Multiple sidelink reference signals

Abstract

Apparatuses, methods, and systems are disclosed for multiple sidelink RSs. A method (1000) includes transmitting (1002), from a transmitter user equipment to a receiver user equipment, information indicating RSs. The information further indicates a beam and / or panel transmitting first layer control signaling indicating target user information, resource configuration for the RSs to be transmitted or received using a default reference signal configuration, and a slot offset and time-frequency resources. Transmitting the information indicating RSs includes determining (1004) to transmit the RSs as part of an initial beam acquisition along with a higher layer discovery request message and / or prior to higher layer signaling. The receiver user equipment determines (1006) the target user information and either generates and transmits beam measurement feedback using beam correspondence or generates and transmits the RSs indicating the beam and / or panel in the slot offset if beam correspondence is not supported.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application Serial No. 63 / 055,180, filed July 22, 2020, entitled “Apparatus, Methods, and Systems for SL Beamforming Operation for GROUPCAST ​​and UNICASTTRANSMISSION,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The topics disclosed in this article generally relate to wireless communication, and more specifically to multiple sidelink reference signals. Background Technology

[0004] In some wireless communication networks, sidelink control information can be used to configure sidelink communication. Sidelink control information can be transmitted in one or more messages. Summary of the Invention

[0005] A method for using multiple sidelink reference signals is disclosed. Apparatus and systems also perform the functions of the method. One embodiment of a method includes transmitting information indicating multiple reference signals from a transmitter user equipment to a receiver user equipment. This information further indicates multiple beams, multiple panels, or combinations thereof for transmitting first-layer control signaling, which, as part of initial beam acquisition, indicates target user information for a set of user equipment devices, resource configuration for configuring the transmitted or receiver-decoded reference signals using default reference signals, and time slot offsets and time-frequency resources for beam measurement feedback reporting. Transmitting the information indicating multiple reference signals includes determining: transmitting multiple reference signals as part of initial beam acquisition along with a higher-layer discovery request message; transmitting multiple reference signals prior to higher-layer signaling; or combinations thereof. The receiver user equipment determines the target user information and: generates and transmits beam measurement feedback using beam mapping; or, if beam mapping is not supported, generates and transmits reference signals indicating multiple beams, multiple panels, or combinations thereof in a time slot offset.

[0006] An apparatus for multiple sidelink reference signals includes a transmitter that transmits, from a transmitter user equipment to a receiver user equipment, information indicating a plurality of reference signals. The information further indicates a plurality of beams, a plurality of panels, or a combination thereof, transmitting a first layer control signaling indicating target user information, resource configuration for transmitting or receiving reference signals using a default reference signal configuration, and a slot offset and time-frequency resources for beam measurement feedback reporting as part of an initial beam acquisition for a set of user equipment devices. Transmitting the information indicating the plurality of reference signals includes determining: transmitting the plurality of reference signals as part of an initial beam acquisition along with a higher layer discovery request message; transmitting the plurality of reference signals prior to higher layer signaling; or a combination thereof. The receiver user equipment determines the target user information and: generates and transmits a beam measurement feedback using beam correspondence; or generates and transmits a reference signal indicating the plurality of beams, the plurality of panels, or the combination thereof in the slot offset if beam correspondence is not supported. BRIEF DESCRIPTION OF DRAWINGS

[0007] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of the scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[0008] Figure 1 is a schematic block diagram illustrating one embodiment of a wireless communication system for multiple sidelink reference signals;

[0009] Figure 2 is a schematic block diagram illustrating one embodiment of an apparatus that can be used for multiple sidelink reference signals;

[0010] Figure 3 is a schematic block diagram illustrating one embodiment of an apparatus that can be used for multiple sidelink reference signals;

[0011] Figure 4 is a schematic block diagram illustrating one embodiment of a system with independent SL CSI-RS transmission prior to transmission of a discovery request message in PC5 RRC;

[0012] Figure 5 is a schematic block diagram illustrating one embodiment of a system for SL CSI-RS transmitted with a discovery request message in PC5 RRC;

[0013] Figure 6 is a schematic block diagram illustrating one embodiment of beamforming for broadcast transmission;

[0014] Figure 7Ais a schematic block diagram illustrating one embodiment of a first option for beamforming for groupcast transmission;

[0015] Figure 7B is a schematic block diagram illustrating one embodiment of a second option for beamforming for groupcast transmission;

[0016] Figure 8 is a schematic block diagram illustrating one embodiment of beamforming for unicast transmission;

[0017] Figure 9 is a schematic block diagram illustrating one embodiment of FDM of PSCCH and PSSCH; and

[0018] Figure 10 is a flow diagram illustrating one embodiment of a method for multiple sidelink reference signals. DETAILED DESCRIPTION

[0019] As will be appreciated by those skilled in the art, aspects of the embodiments can be embodied as a system, device, method or program product. Accordingly, the embodiments can be embodied in hardware alone, software alone, or combinations of software and hardware aspects that can all generally be referred to herein as a "circuit," "module" or "system." Furthermore, the embodiments can be embodied in a program product that is tangibly embodied in one or more computer readable storage devices (storage devices) and / or in one or more machine readable storage media for execution by, or to control the operation of, one or more computers, processors, or other programmable devices. A program interface can be in software, hardware, or a combination thereof. In another aspect, program interfaces can be provided by dedicated circuits, processors or controllers. The program interface can be provided with one or more computer programs tangibly embodied in one or more computer readable storage devices or media. The program interface can include one or more computer program interfaces (APIs). The computer programs, program products, programs, processes, methods, engines, modules and / or the like need not necessarily be embodied in software, as specific embodiments of the application fully could also be implemented in hardware components or circuitry alone.

[0020] Certain of the functional units described in this specification can be labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module can be implemented as a hardware circuit comprising custom very-large-scale integration ("VLSI") circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module can also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

[0021] Modules can also be implemented in code and / or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but the module may

[0022] Indeed, a module of code can be a single instruction, or many instructions, and can even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data can be identified and illustrated herein within modules, and can be embodied in any suitable form and organized within any suitable type of data structure. The operational data can be collected as a single data set, or can be distributed over different locations including over different computer readable storage devices. Where a module or portions of a module are implemented in software, the software portion is stored in one or more computer readable storage devices.

[0023] Any combination of one or more computer readable medium can be utilized. The computer readable medium can be a computer readable storage medium. The computer readable storage medium can be a storage device storing the code. The storage device can 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.

[0024] More specific examples (a non-exhaustive list) of the storage device would include the following: 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 document, a computer readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0025] Code for carrying out operations for embodiments can be any number of lines and can be written in any combination of one or more programming languages including an object oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or machine languages such as assembly languages. The code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network ("LAN") or a wide area network ("WAN"), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0026] References in the specification to “one embodiment,” “an embodiment,” or similar language mean that a particular feature, structure, or characteristic described is included in at least one embodiment. Thus, unless

[0027] Furthermore, the described features, structures, or characteristics of the embodiments can be combined in any suitable manner in one or more embodiments. 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. One skilled in the relevant art will recognize, however, that the embodiments can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail in order to avoid obscuring aspects of the embodiments.

[0028] Aspects of the embodiments are described below with reference to schematic flowcharts and / or schematic block diagrams of methods, apparatuses, systems, and program products according to the embodiments. It will be understood that each block of the schematic flowcharts and / or schematic block diagrams, and combinations of blocks in the schematic flowcharts and / or schematic block diagrams, can be implemented by code. The code can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the

[0029] The code can also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function / act specified in the schematic flowchart and / or schematic block diagram block or blocks.

[0030] The code can also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0031] The flowcharts and / or block diagrams in the drawings illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the flowcharts and / or block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical functions.

