Method and apparatus for co-location of sidelink assistance

Abstract

Technologies for wireless communications are disclosed. In one aspect, a first user equipment (UE) sends a request to perform a positioning procedure to at least one second UE via a sidelink between the first UE and at least one second UE, receives an indication of a set of time resources, frequency resources, or both allocated for the positioning procedure from at least one second UE via the sidelink, and sends at least one positioning reference signal on the set of time and / or frequency resources allocated for the positioning procedure. The second UE receives a request to perform a positioning procedure from the first UE via the sidelink, sends a request to a base station, receives an indication of a set of time and / or frequency resources allocated for the positioning procedure from the base station, and sends an indication to the first UE via the sidelink.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority under 35 U.S.C. §119 to Greek Patent Application No. 20200100147, filed on March 20, 2020, entitled “Method and Apparatus for Co-location for Sidelink Assistance,” which application is assigned to the assignee of the present application and is expressly incorporated herein by reference in its entirety.

[0003] BACKGROUND OF THE DISCLOSURE

[0004] 1. Field of the Disclosure

[0005] Aspects of the present disclosure generally relate to wireless communications.

[0006] 2. Description of Related Technology

[0007] Wireless communication systems have evolved over generations, including first generation analog wireless telephone service (1G), second generation (2G) digital wireless telephone service (including transitional 2.5G and 2.75G networks), third generation (3G) high speed data, Internet-enabled wireless services, and fourth generation (4G) services (e.g., Long Term Evolution (LTE) or WiMax). There are many different types of wireless communication systems in use today, including cellular and personal communications service (PCS) systems. 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), Global System for Mobile Communications (GSM), and the like.

[0008] The fifth generation (5G) wireless standard, known as New Radio (NR), calls for higher data speeds, more connections, and better coverage, among other improvements. According to the Next Generation Mobile Networks Alliance, the 5G standard is designed to provide data rates of tens of megabits per second for each of tens of thousands of users and 1 gigabit per second for dozens of workers on an office floor. To support large sensor deployments, hundreds of thousands of simultaneous connections should be supported. As a result, the spectrum efficiency of 5G mobile communications will be significantly enhanced compared to the current 4G standard. In addition, signaling efficiency should be enhanced and latency should be significantly reduced compared to the current standard.

[0009] Taking advantage of 5G's higher data rates and lower latency, vehicle-to-everything (V2X) communication technology is being implemented to support autonomous driving applications, such as wireless communication between vehicles, between vehicles and roadside infrastructure, and between vehicles and pedestrians. Summary of the invention

[0010] A brief summary of one or more aspects disclosed herein is presented below. Therefore, the following summary should not be considered an extensive review of all contemplated aspects, nor should it be considered to identify key or important elements related to all contemplated aspects or to delineate categories associated with any particular aspect. Therefore, the sole purpose of the following summary is to present certain concepts related to one or more aspects involving the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0011] In one aspect, a method for wireless communication performed at a first user equipment (UE) includes: sending a request to perform a positioning process to at least one second UE via a sidelink between the first UE and at least one second UE; receiving an indication of time resources, frequency resources, or a set of both allocated for the positioning process from at least one second UE via the sidelink; and sending at least one positioning reference signal on the time resources, frequency resources, or a set of both allocated for the positioning process.

[0012] In one aspect, a method for wireless communication performed at a second UE includes: receiving a request to perform a positioning process from a first UE via a sidelink between the second UE and the first UE; sending a request to perform the positioning process to a first network entity; receiving an indication of time resources, frequency resources, or a set of both allocated for the positioning process from the second network entity; and sending an indication of time resources, frequency resources, or a set of both allocated for the positioning process to the first UE via a sidelink.

[0013] In one aspect, a first UE includes a memory, at least one transceiver, and at least one processor coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to: cause the at least one transceiver to send a request to perform a positioning process to at least one second UE via a side link between the first UE and at least one second UE; receive an indication of a set of time resources, frequency resources, or both allocated for the positioning process from at least one second UE via the side link via the at least one transceiver; and cause the at least one transceiver to send at least one positioning reference signal on the time resources, frequency resources, or both allocated for the positioning process.

[0014] In one aspect, the second UE includes a memory, at least one transceiver and at least one processor coupled to the memory and the at least one transceiver, and the at least one processor is configured to: receive a request to perform a positioning process from the first UE via the at least one transceiver through a side link between the second UE and the first UE; cause the at least one transceiver to send a request to perform a positioning process to the first network entity; receive an indication of time resources, frequency resources, or a set of both allocated for the positioning process from the second network entity via the at least one transceiver; and cause the at least one transceiver to send an indication of time resources, frequency resources, or a set of both allocated for the positioning process to the first UE through the side link.

