Sidelink resource conflict display

Abstract

Disclosed are apparatuses, methods, and systems for indicating sidelink resource contention using a feedback channel. An apparatus (600) includes a receiver (635) that receives an SCI (signal control information) from a peer UE on a first resource of a PSCCH (proportional service control channel), the SCI including information indicating future resources reserved for future transmissions. The apparatus (600) includes a processor (605) that determines whether there is resource contention, the resource contention including expected collisions on future resources. The apparatus (600) includes a transmitter (630) that transmits feedback to the peer UE on the feedback resource, the feedback including an indication of whether there is resource contention.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 121,814, entitled "SIDELINK RESOURCE CONFLICT INDICATION USING A FEEDBACK CHANNEL," filed on December 4, 2020, to Karthikeyan Ganesan, Prateek Basu Mallick, Joachim Loehr, and Ravi Kuchibhotla, which is incorporated herein by reference.

[0002] The subject matter disclosed herein relates generally to wireless communications, and more particularly to sidelink ("SL") resource contention indication using a feedback channel. [Background technology]

[0003] Sidelink communication refers to direct peer-to-peer communication between user equipment (“UE”) devices. Thus, UEs communicate with each other without the communications being relayed through a mobile network (i.e., without the need for a base station). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication US2021 / 0058905A1, entitled "USING A CONFIGURED FEEDBACK RESOURCE FOR FEEDBACK," filed on August 19, 2019, to Karthikeyan Ganesan, Prateek Basu Mallick, Joachim Loehr, Alexander Johann Maria Golitschek Edler von Elbwart, and Ravi Kuchibhotla. Summary of the Invention [Means for solving the problem]

[0005] A procedure for sidelink resource contention indication using a feedback channel is disclosed, which may be implemented by an apparatus, a system, a method, or a computer program product.

[0006] One method for a receiver user equipment ("Rx UE") to indicate a sidelink resource conflict using a feedback channel includes receiving sidelink control information ("SCI") from a peer transmitter user equipment ("Tx UE") on a first resource of a physical sidelink control channel ("PSCCH"), the SCI including information indicating future resources reserved for future transmissions. The method includes determining whether there is a resource conflict and sending feedback to the peer Tx UE on the feedback resource, the feedback including an indication of whether there is a resource conflict, the resource conflict including expected collisions on future resources.

[0007] One method for a Tx UE to indicate a sidelink resource conflict using a feedback channel includes transmitting an SCI to a peer Rx UE on a first resource of a PSCCH, the SCI including information indicating future resources reserved for future transmissions. The method includes receiving feedback from the peer Rx UE on the feedback resource, the feedback comprising an indication of whether there is a resource conflict, the resource conflict including expected collisions on future resources.

[0008] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the accompanying drawings, in which the embodiments will be described and explained with additional specificity and detail, with the understanding that these drawings illustrate only some embodiments and therefore should not be considered limiting in scope. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram illustrating an embodiment of a wireless communication system for indicating contention for sidelink resources using a feedback channel. [Figure 2] FIG. 10 is a call flow diagram illustrating an embodiment of indicating contention for sidelink resources using a feedback channel. [Figure 3A] FIG. 1 illustrates an embodiment of a frame structure with PSFCH resources for contention indication. [Figure 3B] FIG. 1 illustrates one embodiment of PSFCH resources within a slot showing options for frequency domain multiplexing and time domain multiplexing. [Figure 4] FIG. 10 illustrates an embodiment of a frame structure using a PSFCH to indicate contention indications and HARQ-ACK reports in different time slots. [Figure 5] FIG. 1 is a block diagram illustrating an embodiment of a sidelink protocol stack. [Figure 6] FIG. 1 is a block diagram illustrating an embodiment of a user equipment device that may be used to indicate contention for sidelink resources using a feedback channel. [Figure 7] FIG. 1 is a block diagram illustrating an embodiment of a network device that may be used to indicate contention for sidelink resources using a feedback channel. [Figure 8] FIG. 1 is a flow chart diagram illustrating an embodiment of a first method for indicating contention for sidelink resources using a feedback channel. [Figure 9]FIG. 10 is a flow chart diagram illustrating an embodiment of a second method for indicating contention for sidelink resources using a feedback channel. DETAILED DESCRIPTION OF THE INVENTION

[0010] As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, the embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects.

[0011] For example, the disclosed embodiments may be implemented as a hardware circuit comprising custom very large scale integrated ("VLSI") circuits or off-the-shelf semiconductors such as gate arrays, logic chips, transistors, or other discrete components. The disclosed embodiments may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, etc. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code which may be organized as, for example, objects, procedures, or functions.

[0012] Furthermore, embodiments may take the form of a program product embodied in one or more computer-readable storage devices storing machine-readable code, computer-readable code, and / or program code, hereinafter referred to as code. The storage devices may be tangible, non-transitory, and / or non-transmittal. The storage devices may not embody signals. In some embodiments, the storage devices use only signals to access the code.

[0013] Any combination of one or more computer-readable mediums may be utilized. The computer-readable medium may be a computer-readable storage medium. The computer-readable storage medium may be a storage device that stores code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

[0014] More specific examples (a non-exhaustive list) of storage devices include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory ("RAM"), a read-only memory ("ROM"), an erasable programmable read-only memory ("EPROM" or flash memory), a portable compact disc read-only memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this specification, a computer-readable storage medium may be any tangible medium that contains or can store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0015] The code for carrying out the operations of the embodiments may be any number of lines and may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Python, Ruby, Java, Smalltalk, C++, and traditional procedural programming languages ​​such as the “C” programming language, and / or machine language such as assembly language. The code may run entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (“LAN”), wireless LAN (“WLAN”), or wide area network (“WAN”), or a connection to an external computer may be made (e.g., via the Internet using an Internet Service Provider (“ISP”)).

[0016] Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of the embodiments. However, one skilled in the art will recognize that the embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the embodiments.

[0017] Reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification mean "one or more but not all embodiments," although they may, but need not, all refer to the same embodiment, unless expressly specified otherwise. The terms "including," "comprising," and "having," and variations thereof, mean "including but not limited to," unless expressly specified otherwise. A listing of enumerated items does not imply that some or all items are mutually exclusive unless expressly specified otherwise. The terms "a," "an," and "the" also mean "one or more," unless expressly specified otherwise.

[0018] As used herein, a list with the conjunction "and / or" includes any single item in the list or combination of items in the list. For example, a list of A, B, and / or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C. As used herein, a list using the term "one or more of" includes any single item in the list or combination of items in the list. For example, one or more of A, B, and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C. As used herein, a list using the term "one of" includes only one of any single item in the list. For example, "one of A, B, and C" includes only A, only B, or only C, and excludes the combination of A, B, and C. As used herein, "a member selected from the group consisting of A, B, and C" includes only one of A, B, or C, and excludes the combination of A, B, and C. As used herein, "a member selected from the group consisting of A, B, and C, and combinations thereof" includes A only, B only, C only, a combination of A and B, a combination of B and C, a combination of A and C, or a combination of A, B, and C.

[0019] Aspects of the embodiments are described below with reference to schematic flowchart illustrations and / or schematic block diagrams of methods, apparatus, systems, and program products according to the embodiments. It will be understood that each block of the schematic flowchart illustrations and / or schematic block diagrams, and combinations of blocks in the schematic flowchart illustrations and / or schematic block diagrams, can be implemented by code. This code can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to generate machine-defined instructions that, when executed by the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart illustrations and / or block diagrams.

[0020] Code may also be stored in a storage device that can cause a computer, other programmable data processing apparatus, or other device to function in a particular way, such that the instructions stored in the storage device produce an article of manufacture that includes instructions that implement the functions / acts specified in the flowchart illustrations and / or block diagrams.

[0021] The code may also be loaded into a computer, other programmable data processing apparatus, or other device to generate a computer-implemented process such that the code executing on the computer or other programmable apparatus provides a process for implementing the functions / acts specified in the flowchart diagrams and / or block diagrams, such that a series of operational steps are performed on the computer, other programmable apparatus, or other device.

[0022] The call flow diagrams, flowchart diagrams, and / or block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, systems, methods, and program products according to various embodiments. In this regard, each block in the flowchart diagrams and / or block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of code for implementing the specified logical function(s).

[0023] It should also be noted that in some alternative embodiments, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending on the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated figures.

[0024] While various arrow types and line types may be used in the call flows, flowcharts, and / or block diagrams, it should be understood that they do not limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the illustrated embodiments. For example, arrows may indicate wait or monitoring periods of indefinite duration between enumerated steps of the depicted embodiments. It should also be noted that each block of the block diagrams and / or flowchart diagrams, and combinations of blocks in the block diagrams and / or flowchart diagrams, can be implemented by dedicated hardware-based systems that perform the specified functions or acts, or by a combination of dedicated hardware and code.

[0025] The description of an element in each drawing may refer to the element in a previous drawing. Like numbers refer to like elements in all drawings, including alternative embodiments of like elements.

[0026] Generally, the present disclosure describes systems, methods, and apparatuses for enabling UE-to-UE coordination for efficient sidelink transmissions when using sidelink DRX. In one embodiment, a set of resources is determined at a first SL UE, denoted UE-A. This set is transmitted to a second SL UE, denoted UE-B, in Mode 2 (i.e., UE-scheduled SL communication mode), which UE-B takes into account in selecting resources for its transmissions. In certain embodiments, the method may be performed using computer code embedded in a computer-readable medium. In certain embodiments, the apparatus or system may include a computer-readable medium including computer-readable code that, when executed by a processor, causes the apparatus or system to perform at least a portion of the solutions described below.

[0027] Inter-UE coordination has the advantages of improving reliability and reducing delay. Specifically, inter-UE coordination helps a transmitter UE select transmission resources that can increase the probability of successful transmission to a given receiver UE.

[0028] Consecutive packet losses in the sidelink can be caused by a variety of factors. The source of errors (in transmission) can be one or more of the following: a. Half-duplex problem where UE-A and UE-B are transmitting in the same time slot and cannot hear each other's transmissions b. Poor radio, e.g. resulting in continuous NACK / DTX reception from the Rx UE c. Congestion in the resource pool d. Interference at the receiver side due to hidden nodes

[0029] Regarding inter-UE coordination, some agreements in 3GPP are as follows: The scheme of inter-UE coordination in Mode 2 is classified as being based on the following types of resource sets transmitted by UE-A to UE-B: In one embodiment, UE-A transmits to UE-B a set of resources that are prioritized for UE-B's transmissions, e.g., based on UE-A's sensing results. In one embodiment, UE-A transmits to UE-B a set of resources that are not prioritized for UE-B's transmissions, e.g., based on UE-A's sensing results and / or expected / potential resource conflicts. In one embodiment, UE-A transmits to UE-B a set of resources for which resource conflicts are detected.

