WO2023168587A1 - Sélection de référence de temporisation pour signal de synchronisation de liaison latérale - Google Patents

Sélection de référence de temporisation pour signal de synchronisation de liaison latérale Download PDF

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Publication number
WO2023168587A1
WO2023168587A1 PCT/CN2022/079686 CN2022079686W WO2023168587A1 WO 2023168587 A1 WO2023168587 A1 WO 2023168587A1 CN 2022079686 W CN2022079686 W CN 2022079686W WO 2023168587 A1 WO2023168587 A1 WO 2023168587A1
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WIPO (PCT)
Prior art keywords
slss
timing reference
wireless node
timing
sidelink
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PCT/CN2022/079686
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English (en)
Inventor
Shuanshuan Wu
Shailesh Patil
Tien Viet NGUYEN
Gene Wesley Marsh
Kapil Gulati
Vincent Douglas Park
James Alan Misener
Yue YIN
Hui Guo
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Qualcomm Incorporated
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Priority to PCT/CN2022/079686 priority Critical patent/WO2023168587A1/fr
Publication of WO2023168587A1 publication Critical patent/WO2023168587A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes

Definitions

  • aspects of the disclosure relate generally to wireless communications.
  • Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G) , a second-generation (2G) digital wireless phone service (including interim 2.5G and 2.75G networks) , a third-generation (3G) high speed data, Internet-capable wireless service and a fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax) .
  • 1G first-generation analog wireless phone service
  • 2G second-generation
  • 3G third-generation
  • 4G fourth-generation
  • LTE Long Term Evolution
  • WiMax Worldwide Interoperability for Microwave Access
  • Examples of known cellular systems include the cellular analog advanced mobile phone system (AMPS) , and digital cellular systems based on code division multiple access (CDMA) , frequency division multiple access (FDMA) , time division multiple access (TDMA) , the Global System for Mobile communications (GSM) , etc.
  • AMPS cellular analog advanced mobile phone system
  • CDMA code division multiple access
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • GSM Global System for Mobile communications
  • a fifth generation (5G) wireless standard referred to as New Radio (NR)
  • NR New Radio
  • the 5G standard according to the Next Generation Mobile Networks Alliance, is designed to provide higher data rates as compared to previous standards, more accurate positioning (e.g., based on reference signals for positioning (RS-P) , such as downlink, uplink, or sidelink positioning reference signals (PRS) ) , and other technical enhancements.
  • RS-P reference signals for positioning
  • PRS sidelink positioning reference signals
  • a method of operating a wireless node includes receiving a first sidelink synchronization signal (SLSS) associated with a first timing reference; receiving a second SLSS associated with a second timing reference; and selecting an earliest of the first timing reference and a second timing reference; and performing one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • a wireless node includes a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receive, via the at least one transceiver, a first sidelink synchronization signal (SLSS) associated with a first timing reference; receive, via the at least one transceiver, a second SLSS associated with a second timing reference; and select an earliest of the first timing reference and a second timing reference; and perform one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • a wireless node includes means for receiving a first sidelink synchronization signal (SLSS) associated with a first timing reference; means for receiving a second SLSS associated with a second timing reference; and means for selecting an earliest of the first timing reference and a second timing reference; and means for performing one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a wireless node, cause the wireless node to: receive a first sidelink synchronization signal (SLSS) associated with a first timing reference; receive a second SLSS associated with a second timing reference; and select an earliest of the first timing reference and a second timing reference; and perform one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • FIG. 1 illustrates an example wireless communications system, according to aspects of the disclosure.
  • FIGS. 2A, 2B, and 2C illustrate example wireless network structures, according to aspects of the disclosure.
  • FIGS. 3A, 3B, and 3C are simplified block diagrams of several sample aspects of components that may be employed in a user equipment (UE) , a base station, and a network entity, respectively, and configured to support communications as taught herein.
  • UE user equipment
  • FIG. 4 illustrates an example of a wireless communications system that supports unicast sidelink establishment, according to aspects of the disclosure.
  • FIG. 5 illustrates the two resource allocation modes for transmissions on a sidelink, according to aspects of the disclosure.
  • FIGS. 6A and 6B are diagrams of example sidelink slot structures with and without feedback resources, according to aspects of the disclosure.
  • FIG. 7 illustrates a communications system, in accordance with aspects of the disclosure.
  • FIG. 8 illustrates a sync chain, in accordance with aspects of the disclosure.
  • FIG. 9 illustrates a sync chain, in accordance with aspects of the disclosure.
  • FIG. 10 illustrates an exemplary process of wireless communication, according to aspects of the disclosure.
  • FIG. 11 illustrates an example implementation of the process of FIG. 10, in accordance with aspects of the disclosure.
  • sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs) ) , by program instructions being executed by one or more processors, or by a combination of both. Additionally, the sequence (s) of actions described herein can be considered to be embodied entirely within any form of non-transitory computer-readable storage medium having stored therein a corresponding set of computer instructions that, upon execution, would cause or instruct an associated processor of a device to perform the functionality described herein.
  • ASICs application specific integrated circuits
  • UE user equipment
  • base station base station
  • a UE may be any wireless communication device (e.g., a mobile phone, router, tablet computer, laptop computer, consumer asset locating device, wearable (e.g., smartwatch, glasses, augmented reality (AR) /virtual reality (VR) headset, etc. ) , vehicle (e.g., automobile, motorcycle, bicycle, etc. ) , Internet of Things (IoT) device, etc. ) used by a user to communicate over a wireless communications network.
  • a UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with a radio access network (RAN) .
  • RAN radio access network
  • the term “UE” may be referred to interchangeably as an “access terminal” or “AT, ” a “client device, ” a “wireless device, ” a “subscriber device, ” a “subscriber terminal, ” a “subscriber station, ” a “user terminal” or “UT, ” a “mobile device, ” a “mobile terminal, ” a “mobile station, ” or variations thereof.
  • AT access terminal
  • client device a “wireless device
  • AT access terminal
  • client device a “wireless device
  • subscriber device a “subscriber terminal, ” a “subscriber station, ” a “user terminal” or “UT”
  • UEs can communicate
  • WLAN wireless local area network
  • a base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed, and may be alternatively referred to as an access point (AP) , a network node, a NodeB, an evolved NodeB (eNB) , a next generation eNB (ng-eNB) , a New Radio (NR) Node B (also referred to as a gNB or gNodeB) , etc.
  • AP access point
  • eNB evolved NodeB
  • ng-eNB next generation eNB
  • NR New Radio
  • a base station may be used primarily to support wireless access by UEs, including supporting data, voice, and/or signaling connections for the supported UEs.
  • a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions.
  • a communication link through which UEs can send signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc. ) .
  • a communication link through which the base station can send signals to UEs is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc. ) .
  • DL downlink
  • forward link channel e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.
  • TCH traffic channel
  • base station may refer to a single physical transmission-reception point (TRP) or to multiple physical TRPs that may or may not be co-located.
  • TRP transmission-reception point
  • the physical TRP may be an antenna of the base station corresponding to a cell (or several cell sectors) of the base station.
  • base station refers to multiple co-located physical TRPs
  • the physical TRPs may be an array of antennas (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming) of the base station.
  • MIMO multiple-input multiple-output
  • the physical TRPs may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station) .
  • DAS distributed antenna system
  • RRH remote radio head
  • the non-co-located physical TRPs may be the serving base station receiving the measurement report from the UE and a neighbor base station whose reference radio frequency (RF) signals the UE is measuring.
  • RF radio frequency
  • a base station may not support wireless access by UEs (e.g., may not support data, voice, and/or signaling connections for UEs) , but may instead transmit reference signals to UEs to be measured by the UEs, and/or may receive and measure signals transmitted by the UEs.
  • a base station may be referred to as a positioning beacon (e.g., when transmitting signals to UEs) and/or as a location measurement unit (e.g., when receiving and measuring signals from UEs) .
  • An “RF signal” comprises an electromagnetic wave of a given frequency that transports information through the space between a transmitter and a receiver.
  • a transmitter may transmit a single “RF signal” or multiple “RF signals” to a receiver.
  • the receiver may receive multiple “RF signals” corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels.
  • the same transmitted RF signal on different paths between the transmitter and receiver may be referred to as a “multipath” RF signal.
  • an RF signal may also be referred to as a “wireless signal” or simply a “signal” where it is clear from the context that the term “signal” refers to a wireless signal or an RF signal.
  • the wireless communications system 100 may include various base stations 102 (labeled “BS” ) and various UEs 104.
  • the base stations 102 may include macro cell base stations (high power cellular base stations) and/or small cell base stations (low power cellular base stations) .
  • the macro cell base stations may include eNBs and/or ng-eNBs where the wireless communications system 100 corresponds to an LTE network, or gNBs where the wireless communications system 100 corresponds to a NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.
  • the base stations 102 may collectively form a RAN and interface with a core network 170 (e.g., an evolved packet core (EPC) or a 5G core (5GC) ) through backhaul links 122, and through the core network 170 to one or more location servers 172 (e.g., a location management function (LMF) or a secure user plane location (SUPL) location platform (SLP) ) .
  • the location server (s) 172 may be part of core network 170 or may be external to core network 170.
  • a location server 172 may be integrated with a base station 102.
  • a UE 104 may communicate with a location server 172 directly or indirectly.
  • a UE 104 may communicate with a location server 172 via the base station 102 that is currently serving that UE 104.
  • a UE 104 may also communicate with a location server 172 through another path, such as via an application server (not shown) , via another network, such as via a wireless local area network (WLAN) access point (AP) (e.g., AP 150 described below) , and so on.
  • WLAN wireless local area network
  • AP wireless local area network access point
  • communication between a UE 104 and a location server 172 may be represented as an indirect connection (e.g., through the core network 170, etc. ) or a direct connection (e.g., as shown via direct connection 128) , with the intervening nodes (ifany) omitted from a signaling diagram for clarity.
  • the base stations 102 may perform functions that relate to one or more of transferring user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages.
  • the base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC /5GC) over backhaul links 134, which may be wired or wireless.
  • the base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. In an aspect, one or more cells may be supported by a base station 102 in each geographic coverage area 110.
  • a “cell” is a logical communication entity used for communication with a base station (e.g., over some frequency resource, referred to as a carrier frequency, component carrier, carrier, band, or the like) , and may be associated with an identifier (e.g., a physical cell identifier (PCI) , an enhanced cell identifier (ECI) , a virtual cell identifier (VCI) , a cell global identifier (CGI) , etc.
  • PCI physical cell identifier
  • ECI enhanced cell identifier
  • VCI virtual cell identifier
  • CGI cell global identifier
  • the term “cell” may refer to either or both of the logical communication entity and the base station that supports it, depending on the context.
  • the terms “cell” and “TRP” may be used interchangeably.
  • the term “cell” may also refer to a geographic coverage area of a base station (e.g., a sector) , insofar as a carrier frequency can be detected and used for communication within some portion of geographic coverage areas 110.
  • While neighboring macro cell base station 102 geographic coverage areas 110 may partially overlap (e.g., in a handover region) , some of the geographic coverage areas 110 may be substantially overlapped by a larger geographic coverage area 110.
  • a small cell base station 102′ (labeled “SC” for “small cell” ) may have a geographic coverage area 110′that substantially overlaps with the geographic coverage area 110 of one or more macro cell base stations 102.
  • a network that includes both small cell and macro cell base stations may be known as a heterogeneous network.
  • a heterogeneous network may also include home eNBs (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) .
  • HeNBs home eNBs
  • CSG closed subscriber group
  • the communication links 120 between the base stations 102 and the UEs 104 may include uplink (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104.
  • the communication links 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity.
  • the communication links 120 may be through one or more carrier frequencies. Allocation of carriers may be asymmetric with respect to downlink and uplink (e.g., more or less carriers may be allocated for downlink than for uplink) .
  • the wireless communications system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with WLAN stations (STAs) 152 via communication links 154 in an unlicensed frequency spectrum (e. g., 5 GHz) .
  • WLAN wireless local area network
  • AP access point
  • the WLAN STAs 152 and/or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure prior to communicating in order to determine whether the channel is available.
  • CCA clear channel assessment
  • LBT listen before talk
  • the small cell base station 102′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station 102′ may employ LTE or NR technology and use the same 5 GHz unlicensed frequency spectrum as used by the WLAN AP 150. The small cell base station 102′, employing LTE /5G in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.
