2 may transmit an SCI indicating LBT failure to the terminal device 110-1. In some other embodiments, the terminal device 110-2 may transmit a PSSCH or PSCCH indicating LBT failure to the terminal device 110-1. Alternatively, the terminal device 110-2 may transmit a media access control (MAC) control element (CE) indicating LBT failure to the terminal device 110-1. In other embodiments, the terminal device 110-2 may transmit PC5-radio resource control (RRC) signaling indicating LBT failure to the terminal device 110-1.

[0049] The terminal device 110-1 may monitor 3070 sidelink feedback for a set of sidelink transmissions at a plurality of sets of sidelink feedback reception opportunities. For example, referring to FIG. 4, the terminal device 110-1 may monitor sidelink feedback for PSSCH 420-1 at PSFCH reception opportunities 431-1, 431-2, ..., and 431-M. The terminal device 110-1 may monitor sidelink feedback for PSSCH 420-2 at PSFCH reception opportunities 432-1, 432-2, ..., and 432-M. The terminal device 110-1 may monitor sidelink feedback for PSSCH 420-3 at PSFCH reception opportunities 433-1, 433-2, ..., and 433-M.

[0050] The terminal device 110-1 transmits (3080) an uplink transmission to the network device 120. The uplink transmission indicates an ACK or NACK for the set of sidelink transmissions. In some embodiments, the uplink transmission may be transmitted in a slot with a slot offset. In this case, the slot may be the slot of the first sidelink feedback reception opportunity in the last set of sidelink feedback reception opportunities, and the slot offset may be larger than the number of slots occupied by the last set of sidelink feedback reception opportunities. With reference to FIG. 6, the first sidelink feedback reception opportunity 433-1 in the set of sidelink feedback reception opportunities 433 is in slot 610. The terminal device may transmit an uplink transmission in slot 630. In this case, the time gap 620 between slots 610 and 630 may include k slots. In other words, for some PSFCH reception opportunities with respect to the slots for PUCCH transmission, the terminal device 110-1 may provide the generated HARQ-ACK information in a PUCCH transmission in slot n+k. where slot n is the slot of the first PSFCH reception opportunity associated to the last PSCCH / PSSCH resource of the set of resources indicated in the dynamic or configuration grant, and k is the number of slots indicated by the PSFCH-to-HARQ_feedback timing indicator field (if any) in the DCI format indicating the slot for PUCCH transmission to report HARQ-ACK information, or k is provided by sl-PSFCH-ToPUCCH for transmissions scheduled by the DCI format or for SL configuration type 2 or by sl-PSFCH-toPUCCH-CG-Type1 for SL configuration grant type 1. k=0 corresponds to the last slot for PUCCH transmission that overlaps with the last PSFCH reception opportunity, assuming that the start of the sidelink frame is the same as the start of the downlink frame.

[0051] If no sidelink feedback is received in the last set of sidelink feedback reception opportunities among the multiple sets of sidelink feedback reception opportunities associated with the set of sidelink transmissions, the terminal device 110-1 transmits an uplink transmission indicating an acknowledgement for the set of sidelink transmissions (3080). With reference to FIG. 4, if the terminal device 110-1 determines that there is no PSFCH reception (i.e., no NACK from another terminal device) for all / each of the last M PSFCH reception opportunities (i.e., set 433 of PSFCH reception opportunities) among the multiple PSFCH reception opportunities corresponding to PSSCH 420-1, 420-2, 420-3, the terminal device 110-1 may generate an ACK. In this case, the uplink transmission 440 may indicate an ACK. The multiple PSFCH receiving opportunities may include PSFCH receiving opportunities 431-1, 431-2, ..., 431-M, PSFCH receiving opportunities 432-1, 432-2, ..., 432-M, and PSFCH receiving opportunities 433-1, 433-2, ..., 433-M.

[0052] Alternatively, in some embodiments, the terminal device 110-1 transmits an uplink transmission indicating a NACK for the set of sidelink transmissions if at least one sidelink feedback was received in the last set of sidelink feedback reception opportunities (3080). With reference to FIG. 4, the terminal device 110-1 may generate a NACK if the terminal device 110-1 detects one or more PSFCH receptions in the last M PSFCH reception opportunities (i.e., set of PSFCH reception opportunities 433) of the multiple PSFCH reception opportunities corresponding to PSSCHs 420-1, 420-2, 420-3. In this case, the uplink transmission 440 may indicate a NACK.

[0053] As mentioned above, the terminal device 110-2 may transmit an indication of LBT failure. In this case, in some embodiments, the terminal device 110-1 may transmit an uplink transmission indicating a NACK for the set of sidelink transmissions. Alternatively, the uplink transmission may indicate HARQ-ACK information pre-configured by the network device 120. In other words, to report HARQ-ACK information in the uplink corresponding to one or more PSSCH transmissions, the terminal device 110-1 may generate HARQ-ACK information with contents instructed by a higher layer when the terminal device 110-1 is notified of consecutive LBT / access failures of the associated receiving terminal device. The priority value of the HARQ-ACK information may be the same as the priority value of the PSSCH transmission. In some other embodiments, if the terminal device 110-1 does not receive a PSFCH in any PSFCH reception opportunity associated with a PSSCH transmission in the resources provided by DCI format 3_0 or the resources of the configuration grant in one period of provided resources, and a PUCCH resource is provided to the terminal device 110-1 to report HARQ-ACK information for that PSFCH and consecutive LBT / access failures of the associated receiving terminal device are indicated, the terminal device 110-1 may generate a NACK. The priority value of the NACK is the same as the priority value of the PSSCH transmission.

[0054] As mentioned above, the sidelink configuration may indicate a scheme for reporting ACK / NACK on multiple resources. If only NACK is selected and multiple PSFCH transmission / reception opportunities are associated with one PSSCH transmission / reception, a first scheme may be selected in which NACK feedback is transmitted on all available PSFCH resources. In this case, the sidelink configuration may indicate the first scheme. In other words, if the first scheme is selected / enabled, the terminal device 110-1 may select positive-negative acknowledgement or negative-only acknowledgement. Alternatively, if positive-negative acknowledgement is selected and multiple PSFCH transmission / reception opportunities are associated with one PSSCH transmission / reception, either the first scheme or the second scheme may be selected. In the second scheme, when reporting A / N, the Rx terminal device may not transmit on the remaining available PSFCH resources. In other words, if the second scheme is selected / enabled, the terminal device 110-1 may select positive-negative acknowledgement. In some embodiments, the first scheme or the second scheme may be configured by the network device 120.