[0032] It should also be noted that in some alternative implementations, the functions noted in the blocks can 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 can sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods can be conceived that are equivalent in function, logic, or effect to those illustrated, with the

[0033] Although various arrow types and line types can be employed in the flowchart and / or block diagrams, these are merely meant as an example, and one of ordinary skill in the art will recognize that some of these steps can be performed, at least at times, in a different order than that shown or that these steps can, at times, be combined or omitted. Additionally, the arrow need not represent the direction of control flow. For instance, a method can comprise a first step followed by a second step, wherein the first step can be performed conditionally on the second step. It will also be noted that each block of the flowchart and / or block diagrams and combinations of blocks in the flowchart and / or block diagrams can be implemented by special purpose hardware-based systems that perform the specified functions or steps, or combinations of special purpose hardware and code.

[0034] The description of elements in each of the figures can refer to elements of previous figures. Like numbers refer to like elements throughout all figures, including alternate embodiments of like elements.

[0035] Figure 1 Embodiments of a wireless communication system 100 for multiple sidelink reference signals are depicted. In one embodiment, the wireless communication system 100 includes remote units 102 and network units 104. While the techniques of this disclosure are sufficiently broad to encompass the use of a variety of systems, including the use of a variety of network units and remote units, the illustrated embodiments are described primarily in the context of a wireless network, including the network units and remote units described below. Figure 1 In some embodiments, a remote unit 102 can include a user equipment (UE) device, a mobile device, a wireless device, a portable device, a desktop device, or any other type of device that is configured to operate in a wireless environment. In some embodiments, a network unit 104 can include a base station, an access point, a wireless router, a wireless modem, a network hub, a network switch, a network bridge, or any other type of wireless communication device that is configured to operate in a wireless environment.

[0036] In one embodiment, the remote units 102 can include computing devices, such as desktop, laptop, personal digital assistant (“PDA”), tablet, smart phone, smart television (e.g., television connected to the Internet), set-top box, game console, security system (including security cameras), vehicle

[0037] The network units 104 can be distributed over a geographic region. In certain embodiments, a network unit 104 can also be referred to as and / or include an access point, an access terminal, a base, a base station, a location server, a core network (“CN”), a radio network entity, a Node-B, an evolved Node-B (“eNB”), a 5G Node-B (“gNB”), a Home Node-B, a relay node, a device, a core network, an aerial server, a radio access node, an access point (“AP”), New Radio (“NR”), a network entity, an access and mobility management function (“AMF”), a unified data management (“UDM”), a unified data repository (“UDR”), UDM / UDR, a policy control function (“PCF”), a radio access network (“RAN”), a network slice selection function (“NSSF”), operations, administration, and management (“OAM”), a session management function (“SMF”), a user plane function (“UPF”), an application function, an authentication server function (“AUSF”), a security anchor function (“SEAF”), a trusted non-3GPP gateway function (“TNGF”), or by any other terminology used in the art. The network units 104 are generally part of a radio access network that can include one or more controllers communicably coupled to one or more corresponding network units 104. The radio access network is usually communicably coupled to one or more core networks, that can be coupled to other networks, like the Internet and public switched telephone networks, among other networks. These and other elements of radio access and core networks are not illustrated but are well known generally by those having ordinary skill in the art.

[0038] In one implementation, the wireless communication system 100 conforms to the NR protocol standardized in the 3rd Generation Partnership Project (“3GPP”), wherein network unit 104 transmits using an OFDM modulation scheme on the downlink (“DL”), and remote unit 102 transmits using a single-carrier frequency division multiple access (“SC-FDMA”) scheme or an orthogonal frequency division multiplexing (“OFDM”) scheme on the uplink (“UL”). However, more generally, the wireless communication system 100 may implement other open or proprietary communication protocols, such as WiMAX, IEEE 802.11 variants, GSM, GPRS, UMTS, LTE variants, and CDMA2000. ZigBee, Sigfoxx, and other protocols. This disclosure is not intended to be limited to any particular wireless communication system architecture or protocol implementation.

[0039] Network unit 104 can serve multiple remote units 102 within a service area (e.g., a cell or cell sector) via a wireless communication link. Network unit 104 transmits DL communication signals in the time, frequency, and / or spatial domains to serve the remote units 102.

[0040] In various embodiments, remote unit 102 can transmit information indicating multiple reference signals from transmitter user equipment to receiver user equipment. This information further indicates multiple beams, multiple panels, or combinations thereof for transmitting first-layer control signaling, which, as part of initial beam acquisition, indicates target user information for a set of user equipment devices, resource configuration for configuring the transmitted or decoded reference signals using default reference signals, and time slot offsets and time-frequency resources for beam measurement feedback reporting. Transmitting information indicating multiple reference signals includes determining: transmitting multiple reference signals as part of initial beam acquisition along with a higher-layer discovery request message; transmitting multiple reference signals prior to higher-layer signaling; or a combination thereof. Receiver user equipment determines the target user information and: generates and transmits beam measurement feedback using beam mapping; or, if beam mapping is not supported, generates and transmits reference signals indicating multiple beams, multiple panels, or combinations thereof in a time slot offset. Therefore, remote unit 102 can be used for multiple sidelink reference signals.

[0041] Figure 2One embodiment of a device 200 that can be used for multiple sidelink reference signals is depicted. The device 200 includes one embodiment of the remote unit 102. Furthermore, the remote unit 102 can include a processor 202, a memory 204, an input device 206, a display 208, a transmitter 210, and a receiver 212. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touch screen. In certain embodiments, the remote unit 102 can not include any input device 206 and / or display 208. In various embodiments, the remote unit 102 can include one or more of the processor 202, the memory 204, the transmitter 210, and the receiver 212, and can not include the input device 206 and / or the display 208.

[0042] In one embodiment, the processor 202 can include any known controller capable of executing computer-readable instructions and / or capable of performing logical operations. For example, the processor 202 can be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), an auxiliary processing unit, a field programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, the processor 202 executes instructions stored in the memory 204 to perform methods and routines described herein. The processor 202 is communicatively coupled to the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212.

[0043] In one embodiment, the memory 204 is a computer readable storage medium. In some embodiments, the memory 204 includes both volatile and nonvolatile computer storage media. For example, the memory 204 can include both a volatile computer storage medium and a non-volatile computer storage medium. In some embodiments, the memory 204 includes a volatile computer storage medium, but not a non-volatile computer storage medium. In some embodiments, the memory 204 includes a non-volatile computer storage medium, but not a volatile computer storage medium. In some embodiments, the memory 204 includes only a volatile computer storage medium. In some embodiments, the memory 204 includes only a non-volatile computer storage medium.

[0044] In one embodiment, input device 206 can include any known computer input device, including a touch panel, buttons, a keyboard, a stylus, a microphone, or the like. In some embodiments, input device 206 can be integrated with display 208, e.g., as a touch screen or similar touch-sensitive display. In some embodiments, input device 206 includes a touch screen such that text can be input using a virtual keyboard displayed on the touch screen and / or by handwriting on the touch screen. In some embodiments, input device 206 includes two or more different devices, such as a keyboard and a touch panel.

[0045] In one embodiment, display 208 can include any known electronically controllable display or display device. Display 208 can be designed to output visual, audible, and / or tactile signals. In some embodiments, display 208 includes an electronic display capable of outputting visual data to a user. For example, display 208 can include, but is not limited to, a liquid crystal display (“LCD”), a light emitting diode (“LED”) display, an organic light emitting diode (“OLED”) display, a projector, or similar display device capable of outputting images, text, etc., to a user. As another non-limiting example, display 208 can include a wearable display such as a smart watch, smart glasses, a heads-up display, or the like. Further, display 208 can be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

[0046] In certain embodiments, display 208 includes one or more speakers for producing sound. For example, display 208 can produce an audible alert or notification (e.g., a beep or chime). In some embodiments, display 208 includes one or more haptic devices for producing vibrations, motion, or other tactile feedback. In some embodiments, all or portions of display 208 can be integrated with input device 206. For example, input device 206 and display 208 can form a touch screen or similar touch-sensitive display. In other embodiments, display 208 can be located near input device 206.