  • NR in unlicensed spectrum may be referred to as NR-U.
  • LTE in an unlicensed spectrum may be referred to as LTE-U, licensed assisted access (LAA) , or MulteFire.
  • the wireless communications system 100 may further include a millimeter wave (mmW) base station 180 that may operate in mmW frequencies and/or near mmW frequencies in communication with a UE 182.
  • Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band may be referred to as a millimeter wave.
  • Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters.
  • the super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave.
  • the mmW base station 180 and the UE 182 may utilize beamforming (transmit and/or receive) over a mmW communication link 184 to compensate for the extremely high path loss and short range.
  • one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Accordingly, it will be appreciated that the foregoing illustrations are merely examples and should not be construed to limit the various aspects disclosed herein.
  • Transmit beamforming is a technique for focusing an RF signal in a specific direction.
  • a network node e.g., a base station
  • transmit beamforming the network node determines where a given target device (e.g., a UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal for the receiving device (s) .
  • a network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters that are broadcasting the RF signal.
  • a network node may use an array of antennas (referred to as a “phased array” or an “antenna array” ) that creates a beam of RF waves that can be “steered” to point in different directions, without actually moving the antennas.
  • the RF current from the transmitter is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling to suppress radiation in undesired directions.
  • Transmit beams may be quasi-co-located, meaning that they appear to the receiver (e.g., a UE) as having the same parameters, regardless of whether or not the transmitting antennas of the network node themselves are physically co-located.
  • the receiver e.g., a UE
  • QCL relation of a given type means that certain parameters about a second reference RF signal on a second beam can be derived from information about a source reference RF signal on a source beam.
  • the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel.
  • the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type D, the receiver can use the source reference RF signal to estimate the spatial receive parameter of a second reference RF signal transmitted on the same channel.
  • the receiver uses a receive beam to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting and/or adjust the phase setting of an array of antennas in a particular direction to amplify (e.g., to increase the gain level of) the RF signals received from that direction.
  • a receiver is said to beamform in a certain direction, it means the beam gain in that direction is high relative to the beam gain along other directions, or the beam gain in that direction is the highest compared to the beam gain in that direction of all other receive beams available to the receiver.
  • RSRP reference signal received power
  • RSRQ reference signal received quality
  • SINR signal-to-interference-plus-noise ratio
  • Transmit and receive beams may be spatially related.
  • a spatial relation means that parameters for a second beam (e.g., a transmit or receive beam) for a second reference signal can be derived from information about a first beam (e.g., a receive beam or a transmit beam) for a first reference signal.
  • a UE may use a particular receive beam to receive a reference downlink reference signal (e.g., synchronization signal block (SSB) ) from a base station.
  • the UE can then form a transmit beam for sending an uplink reference signal (e.g., sounding reference signal (SRS) ) to that base station based on the parameters of the receive beam.
  • an uplink reference signal e.g., sounding reference signal (SRS)
  • a “downlink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. If the UE is forming the downlink beam, however, it is a receive beam to receive the downlink reference signal.
  • an “uplink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the uplink beam, it is an uplink receive beam, and ifa UE is forming the uplink beam, it is an uplink transmit beam.
  • FR1 frequency range designations FR1 (410 MHz -7.125 GHz) and FR2 (24.25 GHz -52.6 GHz) . It should be understood that although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “Sub-6 GHz” band in various documents and articles.
  • FR2 which is often referred to (interchangeably) as a “millimeter wave” band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz -300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band.
  • EHF extremely high frequency
  • ITU International Telecommunications Union
  • FR3 7.125 GHz -24.25 GHz
  • FR3 7.125 GHz -24.25 GHz
  • FR4a or FR4-1 52.6 GHz -71 GHz
  • FR4 52.6 GHz -114.25 GHz
  • FR5 114.25 GHz -300 GHz
  • sub-6 GHz or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies.
  • millimeter wave or the like ifused herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, FR4, FR4-a or FR4-1, and/or FR5, or may be within the EHF band.
  • the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) utilized by a UE 104/182 and the cell in which the UE 104/182 either performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure.
  • RRC radio resource control
  • the primary carrier carries all common and UE-specific control channels, and may be a carrier in a licensed frequency (however, this is not always the case) .
  • a secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once the RRC connection is established between the UE 104 and the anchor carrier and that may be used to provide additional radio resources.
  • the secondary carrier may be a carrier in an unlicensed frequency.
  • the secondary carrier may contain only necessary signaling information and signals, for example, those that are UE-specific may not be present in the secondary carrier, since both primary uplink and downlink carriers are typically UE-specific. This means that different UEs 104/182 in a cell may have different downlink primary carriers.
  • the network is able to change the primary carrier of any UE 104/182 at any time. This is done, for example, to balance the load on different carriers. Because a “serving cell” (whether a PCell or an SCell) corresponds to a carrier frequency /component carrier over which some base station is communicating, the term “cell, ” “serving cell, ” “component carrier, ” “carrier frequency, ” and the like can be used interchangeably.
  • one of the frequencies utilized by the macro cell base stations 102 may be an anchor carrier (or “PCell” ) and other frequencies utilized by the macro cell base stations 102 and/or the mmW base station 180 may be secondary carriers ( “SCells” ) .
  • the simultaneous transmission and/or reception of multiple carriers enables the UE 104/182 to significantly increase its data transmission and/or reception rates. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz) , compared to that attained by a single 20 MHz carrier.
  • the wireless communications system 100 may further include a UE 164 that may communicate with a macro cell base station 102 over a communication link 120 and/or the mmW base station 180 over a mmW communication link 184.
  • the macro cell base station 102 may support a PCell and one or more SCells for the UE 164 and the mmW base station 180 may support one or more SCells for the UE 164.
  • the UE 164 and the UE 182 may be capable of sidelink communication.
  • Sidelink-capable UEs may communicate with base stations 102 over communication links 120 using the Uu interface (i.e., the air interface between a UE and a base station) .
  • SL-UEs e.g., UE 164, UE 182
  • PC5 interface i.e., the air interface between sidelink-capable UEs
  • a wireless sidelink (or just “sidelink” ) is an adaptation of the core cellular (e.g., LTE, NR) standard that allows direct communication between two or more UEs without the communication needing to go through a base station.
  • Sidelink communication may be unicast or multicast, and may be used for device-to-device (D2D) media-sharing, vehicle-to-vehicle (V2V) communication, vehicle-to-everything (V2X) communication (e.g., cellular V2X (cV2X) communication, enhanced V2X (eV2X) communication, etc. ) , emergency rescue applications, etc.
  • D2D device-to-device
  • V2V vehicle-to-vehicle
  • V2X vehicle-to-everything
  • cV2X cellular V2X
  • eV2X enhanced V2X
  • One or more of a group of SL-UEs utilizing sidelink communications may be within the geographic coverage area 110 of a base station 102. Other SL-UEs in such a group may be outside the geographic coverage area 110 of a base station 102 or be otherwise unable to receive transmissions from a base station 102.
  • groups of SL-UEs communicating via sidelink communications may utilize a one-to-many (1 : M) system in which each SL-UE transmits to every other SL-UE in the group.
  • a base station 102 facilitates the scheduling of resources for sidelink communications.
  • sidelink communications are carried out between SL-UEs without the involvement of a base station 102.
  • the sidelink 160 may operate over a wireless communication medium of interest, which may be shared with other wireless communications between other vehicles and/or infrastructure access points, as well as other RATs.
  • a “medium” may be composed of one or more time, frequency, and/or space communication resources (e.g., encompassing one or more channels across one or more carriers) associated with wireless communication between one or more transmitter /receiver pairs.
  • the medium of interest may correspond to at least a portion of an unlicensed frequency band shared among various RATs.
  • FIG. 1 only illustrates two of the UEs as SL-UEs (i.e., UEs 164 and 182) , any of the illustrated UEs may be SL-UEs.
  • UE 182 was described as being capable ofbeamforming, any of the illustrated UEs, including UE 164, may be capable ofbeamforming.
  • SL-UEs are capable ofbeamforming, they may beamform towards each other (i.e., towards other SL-UEs) , towards other UEs (e.g., UEs 104) , towards base stations (e.g., base stations 102, 180, small cell 102’, access point 150) , etc.
  • base stations e.g., base stations 102, 180, small cell 102’, access point 150
  • UEs 164 and 182 may utilize beamforming over sidelink 160.
  • any of the illustrated UEs may receive signals 124 from one or more Earth orbiting space vehicles (SVs) 112 (e.g., satellites) .
  • the SVs 112 may be part of a satellite positioning system that a UE 104 can use as an independent source of location information.
  • a satellite positioning system typically includes a system of transmitters (e.g., SVs 112) positioned to enable receivers (e.g., UEs 104) to determine their location on or above the Earth based, at least in part, on positioning signals (e.g., signals 124) received from the transmitters.
  • Such a transmitter typically transmits a signal marked with a repeating pseudo-random noise (PN) code of a set number of chips. While typically located in SVs 112, transmitters may sometimes be located on ground-based control stations, base stations 102, and/or other UEs 104.
  • a UE 104 may include one or more dedicated receivers specifically designed to receive signals 124 for deriving geo location information from the SVs 112.
  • an SBAS may include an augmentation system (s) that provides integrity information, differential corrections, etc., such as the Wide Area Augmentation System (WAAS) , the European Geostationary Navigation Overlay Service (EGNOS) , the Multi-functional Satellite Augmentation System (MSAS) , the Global Positioning System (GPS) Aided Geo Augmented Navigation or GPS and Geo Augmented Navigation system (GAGAN) , and/or the like.
  • WAAS Wide Area Augmentation System
  • GNOS European Geostationary Navigation Overlay Service
  • MSAS Multi-functional Satellite Augmentation System
  • GPS Global Positioning System Aided Geo Augmented Navigation or GPS and Geo Augmented Navigation system
  • GAGAN Global Positioning System
  • a satellite positioning system may include any combination of one or more global and/or regional navigation satellites associated with such one or more satellite positioning systems.
  • SVs 112 may additionally or alternatively be part of one or more non-terrestrial networks (NTNs) .
  • NTN non-terrestrial networks
  • an SV 112 is connected to an earth station (also referred to as a ground station, NTN gateway, or gateway) , which in turn is connected to an element in a 5G network, such as a modified base station 102 (without a terrestrial antenna) or a network node in a 5GC.
  • This element would in turn provide access to other elements in the 5G network and ultimately to entities external to the 5G network, such as Internet web servers and other user devices.
  • a UE 104 may receive communication signals (e.g., signals 124) from an SV 112 instead of, or in addition to, communication signals from a terrestrial base station 102.
  • the wireless communications system 100 may further include one or more UEs, such as UE 190, that connects indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links (referred to as “sidelinks” ) .
  • D2D device-to-device
  • P2P peer-to-peer
  • sidelinks referred to as “sidelinks”
  • UE 190 has a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., through which UE 190 may indirectly obtain cellular connectivity) and a D2D P2P link 194 with WLAN STA 152 connected to the WLAN AP 150 (through which UE 190 may indirectly obtain WLAN-based Internet connectivity) .
  • the D2D P2P links 192 and 194 may be supported with any well-known D2D RAT, such as LTE Direct (LTE-D) , WiFi Direct (WiFi
  • FIG. 2A illustrates an example wireless network structure 200.
  • a 5GC 210 also referred to as a Next Generation Core (NGC)
  • C-plane control plane
  • U-plane user plane
  • User plane interface (NG-U) 213 and control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210 and specifically to the user plane functions 212 and control plane functions 214, respectively.
  • an ng-eNB 224 may also be connected to the 5GC 210 via NG-C 215 to the control plane functions 214 and NG-U 213 to user plane functions 212. Further, ng-eNB 224 may directly communicate with gNB 222 via a backhaul connection 223.
  • a Next Generation RAN (NG-RAN) 220 may have one or more gNBs 222, while other configurations include one or more of both ng-eNBs 224 and gNBs 222. Either (or both) gNB 222 or ng-eNB 224 may communicate with one or more UEs 204 (e.g., any of the UEs described herein) .
  • a location server 230 which may be in communication with the 5GC 210 to provide location assistance for UE (s) 204.
  • the location server 230 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc. ) , or alternately may each correspond to a single server.