[0030] In certain embodiments, for example, a potential half-duplex and / or collision detection and conflict indication using a feedback channel by a third UE monitoring the SCI may feedback a NACK if it detects a half-duplex and / or resource conflict. However, sending a combined NACK to indicate both the SL HARQ-ACK report and a conflict for the initial transmission and reserved resources may result in the UE decoding the initial transmission, but a retransmission of the initial transmission if a conflict is decoded.

[0031] To further improve contention indication for sidelink communications, a solution is described below in which the feedback channel configuration includes separate bits / separate resources for indicating HARQ-ACK reports and contention indications. As used herein, "HARQ-ACK" may collectively refer to an acknowledgement ("ACK"), a negative acknowledgement ("NACK"), and a discontinuous transmission ("DTX"). An ACK means that a transport block ("TB") (also called a "packet") was correctly received, a NACK (or NAK) means that a TB was received in error, and a DTX means that a TB was not detected.

[0032] In various embodiments, the feedback channel includes separate bits and / or separate resources for indicating the HARQ-ACK report and the conflict indication, and then multiple solutions for resource conflict indication using a multi-bit Physical Sidelink Feedback Channel ("PSFCH"), where the first bit indicates the SL HARQ-ACK report and the remaining bits provide a conflict indication for the reserved resources. In particular embodiments, the resource separation between the HARQ-ACK and the resource conflict may be according to frequency-domain multiplexing or time-domain multiplexing. Finally, a separate PSFCH occasion may be configured for the conflict indication. In some embodiments, PSFCH Format 0 is used to convey the existence of expected / potential resource conflicts in the reserved resources indicated by UE-B's SCI.

[0033] In certain embodiments, there is additional information as part of the assistance information signaling: disable / enablement of assistance information, and finally additional parameters for the sensing procedure to select preferred and non-preferred resource sets.

[0034] FIG. 1 illustrates a wireless communication system 100 for indicating contention for sidelink resources using a feedback channel in accordance with an embodiment of the present disclosure. In one embodiment, the wireless communication system 100 includes at least one remote unit 105, a radio access network (“RAN”) 120, and a mobile core network 140. The RAN 120 and the mobile core network 140 form a mobile communication network. The RAN 120 may be comprised of a base unit 121 with which the remote unit 105 communicates using a wireless communication link 123. While a specific number of remote units 105, base units 121, wireless communication links 123, the RAN 120, and the mobile core network 140 are shown in FIG. 1 , those skilled in the art will recognize that any number of remote units 105, base units 121, wireless communication links 123, the RAN 120, and the mobile core network 140 may be included in the wireless communication system 100.

[0035] In one implementation, the RAN 120 complies with a fifth-generation ("5G") cellular system specified in 3rd Generation Partnership Project ("3GPP") specifications. For example, the RAN 120 may be a next-generation radio access network ("NG-RAN") that implements a New Radio ("NR") radio access technology ("RAT") and / or a long-term evolution ("LTE") RAT. In another example, the RAN 120 may include a non-3GPP RAT (e.g., Wi-Fi or an Institute of Electrical and Electronics Engineers ("IEEE") 802.11 family-compliant WLAN). In another implementation, the RAN 120 complies with an LTE system specified in 3GPP specifications. However, more generally, the wireless communication system 100 may implement some other open or proprietary communication network, such as Worldwide Interoperability for Microwave Access ("WiMAX") or the IEEE 802.16 family of standards, among other networks. This disclosure is not intended to be limited to any particular wireless communication system architecture or protocol implementation.

[0036] In one embodiment, the remote unit 105 may include a computing device such as a desktop computer, a laptop computer, a personal digital assistant ("PDA"), a tablet computer, a smartphone, a smart television (e.g., a television connected to the Internet), a smart appliance (e.g., an appliance connected to the Internet), a set-top box, a game console, a security system (including security cameras), an in-vehicle computer, a network device (e.g., a router, a switch, a modem), etc. In some embodiments, the remote unit 105 includes a wearable device such as a smart watch, a fitness band, an optical head-mounted display, etc. Furthermore, the remote unit 105 may be referred to as a UE, a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a fixed terminal, a subscriber station, a user terminal, a wireless transmit / receive unit ("WTRU"), a device, or other terminology used in the art. In various embodiments, the remote unit 105 includes a subscriber identification and / or identification module ("SIM") and a mobile equipment ("ME") that provides mobile terminal functions (e.g., radio transmission, handover, voice encoding and decoding, error detection and correction, signaling, and access to the SIM). In particular embodiments, the remote unit 105 may include terminal equipment ("TE") and / or may be embedded in an equipment or device (e.g., a computing device as described above).

[0037] The remote units 105 may communicate directly with one or more of the base units 121 in the RAN 120 via uplink (“UL”) and downlink (“DL”) communication signals carried over wireless communication links 123. Furthermore, the UL communication signals may comprise one or more downlink channels, such as a Physical Uplink Control Channel (“PUCCH”) and / or a Physical Uplink Shared Channel (“PUSCH”), and the DL communication signals may comprise one or more downlink channels, such as a Physical Downlink Control Channel (“PDCCH”) and / or a Physical Downlink Shared Channel (“PDSCH”). Here, the RAN 120 is an intermediate network that provides the remote units 105 with access to the mobile core network 140.

[0038] In some embodiments, the remote unit 105 communicates with the application server 151 via a network connection with the mobile core network 140. For example, an application 107 (e.g., a web browser, a media client, a telephone and / or a voice over Internet Protocol (“VoIP”) application) in the remote unit 105 may trigger the remote unit 105 to establish a protocol data unit (“PDU”) session (or other data connection) with the mobile core network 140 over the RAN 120. The mobile core network 140 then uses the PDU session to relay traffic between the remote unit 105 and the application server 151 in the packet data network 150. The PDU session represents a logical connection between the remote unit 105 and the user plane function (“UPF”) 141.

[0039] To establish a PDU session (or PDN connection), the remote unit 105 must register with the mobile core network 140 (also referred to as being "connected to the mobile core network" in the context of a fourth generation ("4G") system). Note that the remote unit 105 may establish one or more PDU sessions (or other data connections) with the mobile core network 140. Thus, the remote unit 105 may have at least one PDU session for communicating with the packet data network 150. The remote unit 105 may establish additional PDU sessions for communicating with other data networks and / or other communication peers.

[0040] In the context of 5G systems ("5GS"), the term "PDU session" refers to a data connection that provides end-to-end ("E2E") user plane ("UP") connectivity between a remote unit 105 and a particular data network ("DN") through the UPF 141. A PDU session supports one or more quality of service ("QoS") flows. In particular embodiments, there may be a one-to-one mapping between QoS flows and QoS profiles, such that all packets belonging to a particular QoS flow have the same 5G QoS identifier ("5QI").

[0041] In the context of a 4G / LTE system, such as an Evolved Packet System ("EPS"), a packet data network ("PDN") connection (also called an EPS session) provides an E2E UP connection between a remote unit and the PDN. The PDN connection procedure establishes an EPS bearer, i.e., a tunnel between the remote unit 105 and a packet gateway ("PGW," not shown) in the mobile core network 140. In certain embodiments, there is a one-to-one mapping between EPS bearers and QoS profiles, such that all packets belonging to a particular EPS bearer have the same QoS class identifier ("QQ").

[0042] The base units 121 may be distributed throughout a geographic region. In particular embodiments, the base units 121 may also be referred to as access terminals, access points, bases, base stations, Node-Bs (“NBs”), evolved Node-Bs (abbreviated as eNodeBs or “eNBs” and also known as evolved Universal Terrestrial Radio Access Network (“E-UTRAN”) Node-Bs), 5G / NR Node-Bs (“gNBs”), Home Node-Bs, relay nodes, RAN nodes, or any other terminology used in the art. The base units 121 are generally part of a RAN, such as the RAN 120, and may include one or more controllers communicatively coupled to one or more corresponding base units 121. These and other elements of a radio access network are not shown but are generally well known by those skilled in the art. The base units 121 connect to the mobile core network 140 via the RAN 120.

[0043] The base unit 121 may serve several remote units 105 within a service area, such as a cell or cell sector, via wireless communication link 123. The base unit 121 may communicate directly with one or more of the remote units 105 via communication signals. In general, the base unit 121 transmits DL communication signals to serve the remote units 105 in the time, frequency, and / or spatial domains. The wireless communication link 123 may be any suitable carrier in a licensed or unlicensed radio spectrum. The wireless communication link 123 facilitates communication between one or more of the remote units 105 and / or one or more of the base units 121. It should be noted that during NR operation in the unlicensed spectrum (referred to as "NR-U"), the base unit 121 and the remote units 105 communicate via an unlicensed (i.e., shared) radio spectrum.

[0044] In one embodiment, the mobile core network 140 is a 5G core network (“5GC”) or an evolved packet core (“EPC”) and may be coupled to a packet data network 150 such as the Internet and private data networks, among other data networks. The remote units 105 may have a subscription or other account with the mobile core network 140. In various embodiments, each mobile core network 140 belongs to a single mobile network operator (“MNO”) and / or public land mobile network (“PLMN”). This disclosure is not intended to be limited to any particular wireless communications system architecture or protocol implementation.

[0045] The mobile core network 140 includes several network functions (“NFs”). As shown, the mobile core network 140 includes at least one UPF 141. The mobile core network 140 also includes multiple control plane (“CP”) functions, including, but not limited to, an access and mobility management function (“AMF”) 143 that serves the RAN 120, a session management function (“SMF”) 145, a policy control function (“PCF”) 147, a unified data management function (“UDM”), and a user data repository (“UDR”). In some embodiments, the UDM is co-located with the UDR and is depicted as a combined entity “UDM / UDR” 149. While a particular number and type of network functions are shown in FIG. 1 , those skilled in the art will recognize that any number and type of network functions may be included in the mobile core network 140.