[0047] In certain embodiments, the transmitter 210 transmits, from a transmitter user equipment to a receiver user equipment, information indicating a plurality of reference signals. The information further indicates a plurality of beams, a plurality of panels, or a combination thereof, transmitting a first layer control signaling indicating target user information, a resource configuration for a reference signal transmitted or received using a default reference signal configuration, and a slot offset and time-frequency resource for a beam measurement feedback report for a set of user equipment devices as part of an initial beam acquisition. Transmitting the information indicating the plurality of reference signals includes determining: transmitting the plurality of reference signals as part of the initial beam acquisition along with a higher layer discovery request message; transmitting the plurality of reference signals prior to the higher layer signaling; or a combination thereof. The receiver user equipment determines the target user information and: generates and transmits a beam measurement feedback using a beam correspondence; or generates and transmits a reference signal indicating the plurality of beams, the plurality of panels, or the combination thereof in the slot offset if the beam correspondence is not supported.

[0048] Although only one transmitter 210 and one receiver 212 are illustrated, the remote unit 102 can have any suitable number of transmitters 210 and receivers 212. The transmitter 210 and the receiver 212 can be any suitable type of transmitters and receivers. In one embodiment, the transmitter 210 and the receiver 212 can be part of a transceiver.

[0049] Figure 3 One embodiment of an apparatus 300 that can be used for a plurality of sidelink reference signals is depicted. The apparatus 300 includes one embodiment of the network unit 104. Furthermore, the network unit 104 can include a processor 302, a memory 304, an input device 306, a display 308, a transmitter 310, and a receiver 312. As can be appreciated, the processor 302, the memory 304, the input device 306, the display 308, the transmitter 310, and the receiver 312 can be substantially similar to the processor 202, the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212 of the remote unit 102, respectively.

[0050] In certain embodiments, there can be beam establishment and best beam feedback reception for unicast with channel state information (“CSI”) reference signal (“RS”) (“CSI-RS”) transmissions; beamforming for transmission of 1st sidelink control information (“SCI”), 2nd SCI, and physical sidelink shared channel (“PSSCH”); configuration for sidelink-specific transmission configuration indicator (“TCI”) table, TCI, and / or playing type state indication in SCI for reception of 2nd SCI and PSSCH for unicast; and beamforming aspects for physical sidelink feedback channel (“PSFCH”) transmission.

[0051] In some embodiments, such as in New Radio (“NR”) vehicle-to-anything (“V2X”) millimeter wave frequencies (e.g., frequency range 2 (“FR2”), frequency range 3 (“FR3”), and / or frequency range 4 (“FR4”)), there can be challenges like for sidelink beams and / or panel establishment for unicast transmission between a transmitting (“TX”) user equipment (“UE”) and a receiver (“RX”) UE, beam and / or panel switching based on measurements for unicast transmission, sidelink beam recovery. In various embodiments, such as in the NR UE-to-network (“Uu”) interface (“NR-Uu”), there can be standardized synchronization signal block (“SSB”) random access channel (“RACH”) (“SSB-RACH”) counterparts for initial beam alignment. In certain embodiments, such as in the NR UE-to-UE interface (“PC5”), not all UEs transmit sidelink (“SL”) SSB (“SL-SSB”) transmissions. In some embodiments, such as in V2X, a sidelink synchronization signal (“SLSS”) is transmitted only by an asynchronous reference (“SyncRef”) UE to provide a synchronization source to all nearby UEs (e.g., so not all UEs transmit SLSS). In various embodiments, a unicast session can be established with a UE that does not transmit SLSS.

[0052] As used herein, the terms eNB and / or gNB can be used for base stations, but can be replaced by other radio access nodes (e.g., base station (“BS”), eNB, gNB, access point (“AP”), NR, etc.). Also, while embodiments herein can be described in the context of 5G NR, they can equally apply to other mobile communication systems that support serving cells and / or carriers configured for sidelink communication over a PC5 interface.

[0053] In certain embodiments described herein, a first UE (“UE-1”) and / or (“UE1”) can be referred to as a TX UE and a second UE (“UE-2”) and / or (“UE2”) can be referred to as a RX UE.

[0054] In a first embodiment, there can be ways to establish unicast sidelink beams, establish CSI-RS resource configuration, and / or provide feedback about beams.

[0055] In a first embodiment, a TX UE can transmit a configured and / or preconfigured SL CSI-RS or any SL RS prior to transmitting a higher layer direct communication request message to initiate SL beam establishment or acquisition.

[0056] In one example, a UE can initiate SL beam establishment or acquisition in response to triggering establishment of a new PC5 unicast link (e.g., at a frequency range above 6 GHz (e.g., millimeter wave frequencies such as FR2, FR3, and / or FR4). The new PC5 unicast link can be used by a V2X application layer in the UE to support data transmission for a V2X service type. The V2X service type can be associated with a PC5 Quality of Service (“QoS”) flow identified by a Packet Format Information (“PFI”) corresponding to special V2X service requirements by the V2X application layer. In such an example, if the UE capability enables transmission of multiple beams at the same time, the SL CSI-RS resources are transmitted via multiple beams and / or panel operation using multiple beams at the same time. In certain embodiments, the CSI-RS can be beam scanned in different spatial directions at different time instants.

[0057] In some implementations of the first embodiment, the TX UE can transmit the SL CSI-RS or any SL RS with a higher layer direction communication request, while the CSI-RS is confined in the actual data transmission sub-channels. In one example, for CSI-RS transmission in the data region, the measurements can be done and the corresponding feedback (e.g., if any) can be based on the usage type set for the CSI-RS, such as being set to “beam management” or being set to a Channel Quality Indicator (“CQI”) “CQI-reporting” usage type for the CSI-RS.

[0058] In various embodiments, the TX UE can repeatedly transmit the SL CSI-RS resources, where the RX UE can assume that the SL CSI-RS resources in different symbols (e.g., in a set of SL CSI-RS resources) are transmitted with the same spatial domain transmission filter (e.g., the same transmit beam). This can facilitate the RX UE to perform receiver-side beam sweeping and / or adjustment through the SL CSI-RS resources.

[0059] In certain embodiments, because the RX UE is not aware of the CSI-RS configuration and the PC5 RRC connection has not been established, the CSI-RS resource configuration can be signaled in Layer 1 (“L1”) control signaling, so that the RX UE is aware of the CSI-RS configuration details including the resources, pattern, density, ports, etc. for decoding.

[0060] In some embodiments, a gNB can configure a sidelink UE with a reduced CSI-RS configuration table and / or a subset of the CSI-RS configuration table (e.g., at least prior to PC5 RRC connection establishment) for SL communication (e.g., based on the table) using Radio Resource Control (“RRC”) common signaling. The number of configurations and the size of the table used can be reduced based on the UE capability in sidelink communication.

[0061] In various embodiments, a new 2nd SCI format can be defined to carry one or more CSI-RS parameters (e.g., such as row index, ports, code division multiplexing (“CDM”) type, density, and / or time and frequency domain locations in a slot).

[0062] In some embodiments, a default SL CSI-RS configuration (e.g., possibly from a set of default SL CSI-RS configurations) can be configured using RRC common signaling for SL UEs. This can be used to transmit and receive SL CSI-RS before establishing a PC5 RRC connection.

[0063] In various embodiments, a default SL CSI-RS configuration includes a fixed number of SL CSI-RS ports, a CDM type, a density within a resource block (“RB”), and / or a subchannel. In certain embodiments, the default configuration can include a fixed number of frequency resources and time symbols within a slot and a fixed periodicity that the same default SL CSI-RS configuration can be repeated using one or more beams. This can avoid any additional information configured for at least initial beam acquisition based on SL CSI-RS. This default RS configuration can be configured per resource pool or SL bandwidth part (“BWP”) and also shared with neighboring gNBs so that receiver UEs belonging to different gNBs can be aware of the default RS configuration.