  • the location server 230 can be configured to support one or more location services for UEs 204 that can connect to the location server 230 via the core network, 5GC 210, and/or via the Internet (not illustrated) .
  • the location server 230 may be integrated into a component of the core network, or alternatively may be external to the core network (e.g., a third party server, such as an original equipment manufacturer (OEM) server or service server) .
  • OEM original equipment manufacturer
  • FIG. 2B illustrates another example wireless network structure 240.
  • a 5GC 260 (which may correspond to 5GC 210 in FIG. 2A) can be viewed functionally as control plane functions, provided by an access and mobility management function (AMF) 264, and user plane functions, provided by a user plane function (UPF) 262, which operate cooperatively to form the core network (i.e., 5GC 260) .
  • AMF access and mobility management function
  • UPF user plane function
  • the functions of the AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between one or more UEs 204 (e.g., any of the UEs described herein) and a session management function (SMF) 266, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and the short message service function (SMSF) (not shown) , and security anchor functionality (SEAF) .
  • the AMF 264 also interacts with an authentication server function (AUSF) (not shown) and the UE 204, and receives the intermediate key that was established as a result of the UE 204 authentication process.
  • AUSF authentication server function
  • the AMF 264 retrieves the security material from the AUSF.
  • the functions of the AMF 264 also include security context management (SCM) .
  • SCM receives a key from the SEAF that it uses to derive access-network specific keys.
  • the functionality of the AMF 264 also includes location services management for regulatory services, transport for location services messages between the UE 204 and a location management function (LMF) 270 (which acts as a location server 230) , transport for location services messages between the NG-RAN 220 and the LMF 270, evolved packet system (EPS) bearer identifier allocation for interworking with the EPS, and UE 204 mobility event notification.
  • LMF location management function
  • EPS evolved packet system
  • the AMF 264 also supports functionalities for non-3GPP (Third Generation Partnership Project) access networks.
  • Functions of the UPF 262 include acting as an anchor point for intra-/inter-RAT mobility (when applicable) , acting as an external protocol data unit (PDU) session point of interconnect to a data network (not shown) , providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering) , lawful interception (user plane collection) , traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., uplink/downlink rate enforcement, reflective QoS marking in the downlink) , uplink traffic verification (service data flow (SDF) to QoS flow mapping) , transport level packet marking in the uplink and downlink, downlink packet buffering and downlink data notification triggering, and sending and forwarding of one or more “end markers” to the source RAN node.
  • the UPF 262 may also support transfer of location services messages over a user plane between the UE 204 and a location server, such as an SLP 272.
  • the functions of the SMF 266 include session management, UE Internet protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering at the UPF 262 to route traffic to the proper destination, control of part of policy enforcement and QoS, and downlink data notification.
  • IP Internet protocol
  • the interface over which the SMF 266 communicates with the AMF 264 is referred to as the N11 interface.
  • LMF 270 may be in communication with the 5GC 260 to provide location assistance for UEs 204.
  • the LMF 270 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc. ) , or alternately may each correspond to a single server.
  • the LMF 270 can be configured to support one or more location services for UEs 204 that can connect to the LMF 270 via the core network, 5GC 260, and/or via the Internet (not illustrated) .
  • the SLP 272 may support similar functions to the LMF 270, but whereas the LMF 270 may communicate with the AMF 264, NG-RAN 220, and UEs 204 over a control plane (e.g., using interfaces and protocols intended to convey signaling messages and not voice or data) , the SLP 272 may communicate with UEs 204 and external clients (e.g., third-party server 274) over a user plane (e.g., using protocols intended to carry voice and/or data like the transmission control protocol (TCP) and/or IP) .
  • TCP transmission control protocol
  • Yet another optional aspect may include a third-party server 274, which may be in communication with the LMF 270, the SLP 272, the 5GC 260 (e.g., via the AMF 264 and/or the UPF 262) , the NG-RAN 220, and/or the UE 204 to obtain location information (e.g., a location estimate) for the UE 204.
  • the third-party server 274 may be referred to as a location services (LCS) client or an external client.
  • the third-party server 274 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc. ) , or alternately may each correspond to a single server.
  • User plane interface 263 and control plane interface 265 connect the 5GC 260, and specifically the UPF 262 and AMF 264, respectively, to one or more gNBs 222 and/or ng-eNBs 224 in the NG-RAN 220.
  • the interface between gNB (s) 222 and/or ng-eNB (s) 224 and the AMF 264 is referred to as the “N2” interface
  • the interface between gNB (s) 222 and/or ng-eNB (s) 224 and the UPF 262 is referred to as the “N3” interface.
  • the gNB (s) 222 and/or ng-eNB (s) 224 of the NG-RAN 220 may communicate directly with each other via backhaul connections 223, referred to as the “Xn-C” interface.
  • One or more of gNBs 222 and/or ng-eNBs 224 may communicate with one or more UEs 204 over a wireless interface, referred to as the “Uu” interface.
  • a gNB 222 may be divided between a gNB central unit (gNB-CU) 226, one or more gNB distributed units (gNB-DUs) 228, and one or more gNB radio units (gNB-RUs) 229.
  • gNB-CU 226 is a logical node that includes the base station functions of transferring user data, mobility control, radio access network sharing, positioning, session management, and the like, except for those functions allocated exclusively to the gNB-DU (s) 228. More specifically, the gNB-CU 226 generally host the radio resource control (RRC) , service data adaptation protocol (SDAP) , and packet data convergence protocol (PDCP) protocols of the gNB 222.
  • RRC radio resource control
  • SDAP service data adaptation protocol
  • PDCP packet data convergence protocol
  • a gNB-DU 228 is a logical node that generally hosts the radio link control (RLC) and medium access control (MAC) layer of the gNB 222. Its operation is controlled by the gNB-CU 226.
  • One gNB-DU 228 can support one or more cells, and one cell is supported by only one gNB-DU 228.
  • the interface 232 between the gNB-CU 226 and the one or more gNB-DUs 228 is referred to as the “F1” interface.
  • the physical (PHY) layer functionality of a gNB 222 is generally hosted by one or more standalone gNB-RUs 229 that perform functions such as power amplification and signal transmission/reception.
  • a UE 204 communicates with the gNB-CU 226 via the RRC, SDAP, and PDCP layers, with a gNB-DU 228 via the RLC and MAC layers, and with a gNB-RU 229 via the PHY layer.
  • a network node such as a Node B (NB) , evolved NB (eNB) , NR base station, 5G NB, access point (AP) , a transmit receive point (TRP) , or a cell, etc.
  • NB Node B
  • eNB evolved NB
  • AP access point
  • TRP transmit receive point
  • An aggregated base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node.
  • a disaggregated base station may be configured to utilize a protocol stack that is physically or logically distributed among two or more units (such as one or more central or centralized units (CUs) , one or more distributed units (DUs) , or one or more radio units (RUs) ) .
  • a CU may be implemented within a RAN node, and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed throughout one or multiple other RAN nodes.
  • the DUs may be implemented to communicate with one or more RUs.
  • Each of the CU, DU and RU also can be implemented as virtual units, i.e., a virtual central unit (VCU) , a virtual distributed unit (VDU) , or a virtual radio unit (VRU) .
  • VCU virtual central unit
  • VDU virtual distributed
  • Base station-type operation or network design may consider aggregation characteristics of base station functionality.
  • disaggregated base stations may be utilized in an integrated access backhaul (IAB) network, an open radio access network (O-RAN (such as the network configuration sponsored by the O-RAN Alliance) ) , or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN) ) .
  • Disaggregation may include distributing functionality across two or more units at various physical locations, as well as distributing functionality for at least one unit virtually, which can enable flexibility in network design.
  • the various units of the disaggregated base station, or disaggregated RAN architecture can be configured for wired or wireless communication with at least one other unit.
  • FIG. 2C is a diagram illustrating an example disaggregated base station architecture 250, according to aspects of the disclosure.
  • the disaggregated base station architecture 250 may include one or more central units (CUs) 280 (e.g., gNB-CU 226) that can communicate directly with a core network 267 (e.g., 5GC 210, 5GC 260) via a backhaul link, or indirectly with the core network 267 through one or more disaggregated base station units (such as a Near-Real Time (Near-RT) RAN Intelligent Controller (RIC) 259 via an E2 link, or a Non-Real Time (Non-RT) RIC 257 associated with a Service Management and Orchestration (SMO) Framework 255, or both) .
  • CUs central units
  • a CU 280 may communicate with one or more distributed units (DUs) 285 (e.g., gNB-DUs 228) via respective midhaul links, such as an F1 interface.
  • the DUs 285 may communicate with one or more radio units (RUs) 287 (e.g., gNB-RUs 229) via respective fronthaul links.
  • the RUs 287 may communicate with respective UEs 204 via one or more radio frequency (RF) access links.
  • RF radio frequency
  • the UE 204 may be simultaneously served by multiple RUs 287.
  • Each of the units may include one or more interfaces or be coupled to one or more interfaces configured to receive or transmit signals, data, or information (collectively, signals) via a wired or wireless transmission medium.
  • Each of the units, or an associated processor or controller providing instructions to the communication interfaces of the units can be configured to communicate with one or more of the other units via the transmission medium.
  • the units can include a wired interface configured to receive or transmit signals over a wired transmission medium to one or more of the other units.
  • the units can include a wireless interface, which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver) , configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.
  • a wireless interface which may include a receiver, a transmitter or transceiver (such as a radio frequency (RF) transceiver) , configured to receive or transmit signals, or both, over a wireless transmission medium to one or more of the other units.
  • RF radio frequency
  • the CU 280 may host one or more higher layer control functions. Such control functions can include radio resource control (RRC) , packet data convergence protocol (PDCP) , service data adaptation protocol (SDAP) , or the like. Each control function can be implemented with an interface configured to communicate signals with other control functions hosted by the CU 280.
  • the CU 280 may be configured to handle user plane functionality (i.e., Central Unit -User Plane (CU-UP) ) , control plane functionality (i.e., Central Unit -Control Plane (CU-CP) ) , or a combination thereof.
  • the CU 280 can be logically split into one or more CU-UP units and one or more CU-CP units.
  • the CU-UP unit can communicate bidirectionally with the CU-CP unit via an interface, such as the E1 interface when implemented in an O-RAN configuration.
  • the CU 280 can be implemented to communicate with the DU 285, as necessary, for network control and signaling.
  • the DU 285 may correspond to a logical unit that includes one or more base station functions to control the operation of one or more RUs 287.
  • the DU 285 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, or the like) depending, at least in part, on a functional split, such as those defined by the 3rd Generation Partnership Project (3GPP) .
  • the DU 285 may further host one or more low PHY layers. Each layer (or module) can be implemented with an interface configured to communicate signals with other layers (and modules) hosted by the DU 285, or with the control functions hosted by the CU 280.
  • Lower-layer functionality can be implemented by one or more RUs 287.
  • an RU 287 controlled by a DU 285, may correspond to a logical node that hosts RF processing functions, or low-PHY layer functions (such as performing fast Fourier transform (FFT) , inverse FFT (iFFT) , digital beamforming, physical random access channel (PRACH) extraction and filtering, or the like) , or both, based at least in part on the functional split, such as a lower layer functional split.
  • the RU (s) 287 can be implemented to handle over the air (OTA) communication with one or more UEs 204.
  • OTA over the air
  • real-time and non-real-time aspects of control and user plane communication with the RU (s) 287 can be controlled by the corresponding DU 285.
  • this configuration can enable the DU (s) 285 and the CU 280 to be implemented in a cloud-based RAN architecture, such as a vRAN architecture.
  • the SMO Framework 255 may be configured to support RAN deployment and provisioning of non-virtualized and virtualized network elements.
  • the SMO Framework 255 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements which may be managed via an operations and maintenance interface (such as an O 1 interface) .
  • the SMO Framework 255 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 269) to perform network element life cycle management (such as to instantiate virtualized network elements) via a cloud computing platform interface (such as an O2 interface) .
  • a cloud computing platform such as an open cloud (O-Cloud) 269
  • network element life cycle management such as to instantiate virtualized network elements
  • a cloud computing platform interface such as an O2 interface
  • Such virtualized network elements can include, but are not limited to, CUs 280, DUs 285, RUs 287 and Near-RT RICs 259.