[0015] In one aspect, a first UE includes: a component for sending a request to perform a positioning process to at least one second UE via a sidelink between the first UE and at least one second UE; a component for receiving an indication of time resources, frequency resources, or a set of both allocated for the positioning process from at least one second UE via a sidelink; and a component for sending at least one positioning reference signal on the time resources, frequency resources, or a set of both allocated for the positioning process.

[0016] In one aspect, the second UE includes: a component for receiving a request to perform a positioning process from the first UE via a sidelink between the second UE and the first UE; a component for sending a request to perform a positioning process to the first network entity; a component for receiving an indication of time resources, frequency resources, or a set of both allocated for the positioning process from the second network entity; and a component for sending an indication of time resources, frequency resources, or a set of both allocated for the positioning process to the first UE via a sidelink.

[0017] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions includes computer-executable instructions, which include: at least one instruction for directing a first UE to send a request to perform a positioning process to at least one second UE via a sidelink between the first UE and at least one second UE; at least one instruction for directing the first UE to receive an indication of time resources, frequency resources, or a set of both allocated for the positioning process from at least one second UE via a sidelink; and at least one instruction for directing the first UE to send at least one positioning reference signal on the time resources, frequency resources, or a set of both allocated for the positioning process.

[0018] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions includes computer-executable instructions, the computer-executable instructions including: at least one instruction directing a second user equipment (UE) to receive a request to perform a positioning procedure from a first UE via a sidelink between the second UE and the first UE; at least one instruction directing the second UE to send a request to perform a positioning procedure to a first network entity; at least one instruction directing the second UE to receive an indication of time resources, frequency resources, or a set of both allocated for the positioning procedure from the second network entity; and at least one instruction directing the second UE to send an indication of time resources, frequency resources, or a set of both allocated for the positioning procedure to the first UE via a sidelink.

[0019] Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings are presented to aid in describing various aspects of the disclosure and are provided solely for purposes of illustration of these aspects and not limitation thereof.

[0021] Figure 1 An example wireless communication system according to aspects of the present disclosure is described.

[0022] Figure 2A and 2B An example wireless network structure is described in accordance with aspects of the present disclosure.

[0023] Figure 3 An example of a wireless communication system supporting unicast sidelink establishment according to aspects of the present disclosure is described.

[0024] Figure 4 is a block diagram illustrating various components of an example user equipment (UE) according to aspects of the present disclosure.

[0025] Figure 5 An example wireless communication system is illustrated in which a vehicle user equipment (V-UE) is exchanging ranging signals with a roadside unit (RSU) and another V-UE in accordance with aspects of the present disclosure.

[0026] Figure 6 is a timeline illustrating a three-phase communication protocol according to aspects of the present disclosure.

[0027] Figure 7 Two resource allocation modes for transmission on the sidelink according to aspects of the present disclosure are described.

[0028] Figure 8 is a diagram showing how a shared channel (SCH) may be established on a sidelink between two or more UEs according to aspects of the present disclosure.

[0029] Fig. 9 and 10 is a diagram illustrating example timing of round trip time (RTT) signals exchanged between a target UE and two assisting UEs according to aspects of the present disclosure.

[0030] Fig.11 and 12

[0013] Example methods for wireless communications according to aspects of the present disclosure are described. DETAILED DESCRIPTION

[0031] Aspects of the present disclosure are provided in the following description and related drawings, which are directed to various examples provided for illustrative purposes. Alternative aspects may be designed without departing from the scope of the present disclosure. In addition, well-known elements of the present disclosure will not be described in detail or will be omitted to avoid confusing the relevant details of the present disclosure.

[0032] The words "exemplary" and / or "example" are used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" and / or "example" is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term "aspects of the disclosure" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation.

[0033] Those skilled in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the following description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the specific application, in part on the desired design, in part on the corresponding technology, etc.

[0034] In addition, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be appreciated that the various actions described herein may be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions executed by one or more processors, or by a combination of the two. In addition, the sequences of actions described herein may be considered to be fully embodied within any form of non-transitory computer-readable storage medium having a corresponding set of computer instructions stored therein, which, when executed, will cause or instruct the associated processor of the device to perform the functionality described herein. Therefore, various aspects of the present disclosure may be embodied in a variety of different forms, all of which are considered to be within the scope of the claimed subject matter. In addition, for each aspect described herein, the corresponding form of any such aspect may be described herein as, for example, "logic" that is "configured to" perform the described actions.