[0055] As described above, according to the first scheme, the NACK feedback can be transmitted on all available PSFCH resources. For example, FIG. 8C shows an example of a timing line between sidelink data transmission in the PSSCH and the PSFCH resources. In the example of FIG. 8C, PSFCH period=1, K=2, and M=4. The terminal device 110-1 may have up to four opportunities to transmit HARQ feedback information. The up to four periods include PSFCH#1, PSFCH#2, PSFCH#3, and PSFCH#4. Because the channel access procedure of the terminal device 110 failed on PSFCH#1, the terminal device 110-1 does not transmit HARQ feedback information. After the channel access procedure is successful, the terminal device 110-1 transmits HARQ feedback information on each of PSFCH#2, PSFCH#3, and PSFCH#4. In other words, the terminal device 110-1 may attempt to transmit HARQ feedback information on all available PSFCH resources. It should be noted that the terminal device 110-1 may perform the channel access procedure on each of PSFCH#2, PSFCH#3, and PSFCH#4, or may perform it on only PSFCH#2. In some embodiments, the terminal device 110-1 may transmit HARQ feedback information on a first feedback channel resource among the third number of feedback channel resources after the channel access procedure is successful. In such an embodiment, unnecessary retransmission of HARQ feedback information can be reduced. This will be described with reference to FIG. 8D.

[0056] Alternatively, according to the second scheme, when reporting A / N, the Rx terminal device may not transmit in the remaining available PSFCH resources. For example, FIG. 8D shows an example of a timing line between sidelink data transmission in the PSSCH and the PSFCH resources. In the example of FIG. 8D, PSFCH period=1, K=2, and M=4. The terminal device 110-1 may have up to four opportunities to transmit HARQ feedback information. The up to four periods include PSFCH#1, PSFCH#2, PSFCH#3, and PSFCH#4. Since the channel access procedure of the terminal device 110-1 failed in PSFCH#1, the terminal device 110-1 does not transmit HARQ feedback information. After the channel access procedure is successful, the terminal device 110-1 transmits HARQ feedback information in the first PSFCH resource, i.e., PSFCH#2. The terminal device 110-1 does not transmit HARQ feedback information in the subsequently available PSFCH#3 and PSFCH#4.

[0057] According to the embodiment of Fig. 3, in case one sidelink transmission is associated with multiple sidelink feedback reception opportunities, the terminal device needs to monitor the last set of sidelink feedback reception opportunities, and generates ACK / NACK for the sidelink transmission based on PSFCH reception in the last set of sidelink feedback reception opportunities and reports HARQ feedback information to the base station taking into account the LBT failure information, the usage of multiple PSFCH resources and the gap between PSFCH and PUCCH / PUSCH. This removes the error cases in reporting SL HARQ-ACK on PUCCH / PUSCH when multiple PSFCHs are associated to one PSSCH transmission.

[0058] Several embodiments of how PSFCH resources may be allocated (eg, in an unlicensed spectrum) are described below.

[0059] In some embodiments, the terminal device 110-1 may determine a third number of feedback channel resources, the third number of feedback channel resources being for HARQ feedback information associated with sidelink data transmission over subchannels in the slot, each of the third number of feedback channel resources including a fourth number of consecutive symbols in the slot and a fifth number of RBs.

[0060] In some embodiments, the HARQ feedback information may include a positive acknowledgement (ACK or A) or a negative acknowledgement (NACK or N). Therefore, in the following, the HARQ feedback information is also referred to as A / N for short.

[0061] In some embodiments, terminal device 110-1 may transmit HARQ feedback information on at least one of the first number of feedback channel resources.

[0062] In some embodiments, terminal device 110-1 may determine the third number of feedback channel resources based on at least one of a preconfiguration or a configuration.

[0063] In some embodiments, the third number may be configured or preconfigured by a network node device, such as network device 120 as shown in Figure 2. In some embodiments, the third number is configured or preconfigured using RRC signaling, such as a System Information Block (SIB) message, an RRC Reconfiguration message, or the like.

[0064] In some embodiments, the terminal device 110-1 may determine a third number of feedback channel resources for at least one of a sidelink resource pool, a bandwidth portion (BWP), an RB set, or a carrier.

[0065] In embodiments where the third number is configured per sidelink resource pool, terminal devices serving a sidelink resource pool should have a common understanding of the candidate PSFCH resources to avoid resource contention between sidelink transmissions.

[0066] In the embodiment where the third number is set per BWP, RB set or carrier, a further advantage can be obtained: terminal devices functioning in a BWP, RB set or carrier should have a common Tx / Rx switching GP and avoid sidelink signal reception loss based on the GP.

[0067] In some embodiments, the fourth number may be equal to or greater than three.

[0068] In some embodiments, terminal device 110-1 may determine the fifth number based on at least one of the following: The third number The fourth number The number of RBs in the resource pool used for feedback channel resources The number of slots in the resource pool used for feedback channel resources The number of subchannels in the resource pool Feedback channel resource duration The number of slots in the resource pool, or Number of interlaces in the resource pool

[0069] In some embodiments, terminal device 110-1 may determine the fifth number as the number of RBs in the resource pool configured for the feedback channel resource divided by the product of the third number, the number of subchannels in the resource pool, and the duration of the feedback channel resource. For example, terminal device 110-1 may determine the fifth number based on:

number

[0070] Alternatively, the terminal device 110-1 may determine the fifth number by rounding down the number of RBs in the resource pool configured for the feedback channel resource divided by the product of the first number, the number of subchannels in the resource pool, and the duration of the feedback channel resource. For example, the terminal device 110-1 may determine the fifth number based on the following:

number

[0071] In some embodiments, interlace-based RB allocation may be used in unlicensed spectrum to meet the requirement of occupied channel bandwidth (OCB). Several non-contiguous PRBs may be allocated as resources for each interlace.

[0072] In some embodiments, the number of interlaces in the resource pool may be equal to the number of subchannels in the resource pool. In such embodiments, the terminal device 110-1 may determine the fifth number as the number of RBs in the resource pool configured for the feedback channel resources divided by the product of the first number, the number of interlaces in the resource pool, and the duration of the feedback channel resources. Alternatively, the terminal device 110-1 may determine the fifth number by truncating the number of RBs in the resource pool configured for the feedback channel resources divided by the product of the third number, the number of interlaces in the resource pool, and the duration of the feedback channel resources.

[0073] In embodiments where interlace-based RB allocation is used, the number of subchannels in the resource pool may be determined based on the number of interlaces in the resource pool. For example, the number of subchannels in the resource pool may be determined based on:

number

[0074] In some embodiments, M PSFCH resources are allocated to M logical consecutive slots including the PSFCH resources, i.e., one PSFCH resource is allocated to each slot. This provides multiple transmission opportunities for the terminal device 110-1 to transmit HARQ feedback information on the sidelink, thereby avoiding unnecessary retransmissions and improving transmission performance. This will be described with reference to Figures 10A to 10E.