[0046] The UPF 141 is responsible for packet routing and forwarding, packet inspection, QoS processing, and external PDU sessions for interconnecting data networks ("DNs") in a 5G architecture. The AMF 143 is responsible for termination of non-access stratum ("NAS") signaling, NAS encryption and integrity protection, registration management, connection management, mobility management, access authentication and authorization, and security context management. The SMF 145 is responsible for session management (i.e., session establishment, modification, and release), remote unit (i.e., UE) Internet Protocol ("IP") address allocation and management, DE data notification, and traffic steering configuration of the UPF 141 for proper traffic routing.

[0047] The PCF 147 is responsible for the unified policy framework, providing policy rules to the CP function and accessing subscription information for policy decisions in the UDR. The UDM is responsible for generating Authentication and Key Agreement ("AKA") credentials, handling user identification, access authorization, and subscription management. The UDR is a repository of subscriber information and can be used to provide numerous network functions. For example, the UDR can store subscription data, policy-related data, subscriber-related data that is allowed to be exposed to third-party applications, etc.

[0048] In various embodiments, the mobile core network 140 may also include a Network Repository Function (“NRF”) (which provides registration and discovery of Network Function (“NF”) services, allowing NFs to identify appropriate services from each other and communicate with each other via application programming interfaces (“APIs”)), a Network Exposure Function (“NEF”) (which is responsible for providing easy access to network data and resources for customers and network partners), an Authentication Server Function (“AUSF”), or other NFs defined for 5GC. If an AUSF is present, the AUSF acts as an authentication server and / or authentication proxy, thereby enabling the AMF 143 to authenticate the remote unit 105. In particular embodiments, the mobile core network 140 may include an Authentication, Authorization, and Accounting (“AAA”) server.

[0049] In various embodiments, the mobile core network 140 supports different types of mobile data connections and different types of network slices, with each mobile data connection utilizing a particular network slice. Here, a “network slice” refers to a portion of the mobile core network 140 optimized for a particular traffic type or communication service. For example, one or more network slices may be optimized for enhanced mobile broadband (“eMBB”) services. As another example, one or more network slices may be optimized for ultra-reliable low-latency communications (“URLLC”) services. In other examples, network slices may be optimized for machine-type communications (“MTC”) services, massive MTC (“mMTC”) services, Internet of Things (“IoT”) services, etc. In yet other examples, network slices may be deployed for particular application services, vertical services, particular use cases, etc.

[0050] A network slice instance may be identified by a single Network Slice Selection Assistance Information (“S-NSSAI”), while a set of network slices that the remote unit 105 is authorized to use is identified by a Network Slice Selection Assistance Information (“NS SAI”), where “NSSAI” refers to a vector value that includes one or more S-NSSAI values. In particular embodiments, various network slices may include separate instances of network functions, such as the SMF 145 and the UPF 141. In some embodiments, different network slices may share some common network functions, such as the AMF 143. For ease of explanation, different network slices are not shown in FIG. 1, although their support is assumed.

[0051] In various embodiments, the remote units 105 may communicate directly with one another (e.g., device-to-device communication) using sidelink (“SL”) communication signals 115. Here, SL transmissions may occur on SL resources, e.g., the Physical Sidelink Control Channel (“PSCCH”), the Physical Sidelink Feedback Channel (“PSFCH”), and / or the Physical Sidelink Shared Channel (“PSSCH”).

[0052] While FIG. 1 illustrates components of a 5G RAN and a 5G core network, the described embodiments for indicating contention for sidelink resources using a feedback channel apply to other types of communication networks and RATs, including IEEE 802.11 variants, Global System for Mobile Communications (“GSM”, i.e., 2G digital cellular network), General Packet Radio Service (“GPRS”), Universal Mobile Telecommunications System (“UMTS”), LTE variants, CDMA2000, Bluetooth, ZigBee, Sigfox, etc.

[0053] Furthermore, in LTE variants where the mobile core network 140 is the EPC, the illustrated network functions may be replaced with appropriate EPC entities, such as a mobility management entity ("MME"), a serving gateway ("SGW"), a PGW, a home subscriber server ("HSS"), etc. For example, the AMF 143 may be mapped to the MME, the SMF 145 may be mapped to the control plane portion of the PGW and / or the MME, the UPF 141 may be mapped to the user plane portion of the SGW and PGW, the UDM / UDR 149 may be mapped to the HSS, etc.

[0054] In the following description, the term "gNB" is used for the base unit 121 but can be replaced by any other radio access node, e.g., a RAN node, a BS, an eNB, a gNB, an access point ("AP"), etc. Furthermore, the term "UE" is used for a mobile station / remote unit but can be replaced by any other remote device, e.g., a remote unit, an MS, an ME, a customer premises equipment ("CPE"), etc. Furthermore, the operation is primarily described in the context of 5G NR. However, the solutions / methods described below are equally applicable to other mobile communication systems for indicating contention for sidelink resources using a feedback channel.

[0055] In duplex communication, connected entities (e.g., UEs) can communicate with each other in both directions, i.e., a duplex UE can both transmit and receive. Duplex communication can be categorized into two types: full duplex and half duplex. In full duplex systems, both entities (i.e., UEs) can communicate with each other simultaneously, i.e., a device can transmit while receiving at the same time. However, in half duplex systems, both entities (UEs) can transmit and receive, but not simultaneously.

[0056] In LTE and NR, sidelink communications are half-duplex. Thus, if a first sidelink UE (denoted "UE-1") transmits during a given time slot, it cannot receive a transmission from a second sidelink UE (denoted "UE-2") during the same time slot. Similarly, UE-2 cannot receive a transmission from UE-1 because both sidelink UEs are transmitting during the same time slot. Note, however, that if UE-1 uses a different frequency resource than UE-2 for transmission, a third sidelink UE (denoted "UE-3") can receive both UE-1 and UE-2 transmissions during the same time slot.

[0057] Furthermore, conventional schemes for sidelink communication assume that peer UEs are permanently available for reception and transmission, and therefore use inter-UE coordination to find only suitable resources given packet delay budget ("PDB") constraints. However, if the peer UE uses a DRX configuration to save power, the peer UE is not permanently available for reception and transmission, and therefore inter-UE coordination is interrupted.

[0058] Therefore, to enhance coordination between UEs, the behavior of peer UEs is modified to indicate contention for sidelink resources using a feedback channel.

[0059] In a first solution, the feedback channel includes separate bits / separate resources for indicating hybrid automatic repeat request ("HARQ") feedback (i.e., one or more HARQ-ACK reports) and resource contention indication feedback. Here, the resource contention indication may use a multi-bit PSFCH, with the first bit indicating a SL HARQ-ACK report and the remaining bits providing contention indication for reserved resources. In the first option, the contention resource indication for all reserved resources can be indicated by a single bit. In the second option, a separate bit is allocated to provide feedback for each reserved resource.

[0060] PSFCH resources may be configured for HARQ-ACK reporting, and contention indications may be frequency-division multiplexed by allocating separate physical resource blocks ("PRBs") and time-domain multiplexed by allocating resources to different symbols in the same slot. Multiple feedback opportunities may be configured, each corresponding to a reserved resource. To allocate PSFCH resources in Scheme 2, at least a set of PRBs for PSFCH transmission / reception (sl-PSFCH-RB-Set) may be configured (or pre-configured) separately from those for SL HARQ-ACK feedback.

[0061] The time gap between the feedback and the reserved resources may be before or m-T3 of each feedback opportunity. After receiving the feedback and before (or at m-T3), the UE may decide to reselect the reserved resources based on the conflict indication. The SCI may include signaling to enable the conflict indication.

[0062] Resource pool level configuration (or pre-configuration) may use one of the following options:

[0063] Option 1: The PSFCH occasion is derived by the slot in which UE-B's SCI is transmitted. In this option, the PSSCH to PSFCH timing may be used to determine the PSFCH occasion of the resource contention indication, as specified in 3GPP Technical Specification ("TS") 38.213 Section 16.3. Furthermore, the time gap between the PSFCH and the slot in which the expected / potential resource contention occurs is equal to or greater than T3.

[0064] Option 2: The PSFCH occasion is derived by the slot where an expected / potential resource conflict occurs on the PSSCH resource indicated by UE-B's SCI. In this option, UE-A transmits the PSFCH in the latest slot that is at least T3 slots in the resource pool before the PSSCH resource indicated by UE-B's SCI, which contains the PSFCH resource for inter-UE coordination information and where an expected / potential resource conflict occurs.

[0065] According to a second solution, the report of SL HARQ enablement / disablement, or SL HARQ feedback option 1, or SL HARQ feedback option 2, or blind retransmission, or maximum number of blind retransmissions is conveyed to UE-B as part of the assistance information.

[0066] According to a third solution, the gNB may enable / disable the inter-UE coordination function or a subset of functions (such as preferred resource set, reserved resources, non-preferred resources, conflicting resources, etc.) for each resource pool based on the channel busy rate / channel occupancy rate.

[0067] According to a fourth solution, a single subchannel configuration can be defined for the transmission of assistance information, and resources for the transmission of assistance information can be reserved by another UE or the gNB (i.e., in sidelink resource allocation mode 1). With regard to sidelink resource allocation, mode 1 corresponds to the NR network-scheduled allocation mode, mode 2 corresponds to the NR UE-scheduled allocation mode, mode 3 corresponds to the LTE network-scheduled allocation mode, and mode 4 corresponds to the LTE UE-scheduled allocation mode.

[0068] According to a fifth solution, a parameter for candidate resource selection to determine preferred / non-preferred resources - an additional Reference Signal Received Power ("RSRP") (alternatively or additionally, an average Reference Signal Received Quality ("RSRQ") and / or a Signal-to-Interference-and-Noise Ratio ("SINR")) threshold for selecting a preferred or non-selected subset of resources is reported. Furthermore, the higher layer parameters include an earliest-in-time flag for selecting a preferred set of resources. Here, the assistance information may include an active UL Configured Grant ("CG") resource configuration, such as time / frequency resources, periodicity, etc.

[0069] 2 shows an example message flow of a procedure 200 for indicating contention for sidelink resources using a feedback channel according to an embodiment of the first solution. The procedure 200 involves a first sidelink UE, denoted UE-A 205, and a second sidelink UE, denoted UE-B 210, each of which may be an embodiment of a remote unit 105.