  • the SMO Framework 255 can communicate with a hardware aspect of a 4G RAN, such as an open eNB (O-eNB) 261, via an O1 interface. Additionally, in some implementations, the SMO Framework 255 can communicate directly with one or more RUs 287 via an O1 interface.
  • the SMO Framework 255 also may include a Non-RT RIC 257 configured to support functionality of the SMO Framework 255.
  • the Non-RT RIC 257 may be configured to include a logical function that enables non-real-time control and optimization of RAN elements and resources, Artificial Intelligence/Machine Learning (AI/ML) workflows including model training and updates, or policy-based guidance of applications/features in the Near-RT RIC 259.
  • the Non-RT RIC 257 may be coupled to or communicate with (such as via an A1 interface) the Near-RT RIC 259.
  • the Near-RT RIC 259 may be configured to include a logical function that enables near-real-time control and optimization of RAN elements and resources via data collection and actions over an interface (such as via an E2 interface) connecting one or more CUs 280, one or more DUs 285, or both, as well as an O-eNB, with the Near-RT RIC 259.
  • the Non-RT RIC 257 may receive parameters or external enrichment information from external servers. Such information may be utilized by the Near-RT RIC 259 and may be received at the SMO Framework 255 or the Non-RT RIC 257 from non-network data sources or from network functions.
  • the Non-RT RIC 257 or the Near-RT RIC 259 may be configured to tune RAN behavior or performance.
  • the Non-RT RIC 257 may monitor long-term trends and patterns for performance and employ AI/ML models to perform corrective actions through the SMO Framework 255 (such as reconfiguration via O1) or via creation of RAN management policies (such as A1 policies) .
  • FIGS. 3A, 3B, and 3C illustrate several example components (represented by corresponding blocks) that may be incorporated into a UE 302 (which may correspond to any of the UEs described herein) , a base station 304 (which may correspond to any of the base stations described herein) , and a network entity 306 (which may correspond to or embody any of the network functions described herein, including the location server 230 and the LMF 270, or alternatively may be independent from the NG-RAN 220 and/or 5GC 210/260 infrastructure depicted in FIGS. 2A and 2B, such as a private network) to support the operations described herein.
  • a UE 302 which may correspond to any of the UEs described herein
  • a base station 304 which may correspond to any of the base stations described herein
  • a network entity 306 which may correspond to or embody any of the network functions described herein, including the location server 230 and the LMF 270, or alternatively may be independent from the NG-RAN 2
  • these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in a system-on-chip (SoC) , etc. ) .
  • the illustrated components may also be incorporated into other apparatuses in a communication system.
  • other apparatuses in a system may include components similar to those described to provide similar functionality.
  • a given apparatus may contain one or more of the components.
  • an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.
  • the UE 302 and the base station 304 each include one or more wireless wide area network (WWAN) transceivers 310 and 350, respectively, providing means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc. ) via one or more wireless communication networks (not shown) , such as an NR network, an LTE network, a GSM network, and/or the like.
  • WWAN wireless wide area network
  • the WWAN transceivers 310 and 350 may each be connected to one or more antennas 316 and 356, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs) , etc., via at least one designated RAT (e.g., NR, LTE, GSM, etc. ) over a wireless communication medium of interest (e.g., some set of time/frequency resources in a particular frequency spectrum) .
  • a wireless communication medium of interest e.g., some set of time/frequency resources in a particular frequency spectrum
  • the WWAN transceivers 310 and 350 may be variously configured for transmitting and encoding signals 318 and 358 (e.g., messages, indications, information, and so on) , respectively, and, conversely, for receiving and decoding signals 318 and 358 (e.g., messages, indications, information, pilots, and so on) , respectively, in accordance with the designated RAT.
  • the WWAN transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, for transmitting and encoding signals 318 and 358, respectively, and one or more receivers 312 and 352, respectively, for receiving and decoding signals 318 and 358, respectively.
  • the UE 302 and the base station 304 each also include, at least in some cases, one or more short-range wireless transceivers 320 and 360, respectively.
  • the short-range wireless transceivers 320 and 360 may be connected to one or more antennas 326 and 366, respectively, and provide means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc. ) with other network nodes, such as other UEs, access points, base stations, etc., via at least one designated RAT (e.g., WiFi, LTE-D, PC5, dedicated short-range communications (DSRC) , wireless access for vehicular environments (WAVE) , near-field communication (NFC) , etc.
  • RAT e.g., WiFi, LTE-D, PC5, dedicated short-range communications (DSRC) , wireless access for vehicular environments (WAVE) , near-field communication (NFC) , etc.
  • the short-range wireless transceivers 320 and 360 may be variously configured for transmitting and encoding signals 328 and 368 (e.g., messages, indications, information, and so on) , respectively, and, conversely, for receiving and decoding signals 328 and 368 (e.g., messages, indications, information, pilots, and so on) , respectively, in accordance with the designated RAT.
  • the short-range wireless transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively.
  • the short-range wireless transceivers 320 and 360 may be WiFi transceivers, transceivers, and/or transceivers, NFC transceivers, or vehicle-to-vehicle (V2V) and/or vehicle-to-everything (V2X) transceivers.
  • V2V vehicle-to-vehicle
  • V2X vehicle-to-everything
  • the UE 302 and the base station 304 also include, at least in some cases, satellite signal receivers 330 and 370.
  • the satellite signal receivers 330 and 370 may be connected to one or more antennas 336 and 376, respectively, and may provide means for receiving and/or measuring satellite positioning/communication signals 338 and 378, respectively.
  • the satellite positioning/communication signals 338 and 378 may be global positioning system (GPS) signals, global navigation satellite system (GLONASS) signals, Galileo signals, Beidou signals, Indian Regional Navigation Satellite System (NAVIC) , Quasi-Zenith Satellite System (QZSS) , etc.
  • GPS global positioning system
  • GLONASS global navigation satellite system
  • Galileo signals Galileo signals
  • Beidou signals Beidou signals
  • NAVIC Indian Regional Navigation Satellite System
  • QZSS Quasi-Zenith Satellite System
  • the satellite positioning/communication signals 338 and 378 may be communication signals (e.g., carrying control and/or user data) originating from a 5G network.
  • the satellite signal receivers 330 and 370 may comprise any suitable hardware and/or software for receiving and processing satellite positioning/communication signals 338 and 378, respectively.
  • the satellite signal receivers 330 and 370 may request information and operations as appropriate from the other systems, and, at least in some cases, perform calculations to determine locations of the UE 302 and the base station 304, respectively, using measurements obtained by any suitable satellite positioning system algorithm.
  • the base station 304 and the network entity 306 each include one or more network transceivers 380 and 390, respectively, providing means for communicating (e.g., means for transmitting, means for receiving, etc. ) with other network entities (e.g., other base stations 304, other network entities 306) .
  • the base station 304 may employ the one or more network transceivers 380 to communicate with other base stations 304 or network entities 306 over one or more wired or wireless backhaul links.
  • the network entity 306 may employ the one or more network transceivers 390 to communicate with one or more base station 304 over one or more wired or wireless backhaul links, or with other network entities 306 over one or more wired or wireless core network interfaces.
  • a transceiver may be configured to communicate over a wired or wireless link.
  • a transceiver (whether a wired transceiver or a wireless transceiver) includes transmitter circuitry (e.g., transmitters 314, 324, 354, 364) and receiver circuitry (e.g., receivers 312, 322, 352, 362) .
  • a transceiver may be an integrated device (e.g., embodying transmitter circuitry and receiver circuitry in a single device) in some implementations, may comprise separate transmitter circuitry and separate receiver circuitry in some implementations, or may be embodied in other ways in other implementations.
  • the transmitter circuitry and receiver circuitry of a wired transceiver may be coupled to one or more wired network interface ports.
  • Wireless transmitter circuitry e.g., transmitters 314, 324, 354, 364
  • wireless receiver circuitry may include or be coupled to a plurality of antennas (e.g., antennas 316, 326, 356, 366) , such as an antenna array, that permits the respective apparatus (e.g., UE 302, base station 304) to perform receive beamforming, as described herein.
  • the transmitter circuitry and receiver circuitry may share the same plurality of antennas (e.g., antennas 316, 326, 356, 366) , such that the respective apparatus can only receive or transmit at a given time, not both at the same time.
  • a wireless transceiver e.g., WWAN transceivers 310 and 350, short-range wireless transceivers 320 and 360
  • NLM network listen module
  • the various wireless transceivers e.g., transceivers 310, 320, 350, and 360, and network transceivers 380 and 390 in some implementations
  • wired transceivers e.g., network transceivers 380 and 390 in some implementations
  • atransceiver at least one transceiver, ” or “one or more transceivers. ”
  • whether a particular transceiver is a wired or wireless transceiver may be inferred from the type of communication performed.
  • backhaul communication between network devices or servers will generally relate to signaling via a wired transceiver
  • wireless communication between a UE (e.g., UE 302) and a base station (e.g., base station 304) will generally relate to signaling via a wireless transceiver.
  • the UE 302, the base station 304, and the network entity 306 also include other components that may be used in conjunction with the operations as disclosed herein.
  • the UE 302, the base station 304, and the network entity 306 include one or more processors 332, 384, and 394, respectively, for providing functionality relating to, for example, wireless communication, and for providing other processing functionality.
  • the processors 332, 384, and 394 may therefore provide means for processing, such as means for determining, means for calculating, means for receiving, means for transmitting, means for indicating, etc.
  • the processors 332, 384, and 394 may include, for example, one or more general purpose processors, multi-core processors, central processing units (CPUs) , ASICs, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , other programmable logic devices or processing circuitry, or various combinations thereof.
  • the UE 302, the base station 304, and the network entity 306 include memory circuitry implementing memories 340, 386, and 396 (e.g., each including a memory device) , respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on) .
  • the memories 340, 386, and 396 may therefore provide means for storing, means for retrieving, means for maintaining, etc.
  • the UE 302, the base station 304, and the network entity 306 may include SLSS component 342, 388, and 398, respectively.
  • the SLSS component 342, 388, and 398 may be hardware circuits that are part of or coupled to the processors 332, 384, and 394, respectively, that, when executed, cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein.
  • the SLSS component 342, 388, and 398 may be external to the processors 332, 384, and 394 (e.g., part of a modem processing system, integrated with another processing system, etc. ) .
  • the SLSS component 342, 388, and 398 may be memory modules stored in the memories 340, 386, and 396, respectively, that, when executed by the processors 332, 384, and 394 (or a modem processing system, another processing system, etc. ) , cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein.
  • FIG. 3A illustrates possible locations of the SLSS component 342, which may be, for example, part of the one or more WWAN transceivers 310, the memory 340, the one or more processors 332, or any combination thereof, or may be a standalone component.
  • FIG. 3A illustrates possible locations of the SLSS component 342, which may be, for example, part of the one or more WWAN transceivers 310, the memory 340, the one or more processors 332, or any combination thereof, or may be a standalone component.
  • FIG. 3B illustrates possible locations of the SLSS component 388, which may be, for example, part of the one or more WWAN transceivers 350, the memory 386, the one or more processors 384, or any combination thereof, or may be a standalone component.
  • FIG. 3C illustrates possible locations of the SLSS component 398, which may be, for example, part of the one or more network transceivers 390, the memory 396, the one or more processors 394, or any combination thereof, or may be a standalone component.
  • the UE 302 may include one or more sensors 344 coupled to the one or more processors 332 to provide means for sensing or detecting movement and/or orientation information that is independent of motion data derived from signals received by the one or more WWAN transceivers 310, the one or more short-range wireless transceivers 320, and/or the satellite signal receiver 330.
  • the sensor (s) 344 may include an accelerometer (e.g., a micro-electrical mechanical systems (MEMS) device) , a gyroscope, a geomagnetic sensor (e.g., a compass) , an altimeter (e.g., a barometric pressure altimeter) , and/or any other type of movement detection sensor.
  • MEMS micro-electrical mechanical systems
  • the senor (s) 344 may include a plurality of different types of devices and combine their outputs in order to provide motion information.
  • the sensor (s) 344 may use a combination of a multi-axis accelerometer and orientation sensors to provide the ability to compute positions in two-dimensional (2D) and/or three-dimensional (3D) coordinate systems.
  • the UE 302 includes a user interface 346 providing means for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on) .
  • a user interface 346 providing means for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on) .
  • the base station 304 and the network entity 306 may also include user interfaces.