[0075] 7A to 7E, each of the third number of feedback channel resources includes different symbols from each other. The third number of feedback channel resources includes logically consecutive symbols used for the feedback channel resources.

[0076] 7A and 7B show example timing lines between sidelink data transmissions in the PSSCH and PSFCH resources, respectively.

[0077] In the example of Figure 7A, PSFCH period = 1, K = 2, and M = 4. HARQ feedback information associated with data transmission on the PSSCH in slot #n may be transmitted on at least one of PSFCH resources #1, #2, #3, #4.

[0078] In the example of Figure 7B, PSFCH period = 2, K = 2, and M = 4. HARQ feedback information associated with data transmission on the PSSCH in slot #n may be transmitted on at least one of PSFCH resources #1, #2, #3, #4.

[0079] Compared with the legacy one-to-one resource mapping between the PSSCH and its corresponding PSFCH, the one-to-M mapping scheme provides more transmission opportunities for sidelink HARQ feedback transmission.

[0080] 7C, 7D and 7E show examples of mapping between sidelink data transmission in the PSSCH and PSFCH resources, respectively.

[0081] In the examples of Figures 7C, 7D, and 7E, the terminal device 110-1 may determine the same RB for each of the third number of feedback channel resources, i.e., the M transmission opportunities for HARQ feedback information associated with sidelink data transmissions over subchannels in a slot are assigned to the same RB in each PSFCH resource.

[0082] TIFF2025501218000005.tif25167

[0083] TIFF2025501218000006.tif51167

[0084] TIFF2025501218000007.tif75150

[0085] In some embodiments, the terminal device 110-1 may determine a fifth number of RBs for each of the first number of feedback channel resources based on the frequency hopping indication. If the frequency hopping indication is assigned as disabled, the terminal device 110-1 may determine the PSFCH resources according to the embodiments as shown in Figures 7A-7E. If the frequency hopping indication is assigned as enabled, the terminal device 110-1 may determine the PSFCH resources according to the embodiments as shown in Figures 7F and 7G. Such an embodiment further provides a frequency diversity gain.

[0086] In such an embodiment, the terminal device 110-1 may determine the frequency hopping indication based on at least one of the pre-configuration or configuration. The terminal device 110-1 may determine the frequency hopping indication for at least one of a sidelink resource pool, a BWP, an RB set, or a carrier.

[0087] 7F and 7G respectively show examples of mapping between sidelink data transmission in PSSCH and PSFCH resources. In the examples of FIG. 7F and FIG. 7G, frequency hopping indication is assigned as valid. Thus, the terminal device 110-1 may determine different RBs for each of the four feedback channel resources in slots n+2, n+3, n+4, and n+5. The terminal device 110-1 may then transmit HARQ feedback information in the corresponding PSFCH resources.

[0088] In some embodiments, the terminal device 110-1 may determine a sixth number of feedback channel resources based on configuration information. The sixth number of feedback channel resources includes a subset of the third number of feedback channel resources. The terminal device 110-1 may then transmit HARQ feedback information on at least one of the sixth number of feedback channel resources. In such embodiments, the terminal device 110-1 may receive configuration information from a communication device. The communication device may be at least one of a network node device (such as the network device 120), a control node device, or a sidelink terminal device. In such embodiments, the communication device may determine the fourth number based on a latency requirement for HARQ feedback. This will be described with reference to FIG. 8A.

[0089] 8A shows an example of a timing line between sidelink data transmission in PSSCH and PSFCH resources. In the example of FIG. 8A, with a resource pool configuration of M=4, the terminal device 110-1 may have up to four opportunities to transmit its HARQ feedback information to the Tx terminal device.

[0090] On the other hand, the allowed waiting time for receiving HARQ feedback information from the terminal device 110 is shorter than the duration of the PSFCH resource of M0. In this case, the Tx terminal device may further indicate M0 to the terminal device 110-1 so as to limit the feedback on the earliest PSFCH resource of M0 configured in the resource pool.

[0091] In such an embodiment, the terminal device 110-1 may be a terminal device paired with the communication device for sidelink unicast communication or one of the member terminal devices in the same sidelink communication group as the communication device. In such an embodiment, the communication device may determine the sixth number based on a latency requirement for HARQ feedback. In this way, the communication device transmitting the sidelink data transmission can further control and allocate available PSFCH resources for the sidelink data transmission.

[0092] In such an embodiment, terminal device 110-1 may receive the configuration information via one of PC5 radio resource control (RRC) signaling or sidelink control information.

[0093] In some embodiments, the terminal device 110-1 may determine the timing interval based on the configuration information. The timing interval starts from the sidelink data transmission. For example, the timing interval may use slots or milliseconds (ms) as a time unit. The terminal device 110-1 may then transmit HARQ feedback information on at least one of the first number of feedback channel resources that are within the timing interval. In such embodiments, the terminal device 110-1 may receive the configuration information from a communication device. The communication device may be at least one of a network node device, a control node device, or a sidelink terminal device. In such embodiments, the communication device may determine the fourth number based on a latency requirement for the HARQ feedback. In this way, the communication device may further control and allocate available PSFCH resources for sidelink data transmission. This will be described with reference to FIG. 8B.

[0094] FIG. 8B shows an example of a timing line between sidelink data transmission in PSSCH and PSFCH resources. In the example of FIG. 8B, according to a resource pool configuration of M=2, the terminal device 110-1 may have up to two opportunities to transmit its HARQ feedback information to the Tx terminal device. Meanwhile, the allowed waiting time for receiving HARQ feedback information from the terminal device 110-1 is T0=6 slots allocated by the Tx UE. In this case, the terminal device 110-1 may transmit HARQ feedback information for PSSCH transmission #1 using PSFCH resource #1, while PSFCH resource #2 is outside the duration of T0. For PSSCH transmission #2, the terminal device 110-1 may use PSFCH resources #1, #2 for transmitting HARQ feedback information at the same T0.

[0095] In such an embodiment, the terminal device 110-1 may be a terminal device paired with the communication device for sidelink unicast communication or one of the member terminal devices in the same sidelink communication group as the communication device.

[0096] In such an embodiment, terminal device 110-1 may receive the configuration information via one of PC5 radio resource control (RRC) signaling or sidelink control information.

[0097] In some embodiments, the terminal device 110-1 may transmit HARQ feedback information in each of the feedback channel resources after the channel access procedure is successful. In other words, the terminal device 110-1 may attempt to transmit HARQ feedback information in all available PSFCH resources. Such an embodiment may improve the performance of HARQ feedback reception and may also be useful for sidelink transmission efficiency, as will be described with reference to FIG. 11C.

[0098] Figure 8C shows an example of a timing line between sidelink data transmission in the PSSCH and PSFCH resources, and Figure 8D shows an example of a timing line between sidelink data transmission in the PSSCH and PSFCH resources, as described above.