[0070] The procedure 200 begins at step 1a when UE-B 210 transmits an SCI to UE-A 205 on the physical sidelink control channel (“PSCCH”) (see messaging 215), where the SCI includes an indication of future resources reserved for future transmissions.

[0071] In step 1b, UE-B 210 also transmits sidelink data (e.g., initial transmission) to UE-A 205 (see messaging 220), where the SL data transmission is accompanied by an SCI containing an indication of future reserved resources.

[0072] In step 2, UE-A 205 determines whether a resource conflict exists for the indicated future resources reserved for future transmissions (see block 225). In one embodiment, the resource conflict may be a time domain collision (half-duplex issue). Alternatively, the resource conflict may be a predicted time / frequency collision.

[0073] In some embodiments, the Rx UE determines the set of sidelink resources by performing a sensing procedure and a sidelink resource selection procedure. The sensing result may be an averaged RSRP from the sensing slots for candidate resource selection by considering a common active period between the UE-A 205 and the UE-B 210. Here, the determined set of sidelink resources may include prioritized resources based on the sensing result, non-preferred resources based on the sensing result, and / or resources with potential collisions.

[0074] In step 3, UE-A 205 sends feedback to UE-B 210 with an indication of whether a resource conflict exists (see messaging 230).

[0075] In condition step 4, UE-B 210 performs resource reselection if the second set of feedback resources indicates resource contention (see block 235).

[0076] According to an embodiment of the first solution, an Rx UE (e.g., UE-A 205) monitoring the SCI may provide feedback indicating potential expected or past conflict indications using a feedback channel, where the feedback channel includes separate bits / separate resources for indicating HARQ-ACK reports and conflict indications.

[0077] 3A-3B show an embodiment of resource contention indication using dedicated bits / resources for contention indication according to an embodiment of the first solution. In some embodiments, the feedback from the Rx UE comprises a multi-bit PSFCH and there is a separate resource for contention indication.

[0078] 3A illustrates a frame structure 300 with PSFCH resources for contention indication, according to an embodiment of the present disclosure. The frame structure 300 comprises multiple slots. In the first slot, an Rx UE (e.g., UE-A 205) receives an SCI 305 carrying an initial transmission and two reservations for future resources, namely, in slots 310 and 315. It is assumed here that the SCI 305 enables contention indication for the reserved resources. In a further embodiment, the SCI 305 also enables HARQ feedback for the initial transmission.

[0079] After receiving the SCI 305 and before the first reserved resource (i.e., in slot 310), the Rx UE transmits a PSFCH 320 that carries feedback for both the initial transmission and the contention indication for the reserved resource. As described in further detail below, the feedback transmitted by the Rx UE may comprise a multi-bit PSFCH multiplexed in the frequency domain or the time domain.

[0080] 3B illustrates PSFCH resources within a slot illustrating options for frequency domain multiplexing 320 and time domain multiplexing 325, according to an embodiment of the present disclosure. In the frequency domain multiplexing option 320, the multi-bit PSFCH comprises separate physical resource blocks for the HARQ report 335 and for the contention indication 330 on a common symbol in the time domain. In the time domain multiplexing option 325, the multi-bit PSFCH comprises separate symbols within a time domain physical resource block on a common slot and on a common set of physical resource blocks (i.e., one or more) for the HARQ report 335 or the contention indication 330.

[0081] In a first implementation of the first solution, a multi-bit PSFCH is proposed, where the first bit carries feedback on the initial transmission and the remaining / last bits carry feedback on conflict indications (if any) for reserved transmissions. An example implementation is shown in Table 1 below, where one or more dedicated bits are configured to report conflict indications and SL HARQ-ACK reports. If a single conflict indication bit is configured for two or more reserved resources, those reserved resources need to be reselected if the conflict indication indicates the existence of a conflict.

[0082] [Table 1]

[0083] If a dedicated bit is configured for each reserved resource, each reserved resource can be reselected based on the presence or absence of a conflict indication.

[0084] In some embodiments, a separate PSFCH format may be defined for multi-bit feedback purposes, and this format used for transmitting the PSFCH 320 may be dynamically indicated in the SCI 305. The PSFCH format used for transmitting feedback / conflict indication / resource set may be pre-configured per resource pool or per UE by the gNB using RRC signaling.

[0085] After receiving information that there is a conflict in the reserved resources, the Tx UE (e.g., UE-B 210) can perform a resource (re)selection trigger or reselect another resource from the candidate set. Otherwise, the Tx UE may select data belonging to another destination ID (even from another logical channel) to transmit in the reserved resources.

[0086] Note that the Tx UE can perform resource (re)selection triggering or reselect another resource from the candidate set only if the PSFCH feedback arrives at or before the resource (re)evaluation timeline / deadline, which is m-T3 defined in 3GPP 38.213, where T3 is the time required to reselect a resource and m is the transmission timeslot of the reserved resource.

[0087] As shown in FIG. 3B, separate PSFCH resources may be configured for HARQ-ACK reporting 335 and contention indication 330, and the resources may be frequency-domain multiplexed in the same PSFCH symbol using separate PRBs or time-domain multiplexed in different PSFCH symbols within the same slot.

[0088] 4 illustrates a frame structure 400 using a PSFCH to indicate contention indications and HARQ-ACK reports in different time slots according to an embodiment of the present disclosure. In another implementation of the first solution, separate PSFCH resources can be configured in different time slots, and the time slot offset for feedback can be configured to be different for HARQ-ACK compared to the time slot offset of the contention indication, as shown in FIG. 4. In the first slot, an Rx UE (e.g., UE-A 205) receives an SCI 405 carrying two reservations, one for an initial transmission and one for future resources, namely, in slots 410 and 415. Here, it is assumed that the SCI 405 enables contention indications for the reserved resources and also enables HARQ feedback for the initial transmission.

[0089] At a time point after receiving the SCI due to the initial transmission, the Rx UE transmits a PSFCH 420 carrying HARQ feedback for the initial transmission. Prior to the first time point of the reserved resources (i.e., slot 410), the Rx UE transmits a PSFCH 425 carrying contention indication feedback for the first-occurring reserved resources. Prior to the second time point of the reserved resources (i.e., slot 415), the Rx UE transmits a PSFCH 430 carrying contention indication feedback for the second-occurring reserved resources. The time slot offset (time gap) can be configured (in advance) for each resource pool or dynamically indicated in the SCI 405. Multiple feedback opportunities can be configured, each corresponding to a reserved resource. The time gap between the feedback and the reserved resources can be m-T3 or earlier for each feedback opportunity. After receiving feedback before or at m-T3, the Tx UE (eg, UE-B 210) may decide to reselect reserved resources based on the contention indication.

[0090] In one implementation, a separate bit may be configured in the SCI to dynamically signal the enablement / disablement of conflict indications, separate from HARQ enablement / disablement and HARQ feedback. In another implementation, a common feedback resource for all reserved resources may be configured, or in another implementation, a common feedback resource may be configured for each reserved resource, with one option assigning different frequency division multiplexing FDM resources to the reserved resources, or another option assigning different cyclic shifts to the reserved resources. In order to limit the number of feedbacks on the common feedback resource, a separate minimum communication range ("MCR") value may be configured, which may be configured (in advance) for each resource pool or signaled in the SCI.

[0091] In various embodiments, the following monitoring conditions apply to half-duplex / collision detection: If the destination group identifiers are identical and / or the resources selected by the group member Tx UEs occupy the same time slots, a half-duplex issue may occur and feedback will be provided to the Tx UE. If the destination group identifiers are not identical and / or the resources selected by the group member Tx UEs do not occupy the same time slots, no half-duplex issue occurs and feedback is provided to the Tx UE. If the destination group identifiers are not identical and / or the resources selected by group member Tx UEs occupy the same time slots, half-duplex issues may occur and the Rx UE may or may not provide feedback to the Tx UE.

[0092] Additional details of these monitoring conditions are described in U.S. Patent Application Publication US2021 / 0058905A1, entitled "USING A CONFIGURED FEEDBACK RESOURCE FOR FEEDBACK," filed on August 19, 2019, to Karthikeyan Ganesan, Prateek Basu Mallick, Joachim Loehr, Alexander Johann Maria Golitschek Edler von Elbwart, and Ravi Kuchibhotla, which is incorporated herein by reference.

[0093] According to an embodiment of the second solution, HARQ enablement / disablement assistance information is reported to the Tx UE. In the second solution, UE-A may assist UE-B by assisting SL HARQ enablement / disablement, or feedback option 1 or option 2, or information related to blind retransmission or the maximum number of blind retransmissions. After receiving the assistance information from UE-A, UE-B may consider the assistance information for the next scheduling period / slot. For example, UE-B can switch between blind retransmission and HARQ-based retransmission based on the assistance information.

[0094] For example, if UE-B's logical channel ("LCH") does not enable SL HARQ feedback, but the UE-A assistance information includes a request to enable SL HARQ feedback, then in one implementation, UE-B may follow the LCH configuration. In another example, UE-B may disable the LCH configuration and follow the request in the assistance information. Separate configurations may be defined whether UE-B follows the LCH configuration or requests it in the assistance information. Similarly, UE-A may assist UE-B for the transmission of a channel state information reference signal ("CSI-RS") or a channel state information ("CSI") trigger by sending a request to transmit CSI-RS.

[0095] According to an embodiment of the third solution, there is UE-to-UE coordination message disabling per resource pool based on channel busy rate and / or channel occupancy rate ("CBR / CR") measurements. In the third solution, the gNB can disable the UE-to-UE coordination function or a subset of functions per resource pool based on the channel busy rate / channel occupancy rate. For example, if there is low congestion in a resource pool, the gNB may disable the UE-to-UE coordination function or a subset of functions. As used herein, a "resource pool" refers to a set of resources allocated for sidelink operation. A resource pool consists of a set of resource blocks (i.e., physical resource blocks ("PRBs")) spanning one or more time units (e.g., subframe, slot, OFDM symbol). In some embodiments, the set of resource blocks comprises consecutive PRBs in the frequency domain. As used herein, a PRB refers to 12 consecutive subcarriers in the frequency domain. In particular embodiments, UEs may be configured with separate transmit resource pools (“Tx RP”) and receive resource pools (“Rx RP”), where the Tx RP of one UE is associated with the Rx RP of another UE to enable sidelink communications.