[0035] As used herein, unless otherwise specified, the terms "user equipment" (UE), "vehicle UE" (V-UE), "pedestrian UE" (P-UE) and "base station" are not intended to be specific or otherwise limited to any specific radio access technology (RAT). In general, a UE can be any wireless communication device used by a user to communicate over a wireless communication network (e.g., an onboard computer, a vehicle navigation device, a mobile phone, a router, a tablet computer, a laptop computer, a tracking device, a wearable device (e.g., a smart watch, glasses, augmented reality (AR) / virtual reality (VR) headsets, etc.), a vehicle (e.g., a car, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.). A UE can be mobile or can be (e.g., at certain times) stationary and can communicate with a radio access network (RAN). As used herein, the term "UE" can be interchangeably referred to as a "mobile device", "access terminal" or "AT", "client device", "wireless device", "subscriber device", "subscriber terminal", "subscriber station", "user terminal" or UT, "mobile terminal", "mobile station" or variants thereof.

[0036] A V-UE is a type of UE and may be any vehicle-mounted wireless communication device, such as a navigation system, a warning system, a head-up display (HUD), an on-board computer, etc. Alternatively, a V-UE may be a portable wireless communication device (e.g., a mobile phone, a tablet computer, etc.) carried by a vehicle driver or a passenger in the vehicle. Depending on the context, the term "V-UE" may refer to an on-board wireless communication device or the vehicle itself. A P-UE is a type of UE and may be a portable wireless communication device carried by a pedestrian (i.e., a user who is not driving or riding in a vehicle). Typically, a UE may communicate with a core network via a RAN, and through the core network, the UE may connect to external networks such as the Internet and other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for the UE, such as through a wired access network, a wireless local area network (WLAN) network (e.g., based on IEEE 802.11, etc.), etc.

[0037] Depending on the network in which the base station is deployed, the base station may operate according to one of several RATs for communicating with the UE, 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) NodeB (also referred to as a gNB or gNodeB), etc. The base station may be primarily used to support wireless access for the UE, including supporting data, voice and / or signaling connections for the supported UE. In some systems, the base station may provide pure edge node signaling functions, while in other systems it may provide additional control and / or network management functions. The communication link through which the UE may send a signal to the base station is referred to as an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). The communication link through which the base station may send a signal to the UE is referred to as a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein, the term traffic channel (TCH) may refer to a UL / reverse or DL / forward traffic channel.

[0038] The term "base station" may refer to a single physical transmit-receive point (TRP) or to multiple physical TRPs that may or may not be co-located. For example, where the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to a cell (or several cell sectors) of the base station. Where the term "base station" refers to multiple co-located physical TRPs, the physical TRP may be an antenna array of the base station (e.g., in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming). Where the term "base station" refers to multiple non-co-located physical TRPs, the physical TRP may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transmission medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRP may be a serving base station that receives measurement reports from a UE and an adjacent base station whose reference radio frequency (RF) signal the UE is measuring. Because a TRP is a point at which a base station transmits and receives wireless signals, as used herein, references to transmissions from a base station or receptions at a base station should be understood to refer to a specific TRP of a base station.

[0039] In some implementations supporting UE positioning, a base station may not support wireless access for a UE (e.g., may not support data, voice, and / or signaling connections for the UE), but may instead send a reference RF signal to the UE for measurement by the UE, and / or may receive and measure signals sent by the UE. Such a base station may be referred to as a positioning beacon (e.g., when sending an RF signal to the UE) and / or a position measurement unit (e.g., when receiving and measuring an RF signal from the UE).

[0040] An "RF signal" includes an electromagnetic wave of a given frequency that conveys information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, due to the propagation characteristics of RF signals through multipath channels, a receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same transmitted RF signal on different paths between a transmitter and a receiver may be referred to as a "multipath" RF signal. As used herein, 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 either a wireless signal or an RF signal.

[0041] Figure 1 An example wireless communication system 100 is illustrated according to aspects of the present disclosure. The wireless communication system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations 102 (labeled as "BS") and various UEs 104. The base stations 102 may include macrocell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). In an aspect, the macrocell base stations 102 may include: eNBs and / or ng-eNBs, where the wireless communication system 100 corresponds to an LTE network; or gNBs, where the wireless communication system 100 corresponds to an NR network; or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0042] The base stations 102 may collectively form a RAN and interface with a core network 174 (e.g., an evolved packet core (EPC) or a 5G core (5GC)) through a backhaul link 122 and interface with one or more location servers 172 (e.g., a location management function (LMF) or a secure user plane location (SUPL) location platform (SLP)) through the core network 174. The location server 172 may be part of the core network 174 or may be external to the core network 174. The base stations 102 may perform, among other functions, functions related to one or more of sending user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (eg, via EPC / 5GC) via a backhaul link 134, which may be wired or wireless.