[0099] In some embodiments, the first number of feedback channel resources may include multiple feedback channel resources in a slot. In such embodiments, the multiple feedback channel resources may be assigned to consecutive symbols in a slot.

[0100] In some embodiments, terminal device 110-1 may determine the first number of feedback channel resources based on at least one of the first type of configuration or the second type of configuration.

[0101] In some embodiments, each of the first type of configuration and the second type of configuration exhibits at least one of the following: Feedback channel resource duration The number of symbols in a slot used for the feedback channel Allocation of symbols in slots to be used for feedback channels The number of RBs in the resource pool that will be used for the feedback channel Allocation of RBs in the resource pool to be used for the feedback channel · Slot offset for feedback channel resource period.

[0102] In the following, the first type of configuration is also referred to as a legacy PSFCH configuration or type 1 configuration, and the second type of configuration is also referred to as an additional configuration or type 2 configuration. The second type of configuration should be assigned to symbols not used for the first type of configuration. In some embodiments, the second type of configuration may be independent of the first type of configuration. If the first type of configuration and the second type of configuration are in the same slot, the symbols used for the subsets must be consecutive. Within a slot, one or more subsets may be assigned by the second type of configuration. Such an embodiment may provide a more flexible configuration for PSFCH resource allocation.

[0103] Such an embodiment will be described with reference to Figures 9A to 9E.

[0104] 9A to 9E respectively show examples of PSFCH resource allocation. In the examples of FIG. 9A to 9E, each of the third number of feedback channel resources includes a fourth number of consecutive symbols, and the fourth number is equal to 3. In the time domain, three consecutive symbols including an AGC symbol, an information symbol, and a GP symbol are used as one subset. One subset of symbols is used as a unit of PSFCH resource allocation in the time domain. One subset corresponds to a transmission occupation period of one A / N in the time domain. One subset includes multiple PSFCH resources with different RBs.

[0105] In the example of Fig. 9A, within a slot, two subsets are assigned as PSFCH resources. The two subsets use consecutive symbols. For each slot that contains PSFCH resources, the number and allocation of subsets is the same. This example can provide more resources for the PSFCH and can be combined with a 1-to-M mapping scheme to improve the performance of sidelink A / N reporting.

[0106] In the example of FIG. 9B, the terminal device 110-1 determines a first number of feedback channel resources based on a first type configuration and a second type configuration. The PSFCH period of the first type configuration is 4, and the PSFCH period of the second type configuration is 2. The terminal device 110-1 determines subsets #0, #3 of PSFCH resources based on the first type configuration. The terminal device 110-1 determines subsets #1, #2 of PSFCH resources based on the second type configuration. Each of the subsets includes three or more consecutive symbols.

[0107] In the example of FIG. 9C, the terminal device 110-1 determines a first number of feedback channel resources based on a first type configuration and a second type configuration. The PSFCH period of the first type configuration is 2, and the PSFCH period of the second type configuration is 4. The terminal device 110-1 determines subsets #1, #2, #4, and #5 of PSFCH resources based on the first type configuration. The terminal device 110 determines subsets #0 and #3 of PSFCH resources based on the second type configuration. Each of the subsets includes three or more consecutive symbols.

[0108] The example of FIG. 9D may be considered as a combination of the example of FIG. 9A and any of the examples of FIG. 7A to FIG. 7G. In the example of FIG. 9D, PSFCH period=2, K=2, and M=2. Two subsets of symbols are configured in each slot including PSFCH resources. The two subsets use consecutive symbols. The same PSFCH allocation is used for each subset in the slot. That is, the PSFCH allocation of the last 3 symbols is a repetition of the previous subset. Each subset includes one PSFCH resource for the corresponding PSSCH transmission. The terminal device 110-1 may transmit HARQ feedback information in at least one of the first PSFCH resource for subchannel #1 and the second PSFCH resource for subchannel #1 for sidelink data transmission by subchannel #1 in slot #n.

[0109] The example of Figure 9E may be considered as a combination of the example of Figure 9B or Figure 9C and any of the examples of Figures 7A to 7G. In the example of Figure 9E, PSFCH period=4, K=2, and M=3.

[0110] The terminal device 110-1 may determine a first PSFCH resource in slot #n+1 for subchannel #1 and a second PSFCH resource in slot #n+2 for subchannel #1 based on the second type configuration for sidelink data transmission via subchannel #1 in slot #n-1. Furthermore, for sidelink data transmission via subchannel #1 in slot #n-1, the terminal device 110 also determines a third PSFCH resource in slot #n+4 for subchannel #1 based on the first type configuration. In other words, for sidelink data transmission, three logically consecutive slots including the PSFCH resource are used as multiple transmission opportunities for HARQ feedback information.

[0111] In each of slots #n+1, #n+2, #n+4, there is one subset of consecutive symbols, ie, the last three symbols of each slot are used for transmitting HARQ feedback information.

[0112] 10 illustrates a flowchart of an exemplary method 1000 according to an embodiment of the present disclosure. The method 1000 may be implemented in any suitable device. For illustrative purposes only, the method 1000 may be implemented in the terminal device 110-1 illustrated in FIG. 2.

[0113] In some embodiments, the terminal device 110-1 may receive a resource configuration for sidelink transmission from the network device 120. In some embodiments, the resource configuration may indicate a resource pool allocated for the sidelink transmission.

[0114] In some embodiments, the resource configuration may include parameters used to manage resource selection. For example, the resource configuration may indicate resources for the PSCCH value, such as subframes or resource blocks of the PSCCH. Alternatively or additionally, the resource configuration may include a time resource pattern index indicating a PSSCH subframe. In some other embodiments, the resource configuration may include a resource allocation parameter indicating a PSSCH resource block.

[0115] In some embodiments, the resource configuration may indicate a first number of sidelink feedback reception opportunities in a set of sidelink feedback reception opportunities. In other words, the resource configuration may indicate that one sidelink transmission can correspond to the first number of sidelink feedback reception opportunities. For example, if the first number is M, this means that one sidelink transmission is associated to M sidelink feedback reception opportunities.

[0116] In some embodiments, the first number of sidelink feedback reception opportunities may be configured per carrier. Alternatively, the first number of sidelink feedback reception opportunities may be configured per bandwidth portion (BWP). In some other embodiments, the first number of sidelink feedback reception opportunities may be configured per resource pool. Alternatively, the first number of sidelink feedback reception opportunities may be predefined in the terminal device 110-1.

[0117] Alternatively, the terminal device 110-1 may determine the second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. For example, the terminal device 110-1 may determine the second number of sidelink feedback reception opportunities based on a traffic packet delay budget (PDB). The packet delay budget can be described as an upper limit of the time a packet may be delayed between the UE and a PCEF (Policy and Charging Enforcement Function). In this case, the second number can be reduced if the PDB is increased. In other words, a larger PDB can be associated with a smaller second number.