[0096] Inter-UE coordination functions / solutions include sharing of preferred resource sets, reserved resources, non-preferred resources, and contention resources. In one implementation, the gNB may disable sharing of preferred resource sets when there is little congestion in the channel. In another implementation, the gNB may enable inter-UE coordination functions / solutions, or a subset of functions / solutions, for each resource pool based on the channel busy rate / channel occupancy rate.

[0097] According to an embodiment of the fourth solution, there is a single sub-channel configuration for transmitting the assistance information. In the fourth solution, a single sub-channel configuration can be defined for the transmission of the assistance information, and resources for the transmission of the assistance information can be reserved by another UE or a gNB (resource allocation mode 1).

[0098] In NR sidelink resource allocation mode 1, a separate scheduling request ("SR") configuration can be associated with the assistance information or a single subchannel configuration for requesting resources from the gNB for transmission of the assistance information. The assistance information may be transmitted using a second SCI format, and the single subchannel configuration may include only the first SCI and the second SCI.

[0099] According to an embodiment of the fifth solution, there is a parameter for candidate resource selection to determine preferred / non-preferred resources. In the fifth solution, the upper layer parameter includes information for determining the subset of resources to be reported to the upper layer as preferred or non-preferred. There may be an additional RSRP threshold for selecting the preferred or non-preferred subset of the reported resources. Furthermore, the upper layer parameter includes a time-wise earliest flag for selecting the preferred set of resources.

[0100] In another implementation, the resource pool configuration includes an additional RSRP threshold for selecting a preferred or non-preferred subset of resources to be reported and / or flagged as earliest in time. In another implementation, the assistance information includes an active UL CG resource configuration, such as time / frequency resources, periodicity, etc. In another implementation, the assistance information includes a preferred SL CG resource from UE-A to UE-B, which may also be Type 1 and Type 2 CG resources and their durations scheduled by the gNB for sidelink devices.

[0101] In another embodiment, UE-A may perform the resource selection procedure by considering the common active period between UE-A and UE-B and using a window (common active period between UE-A and UE-B) to estimate the averaged RSRP from the sensing slots for candidate resource selection, and then the candidate exclusion process is performed only for the common active period between UE-A and UE-B by excluding slots that the UE did not monitor due to half-duplex issues.

[0102] 5 illustrates an SL protocol stack 500 according to an embodiment of the present disclosure. While FIG. 5 illustrates UE-A 205 and UE-B 210, which represent a set of UEs using sidelink communication over a PC5 interface, other embodiments may include different SL UEs. In various embodiments, UE-A 205 and UE-B 210 may each be an embodiment of a remote unit 105.

[0103] As shown, the SL protocol stack (i.e., the PC5 protocol stack) includes a physical ("PHY") layer 515 (also known as Layer 1, or "LI"), a MAC sublayer 520, a radio link control ("RLC") sublayer 525, a packet data convergence protocol ("PDCP") sublayer 530, a service data adaptation protocol ("SDAP") layer 535 (e.g., for the user plane), and a radio resource control ("RRC") layer 540 (e.g., for the control plane). Additional layers may exist above the RRC and SDAP layers, such as an application layer (not shown).

[0104] The access stratum ("AS") layer (also called "AS protocol stack") for the control plane in a PC5 interface consists of at least the RRC, PDCP, RLC, and MAC sublayers and a physical layer. The AS layer (also called "AS protocol stack") for the user plane in a PC5 interface consists of at least the SDAP, PDCP, RLC, and MAC sublayers and a physical layer.

[0105] Layer 1 (“LI”) refers to the PHY layer 515. Layer 2 (“L2”) is divided into SDAP, PDCP, RLC, and MAC sublayers. Layer 3 (“L3”) includes the RRC sublayer and the NAS layer for the control plane, e.g., the Internet Protocol (“IP”) layer or PDU layer (not shown) for the user plane. LI and L2 are commonly referred to as “lower layers,” while L3 and above (e.g., the transport layer, Vehicle-to-Everything (“V2X”) layer, and application layer) are referred to as “higher layers” or “upper layers.”

[0106] The physical layer 515 provides transport channels to the MAC sublayer 520. The MAC sublayer 520 provides logical channels to the RLC sublayer 525. The RLC sublayer 525 provides RLC channels to the PDCP sublayer 530. The PDCP sublayer 530 provides radio bearers to the SDAP sublayer 535 and / or the RRC layer 540. The SDAP sublayer 535 provides QoS flows to higher layers. The RRC layer 540 manages the establishment, configuration, maintenance, and release of signaling radio bearers ("SRBs") and data radio bearers ("DRBs").

[0107] In some embodiments, the PHY layer 515 determines a common active period between the peer UEs and / or identifies an intersection between the active time and the determined set of (sidelink) resources. As described above, the PHY layer 515 may receive parameters and / or indications from the MAC layer 520. In other embodiments, the MAC layer 520 may determine a common active period between the peer UEs and / or identify an intersection between the active time and the determined set of (sidelink) resources, and the MAC layer 520 receives parameters and / or indications from the PHY layer 515.

[0108] SCI format 1-A is used for scheduling the PSSCH and the second stage SCI on the PSSCH. The following information is transmitted using SCI format 1-A: Priority - 3 bits as specified in 3GPP TS 23.287 clause 5.4.3.3 and 3GPP TS 38.321 clause 5.22.1.3.1. Frequency resource allocation - If the value of the upper layer parameter sl-MaxNumPerReserve is set to 2,

[0109]

number

[0110] bits, otherwise if the value of the upper layer parameter sl-MaxNumPerReserve is set to 3 as defined in 3GPP TS 38.214 clause 8.1.2.2

[0111]

number

[0112] bit. · Time resource allocation - 5 bits if the value of the higher layer parameter sl-MaxNumPerReserve is set to 2, otherwise 9 bits if the value of the higher layer parameter sl-MaxNumPerReserve is set to 3, as defined in clause 8.1.2.1 of 3GPP TS 38.214. Resource Reservation Period - as defined in 3GPP TS 38.214, clause 8.1.4

[0113]

number

[0114] bits, and in the above formula, if the upper layer parameter sl-MultiReserveResource is set, N rsv_period is the number of entries in the upper layer parameter sl-ResourceReservePeriodList, otherwise it is a 0 bit. Demodulation Reference Signal ("DMRS") pattern - as defined in 3GPP TS 38.211, clause 8.4.1.1.2

[0115]

number

[0116] bits, and in the above formula, N pattern is the number of DMRS patterns configured by the upper layer parameter sl-PSSCH-DMRS-TimePatternList. · Second stage SCI format - 2 bits as defined in 3GPP TS 38.212, Table 8.3.1.1-1. · Beta_offset indicator - 2 bits provided by the higher layer parameter sl-BetaOffsets2ndSCI and Table 8.3.1.1-2. Number of DMRS ports - 1 bit as defined in 3GPP TS 38.212, Table 8.3.1.1-3. Modulation and coding scheme - 5 bits as defined in 3GPP TS 38.214, clause 8.1.3. Additional Modulation and Coding Scheme ("MCS") Table Indicator - defined in 3GPP TS 38.214, clause 8.1.3.1: 1 bit if one MCS table is configured by the higher layer parameter sl-Additional-MCS-Table, 2 bits if two MCS tables are configured by the higher layer parameter si-Additional-MCS-Table, 0 bit otherwise. ·PSFCH overhead indication - 1 bit as defined in clause 8.1.3.2 of 3GPP TS 38.214 if higher layer parameter sl-PSFCH-Period=2 or 4, otherwise 0 bit. Reserved - The number of bits determined by the higher layer parameter sl-NumReservedBits, whose value is set to 0.

[0117] The fields defined in each of the following second-stage SCI formats are information bits a0 to a1 as follows: A-1 The fields are mapped in the order they appear in the description, with the first field mapped to the least significant information bit, a0, and each subsequent field mapped to a more significant information bit. The most significant bit of each field is mapped to the least significant information bit of that field, e.g., the most significant bit of the first field is mapped to a0.

[0118] SCI format 2-A is used for decoding PSSCH by HARQ operation when the HARQ-ACK information includes an ACK or a NACK, when the HARQ-ACK information includes only a NACK, or when there is no feedback of HARQ-ACK information.

[0119] The following information is transmitted using SCI Format 2-A. HARQ process number - 4 bits defined in 3GPP TS 38.213 clause 16.4. New Data Indicator - 1 bit defined in 3GPP TS 38.213 clause 16.4. · Redundancy Version - 2 bits defined in 3GPP TS 38.214, clause 16.4. · Source ID - 8 bits as defined in 3GPP TS 38.214, clause 8.1. · Destination ID - 16 bits as defined in 3GPP TS 38.214, clause 8.1. HARQ Feedback Enable / Disable Indicator - 1 bit defined in clause 16.3 of 3GPP TS 38.213. Cast Type Indicator - 2 bits defined in GPP TS 38.212, Table 8.4.1.1-1. CSI Request – 1 bit defined in 3GPP TS 38.214, clause 8.2.1.

[0120] [Table 2]

[0121] SCI format 2-B is used for decoding PSSCH with HARQ operation when HARQ-ACK information contains only NACK or when there is no feedback of HARQ-ACK information. The following information is transmitted using SCI format 2-B: HARQ process number - 4 bits defined in 3GPP TS 38.213 clause 16.4. New Data Indicator - 1 bit defined in 3GPP TS 38.213 clause 16.4. · Redundancy Version - 2 bits defined in 3GPP TS 38.214, clause 16.4. · Source ID - 8 bits as defined in 3GPP TS 38.214, clause 8.1. · Destination ID - 16 bits as defined in 3GPP TS 38.214, clause 8.1. HARQ Feedback Enable / Disable Indicator - 1 bit defined in clause 16.3 of 3GPP TS 38.213. Zone ID - 12 bits as defined in 3GPP TS 38.331, clause 5.8.11. · Communication Range Requirements - 4 bits determined by the higher layer parameter sl-ZoneConfigMCR-Index.

[0122] [Table 3]

[0123] [Table 4]

[0124] [Table 5]

[0125] 6 illustrates a user equipment device 600 that may be used to indicate contention for sidelink resources using a feedback channel, according to an embodiment of the present disclosure. In various embodiments, the user equipment device 600 is used to implement one or more of the solutions described above. The user equipment device 600 may be an embodiment of the remote unit 105, UE-A 205, UE-B 210, Rx UE-A, and / or Tx UE described above. Additionally, the user equipment device 600 may include a processor 605, a memory 610, an input device 615, an output device 620, and a transceiver 625.