[0043] Base station 102 can communicate wirelessly with UE 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. In one aspect, the base station 102 in each geographic coverage area 110 can support one or more cells. A "cell" is a logical communication entity for communicating with a base station (e.g., through some frequency resources, referred to as carrier frequency, component carrier, carrier, frequency band, etc.), and can be associated with an identifier (e.g., physical cell identifier (PCI), enhanced cell identifier (ECI), virtual cell identifier (VCI), cell global identifier (CGI), etc.) for distinguishing cells operating via the same or different carrier frequencies. In some cases, different cells can be configured according to different protocol types (e.g., machine type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), etc.) that can provide access to different types of UEs. Because a cell is supported by a specific base station, depending on the context, the term "cell" can refer to one or both of the logical communication entity and the base station supporting it. In some cases, the term "cell" may also refer to a geographic coverage area (eg, a sector) of a base station, as long as a carrier frequency can be detected and used for communications within some portion of the geographic coverage area 110.

[0044] Although the geographic coverage areas 110 of adjacent macrocell base stations 102 may partially overlap (e.g., in a handover zone), some geographic coverage areas 110 may be substantially overlapped by a larger geographic coverage area 110. For example, 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 areas 110 of one or more macrocell base stations 102. A network that includes both small cell base stations and macrocell base stations may be referred to as a heterogeneous network. A heterogeneous network may also include a home eNB (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG).

[0045] The communication link 120 between the base station 102 and the UE 104 may include uplink (also referred to as a reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also referred to as a forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric for the downlink and uplink (e.g., more or fewer carriers may be allocated for the downlink than for the uplink).

[0046] The wireless communication system 100 may also include a wireless local area network (WLAN) access point (AP) 150 that communicates with a WLAN station (STA) 152 in an unlicensed spectrum (e.g., 5 GHz) via a communication link 154. When communicating in the unlicensed spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or a listen before talk (LBT) procedure prior to communication to determine whether a channel is available.

[0047] The small cell base station 102' can operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell base station 102' can adopt LTE or NR technology and use the same 5GHz unlicensed spectrum used by the WLAN AP 150. The small cell base station 102' adopts LTE / 5G in the unlicensed spectrum to expand the coverage of the access network and / or increase the capacity of the access network. NR in the unlicensed spectrum may be referred to as NR-U. LTE in the unlicensed spectrum may be referred to as LTE-U, License Assisted Access (LAA) or MulteFire.

[0048] The wireless communication system 100 may also include a mmW base station 180, which may operate at mmW frequencies and / or near mmW frequencies to communicate with UE 182. Extremely high frequency (EHF) is a portion of RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 mm and 10 mm. The radio waves of this band may be referred to as millimeter waves. Near mmW may extend down to a frequency of 3 GHz and a wavelength of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communications using mmW / near mmW radio frequency bands have high path loss and a relatively short range. The mmW base station 180 and UE 182 may utilize beamforming (sending and / or receiving) through a mmW communication link 184 to compensate for extremely high path loss and short distance. In addition, it will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Therefore, it should be understood that the foregoing description is merely exemplary and should not be construed as limiting the various aspects disclosed herein.

[0049] Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, the network node broadcasts the signal in all directions (omnidirectionally). With transmit beamforming, the network node determines the location of a given target device (e.g., a UE) (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 to the receiving device. In order to change the directionality of the RF signal when transmitting, the 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. For example, a network node can use an antenna array (referred to as a "phased array" or "antenna array") that creates an RF beam that can be "steered" to point in different directions without actually moving the antenna. Specifically, the RF current from the transmitter is fed to each antenna in the correct phase relationship so that the radio waves from the individual antennas are added together to increase the radiation in the desired direction while canceling to suppress the radiation in the undesired direction.

[0050] The transmit beams can be quasi-co-located, meaning that the transmit beams appear to have the same parameters to a receiver (e.g., a UE) regardless of whether the transmit antennas of the network nodes themselves are physically co-located. In NR, there are four types of quasi-co-located (QCL) relationships. Specifically, a given type of QCL relationship means that certain parameters about the second reference RF signal on the second beam can be derived from information about the source reference RF signal on the source beam. Thus, if the source reference RF signal is QCL type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of the second reference RF signal sent 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 the second reference RF signal sent on the same channel. If the source reference RF signal is QCL type D, the receiver may use the source reference RF signal to estimate spatial reception parameters of a second reference RF signal transmitted on the same channel.