  • IP packets from the network entity 306 may be provided to the processor 384.
  • the one or more processors 384 may implement functionality for an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer.
  • PDCP packet data convergence protocol
  • RLC radio link control
  • MAC medium access control
  • the one or more processors 384 may provide RRC layer functionality associated with broadcasting of system information (e.g., master information block (MIB) , system information blocks (SIBs) ) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through automatic repeat request (ARQ) , concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization
  • the transmitter 354 and the receiver 352 may implement Layer-1 (L1) functionality associated with various signal processing functions.
  • Layer-1 which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing.
  • FEC forward error correction
  • the transmitter 354 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) .
  • BPSK binary phase-shift keying
  • QPSK quadrature phase-shift keying
  • M-PSK M-phase-shift keying
  • M-QAM M-quadrature amplitude modulation
  • the coded and modulated symbols may then be split into parallel streams.
  • Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream.
  • OFDM symbol stream is spatially precoded to produce multiple spatial streams.
  • Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing.
  • the channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 302.
  • Each spatial stream may then be provided to one or more different antennas 356.
  • the transmitter 354 may modulate an RF carrier with a respective spatial stream for transmission.
  • the receiver 312 receives a signal through its respective antenna (s) 316.
  • the receiver 312 recovers information modulated onto an RF carrier and provides the information to the one or more processors 332.
  • the transmitter 314 and the receiver 312 implement Layer-1 functionality associated with various signal processing functions.
  • the receiver 312 may perform spatial processing on the information to recover any spatial streams destined for the UE 302. Ifmultiple spatial streams are destined for the UE 302, they may be combined by the receiver 312 into a single OFDM symbol stream.
  • the receiver 312 then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT) .
  • the frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal.
  • FFT fast Fourier transform
  • the symbols on each subcarrier, and the reference signal are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 304. These soft decisions may be based on channel estimates computed by a channel estimator. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station 304 on the physical channel. The data and control signals are then provided to the one or more processors 332, which implements Layer-3 (L3) and Layer-2 (L2) functionality.
  • L3 Layer-3
  • L2 Layer-2
  • the one or more processors 332 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the core network.
  • the one or more processors 332 are also responsible for error detection.
  • the one or more processors 332 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ) , priority handling, and logical channel prioritization.
  • RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement
  • Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 304 may be used by the transmitter 314 to select the appropriate coding and modulation schemes, and to facilitate spatial processing.
  • the spatial streams generated by the transmitter 314 may be provided to different antenna (s) 316.
  • the transmitter 314 may modulate an RF carrier with a respective spatial stream for transmission.
  • the uplink transmission is processed at the base station 304 in a manner similar to that described in connection with the receiver function at the UE 302.
  • the receiver 352 receives a signal through its respective antenna (s) 356.
  • the receiver 352 recovers information modulated onto an RF carrier and provides the information to the one or more processors 384.
  • the one or more processors 384 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 302. IP packets from the one or more processors 384 may be provided to the core network.
  • the one or more processors 384 are also responsible for error detection.
  • the UE 302, the base station 304, and/or the network entity 306 are shown in FIGS. 3A, 3B, and 3C as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated components may have different functionality in different designs. In particular, various components in FIGS. 3A to 3C are optional in alternative configurations and the various aspects include configurations that may vary due to design choice, costs, use of the device, or other considerations. For example, in case of FIG.
  • a particular implementation of UE 302 may omit the WWAN transceiver (s) 310 (e.g., a wearable device or tablet computer or PC or laptop may have Wi-Fi and/or Bluetooth capability without cellular capability) , or may omit the short-range wireless transceiver (s) 320 (e.g., cellular-only, etc. ) , or may omit the satellite signal receiver 330, or may omit the sensor (s) 344, and so on.
  • WWAN transceiver (s) 310 e.g., a wearable device or tablet computer or PC or laptop may have Wi-Fi and/or Bluetooth capability without cellular capability
  • the short-range wireless transceiver (s) 320 e.g., cellular-only, etc.
  • satellite signal receiver 330 e.g., cellular-only, etc.
  • a particular implementation of the base station 304 may omit the WWAN transceiver (s) 350 (e.g., a Wi-Fi “hotspot” access point without cellular capability) , or may omit the short-range wireless transceiver (s) 360 (e.g., cellular-only, etc. ) , or may omit the satellite receiver 370, and so on.
  • WWAN transceiver e.g., a Wi-Fi “hotspot” access point without cellular capability
  • short-range wireless transceiver (s) 360 e.g., cellular-only, etc.
  • satellite receiver 370 e.g., satellite receiver
  • the various components of the UE 302, the base station 304, and the network entity 306 may be communicatively coupled to each other over data buses 334, 382, and 392, respectively.
  • the data buses 334, 382, and 392 may form, or be part of, a communication interface of the UE 302, the base station 304, and the network entity 306, respectively.
  • the data buses 334, 382, and 392 may provide communication between them.
  • FIGS. 3A, 3B, and 3C may be implemented in various ways.
  • the components of FIGS. 3A, 3B, and 3C may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors) .
  • each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality.
  • some or all of the functionality represented by blocks 310 to 346 may be implemented by processor and memory component (s) of the UE 302 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components) .
  • some or all of the functionality represented by blocks 350 to 388 may be implemented by processor and memory component (s) of the base station 304 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components) .
  • some or all of the functionality represented by blocks 390 to 398 may be implemented by processor and memory component (s) of the network entity 306 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components) .
  • various operations, acts, and/or functions are described herein as being performed “by a UE, ” “by a base station, ” “by a network entity, ” etc.
  • the network entity 306 may be implemented as a core network component. In other designs, the network entity 306 may be distinct from a network operator or operation of the cellular network infrastructure (e.g., NG RAN 220 and/or 5GC 210/260) . For example, the network entity 306 may be a component of a private network that may be configured to communicate with the UE 302 via the base station 304 or independently from the base station 304 (e.g., over a non-cellular communication link, such as WiFi) .
  • a non-cellular communication link such as WiFi
  • FIG. 4 illustrates an example of a wireless communications system 400 that supports wireless unicast sidelink establishment, according to aspects of the disclosure.
  • wireless communications system 400 may implement aspects of wireless communications systems 100, 200, and 250.
  • Wireless communications system 400 may include a first UE 402 and a second UE 404, which may be examples of any of the UEs described herein.
  • UEs 402 and 404 may correspond to V-UEs 160 in FIG. 1.
  • the UE 402 may attempt to establish a unicast connection over a sidelink with the UE 404, which may be a V2X sidelink between the UE 402 and UE 404.
  • the established sidelink connection may correspond to sidelinks 162 and/or 168 in FIG. 1.
  • the sidelink connection may be established in an omni-directional frequency range (e.g., FR1) and/or a mmW frequency range (e.g., FR2) .
  • the UE 402 may be referred to as an initiating UE that initiates the sidelink connection procedure
  • the UE 404 may be referred to as a target UE that is targeted for the sidelink connection procedure by the initiating UE.
  • AS access stratum
  • UE 402 and UE 404 For establishing the unicast connection, access stratum (AS) (afunctional layer in the UMTS and LTE protocol stacks between the RAN and the UE that is responsible for transporting data over wireless links and managing radio resources, and which is part of Layer 2) parameters may be configured and negotiated between the UE 402 and UE 404. For example, a transmission and reception capability matching may be negotiated between the UE 402 and UE 404. Each UE may have different capabilities (e.g., transmission and reception, 64 quadrature amplitude modulation (QAM) , transmission diversity, carrier aggregation (CA) , supported communications frequency band (s) , etc. ) .
  • QAM quadrature amplitude modulation
  • CA carrier aggregation
  • s supported communications frequency band
  • a security association may be established between UE 402 and UE 404 for the unicast connection.
  • Unicast traffic may benefit from security protection at a link level (e.g., integrity protection) .
  • Security requirements may differ for different wireless communications systems. For example, V2X and Uu systems may have different security requirements (e.g., Uu security does not include confidentiality protection) .
  • IP configurations e.g., IP versions, addresses, etc. ) may be negotiated for the unicast connection between UE 402 and UE 404.
  • UE 404 may create a service announcement (e.g., a service capability message) to transmit over a cellular network (e.g., cV2X) to assist the sidelink connection establishment.
  • UE 402 may identify and locate candidates for sidelink communications based on a basic service message (BSM) broadcasted unencrypted by nearby UEs (e.g., UE 404) .
  • BSM basic service message
  • the BSM may include location information, security and identity information, and vehicle information (e.g., speed, maneuver, size, etc. ) for the corresponding UE.
  • a discovery channel may not be configured so that UE 402 is able to detect the BSM (s) .
  • the service announcement transmitted by UE 404 and other nearby UEs may be an upper layer signal and broadcasted (e.g., in an NR sidelink broadcast) .
  • the UE 404 may include one or more parameters for itself in the service announcement, including connection parameters and/or capabilities it possesses.
  • the UE 402 may then monitor for and receive the broadcasted service announcement to identify potential UEs for corresponding sidelink connections.
  • the UE 402 may identify the potential UEs based on the capabilities each UE indicates in their respective service announcements.
  • the service announcement may include information to assist the UE 402 (e.g., or any initiating UE) to identify the UE transmitting the service announcement (UE 404 in the example of FIG. 4) .
  • the service announcement may include channel information where direct communication requests may be sent.
  • the channel information may be RAT-specific (e.g., specific to LTE or NR) and may include a resource pool within which UE 402 transmits the communication request.
  • the service announcement may include a specific destination address for the UE (e.g., a Layer 2 destination address) if the destination address is different from the current address (e.g., the address of the streaming provider or UE transmitting the service announcement) .
  • the service announcement may also include a network or transport layer for the UE 402 to transmit a communication request on.
  • the network layer also referred to as “Layer 3” or “L3”
  • the transport layer also referred to as “Layer 4” or “L4”
  • no IP addressing may be needed if the signaling (e.g., PC5 signaling) carries a protocol (e.g., a real-time transport protocol (RTP) ) directly or gives a locally-generated random protocol.
  • the service announcement may include a type of protocol for credential establishment and QoS-related parameters.
  • the initiating UE may transmit a connection request 415 to the identified target UE 404.
  • the connection request 415 may be a first RRC message transmitted by the UE 402 to request a unicast connection with the UE 404 (e.g., an “RRCSetupRequest” message) .
  • the unicast connection may utilize the PC5 interface for the sidelink, and the connection request 415 may be an RRC connection setup request message.
  • the UE 402 may use a sidelink signaling radio bearer 405 to transport the connection request 415.
  • the UE 404 may determine whether to accept or reject the connection request 415.
  • the UE 404 may base this determination on a transmission/reception capability, an ability to accommodate the unicast connection over the sidelink, a particular service indicated for the unicast connection, the contents to be transmitted over the unicast connection, or a combination thereof. For example, if the UE 402 wants to use a first RAT to transmit or receive data, but the UE 404 does not support the first RAT, then the UE 404 may reject the connection request 415. Additionally or alternatively, the UE 404 may reject the connection request 415 based on being unable to accommodate the unicast connection over the sidelink due to limited radio resources, a scheduling issue, etc.
  • the UE 404 may transmit an indication of whether the request is accepted or rejected in a connection response 420. Similar to the UE 402 and the connection request 415, the UE 404 may use a sidelink signaling radio bearer 410 to transport the connection response 420. Additionally, the connection response 420 may be a second RRC message transmitted by the UE 404 in response to the connection request 415 (e.g., an “RRCResponse” message) .
  • sidelink signaling radio bearers 405 and 410 may be the same sidelink signaling radio bearer or may be separate sidelink signaling radio bearers. Accordingly, a radio link control (RLC) layer acknowledged mode (AM) may be used for sidelink signaling radio bearers 405 and 410.
  • RLC radio link control
  • AM layer acknowledged mode
  • a UE that supports the unicast connection may listen on a logical channel associated with the sidelink signaling radio bearers.
  • the AS layer i.e., Layer 2 may pass information directly through RRC signaling (e.g., control plane) instead of a V2X layer (e.g., data plane) .
  • connection response 420 indicates that the UE 404 accepted the connection request 415
  • the UE 402 may then transmit a connection establishment 425 message on the sidelink signaling radio bearer 405 to indicate that the unicast connection setup is complete.
  • the connection establishment 425 may be a third RRC message (e.g., an “RRCSetupComplete” message) .