[0126] In some embodiments, input device(s) 615 and output device(s) 620 are combined into a single device, such as a touchscreen. In particular embodiments, user equipment device 600 may not include input device(s) 615 and / or output device(s) 620. In various embodiments, user equipment device 600 may include one or more of processor 605, memory 610, and transceiver 625, and may not include input device(s) 615 and / or output device(s) 620.

[0127] As shown, the transceiver 625 includes at least one transmitter 630 and at least one receiver 635. In some embodiments, the transceiver 625 communicates with one or more cells (or wireless coverage areas) supported by one or more base units 121. In various embodiments, the transceiver 625 is operable in an unlicensed spectrum. Additionally, the transceiver 625 may include multiple UE panels supporting one or more beams. Additionally, the transceiver 625 may support at least one network interface 640 and / or application interface 645. The application interface 645 may support one or more APIs. The network interface 640 may support 3GPP reference points such as Uu, NI, PC5, etc. As will be appreciated by those skilled in the art, other network interfaces 640 may be supported.

[0128] In one embodiment, the processor 605 may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, the processor 605 may be a microcontroller, microprocessor, central processing unit (“CPU”), graphics processing unit (“GPU”), auxiliary processing unit, field programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, the processor 605 executes instructions stored in the memory 610 to perform the methods and routines described herein. The processor 605 is communicatively coupled to the memory 610, input devices 615, output devices 620, and a transceiver 625.

[0129] In various embodiments, the processor 605 controls the user equipment device 600 to implement the UE behavior described above. In particular embodiments, the processor 605 may include an application processor (also known as a “main processor”) that manages application domain and operating system (“OS”) functions, and a baseband processor (also known as a “baseband radio processor”) that manages radio functions.

[0130] In various embodiments, user equipment device 600 is an Rx UE (e.g., UE-A 205 and / or the Rx UEs described above) that communicates with peer Tx UEs using sidelink communication resources as described herein. In such embodiments, processor 605 controls user equipment device 600 to perform the behavior of an Rx UE described above.

[0131] In some embodiments, the transceiver 625 receives an SCI from the peer UE on a first resource of the physical sidelink control channel, the SCI comprising information indicating future resources reserved for future transmissions. The processor 605 determines whether there is a resource conflict, the resource conflict comprising expected collisions on future resources. The transceiver 625 transmits feedback to the peer UE on a feedback resource, the feedback comprising an indication of whether there is a resource conflict.

[0132] In one embodiment, the resource contention comprises a time domain collision, i.e., the half-duplex problem described above occurs. In another embodiment, the resource contention comprises a time / frequency collision. In some embodiments, the SCI comprises a field (e.g., 1 bit) indicating whether the contention indication is enabled. In a particular embodiment, the SCI further comprises a second field (e.g., 1 bit) indicating whether HARQ feedback is enabled.

[0133] In some embodiments, the transceiver 625 further receives an initial transmission of sidelink data, where the SCI accompanies the initial transmission. In such embodiments, the feedback includes a first set of feedback resources for indicating HARQ feedback (i.e., HARQ-ACK report) and a second set of feedback resources for indicating whether there is a resource conflict. Here, the first set of feedback resources includes HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission (i.e., ACK) and a negative acknowledgment to the initial transmission (i.e., NACK).

[0134] In a particular embodiment, the SCI indicates multiple reservations of future resources, and the second set of feedback resources includes a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. In other embodiments, the second set of feedback resources includes a single conflict indication bit indicating whether there is a resource conflict for any of the future resources.

[0135] In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate physical resource blocks on a common symbol in the time domain. In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate symbols in the time domain on a common slot and on a common set (i.e., one or more) of physical resource blocks.

[0136] In various embodiments, the user equipment device 600 is a Tx UE (e.g., UE-B 210 and / or the Tx UEs described above) that communicates with a peer Rx UE (e.g., UE-A 205) using sidelink communication resources as described herein. In such embodiments, the processor 605 controls the user equipment device 600 to perform the behavior of a Tx UE described above.

[0137] In some embodiments, the processor 605 generates an SCI including information indicating future resources reserved for future transmissions and controls the transceiver 625 to transmit the SCI to the peer UE on a first resource of the PSCCH. The transceiver 625 receives feedback from the peer UE on a feedback resource, the feedback including an indication of whether there is a resource contention, the resource contention including an expected collision on the future resource.

[0138] In some embodiments, the processor 605 triggers resource reselection if feedback from the peer UE indicates resource contention. In one embodiment, the resource contention includes time-domain collision, i.e., the half-duplex problem described above occurs. In another embodiment, the resource contention includes time / frequency collision. In some embodiments, the SCI includes a field (i.e., 1 bit) indicating whether the contention indication is enabled. In a particular embodiment, the SCI further includes a second field (i.e., 1 bit) indicating whether HARQ feedback is enabled.

[0139] In some embodiments, the transceiver 625 further transmits an initial transmission of sidelink data, where the SCI accompanies the initial transmission. In such embodiments, the feedback includes a first set of feedback resources for indicating HARQ feedback (i.e., HARQ-ACK report) and a second set of feedback resources for indicating whether there is a resource conflict. Here, the first set of feedback resources includes HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission (i.e., ACK) and a negative acknowledgment to the initial transmission (i.e., NACK).

[0140] In a particular embodiment, the SCI indicates multiple reservations of future resources, and the second set of feedback resources comprises a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. In other embodiments, the second set of feedback resources comprises a single conflict indication bit indicating whether there is a resource conflict for any of the future resources.

[0141] In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate physical resource blocks on a common symbol in the time domain. In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate symbols in the time domain on a common slot and on a common set (i.e., one or more) of physical resource blocks.

[0142] Memory 610, in one embodiment, is a computer-readable storage medium. In some embodiments, memory 610 includes a volatile computer storage medium. For example, memory 610 may include RAM, including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and / or static RAM (“SRAM”). In some embodiments, memory 610 includes a non-volatile computer storage medium. For example, memory 610 may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, memory 610 includes both volatile and non-volatile computer storage media.

[0143] In some embodiments, the memory 610 stores data related to indicating contention for sidelink resources using a feedback channel and / or mobile behavior. For example, the memory 610 may store various parameters, panel / beam configurations, resource allocations, policies, etc., as described above. In particular embodiments, the memory 610 also stores program code and associated data, such as an operating system or other controller algorithms operating on the device 600.

[0144] The input device 615, in one embodiment, may include any known computer input device, including a touch panel, buttons, a keyboard, a stylus, a microphone, etc. In some embodiments, the input device 615 may be integrated with the output device 620, for example, as a touch screen or similar touch-sensitive display. In some embodiments, the input device 615 includes a touch screen so that text may be entered using a virtual keyboard displayed on the touch screen and / or by handwriting on the touch screen. In some embodiments, the input device 615 includes two or more different devices, such as a keyboard and a touch panel.

[0145] Output device 620, in one embodiment, is designed to output visual, auditory, and / or tactile signals. In some embodiments, output device 620 includes an electronically controllable display or display device capable of outputting visual data to a user. For example, output device 620 may include, but is not limited to, a liquid crystal display ("LCD"), a light-emitting diode ("LED") display, an organic LED ("OLED") display, a projector, or similar display device capable of outputting images, text, and the like to a user. As another non-limiting example, output device 620 may include a wearable display that is separate from but communicatively coupled to the rest of user equipment device 600, such as a smartwatch, smart glasses, a head-up display, or the like. Furthermore, output device 620 may be a component of a smartphone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0146] In particular embodiments, output device(s) 620 include one or more speakers for generating sound. For example, output device(s) 620 may generate audible alerts or notifications (e.g., beeps or chimes). In some embodiments, output device(s) 620 include one or more haptic devices for generating vibration, movement, or other haptic feedback. In some embodiments, all or a portion of output device(s) 620 may be integrated with input device(s) 615. For example, input device(s) 615 and output device(s) 620 may form a touchscreen or similar touch-sensitive display. In other embodiments, output device(s) 620 may be located near input device(s) 615.

[0147] The transceiver 625 communicates with one or more network functions of a mobile communications network via one or more access networks. The transceiver 625 operates under the control of the processor 605 to transmit and receive messages, data, and other signals. For example, the processor 605 may selectively activate the transceiver 625 (or portions thereof) at particular times to transmit and receive messages.

[0148] The transceiver 625 includes at least a transmitter 630 and at least one receiver 635. One or more transmitters 630 may be used to provide UL communication signals, such as the UL transmissions described herein, to the base unit 121. Similarly, one or more receivers 635 may be used to receive DL communication signals from the base unit 121, as described herein. Although only one transmitter 630 and one receiver 635 are shown, the user equipment device 600 may have any suitable number of transmitters 630 and receivers 635. Furthermore, the transmitter 630 and receiver 635 may be any suitable type of transmitter and receiver. In one embodiment, the transceiver 625 includes a first transmitter / receiver pair used to communicate with a mobile communication network over a licensed radio spectrum and a second transmitter / receiver pair used to communicate with a mobile communication network over an unlicensed radio spectrum.

[0149] In particular embodiments, a first transmitter / receiver pair used to communicate with a mobile communications network over a licensed radio spectrum and a second transmitter / receiver pair used to communicate with a mobile communications network over an unlicensed radio spectrum may be combined into a single transceiver unit, e.g., a single chip that performs functions for use in both the licensed and unlicensed radio spectrum. In some embodiments, the first transmitter / receiver pair and the second transmitter / receiver pair may share one or more hardware components. For example, a particular transceiver 625, transmitter 630, and receiver 635 may be implemented as physically separate components that access shared hardware and / or software resources, such as, for example, a network interface 640.

[0150] In various embodiments, one or more transmitters 630 and / or one or more receivers 635 may be implemented and / or integrated in a single hardware component, such as a multi-transceiver chip, a system-on-chip, an application-specific integrated circuit (“ASIC”), or other type of hardware component. In particular embodiments, one or more transmitters 630 and / or one or more receivers 635 may be implemented and / or integrated in a multi-chip module. In some embodiments, other components, such as a network interface 640 or other hardware components / circuits, may be integrated into a single chip with any number of transmitters 630 and / or receivers 635. In such embodiments, the transmitters 630 and receivers 635 may be logically configured as a transceiver 625 using another common control signal or as modular transmitters 630 and receivers 635 implemented in the same hardware chip or multi-chip module.