[0051] In receive beamforming, a receiver uses receive beams to amplify RF signals detected on a given channel. For example, a receiver may increase a gain setting and / or adjust a phase setting of an antenna array in a particular direction to amplify RF signals received from that direction (e.g., increase its gain level). Thus, when a receiver is said to be beamforming in a certain direction, this means that the beam gain in that direction is high relative to beam gains along other directions, or that the beam gain in that direction is the highest compared to the beam gains in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal to interference plus noise ratio (SINR), etc.) of the RF signals received from that direction.

[0052] The transmit and receive beams may be spatially correlated. The spatial relationship means that parameters of a second beam (e.g., a transmit or receive beam) of a second reference signal may be derived from information about a first beam (e.g., a receive beam or a transmit beam) of a first reference signal. For example, a UE may receive a reference downlink reference signal (e.g., a synchronization signal block (SSB)) from a base station using a particular receive beam. The UE may then form a transmit beam for transmitting an uplink reference signal (e.g., a sounding reference signal (SRS)) to the base station based on the parameters of the receive beam.

[0053] It should be noted that a "downlink" beam can be a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station is forming a downlink beam to send a reference signal to the UE, the downlink beam is a transmit beam. However, if the UE is forming a downlink beam, the downlink beam is a receive beam that receives the downlink reference signal. Similarly, an "uplink" beam can be a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station is forming an uplink beam, the uplink beam is an uplink receive beam, and if the UE is forming an uplink beam, the uplink beam is an uplink transmit beam.

[0054] In 5G, the spectrum in which wireless nodes (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into multiple frequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). The mmW band generally includes the FR2, FR3, and FR4 frequency ranges. Therefore, the terms "mmW" and "FR2" or "FR3" or "FR4" are generally used interchangeably.

[0055] In a multi-carrier system (such as 5G), one of the carrier frequencies is referred to as the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell", and the remaining carrier frequencies are referred to as "secondary carriers" or "secondary serving cells" or "SCells". In carrier aggregation, the anchor carrier is a carrier operating on the primary frequency (e.g., FR1) utilized by the UE 104 / 182 and the cell in which the UE 104 / 182 performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection reestablishment procedure. The primary carrier carries all common and UE-specific control channels and can be a carrier in a licensed frequency (however, this is not always the case). The secondary carrier is a carrier operating on a second frequency (e.g., FR2) that can be configured once an RRC connection is established between the UE 104 and the anchor carrier, and can be used to provide additional radio resources. In some cases, the secondary carrier can be a carrier in an unlicensed frequency. The auxiliary carrier may contain only necessary signaling information and signals, for example, UE-specific information and signals may not be present in the auxiliary carrier, because the main uplink and downlink carriers are typically UE-specific. This means that different UEs 104 / 182 in a cell can have different downlink primary carriers. The same is true for the uplink primary carrier. The network is able to change the primary carrier of any UE104 / 182 at any time. For example, this is done to balance the load on different carriers. Because a "serving cell" (whether PCell or SCell) corresponds to a carrier frequency / component carrier through which a base station is communicating, the terms "cell", "serving cell", "component carrier", "carrier frequency", etc. can be used interchangeably.

[0056] For example, still refer to Figure 1 , one of the frequencies utilized by the macrocell base station 102 may be an anchor carrier (or "PCell"), while the other frequencies utilized by the macrocell base station 102 and / or the mmW base station 180 may be supplementary carriers ("SCells"). Simultaneous transmission and / or reception of multiple carriers enables the UE 104 / 182 to significantly increase its data transmission and / or reception rate. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically result in a two-fold increase in data rate (i.e., 40 MHz) compared to the data rate obtained using a single 20 MHz carrier.

[0057] exist Figure 1 In the example of FIG. 1 , one or more Earth-orbiting satellite positioning system (SPS) spacecraft (SV) 112 (eg, satellites) may be used as any of the illustrated UEs (for simplicity, in FIG. 1 ). Figure 1104). UE 104 may include one or more dedicated SPS receivers, which are specially designed to receive SPS signals 124 for deriving geographic location information from SV 112. SPS generally includes a transmitter system (e.g., SV 112), and the transmitter is positioned so that the receiver (e.g., UE 104) can determine the location of the transmitter on or above the earth based on at least part of the signal received from the transmitter (e.g., SPS signal 124). Such a transmitter generally transmits a signal marked with a repetitive pseudo-random noise (PN) code of a set number of chips. Although typically located in SV 112, the transmitter may sometimes be located on a ground-based control station, base station 102 and / or other UE 104.

[0058] The use of the SPS signal 124 may be enhanced by various satellite-based augmentation systems (SBAS) that may be associated with or otherwise capable of use with one or more global and / or regional navigation satellite systems. For example, the SBAS may include augmentation systems that provide integrity information, differential corrections, etc., such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multifunction Satellite Augmentation System (MSAS), the Global Positioning System (GPS) Assisted Geographic Augmentation Navigation or the GPS and Geographic Augmentation Navigation System (GAGAN), etc. Thus, as used herein, an SPS may include any combination of one or more global and / or regional navigation satellite systems and / or augmentation systems, and the SPS signal 124 may include an SPS, a SPS-like, and / or other signals associated with the one or more SPSs.