[0118] In another embodiment, the terminal device 110-1 may determine the second number of sidelink feedback reception opportunities based on a priority of the set of sidelink transmissions. In this case, the second number of sidelink feedback reception opportunities may be large if the set of sidelink transmissions has a high priority. In other words, a higher priority may be associated with a larger second number.

[0119] In block 1010, the terminal device 110-1 transmits a sidelink configuration to the terminal device 110-2. The sidelink configuration also indicates that the type of sidelink feedback for the sidelink transmission is NACK-only.

[0120] The sidelink configuration may indicate that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities. In some embodiments, the sidelink configuration may indicate a first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. As mentioned above, the terminal device 110-1 may determine a second number of sidelink feedback reception opportunities. In this case, the sidelink configuration may indicate the second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. For example, the sidelink configuration may indicate that there are M sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities.

[0121] In block 1020, terminal device 110-1 transmits a set of sidelink transmissions to the set of terminal devices.

[0122] In some embodiments, the time gap between two adjacent sidelink transmissions in a set of sidelink transmissions may include a first time gap between the end of the last symbol of a first sidelink transmission of the set of sidelink transmissions and the start of the first symbol of a first sidelink feedback reception of the set of sidelink feedback reception opportunities, a second time gap between the first symbol of the first sidelink feedback reception opportunity and the first symbol of the last sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, as well as a third time gap required for reception and processing of the last sidelink feedback and preparation of a sidelink retransmission.

[0123] In some embodiments, the time gap between the start of a PSCCH / PSSCH slot and the start symbol of the last PSFCH associated to the preceding PSCCH / PSSCH slot in the same CG or in the set of resources indicated by one DCI must be larger than a predefined duration T_m, which may include the reception of the PSFCH and processing including the required physical channel multiplexing and any TX-RX / RX-TX switching time and sidelink retransmission preparation.

[0124] As mentioned above, the sidelink configuration indicates that the type of sidelink feedback is only NACK. In this case, if the terminal device 110-2 cannot decode or receive the sidelink transmission from the terminal device 110-1, the terminal device 110-2 may transmit a NACK (3050). Alternatively, if the terminal device 110-2 successfully decodes or receives the sidelink transmission from the terminal device 110-1, the terminal device 110-2 may not transmit feedback to the terminal device 110-1.

[0125] In some embodiments, the terminal device 110-1 may monitor sidelink feedback for a set of sidelink transmissions at multiple sets of sidelink feedback reception opportunities.

[0126] In block 1040, the terminal device 110-1 transmits an uplink transmission to the network device 120. The uplink transmission indicates an ACK or NACK for the set of sidelink transmissions. In some embodiments, the uplink transmission may be transmitted in a slot with a slot offset. In this case, the slot may be the slot of the first sidelink feedback reception opportunity in the last set of sidelink feedback reception opportunities, and the slot offset may be larger than the number of slots occupied by the last set of sidelink feedback reception opportunities. In other words, for some PSFCH reception opportunities with respect to the slot for PUCCH transmission, the terminal device 110-1 may provide the generated HARQ-ACK information in a PUCCH transmission in slot n+k. where slot n is the slot of the first PSFCH reception opportunity associated to the last PSCCH / PSSCH resource of the set of resources indicated in the dynamic or configuration grant, and k is the number of slots indicated by the PSFCH-to-HARQ_feedback timing indicator field (if any) in the DCI format indicating the slot for PUCCH transmission to report HARQ-ACK information, or k is provided by sl-PSFCH-ToPUCCH for transmissions scheduled by the DCI format or for SL configuration type 2 or by sl-PSFCH-toPUCCH-CG-Type1 for SL configuration grant type 1. k=0 corresponds to the last slot for PUCCH transmission that overlaps with the last PSFCH reception opportunity, assuming that the start of the sidelink frame is the same as the start of the downlink frame.

[0127] If no sidelink feedback is received in the last set of sidelink feedback reception opportunities of the multiple sidelink feedback reception opportunities, the terminal device 110-1 transmits an uplink transmission indicating an acknowledgment for the set of sidelink transmissions.

[0128] Alternatively, in some embodiments, if at least one sidelink feedback was received in a last set of sidelink feedback reception opportunities of the multiple sidelink feedback reception opportunities, the terminal device 110-1 transmits an uplink transmission indicating a NACK for the set of sidelink transmissions.

[0129] As mentioned above, the terminal device 110-2 may transmit an indication of LBT failure. In this case, in some embodiments, the terminal device 110-1 may transmit an uplink transmission indicating a NACK for the set of sidelink transmissions. Alternatively, the uplink transmission may indicate HARQ-ACK information pre-configured by the network device 120. In other words, to report HARQ-ACK information in the uplink corresponding to one or more PSSCH transmissions, the terminal device 110-1 may generate HARQ-ACK information with contents instructed by a higher layer when the terminal device 110-1 is notified of consecutive LBT / access failures of the associated receiving terminal device. The priority value of the HARQ-ACK information may be the same as the priority value of the PSSCH transmission. In some other embodiments, if the terminal device 110-1 does not receive a PSFCH in any PSFCH reception opportunity associated with a PSSCH transmission in the resources provided by DCI format 3_0 or the resources of the configuration grant in one period of provided resources, and a PUCCH resource is provided to the terminal device 110-1 to report HARQ-ACK information for that PSFCH and consecutive LBT / access failures of the associated receiving terminal device are indicated, the terminal device 110-1 may generate a NACK. The priority value of the NACK is the same as the priority value of the PSSCH transmission.

[0130] As mentioned above, the sidelink configuration may indicate a scheme for reporting ACK / NACK on multiple resources. If only NACK is selected and multiple PSFCH transmission / reception opportunities are associated with one PSSCH transmission / reception, a first scheme may be selected in which NACK feedback is transmitted on all available PSFCH resources. In this case, the sidelink configuration may indicate the first scheme. In other words, if the first scheme is selected / enabled, the terminal device 110-1 may select positive-negative acknowledgement or negative-only acknowledgement. Alternatively, if positive-negative acknowledgement is selected and multiple PSFCH transmission / reception opportunities are associated with one PSSCH transmission / reception, either the first scheme or the second scheme may be selected. In the second scheme, upon reporting A / N, the Rx terminal device should not transmit on the remaining available PSFCH resources. In other words, if the second scheme is selected / enabled, the terminal device 110-1 may select positive-negative acknowledgement. In some embodiments, the first scheme or the second scheme may be configured by the network device 120.