[0064] In certain embodiments, if a default SL CSI-RS configuration is configured for a TX UE from a set of default SL CSI-RS configurations, a RX UE can detect the SL CSI-RS based on the set of default SL CSI-RS configurations (e.g., via blind search).

[0065] In some embodiments, the TX UE can configure a dedicated feedback resource for each SL CSI-RS resource or a group of SL CSI-RS resources with a corresponding slot offset for feedback reception. The feedback from the RX UE (e.g., UE2) can include L1 reference signal receive power (“RSRP”) (“L1-RSRP”) (or L1 signal-to-interference-and-noise ratio (“SINR”) (“L1-SINR”)) feedback measurements corresponding to at least one (e.g., strongest and / or best) SL CSI-RS resource and / or beam, and / or an indication of SL CSI-RS resources and / or beams in a single reporting instance. In one example, if the RX UE feeds back and / or reports measurements for more than one SL CSI-RS resource, the feedback report can include an indication of the SL CSI-RS resources and / or beams included in the report. Also, the report can include measurements (e.g., L1-RSRP) for the strongest beam and differential values of measurements relative to the strongest beam measurements for the remaining beams. In another example, beam correspondence is assumed, and the feedback is transmitted on resources with the same spatial domain transmission filter for reception of the corresponding SL CSI-RS transmissions. Because each of the feedback resources is mapped to a specific CSI-RS resource, it can not be needed to include beam and / or SL CSI-RS resource IDs in the feedback message.

[0066] In various embodiments, the TX UE can configure a feedback resource including a slot offset for feedback reception considering each SL CSI-RS resource, L1-RSRP feedback measurements, a beam ID corresponding to the best beam, and / or an RS ID. In some embodiments, if beam correspondence is supported, UE2 can select a TX beam based on the received RX beam from the TX UE (e.g., UE1).

[0067] In certain embodiments, if beam correspondence is not supported by UE2, UE2 can transmit SL CSI-RS toward UE-1 using multiple simultaneous beams if supported by UE capability or beam sweeping in different spatial directions. UE2 can use the same configuration signaled by UE1 to transmit SL CSI-RS and UE2 can start SL CSI-RS transmission toward UE1 after the time offset signaled by UE1. Also, UE2 can transmit SL CSI-RS in the resources reserved by UE1 and signaled in SCI. In some embodiments, UE2 can send a request to gNB for mode 1 resources for CSI-RS transmission. The time offset signaled by UE1 to UE2 can be sufficient to cover the processing time and / or delay incurred in finding SL CSI-RS resources (e.g., SL CSI-RS resource determination) due to resource allocation. In various embodiments, at least two sets of SL CSI-RS resources are indicated, where one set (e.g., first set) is used for SL CSI-RS transmission from UE1 to UE2 and another set (e.g., second set) is used for SL CSI-RS transmission from UE2 to UE1.

[0068] In some embodiments, the transmission of the feedback message can be based on SCI, PSFCH, a medium access control (“MAC”) control element (“CE”), or multiplexing of the feedback message with PSSCH.

[0069] In various embodiments, for independent CSI-RS: for mode 1 operation, TX UE can be configured with separate SR for requesting SL CSI-RS resources from gNB and SL grant in downlink control information (“DCI”) indicates time-frequency resources for SL CSI-RS. In certain embodiments, resource pool and / or SL CSI-RS bandwidth and frequency domain starting position in SL BWP are indicated and TX UE can use these mode 1 resources for transmitting SL CSI-RS in multiple beams to one or more destinations.

[0070] Figure 4is a schematic block diagram illustrating one embodiment of system 400 with independent SL CSI-RS transmission prior to transmission of a discovery request message in PC5 RRC. System 400 includes a first UE 402 (UE-1), a second UE 404 (UE-2), and a third UE 406 (UE-3). The second UE 404 determines 408 a destination Layer 2 ID for signaling reception. The third UE 406 determines 410 a destination Layer 2 ID for signaling reception. A V2X application layer of the first UE 402 provides 412 application information for a PC5 unicast connection. The first UE 402 optionally transmits 414 a physical sidelink control channel (“PSCCH”) + CSI-RS using a transmission 416 to the second UE 404 and / or a transmission 418 to the third UE 406. The second UE 404 provides feedback on the best beam or transmits a CSI-RS to the first UE 402. The first UE 402 provides 422 a direct communication request (e.g., via higher layers).

[0071] Figure 5 is a schematic block diagram illustrating one embodiment of system 500 for SL CSI-RS transmitted with a discovery request message in PC5 RRC. System 500 includes a first UE 502 (UE-1), a second UE 504 (UE-2), and a third UE 506 (UE-3). The second UE 504 determines 508 a destination Layer 2 ID for signaling reception. The third UE 506 determines 510 a destination Layer 2 ID for signaling reception. A V2X application layer of the first UE 502 provides 512 application information for a PC5 unicast connection. The first UE 502 optionally transmits 514 a PSCCH + CSI-RS using a transmission 516 to the second UE 504 and / or a transmission 518 to the third UE 506 (e.g., via a direct communication request and / or via higher layers). The second UE 504 provides 520 feedback on the best beam or transmits a CSI-RS to the first UE 502 using a direct communication accept message.

[0072] In a second embodiment, a synchronization signal block (“SSB”) can be used for SL beamforming, and / or a source-destination ID can be linked to a synchronization signal ID (“SSID”).

[0073] In some embodiments, the UE can know the SSID based on the reception of the sidelink primary synchronization signal (“PSS”) and secondary synchronization signal (“SSS”), and the SSID can inform the UE about the type of synchronization source being used for the transmission of the sidelink synchronization signal (“SLSS”). If UE1 is a synchronization reference UE and it wants to initiate a unicast transmission with UE2, UE2 after receiving the discovery request can still not be aware that the TX UE (UE1) is also a synchronization reference UE and there is no linkage between the source-destination ID and the SSID.

[0074] In various embodiments, UE1 can signal the SSID to UE2 in L1 control signaling or higher layer signaling, such as in SCI, MAC CE, and / or PC5 RRC linking the SSID with the source-destination ID.

[0075] In some embodiments, the synchronization reference UE can include the source ID in the physical sidelink broadcast channel (“PSBCH”).

[0076] In various embodiments, the PSBCH includes time-frequency resource information or multiplexing pattern of the SCI that is linked and multiplexed with the sidelink SSB transmission, where the SCI can indicate additional information about the source-destination ID to the RX UE or can provide the RX UE with a sidelink grant of PSSCH for conveying additional information. In certain embodiments, the pattern informs whether the multiplexing of the SCI and SSB is time-domain multiplexing or frequency-domain multiplexing and the fixed time or frequency offset between the SSB and the SCI can be specified. In some embodiments, an invalid assignment can indicate that there is no linkage of the source-destination ID and the SSID.

[0077] In a third embodiment, the PC5 RRC signaling can indicate the TCI table configuration, TCI state, and the play-type indication for the 2nd SCI and PSSCH.

[0078] In a third embodiment, a TX UE can configure a sidelink TCI table based on its supported configuration of multiple sidelink reference signals such as SL CSI-RS, SL SSB, SL positioning reference signal (“PRS”), demodulation reference signal (“DMRS”), SL phase tracking reference signal (“PTRS”), etc. The TX UE can signal a dedicated sidelink TCI table configuration to use during sidelink unicast communication using PC5 RRC signaling. In various embodiments, a MAC CE can signal the sidelink TCI table configuration with a corresponding destination ID. In certain embodiments, the TX UE can signal a dedicated reference signal configuration with the TCI state table in PC5 RRC or MAC CE. In some embodiments, a DMRS base sequence, cyclic shift, DMRS pattern, DMRS resource, etc. can be exchanged in PC5 RRC between the TX UE and RX UE. In various embodiments, multiple DMRS resources (e.g., each corresponding to a beam and / or panel) can be signaled.