[0059] Leveraging NR’s higher data rates and lower latency, vehicle-to-everything (V2X) communication technology is being implemented to support intelligent transportation system (ITS) applications such as wireless communication between vehicles (vehicle-to-vehicle (V2V)), between vehicles and roadside infrastructure (vehicle-to-infrastructure (V2I)), and between vehicles and pedestrians (vehicle-to-pedestrian (V2P)). The goal is to enable vehicles to sense their surroundings and communicate information to other vehicles, infrastructure, and personal mobile devices. This vehicle communication will enable safety, mobility, and environmental advances that current technology cannot provide. Once fully realized, the technology is expected to reduce 80% of collisions involving unimpaired vehicles.

[0060] Still reference Figure 1, the wireless communication system 100 may include a plurality of V-UEs 160, which may communicate with a base station 102 via a communication link 120 (e.g., using a Uu interface). The V-UEs 160 may also communicate directly with each other via a wireless sidelink 162, with a roadside access point 164 (also referred to as a "roadside unit") via a wireless sidelink 166, or with a UE 104 via a wireless sidelink 168. A wireless sidelink (or simply a "sidelink") is an improvement to a core cellular (e.g., LTE, NR) standard that allows direct communication between two or more UEs without the need to communicate through a base station. Sidelink communications may be unicast or multicast, and may be used for device-to-device (D2D) media sharing, V2V communications, V2X communications (e.g., cellular V2X (cV2X) communications, enhanced V2X (eV2X) communications, etc.), emergency rescue applications, etc. One or more of a group of V-UEs 160 utilizing sidelink communication may be within the geographic coverage area 110 of the base station 102. Other V-UEs 160 in the group may be outside the geographic coverage area 110 of the base station 102 or unable to receive transmissions from the base station 102. In some cases, a group of V-UEs 160 communicating via sidelink communication may utilize a one-to-many (1:M) system, where each V-UE 160 transmits to every other V-UE 160 in the group. In some cases, the base station 102 facilitates scheduling of resources for sidelink communication. In other cases, sidelink communication is performed between V-UEs 160 without involving the base station 102.

[0061] In one aspect, the sidelinks 162, 166, 168 can operate over a wireless communication medium of interest, which can be shared with other vehicles and / or infrastructure access points, as well as other wireless communications between other RATs. The "medium" can consist of one or more time, frequency, and / or spatial communication resources (e.g., covering one or more channels across one or more carriers) associated with wireless communications between one or more transmitter / receiver pairs.

[0062] In one aspect, the sidelinks 162, 166, 168 may be cV2X links. The first generation of cV2X has been standardized in LTE, and the next generation is expected to be defined in NR. cV2X is a cellular technology that also enables device-to-device communications. In the United States and Europe, cV2X is expected to operate in licensed ITS bands in the sub-6 GHz range. Other bands may be allocated in other countries. Thus, as a specific example, the medium of interest utilized by the sidelinks 162, 166, 168 may correspond to at least a portion of a licensed ITS band in the sub-6 GHz range. However, the present disclosure is not limited to this band or cellular technology.

[0063] In one aspect, the sidelinks 162, 166, 168 may be dedicated short-range communication (DSRC) links. DSRC is a one-way or two-way short-range to medium-range wireless communication protocol that uses the Wireless Access to Vehicular Environment (WAVE) protocol, also known as IEEE 802.11p, for V2V, V2I, and V2P communications. IEEE 802.11p is an approved revision of the IEEE 802.11 standard and operates in the licensed ITS band 5.9GHz (5.85 to 5.925GHz) CIA in the United States. In Europe, IEEE 802.11p operates in the ITS G5A band (5.875 to 5.905MHz). Other bands may be allocated in other countries. The V2V communications briefly described above occur on a safety channel, which in the United States is typically a 10MHz channel dedicated to safety purposes. The remainder of the DSRC band (75MHz in total bandwidth) is used for other services of interest to drivers, such as road rules, toll collection, parking automation, and the like. Thus, as a specific example, the medium of interest utilized by the sidelinks 162, 166, 168 may correspond to at least a portion of the licensed ITS band at 5.9 GHz.