[0131] 11 illustrates a flowchart of an exemplary method 1100 according to an embodiment of the present disclosure. The method 1100 may be implemented in any suitable device. For illustrative purposes only, the method 1100 may be implemented in the terminal device 110-2 illustrated in FIG. 2.

[0132] In block 1110, the terminal device 110-2 receives a sidelink configuration from the terminal device 110-1. The sidelink configuration also indicates that the type of sidelink feedback for a sidelink transmission is NACK-only.

[0133] The sidelink configuration may indicate that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities. In some embodiments, the sidelink configuration may indicate a first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. As mentioned above, the terminal device 110-1 may determine a second number of sidelink feedback reception opportunities. In this case, the sidelink configuration may indicate the second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. For example, the sidelink configuration may indicate that there are M sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities.

[0134] In block 1120, terminal device 110-2 receives a set of sidelink transmissions from terminal device 110-1. In some embodiments, the time gap between two adjacent sidelink transmissions in the set of sidelink transmissions may include a first time gap between an end of a last symbol of a first sidelink transmission of the set of sidelink transmissions and a start of a first symbol of a first sidelink feedback reception of the set of sidelink feedback reception opportunities, a second time gap between a first symbol of the first sidelink feedback reception opportunity and a first symbol of a last sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, as well as a third time gap required for receiving the last sidelink feedback and processing and preparing a sidelink retransmission.

[0135] In some embodiments, the time gap between the start of a PSCCH / PSSCH slot and the start symbol of the last PSFCH associated to the preceding PSCCH / PSSCH slot in the same CG or in the set of resources indicated by one DCI must be larger than a predefined duration T_m, which may include the reception of the PSFCH and processing including the required physical channel multiplexing and any TX-RX / RX-TX switching time and sidelink retransmission preparation.

[0136] As mentioned above, the sidelink configuration indicates that the type of sidelink feedback is only NACK. In this case, if the terminal device 110-2 cannot decode or receive the sidelink transmission from the terminal device 110-1, the terminal device 110-2 may transmit a NACK. Alternatively, if the terminal device 110-2 successfully decodes or receives the sidelink transmission from the terminal device 110-1, the terminal device 110-2 may not transmit feedback to the terminal device 110-1.

[0137] In some embodiments, the sidelink configuration may further indicate a scheme for reporting ACK / NACK on multiple resources, e.g., the sidelink configuration may indicate that sidelink feedback for a sidelink transmission needs to be transmitted on each set of sidelink feedback reception opportunities.

[0138] In some embodiments, the terminal device 110-2 may perform listen-before-talk (LBT) or clear channel assessment (CCA) before transmitting the NACK. As used herein, the term "listen-before-talk (LBT)" may refer to a technique used in wireless communication where a wireless transmitter senses its wireless environment before starting transmission. A wireless device may use LBT to find a network in which it can operate or to find a free wireless channel to operate on. As used herein, the term "clear channel assessment (CCA)" refers to a technique to evaluate the RF medium. CCA involves listening to RF transmissions in the physical layer radio. A CCA threshold is used when listening to the RF medium. For example, energy detection may be used in CCA. An energy detection (ED) threshold is used to detect other types of RF transmissions during CCA. If the energy detected on the channel is less than the energy detection threshold, the channel may be considered available for performing transmission. If the energy detected on the channel is greater than the energy detection threshold, the channel may be considered busy. For example, the terminal device 110-2 may determine the result of the LBT (or CCA) in the unlicensed spectrum band based on the difference between the energy of the sidelink transmission in the unlicensed spectrum band and the measured energy of the LBT (or CCA). For example, if the difference is within a threshold difference, the terminal device 310-1 may be deemed to have successfully acquired the COT in the LBT. In other words, if the energy detection in the LBT is similar to the calculated energy level of the monitored SL-U transmission, the COT initiator may be deemed to have successfully acquired the COT in the LBT. Alternatively, if the energy detection value of the LBT is higher than the calculated energy level of the monitored SL-U transmission by more than a set threshold, the LBT may be deemed to have failed.

[0139] If the LBT is successful, the terminal device 110-2 may transmit a NACK to the terminal device 110-1. Alternatively, if the LBT fails, the terminal device 110-2 may transmit an indication of LBT failure to the terminal device 110-1. For example, in some embodiments, the terminal device 110-2 may transmit an SCI indicating LBT failure to the terminal device 110-1. In some other embodiments, the terminal device 110-2 may transmit a PSSCH or PSCCH indicating LBT failure to the terminal device 110-1. Alternatively, the terminal device 110-2 may transmit a media access control (MAC) control element (CE) indicating LBT failure to the terminal device 110-1. In other embodiments, the terminal device 110-2 may transmit PC5-radio resource control (RRC) signaling indicating LBT failure to the terminal device 110-1.

[0140] In some embodiments, the terminal device includes circuitry configured to: transmit a sidelink configuration to the set of terminal devices; transmit a set of sidelink transmissions to the set of terminal devices; and, according to a determination that no sidelink feedback is received in a last set of sidelink feedback reception opportunities of the multiple sets of sidelink feedback reception opportunities associated with the set of sidelink transmissions, transmit an uplink transmission indicating an acknowledgment for the set of sidelink transmissions to the network device. The sidelink configuration indicates that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities, and the sidelink configuration also indicates that a type of sidelink feedback for the sidelink transmissions is NACK-only.

[0141] In some embodiments, the terminal device includes circuitry configured to transmit, to the network device, an uplink transmission indicating a NACK for the set of sidelink transmissions in accordance with a determination that at least one sidelink feedback has been received in the last set of sidelink feedback reception opportunities.

[0142] In some embodiments, the terminal device includes a circuit configured to receive, at a first terminal device, from a network device, a resource configuration for a sidelink, the resource configuration indicating a first number of sidelink feedback reception opportunities in a set of sidelink feedback reception opportunities, the sidelink configuration further indicating the first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities.

[0143] In some embodiments, the first number of sidelink feedback reception opportunities is configured per carrier, or the first number of sidelink feedback reception opportunities is configured per bandwidth portion, or the first number of sidelink feedback reception opportunities is configured per resource pool.

[0144] In some embodiments, the terminal device comprises circuitry configured to determine a second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities based on a traffic packet delay budget or a priority of the set of sidelink transmissions, the sidelink configuration indicating the second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities.

[0145] In some embodiments, the terminal device includes circuitry configured to receive an indication of listen-before-talk (LBT) failure from one of the set of terminal devices and to transmit an uplink transmission to the network device indicating a NACK for the set of sidelink transmissions.

[0146] In some embodiments, the sidelink configuration further indicates that sidelink feedback has to be transmitted at each sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities corresponding to a sidelink transmission.