[0079] In certain embodiments, the 1st SCI is always broadcast to inform proximate UEs about resource usage to avoid the hidden node problem. The 1st SCI can inform the resource reservation of the RX UE, which can help the RX UE to receive a subsequent 1st SCI reception in the reserved resource using a signal transmission via an RX spatial filter and / or RX beam. In some embodiments, a TCI state indicating the RX spatial filter and / or RX beam for receiving the 1st SCI can be signaled to the RX UE as part of PC5 RRC signaling (or PC5-S signaling). In various embodiments, a sidelink UE is configured and / or preconfigured with a common reference signal configuration, which can be based on a SL CSI-RS or DMRS, associated with a common TCI state table for receiving the 1st SCI and any broadcast type traffic.

[0080] In certain embodiments, a TCI state can be signaled in the 1st SCI informing the RX UE about the RX spatial filter and / or RX beam for receiving the 2nd SCI and PSSCH, and can be used by proximate UEs for sensing procedures (e.g., SCI decoding) to be aware of resource usage and / or occupation per beam.

[0081] In some embodiments, the play type can be signaled in the 1st SCI and can be used to implicitly inform the RX UE to switch the RX spatial filter and / or RX beam for receiving the 2nd SCI and PSSCH (e.g., between broadcast and unicast reception). In various embodiments, the play type can be used to switch between a common TCI state table for broadcast and a dedicated TCI state table for unicast and / or groupcast. In such embodiments, the TCI state notification in the 1st SCI would be the TCI state in the corresponding TCI table used by the RX UE.

[0082] In certain embodiments, there can be joint encoding of the play type and the play type using the reserved state in SCI 1-A with the 2nd SCI format indication as shown in Table 1.

[0083] Table 1: 2nd Stage SCI Format and Play Type Indicator

[0084] Values for the 2nd level SCI format and play type indicator field 2nd level SCI format, play type 00 SCI format 2-A, broadcast 01 SCI format 2-A, groupcast 10 SCI format 2-A, unicast 11 SCI format 2-B, groupcast

[0085] In a fourth embodiment, beams can be used for transmission of the 1st SCI, 2nd SCI, and PSSCH.

[0086] In the fourth embodiment, for broadcast transmission, the 1st SCI, 2nd SCI, and PSSCH are transmitted in different beam directions as shown in Figure 6

[0087] In particular, Figure 6 is a schematic block diagram 600 illustrating one embodiment of beamforming for broadcast transmission. The transmission includes 1st SCI, 2nd SCI, and PSSCH (TB#1) transmission transmitted through a first beam 602 (Beam #1), a second beam 604 (Beam #2), and a third beam 606 (Beam #3).

[0088] In certain embodiments, for groupcast, the 1st SCI can be a notification of beam sweeping in all directions (e.g., omni-directional or substantially spherical coverage) about resource occupation, while the 2nd SCI and PSSCH are transmitted in a subset of beams using one of the options for destination group ID as shown in Figure 7A and Figure 7B The subset of beams can be determined based on reception of dedicated hybrid automatic repeat request (“HARQ”) acknowledgement (“ACK”) (“HARQ-ACK”) feedback from RX UEs belonging to the same destination group ID. In various embodiments, the subset of beams can be determined based on previous transmissions to the same destination group and corresponding feedback reception. The starting symbol for 2nd SCI reception can be signaled in the 1st SCI.

[0089] ​Figure 7A is a schematic block diagram 700 illustrating one embodiment of a first option for beamforming for groupcast transmission. The transmission includes a 1st SCI, a 2nd SCI, and a PSSCH (TB#1) transmission transmitted over a first beam 702 (Beam #1), a second beam 704 (Beam #2), a third beam 706 (Beam #3), and a fourth beam 708 (Beam #4).

[0090] Figure 7B is a schematic block diagram 750 illustrating one embodiment of a second option for beamforming for groupcast transmission. The transmission includes a 1st SCI, a 2nd SCI, and a PSSCH (TB#1) transmission transmitted over a first beam 752 (Beam #1), a second beam 754 (Beam #2), a third beam 756 (Beam #3), and a fourth beam 758 (Beam #4).

[0091] In certain embodiments, for unicast, the 1st SCI is announcing beam sweeping in all directions regarding resource occupation, while the 2nd SCI and PSSCH are transmitted in one of the beams established during unicast beam setup, as shown in Figure 8 .

[0092] In some embodiments, the TX UE and / or RX UE can store the use of beam pair identifiers (“IDs”) with source-destination IDs, such that the TX UE and / or RX UE knows which beam should be used for transmission and / or reception for each source-destination ID.

[0093] Figure 8 is a schematic block diagram illustrating one embodiment of beamforming for unicast transmission. The transmission includes a 1st SCI, a 2nd SCI, and a PSSCH (TB#1) transmission transmitted over a first beam 802 (Beam #1), a second beam 804 (Beam #2), a third beam 806 (Beam #3), and a fourth beam 808 (Beam #4).

[0094] In various embodiments, for frequency division multiplexing (“FDM”) of the 1st SCI and PSSCH, if the UE supports multi-beam operation, the UE can use two spatial filters and / or beams - one for reception of PSCCH and the other beam for reception of PSSCH. In certain embodiments, the number of potential simultaneous beams to be used for sidelink communication can be semi-statically configured and / or preconfigured.

[0095] Figure 9 is a schematic block diagram 900 illustrating one embodiment of FDM of PSCCH and PSSCH. The transmission includes an automatic gain control (“AGC”), a PSSCH, a PSCCH, a DMRS, and a guard transmission. At time 902, the PSSCH and PSCCH are FDMed.

[0096] In a fifth embodiment, the PSFCH resource configuration can be based on beamforming.

[0097] In a fifth embodiment, for groupcast feedback option 1 common HARQ-ACK, in one embodiment, if the UE is capable of beam correspondence, multiple resource occasions for PSFCH are configured to correspond to each beam, panel, and / or spatial filter on which the PSSCH is transmitted, where the same spatial filter is used to transmit PSFC as has been used to receive the corresponding PDSCH. Each of the PSFCH resources corresponding to each transmission of PSSCH in certain spatial directions, beams, panels, and / or spatial filters is configured with a certain offset. As an example, PSFCH resource #1 is configured in slot #4 for the corresponding PSSCH transmission with beam ID #1 on slot #0, PSFCH resource #2 is configured in slot #5 for the corresponding PSSCH transmission with beam ID #2 on slot #1, and so on.

[0098] In a fifth embodiment, for groupcast feedback option 1 common HARQ-ACK, in another embodiment, a single resource for PSFCH can be configured considering all or a subset of the beams, panels, and / or spatial filters on which the PSSCH is transmitted. The beam to be used for transmitting PSFCH can be indicated to the UE with a separate TCI state for PSFCH in SCI.

[0099] Also, in a fifth embodiment, for groupcast feedback option 1 common HARQ-ACK, in certain embodiments, the UE can determine to perform transmission in each beam (e.g., all beams) or a subset of beams, panel, and / or spatial filter based on the negative acknowledgement (“NACK”) feedback reception from each configured PSFCH resource occasion, where each PDSCH resource occasion corresponds to each PDSCH transmission in each beam, panel, and / or spatial filter.

[0100] Further, in a fifth embodiment, for groupcast feedback option 1 common HARQ-ACK, in some embodiments, the UE can schedule retransmission in the beam and / or spatial filter upon receiving NACK from each PSFCH resource occasion corresponding to the PSSCH transmission and it is not necessary to wait until it receives NACK feedback from all PSFCH resource occasions corresponding to each PSSCH transmission. In certain embodiments, the UE can schedule retransmission after receiving NACK feedback from each configured PSSCH transmission corresponding to each PSFCH transmission.

[0101] In various embodiments, for mode 1, if only one physical uplink control channel (“PUCCH”) resource is assigned for multiple PSFCH resource occasions, if the UE receives a NACK from one of the configured PSFCH resource occasions, the UE can feedback a NACK in the PUCCH resource while if the transmitter UE does not receive a NACK from each PSFCH resource occasion, the UE can feedback an ACK in the PUCCH resource.