[0064] Alternatively, the medium of interest may correspond to at least a portion of an unlicensed band shared among the various RATs. Although different licensed bands have been reserved for certain communication systems (e.g., by government entities such as the Federal Communications Commission (FCC) in the United States), these systems, particularly those employing small cell access points, have recently expanded operations to unlicensed bands such as the Unlicensed National Information Infrastructure (U-NII) bands used by wireless local area network (WLAN) technologies, most notably the IEEE 802.11x WLAN technology commonly referred to as "Wi-Fi". Example systems of this type include different variants of CDMA systems, TDMA systems, FDMA systems, orthogonal FDMA (OFDMA) systems, single carrier FDMA (SC-FDMA) systems, and the like.

[0065] Communications between V-UEs 160 are referred to as V2V communications, communications between V-UEs 160 and one or more roadside access points 164 are referred to as V2I communications, and communications between V-UEs 160 and one or more UEs 104 (where UEs 104 are P-UEs) are referred to as V2P communications. V2V communications between V-UEs 160 may include, for example, information about the position, speed, acceleration, heading, and other vehicle data of the V-UEs 160. V2I information received at the V-UEs 160 from one or more roadside access points 164 may include, for example, road rules, parking automation information, etc. V2P communications between V-UEs 160 and UEs 104 may include information about, for example, the position, speed, acceleration, and heading of the V-UEs 160 and the position, speed (e.g., where the UEs 104 are carried by a user on a bicycle), and heading of the UEs 104.

[0066] It should be noted that although Figure 1 Only two UEs are illustrated as V-UEs (V-UE 160), but any of the illustrated UEs (e.g., UEs 104, 152, 182, 190) may be V-UEs. In addition, although only V-UE 160 and a single UE 104 are illustrated as being connected via a sidelink, Figure 1 Any UE illustrated in the description, whether V-UE, P-UE, etc., may be capable of sidelink communications. Furthermore, although only UE 182 is described as being capable of beamforming, any illustrated UE, including V-UE 160, may be capable of beamforming. Where V-UE 160 is capable of beamforming, V-UE 160 may beamform toward each other (i.e., toward other V-UE 160), toward roadside access point 164, toward other UEs (e.g., UE 104, 152, 182, 190), etc. Thus, in some cases, V-UE 160 may utilize beamforming via sidelinks 162, 166, and 168.

[0067] The wireless communication system 100 may also include one or more UEs, such as UE 190, which are indirectly connected to one or more communication networks via one or more device-to-device (D2D) or peer-to-peer (P2P) links. Figure 1In the example of FIG. 1 , UE 190 has a D2D P2P link 192 with one of UEs 104 connected to one of base stations 102 (e.g., through which UE 190 can indirectly obtain cellular connectivity) and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (through which UE 190 can indirectly obtain WLAN-based Internet connectivity). In the example, the D2D P2P links 192 and 194 can be supported by any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Etc. As another example, the D2D P2P links 192 and 194 may be sidelinks, as described above with reference to the sidelinks 162 , 166 , and 168 .

[0068] Figure 2A An example wireless network architecture 200 is illustrated. For example, the 5GC 210 (also referred to as the Next Generation Core (NGC)) can be functionally viewed as a control plane function (C-plane) 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and a user plane function (U-plane) 212 (e.g., UE gateway function, access to data networks, IP routing, etc.), which operate in conjunction to form a core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210, and specifically to the user plane function 212 and the control plane function 214, respectively. In additional configurations, the ng-eNB 224 can also be connected to the 5GC 210 via the NG-C 215 to the control plane function 214 and via the NG-U 213 to the user plane function 212. In addition, the ng-eNB 224 can communicate directly with the gNB 222 via the backhaul connection 223. In some configurations, the next generation RAN (NG-RAN) 220 may have only one or more gNBs 222, while other configurations include one or more of both ng-eNBs 224 and gNBs 222. Either (or both) of the gNBs 222 or ng-eNBs 224 may communicate with a UE 204 (e.g., any UE described herein). In one aspect, two or more UEs 204 may communicate with each other via a wireless sidelink 242, which may correspond to a wireless sidelink 242. Figure 1 The wireless sidelink 162 in.

[0069] Another optional aspect may include a location server 230 that can communicate with the 5GC 210 to provide location assistance for the UE 204. The location server 230 can be implemented as multiple independent servers (e.g., physically independent servers, different software modules on a single server, different software modules distributed on multiple physical servers, etc.), or alternatively, each can correspond to a single server. The location server 230 can be configured to support one or more location services for the UE 204, and the UE 204 can be connected to the location server 230 via the core network, the 5GC 210, and / or via the Internet (not illustrated). In addition, the location server 230 can be integrated into a component of the core network, or alternatively, it can be external to the core network.