[0147] In some embodiments, the time gap between two adjacent sidelink transmissions in a set of sidelink transmissions comprises a first time gap between the end of the last symbol of a first sidelink transmission of the set of sidelink transmissions and the start of the first symbol of the first sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, a second time gap between the first symbol of the first sidelink feedback reception opportunity and the first symbol of the last sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, as well as a third time gap required for receiving and processing the last sidelink feedback and preparing a sidelink retransmission.

[0148] In some embodiments, the terminal device includes circuitry configured to transmit an uplink transmission by transmitting the uplink transmission in a first slot having a slot offset, the first slot being the slot of a first sidelink feedback reception opportunity in a last set of sidelink feedback reception opportunities.

[0149] In some embodiments, the slot offset is greater than the number of slots occupied by the last set of sidelink feedback reception opportunities.

[0150] In some embodiments, the terminal device includes circuitry configured to receive an indication of listen-before-talk (LBT) failure from one of the set of terminal devices and to send an uplink transmission to the network device indicating hybrid automatic repeat request (HARQ)-ACK information preconfigured by the network device.

[0151] In some embodiments, the terminal device includes circuitry configured to receive a sidelink configuration from a first terminal device and to receive a set of sidelink transmissions from the first terminal device, the sidelink configuration indicating that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities, the sidelink configuration also indicating that a type of sidelink feedback for the sidelink transmissions is NACK-only.

[0152] In some embodiments, the sidelink configuration further indicates a first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities.

[0153] In some embodiments, the terminal device includes circuitry configured to perform a listen-before-talk (LBT) before transmitting sidelink feedback for a sidelink transmission of the set of sidelink transmissions, and, pursuant to a determination that the LBT has failed, to send an indication of the LBT failure to the first device.

[0154] In some embodiments, the sidelink configuration further indicates that sidelink feedback has to be transmitted at each sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities corresponding to a sidelink transmission.

[0155] In some embodiments, the time gap between two adjacent sidelink transmissions in a set of sidelink transmissions comprises a first time gap between the end of the last symbol of a first sidelink transmission of the set of sidelink transmissions and the start of the first symbol of the first sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, a second time gap between the first symbol of the first sidelink feedback reception opportunity and the first symbol of the last sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, as well as a third time gap required for receiving and processing the last sidelink feedback and preparing a sidelink retransmission.

[0156] Fig. 12 is a schematic block diagram of an apparatus 1200 suitable for implementing an embodiment of the present disclosure. The apparatus 1200 can be considered as another exemplary implementation of the terminal device 110-1 or the network device 120 shown in Fig. 2. Thus, the apparatus 1200 can be implemented in, or at least as part of, the terminal device 110-1 or the network device 120.

[0157] As shown, the apparatus 1200 includes a processor 1210, a memory 1220 coupled to the processor 1210, a suitable transmitter (TX) and receiver (RX) 1240 coupled to the processor 1210, and a communication interface coupled to the TX / RX 1240. The memory 1220 stores at least a portion of a program 1230. The TX / RX 1240 is for bidirectional communication. The TX / RX 1240 has at least one antenna to facilitate communication, although in practice, the access nodes discussed herein may have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a Mobility Management Entity (MME) / Serving Gateway (S-GW) and an eNB, an Un interface for communication between an eNB and a Relay Node (RN), or an Uu interface for communication between an eNB and a terminal device.

[0158] The program 1230 may be considered to include program instructions that, when executed by an associated processor 1210, enable the device 1200 to operate in accordance with embodiments of the present disclosure, as discussed herein with reference to Figures 2-11. The embodiments of the present disclosure may be implemented by computer software, hardware, or a combination of software and hardware executable by the processor 1210 of the device 1200. The processor 1210 may be configured to implement various embodiments of the present disclosure. The combination of the processor 1210 and the memory 1220 may also constitute a processing means 1250 suitable for implementing embodiments of the present disclosure.

[0159] The memory 1220 may be of any type suitable for the local technology network and may be implemented by any suitable data storage technology, including, but not limited to, computer-readable non-transitory storage media, semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed and removable memories, etc. Although only one memory 1220 is shown in the device 1200, multiple physically distinct memory modules may be installed in the device 2700. The processor 1210 may be of any type suitable for the local technology network and may include, but is not limited to, one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor configurations. The device 1200 may have multiple processors, for example application specific integrated circuit chips time-slaved to a clock synchronous with a master processor.

[0160] In general, various embodiments of the present disclosure may be implemented by hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented by hardware, and other aspects may be implemented by firmware or software that may be executed by a controller, microprocessor, or other computing device. Various aspects of the embodiments of the present disclosure have been shown and described as block diagrams, flow charts, or illustrated by some other pictorial representation, and it will be understood that the blocks, apparatus, systems, techniques, or methods described herein may be implemented by, for example, but not limited to, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or combinations thereof.

[0161] The present disclosure further provides at least one computer program product tangibly stored in a computer readable non-transitory storage medium. The computer program product includes computer executable instructions, such as instructions included in program modules. The instructions execute on a target real or virtual processor device to perform, for example, the processes or methods described above with reference to Figures 2-11. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split among program modules as desired. The machine readable instructions of the program modules may be executed in local or distributed devices. In distributed devices, the program modules may be located in both local and remote storage media.

[0162] The program codes for carrying out the 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, a special purpose computer or other programmable data processing apparatus, and when the program codes are executed by the processor or controller, the functions / operations specified in the flowcharts and / or block diagrams are performed. The program codes may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0163] The above program code may be embodied on a machine-readable medium, which may be any tangible medium that contains or stores a program for use by or in conjunction 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. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Even more specific examples of machine-readable storage media include 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.

[0164] It should be understood that although operations have been described in a particular order, it is not required that such operations be performed in the particular order or sequence shown, or that all of the operations shown be performed, in order to achieve desired results. In some situations, multitasking and parallel processing may be advantageous. Similarly, although the above discussion includes some specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to certain embodiments. Some features that are described in the context of individual embodiments may be implemented in combination in an embodiment. Conversely, various features that are described in the context of an embodiment may be implemented in multiple embodiments separately or in any suitable subcombination.

[0165] 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, as defined by 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.

[0166] In this specification, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include user equipment (UE), personal computers, desktops, mobile phones, mobile phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, internet of things (IoT) devices, ultra-reliable low latency communication (URLLC) devices, internet of everything (IoE) devices, machine type communication (MTC) devices, vehicle-mounted devices for V2X communication (where X stands for pedestrian, vehicle, or infrastructure / network), integrated access and backhaul (IAB), small data transmission (SDT), mobility, multicast broadcast services (MBS), positioning, dynamic / flexible duplexing in commercial networks, devices for reduced capability (RedCap), high altitude platforms (HAPs) including unmanned aerial systems (UASs) and spacecraft or aircraft in non-terrestrial networks (NTNs) including satellites, and extended reality (XR) including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR). Examples of such devices include, but are not limited to, Reality (VR) devices, unmanned aerial vehicles (UAVs) that do not require a human pilot, commonly known as drones, devices on high speed trains (HST), imaging devices such as digital cameras, sensors, gaming devices, music storage and playback devices, or Internet appliances that allow wireless or wired Internet access and browsing. A "terminal device" may also have multicast / broadcast capabilities to support public safety and mission critical, V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, wireless software distribution, group communication, and IoT applications. It may also incorporate one or more subscriber identity modules (SIMs), known as multi-SIMs.The term "terminal equipment" may be used interchangeably with UE, mobile station, subscriber equipment, mobile terminal, user terminal, or wireless equipment.