  • RRC Radio Resource Control
  • identifiers may be used for each of the connection request 415, the connection response 420, and the connection establishment 425.
  • the identifiers may indicate which UE 402/404 is transmitting which message and/or for which UE 402/404 the message is intended.
  • the RRC signaling and any subsequent data transmissions may use the same identifier (e.g., Layer 2 IDs) .
  • the identifiers may be separate for the RRC signaling and for the data transmissions.
  • the RRC signaling and the data transmissions may be treated differently and have different acknowledgement (ACK) feedback messaging.
  • ACK acknowledgement
  • a physical layer ACK may be used for ensuring the corresponding messages are transmitted and received properly.
  • One or more information elements may be included in the connection request 415 and/or the connection response 420 for UE 402 and/or UE 404, respectively, to enable negotiation of corresponding AS layer parameters for the unicast connection.
  • the UE 402 and/or UE 404 may include packet data convergence protocol (PDCP) parameters in a corresponding unicast connection setup message to set a PDCP context for the unicast connection.
  • the PDCP context may indicate whether or not PDCP duplication is utilized for the unicast connection.
  • the UE 402 and/or UE 404 may include RLC parameters when establishing the unicast connection to set an RLC context for the unicast connection.
  • the RLC context may indicate whether an AM (e.g., a reordering timer (t-reordering) is used) or an unacknowledged mode (UM) is used for the RLC layer of the unicast communications.
  • AM e.g., a reordering timer (t-reordering)
  • the UE 402 and/or UE 404 may include medium access control (MAC) parameters to set a MAC context for the unicast connection.
  • MAC context may enable resource selection algorithms, a hybrid automatic repeat request (HARQ) feedback scheme (e.g., ACK or negative ACK (NACK) feedback) , parameters for the HARQ feedback scheme, carrier aggregation, or a combination thereof for the unicast connection.
  • HARQ hybrid automatic repeat request
  • NACK negative ACK
  • the UE 402 and/or UE 404 may include PHY layer parameters when establishing the unicast connection to set a PHY layer context for the unicast connection.
  • the PHY layer context may indicate a transmission format (unless transmission profiles are included for each UE 402/404) and a radio resource configuration (e.g., bandwidth part (BWP) , numerology, etc. ) for the unicast connection.
  • a radio resource configuration e.g., bandwidth part (BWP) , numerology, etc.
  • BWP bandwidth part
  • FR1 and FR2 frequency range configurations
  • a security context may also be set for the unicast connection (e.g., after the connection establishment 425 message is transmitted) .
  • a security association e.g., security context
  • the sidelink signaling radio bearers 405 and 410 may not be protected.
  • the sidelink signaling radio bearers 405 and 410 may be protected. Accordingly, the security context may enable secure data transmissions over the unicast connection and the sidelink signaling radio bearers 405 and 410.
  • IP layer parameters e.g., link-local IPv4 or IPv6 addresses
  • the IP layer parameters may be negotiated by an upper layer control protocol running after RRC signaling is established (e.g., the unicast connection is established) .
  • the UE 404 may base its decision on whether to accept or reject the connection request 415 on a particular service indicated for the unicast connection and/or the contents to be transmitted over the unicast connection (e.g., upper layer information) .
  • the particular service and/or contents may be also indicated by an upper layer control protocol running after RRC signaling is established.
  • the UE 402 and UE 404 may communicate using the unicast connection over a sidelink 430, where sidelink data 435 is transmitted between the two UEs 402 and 404.
  • the sidelink 430 may correspond to sidelinks 162 and/or 168 in FIG. 1.
  • the sidelink data 435 may include RRC messages transmitted between the two UEs 402 and 404.
  • UE 402 and/or UE 404 may transmit a keep alive message (e.g., “RRCLinkAlive” message, a fourth RRC message, etc. ) .
  • the keep alive message may be triggered periodically or on-demand (e.g., event-triggered) . Accordingly, the triggering and transmission of the keep alive message may be invoked by UE 402 or by both UE 402 and UE 404. Additionally or alternatively, a MAC control element (CE) (e.g., defined over sidelink 430) may be used to monitor the status of the unicast connection on sidelink 430 and maintain the connection. When the unicast connection is no longer needed (e.g., UE 402 travels far enough away from UE 404) , either UE 402 and/or UE 404 may start a release procedure to drop the unicast connection over sidelink 430. Accordingly, subsequent RRC messages may not be transmitted between UE 402 and UE 404 on the unicast connection.
  • CE MAC control element
  • FIG. 5 illustrates the two resource allocation modes for transmissions on NR sidelinks, according to aspects of the disclosure.
  • the base station 502 e.g., any of the base stations described herein
  • the base station 502 allocates time and/or frequency resources for sidelink communication between the involved V-UEs 504 and 506 (e.g., any of the V-UEs or sidelink-capable UEs described herein) via DCI 3_0.
  • Each V-UE uses the allocated resources to transmit ranging signals (e.g., SL-PRS) to the other V-UE(s) .
  • ranging signals e.g., SL-PRS
  • the involved UEs 504 and 506 autonomously select sidelink resources to use for transmission of ranging signals.
  • a V-UE can only use the first mode if it has cellular coverage, and can use the second mode regardless of whether or not it has cellular coverage.
  • FIG. 5 illustrates two V-UEs, as will be appreciated, they need not be V-UEs, and may instead be any other type of UE capable of sidelink communication. In addition, there may be more than the two V-UEs 504 and 506 illustrated.
  • Signaling over the sidelink is the same between the two resource allocation modes. From the point of view of the receiver (e.g., V-UE 506) , there is no difference between the modes. That is, it does not matter to the receiver whether the resources for the ranging signals were allocated by the base station 502 or the transmitter.
  • Mode 1 supports dynamic grant (DG) , configured grant (CG) Type 1, and CG Type 2.
  • CG Type 1 is activated via RRC signaling from the base station 502.
  • MCS modulation and coding scheme
  • the transmitting V-UE e.g., V-UE 504 performs channel sensing by blindly decodes all physical sidelink control channels (PSCCHs) to determine the resources reserved for other sidelink transmissions.
  • PSCCHs physical sidelink control channels
  • the transmitting V-UE 504 reports available resources to its upper layer and the upper layer determines resource usage.
  • NR sidelinks support hybrid automatic repeat request (HARQ) retransmission.
  • HARQ hybrid automatic repeat request
  • the base station 502 provides a dynamic grant for HARQ feedback or activates a configured sidelink grant.
  • the sidelink feedback can be reported back to the base station by the transmitting UE (e.g., V-UE 504) .
  • Sidelink communication takes place in transmission or reception resource pools.
  • the minimum resource allocation unit is a sub-channel (e.g., a collection of consecutive PRBs in the frequency domain) .
  • resource allocation is in one slot intervals.
  • some slots are not available for sidelink, and some slots contain feedback resources.
  • sidelink resources can be (pre) configured to occupy fewer than the 14 symbols of a slot.
  • Radio resource control (RRC) layer is configured at the radio resource control (RRC) layer.
  • the RRC configuration can be by pre-configuration (e.g., preloaded on the UE) or configuration (e.g., from a serving base station) .
  • FIG. 6A is a diagram 600 of an example slot structure without feedback resources, according to aspects of the disclosure.
  • time is represented horizontally and frequency is represented vertically.
  • the length of each block is one orthogonal frequency division multiplexing (OFDM) symbol, and the 14 symbols make up a slot.
  • the height of each block is one sub-channel.
  • the (pre) configured sub-channel size can be selected from the set of ⁇ 10, 15, 20, 25, 50, 75, 100 ⁇ physical resource blocks (PRBs) .
  • PRBs physical resource blocks
  • the first symbol is a repetition of the preceding symbol and is used for automatic gain control (AGC) setting.
  • AGC automatic gain control
  • FIG. 6A the vertical and horizontal hashing.
  • the PSCCH physical sidelink control channel
  • PSSCH physical sidelink shared channel
  • the PSCCH carries control information about sidelink resource allocation and descriptions about sidelink data transmitted to the UE.
  • the PSSCH carries user date for the UE.
  • the PSCCH occupies half the bandwidth of the sub-channel and only three symbols. Finally, a gap symbol is present after the PSSCH.
  • FIG. 6B is a diagram 650 of an example slot structure with feedback resources, according to aspects of the disclosure.
  • time is represented horizontally and frequency is represented vertically.
  • the length of each block is one OFDM symbol, and the 14 symbols make up a slot.
  • the height of each block is one sub-channel.
  • the slot structure illustrated in FIG. 6B is similar to the slot structure illustrated in FIG. 6A, except that the slot structure illustrated in FIG. 6B includes feedback resources. Specifically, two symbols at the end of the slot have been dedicated to the physical sidelink feedback channel (PSFCH) .
  • the first PSFCH symbol is a repetition of the second PSFCH symbol for AGC setting.
  • resources for the PSFCH can be configured with a periodicity selected from the set of ⁇ 0, 1, 2, 4 ⁇ slots.
  • SLSS sidelink synchronization signals
  • S-SSB sidelink synchronization signals
  • Different UEs may transmit the same SLSS/S-SSB at the same time/frequency resources when the respective UEs are eligible to transmit SLSS/S-SSB.
  • UEs receiving SLSS determine frame and slot boundaries for sidelink communication based on reception timing of the SLSS. With decoupling of synchronization and communication and SFN-type SLSS transmission, UEs in vicinity will maintain a common timing for communication, which may be optimal for one-to-many sidelink communication (e.g., groupcast or broadcast) considering potential synchronization overhead and interference, especially when sidelink operation is in distributed manner
  • GNSS Global Navigation Satellite System
  • a UE may attempt to synchronize itself with GNSS whenever a GNSS signal is available.
  • a second highest synchronization priority may be with respect to another UE that is GNSS-synced (1-hop to GNSS) .
  • a third highest synchronization priority may be with respect to a UE that is 1 hop away from a UE that is GNSS-synced (2-hop to GNSS) .
  • a fourth highest synchronization priority may be with respect to a UE that is 2 hops away from a UE that is GNSS-synced (3+ hops to GNSS) .
  • the various UEs that are synced across various hops are referred to as a “synchronization chain” (or “sync chain” ) .
  • This synchronization priority hierarchy may be characterized in terms of four distinct priority groups (PGs) , e.g.:
  • ⁇ PG1 GNSS (e.g., UE shall select GNSS as sync source whenever GNSS signal is reliable) ,
  • the above-noted “inCoverage” parameter may be indicated to the wireless node via SL master information block (MIB) .
  • MIB SL master information block
  • two sync resources are configured per sync period (e.g., 160ms as in 3GPP) .
  • SLSS and S-SSB are two terms used in LTE and NR, respectively. Below, unless otherwise indicated, reference to SLSS is used to refer to any sidelink synchronization signal irrespective of RAT-type (e.g., SLSS may implicate S-SSB in an NR context, etc. ) .
  • Various areas without GNSS coverage may be associated with V2X deployments (e.g., tunnels, underground parking, etc. ) .
  • V2X deployments e.g., tunnels, underground parking, etc.
  • SLSS/S-SSB becomes critical in sidelink/V2X communication for UE maintaining common timing and frequency reference.
  • One possible solution for V2X synchronization is deploying roadside units (RSUs) (e.g., infrastructure UEs) .
  • RSUs may be deployed in tunnels or other shielded places (e.g., inaccessible to GNSS) to serve as synchronization source.
  • RSUs may send SLSS/S-SSB over sidelink, and vehicle UEs without GNSS connection may be synchronized to RSU by detecting SLSS/S-SSB (e.g., note that vehicle UEs may or may not have capability to transmit SLSS/S-SSB) .
  • FIG. 7 illustrates a communications system 700, in accordance with aspects of the disclosure.
  • the communications system 700 includes GNSS satellites 705 and 710, and sidelink wireless nodes 1... N (e.g., RSUs, vehicle UEs capable of transmitting SLSS/S-SSB, etc. ) .
  • SL wireless node 1 is in-coverage of GNSS signal (s) 720 from GNSS satellite 705, and SL wireless node N is in-coverage of GNSS signal (s) 725 from GNSS satellite 710.
  • SL wireless nodes 2 ... 1-N by contrast are in a shielded region 715 (e.g., a tunnel, underground parking, etc. ) and are out-of-coverage with respect to GNSS.