[0102] In certain embodiments, for mode 1, if multiple PUCCH resources are assigned for each PSFCH resource occasion, if the UE receives a NACK from the corresponding PSFCH resource occasion, the UE can feedback an ACK in the PUCCH resource while if the TX UE does not receive any NACK in the corresponding PSFCH resource occasion, the UE can feedback an ACK in the PUCCH resource.

[0103] In a fifth embodiment, for dedicated HARQ-ACK for groupcast feedback option 2, in one embodiment, multiple resources for PSFCH carrying dedicated HARQ-ACK for each UE belonging to one group are configured to correspond to each beam, panel, and / or spatial filter on which PSSCH is transmitted. Each PSFCH resource corresponding to each transmission of PSSCH on certain spatial direction, beam, panel, and / or spatial filter is configured with a certain offset. As an example, PSFCH resource #1 is configured in slot #4 for corresponding PSSCH transmission with beam ID #1 on slot #0, PSFCH resource #2 is configured in slot #5 for corresponding PSSCH transmission with beam ID #2 on slot #1, and so on.

[0104] In certain embodiments, the UE can determine to perform retransmission in each beam (e.g., all beams) or a subset of beams, panel, and / or spatial filter based on NACK feedback reception from each configured PSFCH resource occasion, where each PSFCH resource occasion corresponds to each PSSCH transmission in each beam, panel, and / or spatial filter.

[0105] In some embodiments, the UE can schedule retransmission only after receiving NACK feedback from each configured PSSCH transmission corresponding to each PSFCH transmission.

[0106] In various embodiments, the UE can determine whether to perform a new transmission or retransmission in each beam (e.g., all beams) or a subset of beams, panel, and / or spatial filter after receiving at least one ACK or NACK from all RX UEs belonging to one group from each configured PSFCH reception occasion. For Mode 1, the UE can generate ACK in one PUCCH resource only when the UE determines ACK from at least one PSFCH reception occasion.

[0107] In certain embodiments, a single resource for carrying dedicated HARQ-ACK PSFCH can be configured at the end of the PSSCH transmission occasion in each beam on which PSSCH is transmitted.

[0108] In some embodiments, for RX UEs transmitting multiple PSFCH transmissions in a slot, each dedicated HARQ-ACK can be transmitted on a specific resource in a specific beam direction corresponding to the beam intended for that UE.

[0109] In various embodiments, for beam correspondence, PSFCH transmission can be made using the same transmission as the reception beam of PSSCH.

[0110] In certain embodiments, in SCI, a separate TCI state can be signaled for transmission of PSFCH from RX UE to TX UE. The separate TCI state can be configured as part of the same TCI table configured by the PC5 RRC connection. In such embodiments, at least two TCI states can be configured for the index such that one TCI state is applied for transmission of PSSCH (e.g., along with SCI) from TX UE to RX UE and the second TCI state is applied for transmission of PSFCH from RX UE to TX UE. In another example, two separate TCI tables are configured, where each table is used for opposite link directions between the same pair of UEs.

[0111] In a sixth embodiment, sidelink beam failure and recovery can be performed. In the sixth embodiment, in V2X configuration with vehicle mobility, there can be a high probability that SL beam based transmission can fail, and therefore, if there is SL beam failure, SL beam recovery procedure can be triggered.

[0112] In certain embodiments, there can be SL beam failure detection (“BFD”): An RX UE can detect SL beam failure based on a measured L1-RSRP SL CSI-RS or any sidelink reference signal (“SL-RS”) below a configured threshold or SL HARQ-feedback counter (e.g., NACK or discontinuous transmission (“DTX”)) or based on a configured threshold of angle of departure (“AoD”), time difference of arrival (“TDoA”), and / or angle of arrival (“AoD”) between beams and / or beam pairs. A TX UE can configure the beam failure threshold and / or maximum counter via PC5 RRC, a gNB can configure a common threshold and / or maximum counter via RRC common signaling (e.g., system information broadcast signaling), or this threshold and / or maximum counter can be preconfigured. In some embodiments, other SL beam quality metrics such as reference signal received quality (“RSRQ”) and SINR and assumed block error rate (“BLER”) of SCI (e.g., 1st SCI) can be considered for SL BFD.

[0113] In various embodiments, there can be new SL beam candidate identification: An RX UE initiates a procedure to identify a new SL beam from a SL beam candidate list at SL BFD. The identification of a new TX SL beam can be based on a SL CSI-RS or any SL-RS L1-RSRP best measured by the RX UE from a SL beam candidate list (e.g., TX-UE common beam list). In certain embodiments, an RX UE can perform TX UE measurement based on beam quality metrics and can report a better beam candidate to the TX UE for beam and / or panel reselection and / or switching using the following criteria: 1) the RX UE measures SL TX beams periodically at a configured interval; 2) a congestion level of a certain resource pool within a beam exceeds a configured threshold; 3) TX and RX distance exceeds a threshold, where TX-RX distance can be calculated using radio access technology (“RAT”) dependent (“RAT-dependent”) (e.g., AoD, TDoA) or RAT independent (“RAT-independent”) (e.g., global navigation satellite system (“GNSS”), inertial measurement unit (“IMU”)) techniques; and / or 4) TX-RX beam measurements like AoD, TDoA can be calculated for each candidate beam and / or panel.

[0114] In some embodiments, there can be a new SL beam recovery request: the RX UE can report the SL BF indication to the TX UE in mode 1 via a SL beam recovery request message or similar message for SL beam recovery response. In various embodiments, the RX UE can report the SL BF indication and the newly identified beams to the TX UE via a SL beam recovery request message or similar message (e.g., PC5-Sidelink (“S”) (“PC5-S”) signaling message exchange), and the TX UE can report the SL BF indication to the gNB for re-allocation of SL CSI-RS resources to the TX UE in mode 1. In certain embodiments, the gNB can signal a SL beam recovery message with a list of candidate beams to the TX UE and / or RX UE. In some embodiments, the RX UE can initiate transmission of SL CSI-RS and / or SL RS as part of the beam recovery procedure towards the TX UE instead of transmitting a beam failure indication. The RX UE can start the SL CSI-RS and / or SL RS transmission using multiple beams and / or panels scanned in differential spatial directions or start simultaneous transmission using multi-beam operation to establish a beam with the peer UE using a default CSI-RS configuration for beam setup or a default CSI-RS configuration configured as part of beam failure.

[0115] Figure 10 FIG. 10 is a flow diagram illustrating one embodiment of a method 1000 for multiple sidelink reference signals. In some embodiments, the method 1000 is performed by a device, such as the remote unit 102. In certain embodiments, the method 1000 can be performed by a processor executing program code, for example, a microcontroller, microprocessor, CPU, GPU, auxiliary processing unit, FPGA, etc.

[0116] In various embodiments, the method 1000 includes transmitting 1002, from a transmitter user equipment to a receiver user equipment, information indicating a plurality of reference signals. The information further indicates a plurality of beams, a plurality of panels, or a combination thereof, transmitting first layer control signaling, the first layer control signaling indicating target user information for a set of user equipment devices as part of an initial beam acquisition, a resource configuration for a reference signal for transmission or receiver decoding using a default reference signal configuration, and a time slot offset and time-frequency resources for a beam measurement feedback report. Transmitting the information indicating the plurality of reference signals includes determining 1004 to transmit: the plurality of reference signals as part of the initial beam acquisition along with a higher layer discovery request message; the plurality of reference signals prior to a higher layer signaling; or a combination thereof. The receiver user equipment determines 1006 the target user information and: generates and transmits a beam measurement feedback using beam correspondence or generates and transmits a reference signal indicating the plurality of beams, the plurality of panels, or the combination thereof in the time slot offset if beam correspondence is not supported.