[0167] The term "network device" refers to a device capable of providing or hosting a cell or coverage through which terminal devices can communicate. Examples of network devices include, but are not limited to, a Node B (NodeB or NB), an Evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a transmit / receive 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), a network-controlled repeater (NCR), etc.

[0168] A terminal device or a network device may have artificial intelligence (AI) or machine learning capabilities, typically including models that can be used to learn from a large amount of data collected for a specific function and predict some information.

[0169] The terminal device or network device may function in multiple frequency ranges, e.g., FR1 (410 MHz-7125 MHz), FR2 (24.25 GHz-71 GHz), higher than 100 GHz, Terahertz (THz), etc. Furthermore, it can function in licensed / unlicensed / shared spectrum. The terminal device may have multiple connections with the network device in a multi-radio dual connectivity (MR-DC) application scenario. The terminal device or network device can function in full duplex, flexible duplex, and cross division duplex modes.

[0170] The network device may have the function of network energy saving, self-organizing network (SON) / minimization of drive test (MDT). The terminal may have the function of power saving.

[0171] Embodiments of the present disclosure may be implemented in test equipment, such as, for example, a signal generator, a signal analyzer, a spectrum analyzer, a network analyzer, a test terminal equipment, a test network equipment, a channel emulator, and the like.

[0172] Embodiments of the present disclosure may be performed in accordance with any generation of communication protocols now known or developed in the future, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

Claims

1. transmitting, in a first terminal device, a sidelink configuration to a set of terminal devices, the sidelink configuration indicating that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities and also indicating that a type of sidelink feedback for the sidelink transmissions is negative acknowledgement only (NACK-only); transmitting a set of sidelink transmissions to the set of terminal devices; transmitting to the network device an uplink transmission indicating an acknowledgment for the set of sidelink transmissions according to a determination that no sidelink feedback is received in a last set of sidelink feedback reception opportunities of the plurality of sets of sidelink feedback reception opportunities associated with the set of sidelink transmissions; Including, Communication methods.

2. and transmitting, to the network device, the uplink transmission indicating a NACK for the set of sidelink transmissions in accordance with a determination that at least one sidelink feedback has been received in a last set of sidelink feedback reception opportunities. The method of claim 1.

3. and receiving, at the first terminal device, a resource configuration for a sidelink from the network device, the resource configuration indicating a first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities; and wherein the sidelink configuration further indicates the first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. The method of claim 1.

4. or the first number of sidelink feedback reception opportunities is configured per bandwidth portion, or the first number of sidelink feedback reception opportunities is configured per resource pool. The method according to claim 3.

5. and determining a second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities based on a traffic packet delay budget or a priority of the set of sidelink transmissions. and wherein the sidelink configuration indicates the second number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. The method of claim 1.

6. receiving an indication of a listen-before-talk (LBT) failure from one of the set of terminal devices; transmitting the uplink transmission to the network device indicating a NACK for the set of sidelink transmissions; Further comprising: The method of claim 1.

7. - the sidelink configuration further indicates that sidelink feedback has to be transmitted at each sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities corresponding to the sidelink transmission. The method of claim 1.

8. The time gap between two adjacent sidelink transmissions in the set of sidelink transmissions may be a first time gap between an end of a last symbol of a first sidelink transmission of the set of sidelink transmissions and a start of a first symbol of a first sidelink feedback reception of the set of sidelink feedback reception opportunities; a second time gap between a first symbol of the first sidelink feedback reception opportunity and a first symbol of a last sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, and a third time gap required for receiving the last sidelink feedback and for processing and preparing a sidelink retransmission Including, The method of claim 1.

9. Transmitting the uplink transmission comprises: transmitting the uplink transmission in a first slot having a slot offset; the first slot being a first sidelink feedback reception opportunity slot in a last set of sidelink feedback reception opportunities. The method of claim 1.

10. the slot offset is greater than the number of slots occupied by the last set of sidelink feedback reception opportunities.

10. The method of claim 9.

11. receiving an indication of a listen-before-talk (LBT) failure from one of the set of terminal devices; sending the uplink transmission to a network device indicating hybrid automatic repeat request (HARQ)-ACK information preconfigured by the network device; Further comprising: The method of claim 1.

12. receiving, in a second terminal device, a sidelink configuration from the first terminal device, the sidelink configuration indicating that one sidelink transmission corresponds to one set of sidelink feedback reception opportunities and also indicating that a type of sidelink feedback for the sidelink transmission is NACK-only; receiving a set of sidelink transmissions from the first terminal device; Including, Communication methods.

13. [0023] The sidelink configuration further indicates a first number of sidelink feedback reception opportunities in the set of sidelink feedback reception opportunities. The method of claim 12.

14. performing a listen-before-talk (LBT) before transmitting sidelink feedback for a sidelink transmission of the set of sidelink transmissions; and sending an indication of an LBT failure to the first device in response to a determination that the LBT has failed; Further comprising: The method of claim 12.

15. - the sidelink configuration further indicates that sidelink feedback has to be transmitted at each sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities corresponding to the sidelink transmission. The method of claim 12.

16. The time gap between two adjacent sidelink transmissions in the set of sidelink transmissions may be a first time gap between an end of a last symbol of a first sidelink transmission of the set of sidelink transmissions and a start of a first symbol of a first sidelink feedback reception of the set of sidelink feedback reception opportunities; a second time gap between a first symbol of a first sidelink feedback reception opportunity and a first symbol of a last sidelink feedback reception opportunity of the set of sidelink feedback reception opportunities, and a third time gap required for receiving the last sidelink feedback and for processing and preparing a sidelink retransmission Including, The method of claim 12.

17. A processor; a memory coupled to the processor and having instructions stored therein; Equipped with The instructions, when executed by the processor, perform operations including the method of any one of claims 1 to 11 or any one of claims 12 to 16. Terminal device.

18. A computer-readable medium having instructions stored thereon, comprising: The instructions, when executed on at least one processor, cause the at least one processor to perform a method according to any one of claims 1 to 11 or any one of claims 12 to 16. Computer-readable medium.

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