  • a shielded region 715 e.g., a tunnel, underground parking, etc.
  • the SL wireless nodes 2 ... 1-N may be used to propagate GNSS timing through the shielded region 715. This ensures that a (roughly) common timing is maintained in and out of tunnel, so UEs in and/or out of tunnel can communication with each other.
  • a synchronization procedure will result in a stable sync chain once the SL wireless nodes are powered up.
  • a “stable” sync chain means that all the SL wireless nodes (e.g., RSUs, etc. ) can eventually inherit timing from GNSS, directly or indirectly (common source) , and that the sync timing propagation through the sync chain is ‘shortest’ (e.g., RSU n+1 is synchronized to RSU n, which is synchronized to RSU n-1, etc.
  • FIG. 8 illustrates a sync chain 800, in accordance with aspects of the disclosure.
  • the sync chain 800 is a representative example of a stable sync chain.
  • GNSS satellite 715 belongs to priority group 1 (or PG1)
  • SL wireless node 1 belongs to priority group 2 (or PG2) and is GNSS-synced
  • SL wireless node 2 (PG3) is synced with SL wireless node 1
  • SL wireless nodes 3 and 4 (PG4) are synced with SL wireless node 2
  • SL wireless nodes 5 and 6 (PG4) are synced with SL wireless node 4
  • SL wireless node 7 (PG4) is synced with SL wireless node 6, and so on.
  • FIG. 9 illustrates a sync chain 900, in accordance with aspects of the disclosure.
  • the sync chain 900 is a representative example of an unstable sync chain.
  • GNSS satellite 715 belongs to priority group 1 (or PG1)
  • SL wireless node 1 belongs to priority group 2 (or PG2) and is GNSS-synced
  • SL wireless node 2 (PG3) is synced with SL wireless node 1
  • SL wireless nodes 3 and 4 (PG4) are synced with SL wireless node 2
  • SL wireless node 5 (PG4) is synced with SL wireless node 4.
  • the SLSSs from SL wireless nodes 6 and 7 are cross-synced with each other, resulting in an unstable condition.
  • the unstable condition depicted in FIG. 9 may arise for various reasons.
  • the synchronization priority levels (PG1-PG4) defined in 3GPP standards are limited, so for a long tunnel, there may be many SL wireless nodes (e.g., RSUs) having same (lowest) synchronization priority, such that the desired (stable) sync chain cannot be guaranteed.
  • RSUs are stationary and fixed, once a non-desirable (unstable) sync chain is formed, the system cannot self-correct (i.e., system may be stuck in that wrong status) .
  • aspects of the disclosure are directed to selecting between timing references associated with different SLSSs based at least in part on which of the timing references is the earliest (e.g., although as noted above, the earliest timing reference need not correspond to the SLSS that happens to be received first at a UE) .
  • Such aspects may provide various technical advantages, such as avoiding, reducing or eliminating an unstable condition in a synchronization chain (e.g., through some or all of a shielded region, such as a tunnel or underground parking garage) , which may improve communication in various ways.
  • FIG. 10 illustrates an exemplary process 1000 of wireless communication, according to aspects of the disclosure.
  • the process 1000 may be performed by a wireless node, which may correspond to a UE such as UE 302, an RSU (e.g., which may be considered an infrastructure UE or a network component such as a BS or gNB or RU, etc. ) .
  • a wireless node which may correspond to a UE such as UE 302, an RSU (e.g., which may be considered an infrastructure UE or a network component such as a BS or gNB or RU, etc. ) .
  • RSU e.g., which may be considered an infrastructure UE or a network component such as a BS or gNB or RU, etc.
  • the wireless node receives a first SLSS associated with a first timing reference.
  • the wireless node receives a second SLSS associated with a second timing reference.
  • the wireless node selects an earliest of the first timing reference and a second timing reference.
  • the earliest timing reference may correspond to the SLSS associated with a first detected path.
  • the wireless node e.g., transmitter 314 or 324 or 354 or 364, RU 287, etc. ) performs one or more sidelink transmissions based on the selected timing reference.
  • the one or more sidelink transmissions may include SLSS transmission (s) or communication transmission (s) (e.g., PSSCH/PSCCH) .
  • a synchronization period may be defined, with a particular subset of time-frequency resources being reserved, configured, or pre-configured for SLSS transmission.
  • two time-frequency resources may be reserved for SLSS per synchronization period.
  • the selected timing reference is associated with an earliest detected path (e.g., first detected path) among the first SLSS and the second SLSS.
  • the first and second SLSS signals may be interpreted as multi-path signals.
  • the wireless node may select the first detected path in that resource, as its SL frame/slot timing reference.
  • the wireless node may then transmit SLSS and/or other SL transmission (s) (e.g., PSSCH/PSCCH) based on its SL frame/slot timing.
  • the first SLSS may be associated with a first time-frequency resource
  • the second SLSS may be associated with a second time-frequency resource that is different than the first time-frequency resource, as illustrated in FIG. 11.
  • the first timing reference is determined based on an earliest detected path (e.g., first detected path) associated with the first SLSS
  • the second timing reference associated with the second SLSS is determined based on an earliest detected path (e.g., first detected path) associated with the second SLSS.
  • the first timing reference associated with the first SLSS is determined based on a strongest detected path associated with the first SLSS
  • the second timing reference associated with the second SLSS is determined based on a strongest detected path associated with the second SLSS.
  • FIG. 11 illustrates an example implementation 1100 of the process 1000 of FIG. 10, in accordance with aspects of the disclosure.
  • the first SLSS (SLSS-1) is received in a later time-frequency resource 1102 (SLSS Resource 2) of sync period n
  • the second SLSS (SLSS-2) is received in an earlier time-frequency resource 1104 (SLSS Resource 1) of sync period n+1.
  • SLSS-1 and SLSS-2 have the same priority (e.g., associated with the same priority group or PG) .
  • SLSS Resource 2 of SLSS period n and SLSS Resource 1 of SLSS period n+1 are m ms (or subframes) away (not accounting for relative difference between timing references) .
  • the interval between receiving timing of SLSS-1 and receiving timing of SLSS-2 is m’ ms (which factors the relative difference between timing references) . If m > m’, then the wireless node determines that the timing reference of SLSS-2 is earlier; otherwise: timing reference of SLSS-1 is earlier.
  • the first timing reference may be associated with the first SLSS is established as a first timing reference when the second SLSS is received (e.g., the wireless node already has knowledge of sidelink frame/slot timing (e.g., slot boundary) based on its detection of the first SLSS, and the wireless node later detects the second SLSS, which may have a different timing) .
  • the wireless node may select (at 1030) the second SLSS as the selected SLSS so as to transition from the first timing reference associated with the first SLSS to the second timing reference associated with the second SLSS.
  • the wireless node may compare whether the frame/slot timing based on the newly detected SLSS is earlier, and if so, the wireless node may re-establish the sidelink frame/slot timing based on the newly detected SLSS. For example, the wireless node may transmit SLSS or other sidelink transmissions based on the newly established timing.
  • the timing-based selection of the timing reference at 1030 of FIG. 10 may be triggered based on one or more conditions, from among a set of conditions, being satisfied.
  • the wireless node need not always select the earliest timing reference (e.g., timing reference associated with first detected path) associated with available SLSSs.
  • the set of conditions may include:
  • the first timing reference and the second timing reference each being associated with a GNSS source while a direct GNSS source is unavailable to the wireless node (e.g., a shielded place/region) , or
  • the first timing reference and the second timing reference each being associated with the GNSS source based on respective SLSS identifiers (e.g., in LTE V2X, the detected SLSS has ID 168 or 169, in NR V2X, the ID 336 or 337, etc. ) , or
  • the first timing reference being associated with a first reference signal received power (RSRP) and the second timing reference being associated with a second RSRP that is within a signal strength threshold (e.g., a pre-configured signal strength threshold, a pre-defined signal strength threshold, etc. ) of the first RSRP, or
  • a signal strength threshold e.g., a pre-configured signal strength threshold, a pre-defined signal strength threshold, etc.
  • the wireless node being pre-configured to implement a timing-based SLSS selection (e.g., in-tunnel RSUs are configured to determine SL timing based on earlier timing reference, but ‘regular’ vehicle UE may not be configured to do so, etc. ) , or
  • the first SLSS and the second SLSS each belonging to the same SLSS priority class (e.g., PG2, PG3, PG4, etc. ) (, or
  • ⁇ the first SLSS and the second SLSS each belonging to a lowest SLSS priority class e.g., PG4
  • a lowest SLSS priority class e.g., PG4
  • TA non-zero timing advance
  • the first SLSS and the second SLSS being associated with the same radio access technology (RAT) (e.g., the first and second SLSSs are both LTE SLSS or both NR S-SSB, etc. ) , or
  • RAT radio access technology
  • the first SLSS being associated with a first RAT (e.g., LTE, NR, etc. ) and the second SLSS being associated with a second RAT (e.g., NR, LTE, etc. ) that is different than the first RAT (e.g., some wireless nodes may be dual-mode UEs supporting both LTE and NR, such as LTE V2X and NR V2X in a specific example) , or
  • the one or more conditions may include two or more conditions from the set of conditions.
  • the one or more conditions are pre-defined.
  • the one or more conditions may be pre-defined in 3GPP Specification (e.g., 3GPP Specification, such as 3GPP 38.331/38.133, may specify that the UE should select the earlier timing reference as its SL transmission timing reference, either conditionally based on various triggering criteria or as a default solution) or in a regional V2X standard (e.g., in Society of Automotive Engineers, (SAE) , C-SAE, etc. ) .
  • the one or more conditions may be left up to UE implementation. (e.g., for unique or specialized scenarios, e.g., RSU transmitting SLSS in tunnel) .
  • the wireless node may select, for the SL timing, the SLSS signal with stronger strength (higher S-RSRP measurement) .
  • the wireless node may detect two SLSS signals, but the SLSS ID is one of those for out-of-coverage wireless nodes and is not 168 or 169 (not 336 and 337 for NR V2X) . In this case, the wireless node may just select the SLSS with higher S-RSRP as timing reference.
  • SLSS ID is one of those for out-of-coverage is not 168/169 means the ID is one of those used by independent SyncRef UE (SyncRef UE is in PG4 but timing may not be inherited from GNSS) .
  • the wireless node may (pseudo) randomly select one as SL timing.
  • the wireless node may select a timing reference associated with one of the two or more additional SLSSs pseudo-randomly or based on a signal strength parameter.
  • example clauses can also include a combination of the dependent clause aspect (s) with the subject matter of any other dependent clause or independent clause or a combination of any feature with other dependent and independent clauses.
  • the various aspects disclosed herein expressly include these combinations, unless it is explicitly expressed or can be readily inferred that a specific combination is not intended (e.g., contradictory aspects, such as defining an element as both an electrical insulator and an electrical conductor) .
  • aspects of a clause can be included in any other independent clause, even if the clause is not directly dependent on the independent clause.
  • a method of operating a wireless node comprising: receiving a first sidelink synchronization signal (SLSS) associated with a first timing reference; receiving a second SLSS associated with a second timing reference; and selecting an earliest of the first timing reference and a second timing reference; and performing one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • Clause 2 The method of clause 1, wherein the wireless node corresponds to a roadside unit (RSU) , or wherein the wireless node corresponds to a user equipment (UE) .
  • RSU roadside unit
  • UE user equipment
  • Clause 3 The method of any of clauses 1 to 2, wherein the first SLSS and the second SLSS are received on the same time-frequency resource, and wherein the selected timing reference is associated with an earliest detected path among the first SLSS and the second SLSS.
  • Clause 4 The method of any of clauses 1 to 3, wherein the first SLSS is associated with a first time-frequency resource, and wherein the second SLSS is associated with a second time-frequency resource that is different than the first time-frequency resource.
  • Clause 6 The method of any of clauses 4 to 5, wherein the first timing reference associated with the first SLSS is determined based on a strongest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on a strongest detected path associated with the second SLSS.
  • Clause 7 The method of any of clauses 1 to 6, wherein the first timing reference associated with the first SLSS is established as a first timing reference when the second SLSS is received, and wherein the selecting selects the second SLSS as the selected SLSS so as to transition from the first timing reference associated with the first SLSS to the second timing reference associated with the second SLSS.