[0117] In certain embodiments, the method 1000 further includes configuring a separate scheduling request resource for requesting, from the network device, sidelink resources for transmission of independent channel state information reference signals. In some embodiments, the method 1000 further includes receiving downlink control information indicating sidelink resources for transmission of multiple reference signals. In various embodiments, the method 1000 further includes configuring a dedicated feedback resource for each channel state information reference signal resource with a corresponding slot offset for feedback reception, wherein feedback carried by the dedicated feedback resource includes first layer reference signal received power feedback measurements of the corresponding channel state information reference signal resource from the receiver user equipment.

[0118] In one embodiment, the method 1000 further includes transmitting configuration information for a dedicated transmission configuration indicator state table to the receiver user equipment via radio resource control signaling. In certain embodiments, the method 1000 further includes indicating a transmission configuration indicator state or play type in a first sidelink control information, wherein the first sidelink control information indicates a receive spatial filter, a receive beam, or a combination thereof for a second sidelink control information and a physical sidelink shared channel reception. In some embodiments, the method 1000 further includes selecting a dedicated transmission configuration indicator state table from at least one configured transmission configuration indicator state table using a play type indicator.

[0119] In various embodiments, the method 1000 further includes transmitting configuration information for a dedicated transmission configuration indicator state table to the receiver user equipment via a medium access control control element or a destination identifier. In one embodiment, the method 1000 further includes: transmitting a first sidelink control information informing user equipment about resource occupation in all directions via a beam sweep transmission; transmitting a second sidelink control information and a physical sidelink shared channel transmission in a subset of beams based on reception of a dedicated hybrid automatic repeat request report or based on previous transport block transmission to a same destination identifier via a groupcast transmission; transmitting the first sidelink control information, the second sidelink control information, and a physical sidelink control channel transmission in all configured potential transmit beams via a broadcast transmission; and transmitting the second sidelink control information and a physical sidelink control channel in one beam via a unicast transmission.

[0120] In certain embodiments, the method 1000 further includes allocating multiple physical sidelink feedback channel resources corresponding to different beams on which a physical sidelink channel is transmitted. In some embodiments, the method 1000 further includes allocating a single resource for a physical sidelink feedback channel that aggregates hybrid automatic repeat request feedback from all beams transmitting a physical sidelink channel. In various embodiments, a receiver user equipment performs sidelink beam failure detection based on a configured event trigger and reports a sidelink beam failure event to a network device or to a transmitter user equipment.

[0121] In one embodiment, a receiver user equipment performs a new sidelink beam candidate identification and reports a best available beam from a beam candidate list to a transmitter user equipment. In certain embodiments, the method 1000 further includes repeatedly transmitting a plurality of reference signals, wherein the plurality of reference signals are transmitted using a same spatial domain transmission filter.

[0122] In some embodiments, a default reference signal configuration includes a fixed port, a code division multiplexing type, a density within a resource block, a density within a subchannel, a fixed number of frequency resources, a fixed number of time symbols, a fixed periodicity, or some combination thereof. In various embodiments, a default reference signal configuration is configured per resource pool or per sidelink bandwidth part.

[0123] In one embodiment, a method includes transmitting, from a transmitter user equipment to a receiver user equipment, information indicating a plurality of reference signals, wherein the information further indicates a plurality of beams, a plurality of panels, or a combination thereof, transmitting first layer control signaling as part of an initial beam acquisition indicating target user information for a set of user equipment devices, a resource configuration for a reference signal transmitted or received using a default reference signal configuration, and a slot offset and time-frequency resources for a beam measurement feedback report; wherein transmitting the information indicating the plurality of reference signals includes determining: transmitting the plurality of reference signals as part of the initial beam acquisition along with a higher layer discovery request message; transmitting the plurality of reference signals prior to the higher layer signaling; or a combination thereof; and wherein the receiver user equipment determines the target user information and: generates and transmits a beam measurement feedback using a beam correspondence; or generates and transmits a reference signal indicating the plurality of beams, the plurality of panels, or the combination thereof in the slot offset if the beam correspondence is not supported.

[0124] In certain embodiments, the method further includes configuring a separate scheduling request resource for requesting, from a network device, a sidelink resource for transmission of an independent channel state information reference signal.

[0125] In some embodiments, the method further includes receiving a downlink control information indicating a sidelink resource for transmission of a plurality of reference signals.

[0126] In various embodiments, the method further includes configuring a dedicated feedback resource for each channel state information reference signal resource with a corresponding time slot offset for feedback reception, wherein the feedback carried by the dedicated feedback resource includes a first-layer reference signal received power feedback measurement from the corresponding channel state information reference signal resource of the receiver user equipment.

[0127] In one embodiment, the method further includes transmitting configuration information for a dedicated transmission configuration indicator status table to a receiver user equipment via radio resource control signaling.

[0128] In some embodiments, the method further includes indicating a transmission configuration indicator status or playback type in first side-link control information, wherein the first side-link control information indicates a receive spatial filter, a receive beam, or a combination thereof for receiving second side-link control information and physical side-link shared channel.

[0129] In some embodiments, the method further includes selecting a dedicated transport configuration indicator state table from at least one configured transport configuration indicator state table using a playback type indicator.

[0130] In various embodiments, the method further includes transmitting configuration information for a dedicated transport configuration indicator status table to the receiver user equipment via a media access control control element or a destination identifier.

[0131] In one embodiment, the method further includes: transmitting first sidelink control information in all directions, notifying user equipment about resource occupancy, via beam scanning transmission; transmitting second sidelink control information and physical sidelink shared channel transmission in a subset of the beam via multicast transmission, wherein the subset of the beam is identified based on the receipt of a dedicated hybrid automatic repeat request report or based on previous transport block transmissions to the same destination identifier; transmitting the first sidelink control information, second sidelink control information, and physical sidelink control channel transmission in all configured potential transmit beams via broadcast transmission; and transmitting the second sidelink control information and physical sidelink control channel in one beam via unicast transmission.

[0132] In some embodiments, the method further includes allocating a plurality of physical sidelink feedback channel resources corresponding to different beams on which physical sidelink channels are transmitted.

[0133] In some embodiments, the method further includes allocating a single resource for a physical sidelink feedback channel that aggregates hybrid automatic repeat request feedback from all beams transmitting the physical sidelink channel.

[0134] In various embodiments, the receiver user equipment performs sidelink beam failure detection based on configured event triggering and reports the sidelink beam failure event to the network device or to the transmitter user equipment.

[0135] In one embodiment, the receiver user equipment performs a new sidelink beam candidate identification and reports the best available beam from the beam candidate list to the transmitter user equipment.

[0136] In some embodiments, the method further includes repeatedly transmitting a plurality of reference signals, wherein the plurality of reference signals are transmitted using the same spatial domain transfer filter.

[0137] In some embodiments, the default reference signal configuration includes a fixed port, a code division multiplexing type, a density within a resource block, a density within a subchannel, a fixed number of frequency resources, a fixed number of time symbols, a fixed periodicity, or some combination thereof.

[0138] In various embodiments, a default reference signal configuration is configured for each resource pool or each side link bandwidth portion.

[0139] In one embodiment, an apparatus includes: a transmitter transmitting information indicating a plurality of reference signals from a transmitter user equipment to a receiver user equipment, wherein the information further transmits first-layer control signaling indicating a plurality of beams, a plurality of panels, or a combination thereof, the first-layer control signaling indicating, as part of initial beam acquisition, target user information for a set of user equipment devices, resource configuration for configuring transmitted or decoded reference signals using default reference signals, and time slot offsets and time-frequency resources for beam measurement feedback reporting; wherein transmitting the information indicating the plurality of reference signals includes determining: transmitting the plurality of reference signals as part of initial beam acquisition along with a higher-layer discovery request message; transmitting the plurality of reference signals prior to higher-layer signaling; or a combination thereof; and wherein the receiver user equipment determines the target user information and: generates and transmits beam measurement feedback using beam correspondence; or, if beam correspondence is not supported, generates and transmits reference signals indicating the plurality of beams, a plurality of panels, or a combination thereof in a time slot offset.