[0151] 7 illustrates a network device 700 that may be used to indicate contention for sidelink resources using a feedback channel, according to an embodiment of the present disclosure. In one embodiment, the network device 700 may be an implementation of a RAN entity used to implement one or more of the above solutions. The network device 700 may be an embodiment of the base unit 121, as described above. Furthermore, the network device 700 may include a processor 705, a memory 710, an input device 715, an output device 720, and a transceiver 725.

[0152] In some embodiments, the input device(s) 715 and the output device(s) 720 are combined into a single device, such as a touchscreen. In particular embodiments, the network device 700 may not include the input device(s) 715 and / or the output device(s) 720. In various embodiments, the network device 700 may include one or more of the processor 705, the memory 710, and the transceiver 725, and may not include the input device(s) 715 and / or the output device(s) 720.

[0153] As shown, the transceiver 725 includes at least one transmitter 730 and at least one receiver 735, where the transceiver 725 communicates with one or more remote units 105. Additionally, the transceiver 725 may support at least one network interface 740 and / or application interface 745. The application interface 745 may support one or more APIs. The network interface 740 may support 3GPP reference points such as Uu, Nl, N2, and N3. As will be appreciated by those skilled in the art, other network interfaces 740 may be supported.

[0154] In one embodiment, the processor 705 may include any known controller capable of executing computer-readable instructions and / or performing logical operations. For example, the processor 705 may be a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, or similar programmable controller. In some embodiments, the processor 705 executes instructions stored in the memory 710 to perform the methods and routines described herein. The processor 705 is communicatively coupled to the memory 710, the input device 715, the output device 720, and the transceiver 725.

[0155] In various embodiments, the network device 700 is a RAN node (e.g., a gNB) that communicates with one or more UEs as described herein. In such embodiments, the processor 705 controls the network device 700 to perform the RAN behavior described above. When operating as a RAN node, the processor 705 may include an application processor (also known as a “main processor”) that manages application domain and operating system (“OS”) functions, and a baseband processor (also known as a “baseband radio processor”) that manages radio functions.

[0156] In some embodiments, the processor 705 may control the transceiver to transmit configurations and / or resource assignments for sidelink operation to one or more UEs.

[0157] Memory 710, in one embodiment, is a computer-readable storage medium. In some embodiments, memory 710 includes a volatile computer storage medium. For example, memory 710 may include RAM, including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and / or static RAM (“SRAM”). In some embodiments, memory 710 includes a non-volatile computer storage medium. For example, memory 710 may include a hard disk drive, flash memory, or any other suitable non-volatile computer storage device. In some embodiments, memory 710 includes both volatile and non-volatile computer storage media.

[0158] In some embodiments, memory 710 stores data related to indicating contention for sidelink resources using a feedback channel and / or mobile behavior. For example, memory 710 may store parameters, configurations, resource allocations, policies, etc., as described above. In particular embodiments, memory 710 also stores program code and associated data, such as an operating system or other controller algorithms operating on device 700.

[0159] Input device(s) 715, in one embodiment, may include any known computer input device, including a touch panel, buttons, a keyboard, a stylus, a microphone, etc. In some embodiments, input device(s) 715 may be integrated with output device(s) 720, for example, as a touch screen or similar touch-sensitive display. In some embodiments, input device(s) 715 includes a touch screen so that text may be entered using a virtual keyboard displayed on the touch screen and / or by handwriting on the touch screen. In some embodiments, input device(s) 715 includes two or more different devices, such as a keyboard and a touch panel.

[0160] Output device 720, in one embodiment, is designed to output visual, auditory, and / or tactile signals. In some embodiments, output device 720 includes an electronically controllable display or display device capable of outputting visual data to a user. For example, output device 720 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or similar display device capable of outputting images, text, etc. to a user. As another non-limiting example, output device 720 may include a wearable display that is separate from but communicatively coupled to the rest of network apparatus 700, such as a smartwatch, smart glasses, a head-up display, etc. Furthermore, output device 720 may be a component of a smartphone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, etc.

[0161] In particular embodiments, output device(s) 720 include one or more speakers for generating sound. For example, output device(s) 720 may generate audible alerts or notifications (e.g., beeps or chimes). In some embodiments, output device(s) 720 include one or more haptic devices for generating vibration, movement, or other haptic feedback. In some embodiments, all or a portion of output device(s) 720 may be integrated with input device(s) 715. For example, input device(s) 715 and output device(s) 720 may form a touchscreen or similar touch-sensitive display. In other embodiments, output device(s) 720 may be located near input device(s) 715.

[0162] The transceiver 725 includes at least a transmitter 730 and at least one receiver 735. As described herein, one or more transmitters 730 may be used to communicate with a UE. Similarly, as described herein, one or more receivers 735 may be used to communicate with a public land mobile network ("PLMN") and / or network functions in the RAN. Although only one transmitter 730 and one receiver 735 are shown, the network device 700 may have any suitable number of transmitters 730 and receivers 735. Furthermore, the transmitter 730 and receiver 735 may be any suitable type of transmitter and receiver.

[0163] 8 illustrates one embodiment of a method 800 for indicating contention for sidelink resources using a feedback channel in accordance with embodiments of the present disclosure. In various embodiments, method 800 is performed by an Rx UE, such as the remote unit 105, UE-A 205, Rx UE, and / or user equipment device 600, as described above. In some embodiments, method 800 is performed by a processor, such as a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, etc.

[0164] The method 800 begins by receiving an SCI from a peer UE on a first resource of a PSCCH (805), the SCI including information indicating future resources reserved for future transmissions. The method 800 includes determining whether there is a resource conflict (810), the resource conflict including expected collisions on future resources. The method 800 includes transmitting feedback to the peer UE on a feedback resource (815), the feedback including an indication of whether there is a resource conflict. The method 800 ends. In one embodiment, the resource conflict comprises a time-domain conflict, i.e., the half-duplex problem described above occurs. In another embodiment, the resource conflict comprises a time / frequency collision.

[0165] 9 illustrates one embodiment of a method 900 for indicating contention for sidelink resources using a feedback channel in accordance with embodiments of the present disclosure. In various embodiments, the method 900 is performed by a Tx UE device, such as the remote unit 105, the UE-B 210, the Tx UE, and / or the user equipment device 600, as described above. In some embodiments, the method 900 is performed by a processor, such as a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, an FPGA, or the like.

[0166] The method 900 begins by transmitting an SCI to a peer UE on a first resource of a physical sidelink control channel (905), the SCI comprising information indicating future resources reserved for future transmissions. The method 900 includes receiving feedback from the peer UE on a feedback resource (910), the feedback comprising an indication of whether there is resource contention, the resource contention comprising expected collisions on future resources. The method 900 then ends. In one embodiment, the resource contention comprises a time-domain collision, i.e., resulting in the half-duplex problem described above. In another embodiment, the resource contention comprises a time-frequency collision.

[0167] Disclosed herein is a first apparatus for indicating a sidelink resource conflict using a feedback channel according to an embodiment of the present disclosure. The first apparatus may be implemented by a receiver UE, such as the remote unit 105, the UE-A 205, the Rx UE, and / or the user equipment device 600, as described above. The first apparatus includes a receiver that receives an SCI from a peer UE in a first resource of a PSCCH, the SCI including information indicating future resources reserved for future transmissions. The first apparatus includes a processor that determines whether there is a resource conflict, the resource conflict including expected collisions in the future resources. The first apparatus includes a transmitter that transmits feedback to the peer UE in the feedback resource, the feedback including an indication of whether there is a resource conflict.

[0168] In one embodiment, the resource contention comprises a time domain collision, i.e., the half-duplex problem described above occurs. In another embodiment, the resource contention comprises a time / frequency collision. In some embodiments, the SCI comprises a field (e.g., 1 bit) indicating whether the contention indication is enabled. In particular embodiments, the SCI further comprises a second field (e.g., 1 bit) indicating whether HARQ feedback is enabled.

[0169] In some embodiments, the receiver further receives an initial transmission of sidelink data, and the SCI accompanies the initial transmission. In such embodiments, the feedback includes a first set of feedback resources for indicating HARQ feedback (i.e., HARQ-ACK report) and a second set of feedback resources for indicating whether there is a resource conflict. Here, the first set of feedback resources includes HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission (i.e., ACK) and a negative acknowledgment to the initial transmission (i.e., NACK).

[0170] In a particular embodiment, the SCI indicates multiple reservations of future resources, and the second set of feedback resources includes a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. In other embodiments, the second set of feedback resources includes a single conflict indication bit indicating whether there is a resource conflict for any of the future resources.

[0171] In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate physical resource blocks on a common symbol in the time domain. In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate symbols in the time domain on a common slot and on a common set (i.e., one or more) of physical resource blocks.

[0172] A first method for indicating a sidelink resource conflict using a feedback channel according to an embodiment of the present disclosure is disclosed herein. The first method may be performed by a receiver UE, such as the remote unit 105, the UE-A 205, an Rx UE, and / or an Rx UE, such as the user equipment device 600, as described above. The first method includes receiving an SCI from a peer Tx UE in a first resource of a PSCCH, the SCI including information indicating future resources reserved for future transmissions. The first method includes determining whether there is a resource conflict, the resource conflict including expected collisions in the future resources. The first method includes transmitting feedback to the peer UE in a feedback resource, the feedback including an indication of whether there is a resource conflict.

[0173] In one embodiment, the resource contention comprises a time domain collision, i.e., the half-duplex problem described above occurs. In another embodiment, the resource contention comprises a time / frequency collision. In some embodiments, the SCI includes a field (e.g., 1 bit) indicating whether the contention indication is enabled. In particular embodiments, the SCI further includes a second field (e.g., 1 bit) indicating whether HARQ feedback is enabled.

[0174] In some embodiments, the first method further includes receiving an initial transmission of sidelink data, where the SCI accompanies the initial transmission. In such embodiments, the feedback includes a first set of feedback resources for indicating HARQ feedback (i.e., HARQ-ACK report) and a second set of feedback resources for indicating whether there is a resource conflict. Here, the first set of feedback resources includes HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission (i.e., ACK) and a negative acknowledgment to the initial transmission (i.e., NACK).

[0175] In a particular embodiment, the SCI indicates multiple reservations of future resources, and the second set of feedback resources includes a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. In other embodiments, the second set of feedback resources includes a single conflict indication bit indicating whether there is a resource conflict for any of the future resources.