  • Clause 8 The method of any of clauses 1 to 7, wherein the selecting is triggered based on one or more conditions, from among a set of conditions, being satisfied.
  • the set of conditions comprise: the first timing reference and the second timing reference each being associated with a Global navigation satellite system (GNSS) source while a direct GNSS source is unavailable to the wireless node, or the first timing reference and the second timing reference each being associated with the GNSS source based on respective SLSS identifiers, or the first timing reference being associated with a first reference signal received power (RSRP) and the second timing reference being associated with a second RSRP that is within a signal strength threshold of the first RSRP, or the wireless node being pre-configured to implement a timing-based SLSS selection, or the first SLSS and the second SLSS each belonging to the same SLSS priority class, or the first SLSS and the second SLSS each belonging to a lowest SLSS priority class, or neither of the first SLSS nor the second SLSS being associated with a non-zero timing advance (TA) , or the first SLSS and the second SLSS being associated with the same radio access technology (TA) , or the first SL
  • Clause 10 The method of clause 9, wherein the one or more conditions comprise two or more conditions from the set of conditions.
  • Clause 11 The method of any of clauses 8 to 10, wherein the one or more conditions are pre-defined.
  • Clause 12 The method of any of clauses 8 to 11, wherein, for two or more additional SLSSs received at the wireless node, the one or more conditions are not satisfied, further comprising: selecting a timing reference associated with one of the two or more additional SLSSs pseudo-randomly or based on a signal strength parameter.
  • a wireless node comprising: a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receive, via the at least one transceiver, a first sidelink synchronization signal (SLSS) associated with a first timing reference; receive, via the at least one transceiver, a second SLSS associated with a second timing reference; and select an earliest of the first timing reference and a second timing reference; and perform one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • Clause 14 The wireless node of clause 13, wherein the wireless node corresponds to a roadside unit (RSU) , or wherein the wireless node corresponds to a user equipment (UE) .
  • RSU roadside unit
  • UE user equipment
  • Clause 15 The wireless node of any of clauses 13 to 14, wherein the first SLSS and the second SLSS are received on the same time-frequency resource, and wherein the selected timing reference is associated with an earliest detected path among the first SLSS and the second SLSS.
  • Clause 16 The wireless node of any of clauses 13 to 15, wherein the first SLSS is associated with a first time-frequency resource, and wherein the second SLSS is associated with a second time-frequency resource that is different than the first time-frequency resource.
  • Clause 17 The wireless node of clause 16, wherein the first timing reference is determined based on an earliest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on an earliest detected path associated with the second SLSS.
  • Clause 18 The wireless node of any of clauses 16 to 17, wherein the first timing reference associated with the first SLSS is determined based on a strongest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on a strongest detected path associated with the second SLSS.
  • Clause 19 The wireless node of any of clauses 13 to 18, wherein the first timing reference associated with the first SLSS is established as a first timing reference when the second SLSS is received, and wherein the selecting selects the second SLSS as the selected SLSS so as to transition from the first timing reference associated with the first SLSS to the second timing reference associated with the second SLSS.
  • Clause 20 The wireless node of any of clauses 13 to 19, wherein the selecting is triggered based on one or more conditions, from among a set of conditions, being satisfied.
  • the wireless node of clause 20 wherein the set of conditions comprise: the first timing reference and the second timing reference each being associated with a Global navigation satellite system (GNSS) source while a direct GNSS source is unavailable to the wireless node, or the first timing reference and the second timing reference each being associated with the GNSS source based on respective SLSS identifiers, or the first timing reference being associated with a first reference signal received power (RSRP) and the second timing reference being associated with a second RSRP that is within a signal strength threshold of the first RSRP, or the wireless node being pre-configured to implement a timing-based SLSS selection, or the first SLSS and the second SLSS each belonging to the same SLSS priority class, or the first SLSS and the second SLSS each belonging to a lowest SLSS priority class, or neither of the first SLSS nor the second SLSS being associated with a non-zero timing advance (TA) , or the first SLSS and the second SLSS being associated with the same radio
  • Clause 22 The wireless node of clause 21, wherein the one or more conditions comprise two or more conditions from the set of conditions.
  • Clause 23 The wireless node of any of clauses 20 to 22, wherein the one or more conditions are pre-defined.
  • Clause 24 The wireless node of any of clauses 20 to 23, wherein, for two or more additional SLSSs received at the wireless node, the one or more conditions are not satisfied, further comprising: select a timing reference associated with one of the two or more additional SLSSs pseudo-randomly or based on a signal strength parameter.
  • a wireless node comprising: means for receiving a first sidelink synchronization signal (SLSS) associated with a first timing reference; means for receiving a second SLSS associated with a second timing reference; and means for selecting an earliest of the first timing reference and a second timing reference; and means for performing one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • Clause 26 The wireless node of clause 25, wherein the wireless node corresponds to a roadside unit (RSU) , or wherein the wireless node corresponds to a user equipment (UE) .
  • RSU roadside unit
  • UE user equipment
  • Clause 27 The wireless node of any of clauses 25 to 26, wherein the first SLSS and the second SLSS are received on the same time-frequency resource, and wherein the selected timing reference is associated with an earliest detected path among the first SLSS and the second SLSS.
  • Clause 28 The wireless node of any of clauses 25 to 27, wherein the first SLSS is associated with a first time-frequency resource, and wherein the second SLSS is associated with a second time-frequency resource that is different than the first time-frequency resource.
  • Clause 29 The wireless node of clause 28, wherein the first timing reference is determined based on an earliest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on an earliest detected path associated with the second SLSS.
  • Clause 30 The wireless node of any of clauses 28 to 29, wherein the first timing reference associated with the first SLSS is determined based on a strongest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on a strongest detected path associated with the second SLSS.
  • Clause 31 The wireless node of any of clauses 25 to 30, wherein the first timing reference associated with the first SLSS is established as a first timing reference when the second SLSS is received, and wherein the selecting selects the second SLSS as the selected SLSS so as to transition from the first timing reference associated with the first SLSS to the second timing reference associated with the second SLSS.
  • Clause 32 The wireless node of any of clauses 25 to 31, wherein the selecting is triggered based on one or more conditions, from among a set of conditions, being satisfied.
  • the wireless node of clause 32 wherein the set of conditions comprise: the first timing reference and the second timing reference each being associated with a Global navigation satellite system (GNSS) source while a direct GNSS source is unavailable to the wireless node, or the first timing reference and the second timing reference each being associated with the GNSS source based on respective SLSS identifiers, or the first timing reference being associated with a first reference signal received power (RSRP) and the second timing reference being associated with a second RSRP that is within a signal strength threshold of the first RSRP, or the wireless node being pre-configured to implement a timing-based SLSS selection, or the first SLSS and the second SLSS each belonging to the same SLSS priority class, or the first SLSS and the second SLSS each belonging to a lowest SLSS priority class, or neither of the first SLSS nor the second SLSS being associated with a non-zero timing advance (TA) , or the first SLSS and the second SLSS being associated with the same
  • Clause 34 The wireless node of clause 33, wherein the one or more conditions comprise two or more conditions from the set of conditions.
  • Clause 35 The wireless node of any of clauses 32 to 34, wherein the one or more conditions are pre-defined.
  • Clause 36 The wireless node of any of clauses 32 to 35, wherein, for two or more additional SLSSs received at the wireless node, the one or more conditions are not satisfied, further comprising: means for selecting a timing reference associated with one of the two or more additional SLSSs pseudo-randomly or based on a signal strength parameter.
  • a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a wireless node, cause the wireless node to: receive a first sidelink synchronization signal (SLSS) associated with a first timing reference; receive a second SLSS associated with a second timing reference; and select an earliest of the first timing reference and a second timing reference; and perform one or more sidelink transmissions based on the selected timing reference.
  • SLSS sidelink synchronization signal
  • Clause 38 The non-transitory computer-readable medium of clause 37, wherein the wireless node corresponds to a roadside unit (RSU) , or wherein the wireless node corresponds to a user equipment (UE) .
  • RSU roadside unit
  • UE user equipment
  • Clause 39 The non-transitory computer-readable medium of any of clauses 37 to 38, wherein the first SLSS and the second SLSS are received on the same time-frequency resource, and wherein the selected timing reference is associated with an earliest detected path among the first SLSS and the second SLSS.
  • Clause 40 The non-transitory computer-readable medium of any of clauses 37 to 39, wherein the first SLSS is associated with a first time-frequency resource, and wherein the second SLSS is associated with a second time-frequency resource that is different than the first time-frequency resource.
  • Clause 41 The non-transitory computer-readable medium of clause 40, wherein the first timing reference is determined based on an earliest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on an earliest detected path associated with the second SLSS.
  • Clause 42 The non-transitory computer-readable medium of any of clauses 40 to 41, wherein the first timing reference associated with the first SLSS is determined based on a strongest detected path associated with the first SLSS, and the second timing reference associated with the second SLSS is determined based on a strongest detected path associated with the second SLSS.
  • Clause 43 The non-transitory computer-readable medium of any of clauses 37 to 42, wherein the first timing reference associated with the first SLSS is established as a first timing reference when the second SLSS is received, and wherein the selecting selects the second SLSS as the selected SLSS so as to transition from the first timing reference associated with the first SLSS to the second timing reference associated with the second SLSS.
  • Clause 44 The non-transitory computer-readable medium of any of clauses 37 to 43, wherein the selecting is triggered based on one or more conditions, from among a set of conditions, being satisfied.
  • the set of conditions comprise: the first timing reference and the second timing reference each being associated with a Global navigation satellite system (GNSS) source while a direct GNSS source is unavailable to the wireless node, or the first timing reference and the second timing reference each being associated with the GNSS source based on respective SLSS identifiers, or the first timing reference being associated with a first reference signal received power (RSRP) and the second timing reference being associated with a second RSRP that is within a signal strength threshold of the first RSRP, or the wireless node being pre-configured to implement a timing-based SLSS selection, or the first SLSS and the second SLSS each belonging to the same SLSS priority class, or the first SLSS and the second SLSS each belonging to a lowest SLSS priority class, or neither of the first SLSS nor the second SLSS being associated with a non-zero timing advance (TA) , or the first SLSS and the second SL
  • Clause 46 The non-transitory computer-readable medium of clause 45, wherein the one or more conditions comprise two or more conditions from the set of conditions.
  • Clause 47 The non-transitory computer-readable medium of any of clauses 44 to 46, wherein the one or more conditions are pre-defined.
  • Clause 48 The non-transitory computer-readable medium of any of clauses 44 to 47, wherein, for two or more additional SLSSs received at the wireless node, the one or more conditions are not satisfied, further comprising: select a timing reference associated with one of the two or more additional SLSSs pseudo-randomly or based on a signal strength parameter.
  • DSP digital signal processor
  • ASIC application-specific integrated circuit
  • FPGA field-programable gate array
  • a general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine.
  • a processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
  • a software module may reside in random access memory (RAM) , flash memory, read-only memory (ROM) , erasable programmable ROM (EPROM) , electrically erasable programmable ROM (EEPROM) , registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
  • An example storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium.
  • the storage medium may be integral to the processor.
  • the processor and the storage medium may reside in an ASIC.
  • the ASIC may reside in a user terminal (e. g., UE) .
  • the processor and the storage medium may reside as discrete components in a user terminal.
  • the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium.
  • Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
  • a storage media may be any available media that can be accessed by a computer.
  • such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
  • any connection is properly termed a computer-readable medium.
  • the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave
  • the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.
  • Disk and disc includes compact disc (CD) , laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

Abstract

Des techniques de communication sans fil sont divulguées. Selon un aspect, un nœud sans fil (par exemple, UE, RSU, etc.) reçoit un premier signal de synchronisation de liaison latérale (SLSS) associé à une première référence de temporisation. Le nœud sans fil reçoit en outre un second SLSS associé à une seconde référence de temporisation. Le nœud sans fil sélectionne en outre une référence arrivée le plus tôt parmi la première référence de temporisation et une seconde référence de temporisation. Le nœud sans fil effectue en outre une ou plusieurs transmissions de liaison latérale (par exemple, SLSS ou S-SSB, PSSCH/PSCCH, etc.) sur la base de la référence de temporisation sélectionnée.
PCT/CN2022/079686 2022-03-08 2022-03-08 Sélection de référence de temporisation pour signal de synchronisation de liaison latérale WO2023168587A1 (fr)

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