[0140] In some embodiments, the apparatus further includes a processor configured to request separately scheduled resources from the network device for the transmission of sidelink resources for independent channel state information reference signals.

[0141] In some embodiments, the apparatus further includes a receiver that receives downlink control information indicating sidelink resources for the transmission of a plurality of reference signals.

[0142] In various embodiments, the apparatus further includes a processor that configures a dedicated feedback resource for each channel state information reference signal resource with a corresponding slot offset for feedback reception, wherein feedback carried by the dedicated feedback resource includes first layer reference signal received power feedback measurements for the corresponding channel state information reference signal resource from a receiver user equipment.

[0143] In one embodiment, the transmitter transmits configuration information for a dedicated transmission configuration indicator state table to a receiver user equipment via radio resource control signaling.

[0144] In certain embodiments, the apparatus further includes a processor that indicates a transmission configuration indicator state or a play type in a first sidelink control information, wherein the first sidelink control information indicates a receive spatial filter, a receive beam, or a combination thereof for a second sidelink control information and a physical sidelink shared channel reception.

[0145] In some embodiments, the apparatus further includes a processor that selects a dedicated transmission configuration indicator state table from at least one configured transmission configuration indicator state table using a play type indicator.

[0146] In various embodiments, the transmitter transmits configuration information for a dedicated transmission configuration indicator state table to a receiver user equipment via a medium access control control element or a destination identifier.

[0147] In one embodiment, the transmitter: transmits a first sidelink control information via a beam sweep transmission, the first sidelink control information notifying a user equipment about resource occupation in all directions; transmits a second sidelink control information and a physical sidelink shared channel transmission via a groupcast transmission, the second sidelink control information and the physical sidelink shared channel transmission being transmitted in a subset of beams, wherein the subset of beams is identified based on a reception of a dedicated hybrid automatic repeat request report or based on a previous transport block transmission to a same destination identifier; transmits the first sidelink control information, the second sidelink control information, and a physical sidelink control channel transmission via a broadcast transmission, the first sidelink control information, the second sidelink control information, and the physical sidelink control channel transmission being transmitted in all configured potential transmit beams; and transmits the second sidelink control information and the physical sidelink control channel via a unicast transmission, the second sidelink control information and the physical sidelink control channel being transmitted in one beam.

[0148] In certain embodiments, the apparatus further includes a processor that allocates a plurality of physical sidelink feedback channel resources corresponding to different beams on which a physical sidelink channel is transmitted.

[0149] In some embodiments, the apparatus further includes a processor that allocates a single resource for a physical sidelink feedback channel that aggregates hybrid automatic repeat request feedback from all beams transmitting a physical sidelink channel.

[0150] In various embodiments, the receiver user equipment performs sidelink beam failure detection based on a configured event trigger and reports a sidelink beam failure event to the network equipment or to the transmitter user equipment.

[0151] In one embodiment, the receiver user equipment performs a new sidelink beam candidate identification and reports the best available beam from the beam candidate list to the transmitter user equipment.

[0152] In certain embodiments, the transmitter repeatedly transmits a plurality of reference signals, wherein the plurality of reference signals are transmitted using a same spatial domain transmission filter.

[0153] In some embodiments, the default reference signal configuration includes a fixed port, a code division multiplexing type, a density within a resource block, a density within a subchannel, a fixed number of frequency resources, a fixed number of time symbols, a fixed periodicity, or some combination thereof.

[0154] In various embodiments, a default reference signal configuration is configured per resource pool or per sidelink bandwidth part.

[0155] Embodiments can be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the application is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning of and equivalency of the claims are to be embraced within their scope.

Claims

1. A user equipment, comprising: A transmitter transmits information to a receiver user equipment indicating multiple reference signals, wherein the information further indicates multiple beams, multiple panels, or combinations thereof for transmitting first-layer control signaling, the first-layer control signaling being part of initial beam acquisition indicating target user information for a set of user equipment devices, resource configuration for configuring the reference signals to be transmitted or decoded using default reference signals, and time slot offsets and time-frequency resources for beam measurement feedback reporting; The information indicating the transmission of the plurality of reference signals includes determining: As part of the initial beam acquisition, the plurality of reference signals are transmitted together with a higher-level discovery request message; The plurality of reference signals are transmitted prior to higher-level signaling; or combinations thereof; and Wherein, the receiver user equipment determines the target user information, and: Use beam correspondence to generate and transmit beam measurement feedback; or If beam correspondence is not supported, a reference signal indicating the plurality of beams, the plurality of panels, or a combination thereof is generated and transmitted in the time slot offset.

2. The user equipment of claim 1, further comprising a processor configured to request separately scheduled request resources from a network device for the transmission of an independent channel state information reference signal for sidelink resources.

3. The user equipment according to claim 2, further comprising a receiver, the receiver receiving downlink control information indicating sidelink resources for the transmission of the plurality of reference signals.

4. The user equipment according to claim 1, further comprising a processor, the processor configuring a corresponding time slot offset for feedback reception for each dedicated feedback resource for channel state information reference signal resource, wherein, The feedback carried by the dedicated feedback resource includes a first-layer reference signal received power feedback measurement from the corresponding channel state information reference signal resource of the receiver user equipment.

5. The user equipment according to claim 1, wherein, The transmitter transmits configuration information for a dedicated transmission configuration indicator status table to the receiver user equipment via radio resource control signaling.

6. The user equipment according to claim 5, further comprising a processor, the processor indicating a transmission configuration indicator status or playback type in the first side link control information, wherein, The first sidelink control information indicates a receive spatial filter, a receive beam, or a combination thereof for use in receiving the second sidelink control information and the physical sidelink shared channel.

7. The user equipment of claim 5, further comprising a processor, the processor selecting the dedicated transport configuration indicator state table from at least one configured transport configuration indicator state table using a playback type indicator.

8. The user equipment according to claim 1, wherein, The transmitter transmits configuration information for a dedicated transmission configuration indicator status table to the receiver user equipment via a media access control control element or a destination identifier.

9. The user equipment according to claim 1, wherein, The transmitter: Transmit first-side link control information about resource occupancy to user equipment in all directions via beam scanning transmission; Second side link control information and physical side link shared channel transmission are transmitted in subsets of the beam via multicast transmission, wherein the subsets of the beam are identified based on the reception of a dedicated hybrid automatic repeat request report or based on previous transport block transmissions to the same destination identifier. Transmit the first sidelink control information, the second sidelink control information, and the physical sidelink control channel via broadcast transmission in all configured potential transmit beams; and The second side link control information and the physical side link control channel are transmitted in a beam via unicast transmission.

10. The user equipment of claim 1, further comprising a processor that allocates a plurality of physical sidelink feedback channel resources corresponding to different beams on which physical sidelink channels are transmitted.

11. The user equipment of claim 1, further comprising a processor that allocates a single resource for a physical sidelink feedback channel, the physical sidelink feedback channel aggregating hybrid automatic repeat request feedback from all beams transmitting the physical sidelink channel.

12. The user equipment according to claim 1, wherein, The receiver user equipment performs sidelink beam failure detection based on configured event triggering and reports the sidelink beam failure event to the network device or to the user equipment.

13. The user equipment according to claim 1, wherein, The receiver user equipment executes a new sidelink beam candidate identifier and reports the best available beam from the beam candidate list to the user equipment.

14. The user equipment according to claim 1, wherein, The transmitter repeatedly transmits the plurality of reference signals, wherein the plurality of reference signals are transmitted using the same spatial domain transmission filter.

15. The user equipment according to claim 1, wherein, The default reference signal configuration includes fixed ports, code division multiplexing type, density within resource blocks, density within subchannels, a fixed number of frequency resources, a fixed number of time symbols, a fixed periodicity, or some combination thereof, and the default reference signal configuration is configured for each resource pool or each side link bandwidth portion.

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