[0176] In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate physical resource blocks on a common symbol in the time domain. In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate symbols in the time domain on a common slot and on a common set (i.e., one or more) of physical resource blocks.

[0177] Disclosed herein is a second apparatus for indicating sidelink resource contention using a feedback channel according to embodiments of the present disclosure. The second apparatus may be implemented by a transmitter UE device, such as the remote unit 105, the UE-B 210, the Tx UE, and / or the user equipment device 600, described above. The second apparatus includes a processor for generating an SCI including information indicating future resources reserved for future transmissions, and a transmitter for transmitting the SCI to a peer UE on a first resource of a PSCCH. The second apparatus includes a receiver for receiving feedback from the peer UE on the feedback resource, the feedback including an indication of whether there is resource contention, the resource contention including expected collisions on the future resources.

[0178] In some embodiments, the processor triggers resource reselection in response to feedback from a peer UE indicating resource contention. In one embodiment, the resource contention comprises a time domain collision, i.e., resulting in the half-duplex problem described above. In another embodiment, the resource contention comprises a time / frequency collision. In some embodiments, the SCI includes a field (i.e., 1 bit) indicating whether the contention indication is enabled. In a particular embodiment, the SCI further includes a second field (i.e., 1 bit) indicating whether HARQ feedback is enabled.

[0179] In some embodiments, the transmitter further transmits an initial transmission of sidelink data, and the SCI accompanies the initial transmission. In such embodiments, the feedback includes a first set of feedback resources for indicating HARQ feedback (i.e., HARQ-ACK report) and a second set of feedback resources for indicating whether there is a resource conflict. Here, the first set of feedback resources includes HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission (i.e., ACK) and a negative acknowledgment to the initial transmission (i.e., NACK).

[0180] In a particular embodiment, the SCI indicates multiple reservations of future resources, and the second set of feedback resources comprises a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. In other embodiments, the second set of feedback resources comprises a single conflict indication bit indicating whether there is a resource conflict for any of the future resources.

[0181] In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate physical resource blocks on a common symbol in the time domain. In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate symbols in the time domain on a common slot and on a common set (i.e., one or more) of physical resource blocks.

[0182] A second method for indicating a sidelink resource conflict using a feedback channel according to embodiments of the present disclosure is disclosed herein. The second method may be performed by a transmitter UE device, such as the remote unit 105, the UE-B 210, the Tx UE, and / or the user equipment device 600, as described above. The second method includes transmitting a SCI to a peer UE on a first resource of a physical sidelink control channel, the SCI including information indicating future resources reserved for future transmissions. The second method includes receiving feedback from the peer UE on a feedback resource, the feedback including an indication of whether there is a resource conflict, the resource conflict including an expected collision on the future resource.

[0183] In some embodiments, the second method further includes triggering resource reselection in response to feedback from the peer UE indicating resource contention. In one embodiment, the resource contention comprises a time-domain collision, i.e., resulting in the half-duplex problem described above. In another embodiment, the resource contention comprises a time / frequency collision. In some embodiments, the SCI includes a field (i.e., 1 bit) indicating whether the contention indication is enabled. In a particular embodiment, the SCI further includes a second field (i.e., 1 bit) indicating whether HARQ feedback is enabled.

[0184] In some embodiments, the second method further includes transmitting an initial transmission of sidelink data, where the SCI accompanies the initial transmission. In such embodiments, the feedback includes a first set of feedback resources for indicating HARQ feedback (i.e., HARQ-ACK report) and a second set of feedback resources for indicating whether there is a resource conflict. Here, the first set of feedback resources includes HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission (i.e., ACK) and a negative acknowledgment to the initial transmission (i.e., NACK).

[0185] In a particular embodiment, the SCI indicates multiple reservations of future resources, and the second set of feedback resources comprises a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. In other embodiments, the second set of feedback resources comprises a single conflict indication bit indicating whether there is a resource conflict for any of the future resources.

[0186] In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate physical resource blocks on a common symbol in the time domain. In a particular embodiment, the first set of feedback resources and the second set of feedback resources comprise separate symbols in the time domain on a common slot and on a common set (i.e., one or more) of physical resource blocks.

[0187] The embodiments may be embodied in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is therefore indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope. [Explanation of symbols]

[0188] 100 Wireless Communication System 105 Remote Unit 107 Applications 115 Sidelink ("SL") Communication Signals 120 Radio Access Network (“RAN”) 121 Base Unit 123 Wireless Communication Links 140 Mobile Core Network 141 User Plane Function ("UPF") 143 Access and Mobility Management Function (“AMF”) 145 Session Management Facility ("SMF") 146 Location Management Function (“LMF”) 147 Policy Control Function ("PCF") 149 Combined entity "UDM / UDR" 150 Packet Data Network 151 Application Server 200 steps 205 UE-A 210 UE-B 215 Messaging 220 Messaging 230 Messaging 300 frame structure 305 SCI 310 Slots 315 Slots 320 Frequency Domain Multiplexing, PSFCH 325 Time Domain Multiplexing 330 Conflict display 335 HARQ report 400 frame structure 410 Slots 415 Slots 420 PSFCH 425 PSFCH 430 PSFCH 500 SL Protocol Stack 515 Physical ("PHY") Layer 520 Medium Access Control ("MAC") Sublayer 525 Radio Link Control ("RLC") Sublayer 530 Packet Data Convergence Protocol ("PDCP") Sublayer 535 Service Data Adaptation Protocol ("SDAP") Layer, SDAP Sublayer 540 Radio Resource Control ("RRC") Layer 600 User Equipment Device 605 processor 610 memory 615 Input Devices 620 output device 625 Transceiver 630 Transmitter 635 receiver 640 network interface 645 Application Interface 700 Network Equipment 705 processor 710 memory 715 Input Devices 720 output device 725 Transceiver 730 Transmitter 735 receiver 740 network interface 745 Application Interface 800 ways 900 ways

Claims

1. 1. A method for a user equipment ("UE"), comprising: receiving sidelink control information ("SCI") comprising an indication of a set of resources reserved for sidelink communication; determining a conflict for reserved resources from the set of resources reserved for the sidelink communication; transmitting the indication of contention over a physical sidelink feedback channel. wherein the SCI comprises a field indicating whether conflict indication is enabled.

2. 2. The method of claim 1, wherein the SCI further comprises a second field indicating whether hybrid automatic repeat request ("HARQ") feedback is enabled.

3. 2. The method of claim 1, further comprising receiving an initial transmission of sidelink data, wherein the SCI accompanies the initial transmission, and wherein the physical sidelink feedback channel comprises a first set of feedback resources for indicating Hybrid Automatic Repeat Request (HARQ) feedback and a second set of feedback resources for indicating whether there is a resource contention, the first set of feedback resources comprising HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission and a negative acknowledgment to the initial transmission.

4. 4. The method of claim 3, wherein the second set of feedback resources comprises a single conflict indication bit that indicates whether there is a resource conflict for any of the future resources.

5. 4. The method of claim 3, wherein the SCI indicates multiple reservations of future resources, and the second set of feedback resources comprises a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for a corresponding reservation.

6. the first set of feedback resources and the second set of feedback resources separate physical resource blocks on a common symbol in the time domain; and distinct symbols in the time domain on a common slot and on a common set of physical resource blocks The method of claim 3, comprising one of:

7. a processor; a memory coupled to the processor, the memory comprising: receiving sidelink control information (“SCI”) comprising an indication of a set of resources reserved for sidelink communications; determining a conflict for reserved resources among the set of resources reserved for the sidelink communication; and transmitting the indication of contention over a physical sidelink feedback channel; and the SCI includes a field indicating whether a contention indication is enabled. UE.

8. The SCI further comprises a second field indicating whether hybrid automatic repeat request ("HARQ") feedback is enabled. The UE of claim 7.

9. receiving an initial transmission of sidelink data, wherein the SCI accompanies the initial transmission, and wherein the physical sidelink feedback channel comprises a first set of feedback resources for indicating Hybrid Automatic Repeat Request ("HARQ") feedback and a second set of feedback resources for indicating whether there is resource contention, the first set of feedback resources comprising HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission and a negative acknowledgment to the initial transmission. The UE of claim 7.

10. the second set of feedback resources comprises a single conflict indication bit that indicates whether there is a resource conflict for any of the future resources. The UE of claim 9.

11. The SCI indicates multiple reservations of future resources, and the second set of feedback resources comprises a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for the corresponding reservation. The UE of claim 9.

12. the first set of feedback resources and the second set of feedback resources separate physical resource blocks on a common symbol in the time domain; and separate symbols in the time domain on a common slot and on a common set of physical resource blocks. The UE of claim 9.

13. a processor for generating sidelink control information ("SCI") comprising information indicative of future resources reserved for future transmissions; a transmitter for transmitting the SCI to a peer UE on a first resource of a physical sidelink control channel; a receiver for receiving feedback from the peer UE at a feedback resource; Equipped with a user equipment ("UE") device, wherein the feedback comprises an indication of whether there is a resource conflict, the resource conflict comprising an expected conflict in the future resource, and the SCI comprises a field indicating whether the conflict indication is enabled.

14. 14. The apparatus of claim 13, wherein the processor triggers resource reselection in response to the feedback from the peer UE indicating contention for the resource.

15. 14. The apparatus of claim 13, wherein the transmitter sends an initial transmission of sidelink data, the SCI accompanies the initial transmission, and the feedback comprises a first set of feedback resources for indicating Hybrid Automatic Repeat Request ("HARQ") feedback and a second set of feedback resources for indicating whether there is a resource contention, the first set of feedback resources comprising HARQ feedback bits reporting one of a positive acknowledgment to the initial transmission and a negative acknowledgment to the initial transmission.

16. 16. The apparatus of claim 15, wherein the second set of feedback resources comprises a single conflict indication bit that indicates whether there is a resource conflict for any of the future resources.

17. 16. The apparatus of claim 15, wherein the SCI indicates multiple reservations of future resources, and the second set of feedback resources comprises a conflict indication bit for each reservation, each conflict indication bit indicating whether there is a resource conflict for a corresponding reservation.

18. the first set of feedback resources and the second set of feedback resources separate physical resource blocks on a common symbol in the time domain; and distinct symbols in the time domain on a common slot and on a common set of physical resource blocks 16. The apparatus of claim 15, comprising one of:

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