[0070] Figure 2B Another example wireless network structure 250 is described. 5GC 260 (may correspond to Figure 2A The 5GC 210 in the 5GC 210 can be functionally viewed as a control plane function provided by an access and mobility management function (AMF) 264 and a user plane function provided by a user plane function (UPF) 262, which operate in conjunction to form a core network (i.e., 5GC 260). The user plane interface 263 and the control plane interface 265 connect the ng-eNB 224 to the 5GC 260, and specifically to the UPF 262 and the AMF 264, respectively. In additional configurations, the gNB 222 may also be connected to the 5GC 260 via a control plane interface 265 to the AMF 264 and a user plane interface 263 to the UPF 262. In addition, the ng-eNB 224 may communicate directly with the gNB 222 via a backhaul connection 223, with or without gNB direct connectivity to the 5GC 260. In some configurations, the NG-RAN 220 may have only one or more gNBs 222, while other configurations include one or more of the ng-eNB 224 and the gNB 222. The base stations of the NG-RAN 220 communicate with the AMF 264 via the N2 interface and with the UPF 262 via the N3 interface. Either (or both) the gNB 222 or the ng-eNB 224 may communicate with the UE 204 (e.g., any UE described herein). In one aspect, two or more UEs 204 may communicate with each other via the sidelink 242, which may correspond to the sidelink 242. Figure 1 The side link 162 in.

[0071] The functions of AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, delivery of session management (SM) messages between UE 204 and session management function (SMF) 266, transparent proxy service for routing SM messages, access authentication and access authorization, delivery of short message service (SMS) messages between UE 204 and short message service function (SMSF) (not shown), and security anchor functionality (SEAF). AMF 264 also interacts with authentication server function (AUSF) (not shown) and UE 204, and receives intermediate keys established as a result of the UE 204 authentication process. In the case of authentication based on UMTS (Universal Mobile Telecommunications System) Subscriber Identity Module (USIM), AMF 264 retrieves security materials from AUSF. The functions of AMF 264 also include security context management (SCM). SCM receives keys from SEAF, which it uses to derive access network specific keys. The functionality of AMF 264 also includes location service management for regulatory services, delivery of location service messages between UE 204 and LMF 270 acting as location server 230, delivery of location service messages between NG-RAN 220 and LMF 270, allocation of EPS bearer identifiers for interworking with Evolved Packet System (EPS), and notification of mobility events for UE 204. In addition, AMF 264 also supports the functionality of non-3GPP access networks.

[0072] The functions of UPF 262 include: acting as an anchor point for intra-RAT / inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point for interconnection with 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, user plane quality of service (QoS) handling (e.g., uplink / downlink rate enforcement, reflected QoS marking in downlink), uplink traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in uplink and downlink, downlink packet buffering and downlink data notification triggering, and sending and forwarding one or more "end markers" to the source RAN node. UPF 262 can also support the sending of location service messages through the user plane between UE 204 and a location server (such as SLP 272).

[0073] The functions of SMF 266 include session management, UE Internet Protocol (IP) address allocation and management, selection and control of user plane functions, configuring traffic steering at UPF 262 to route traffic to the appropriate destination, controlling partial policy enforcement and QoS, and downlink data notification. The interface through which SMF 266 communicates with AMF 264 is called the N11 interface.

[0074] Another optional aspect may include LMF 270, which can communicate with 5GC 260 to provide location assistance for UE 204. LMF 270 can be implemented as multiple independent servers (e.g., physically independent servers, different software modules on a single server, different software modules distributed on multiple physical servers, etc.), or alternatively, each can correspond to a single server. LMF 270 can be configured to support one or more location services for UE 204, and UE 204 can be connected to LMF 270 via the core network, 5GC 260 and / or via the Internet (not illustrated). SLP 272 can support similar functionality as LMF 270, but while LMF 270 can communicate with AMF 264, NG-RAN 220, and UE 204 via the control plane (e.g., using interfaces and protocols intended to transmit signaling messages rather than voice or data), SLP 272 can communicate with UE 204 and external clients ( Figure 2B ) to communicate (e.g., using protocols intended to carry voice and / or data, such as the Transmission Control Protocol (TCP) and / or IP).

[0075] Figure 3 An example of a wireless communication system 300 that supports wireless unicast sidelink establishment according to aspects of the present disclosure is illustrated. In some examples, the wireless communication system 300 can implement various aspects of the wireless communication systems 100, 200, and 250. The wireless communication system 300 can include a first UE 302 and a second UE 304, which can be examples of any UE described herein. As a specific example, the UEs 302 and 304 can correspond to Figure 1 V-UE 160 in the Figure 1 UE 190 and UE 104 or Figure 2A and 2B UE 204 in.

[0076] exist Figure 3 In the example of , UE 302 may attempt to establish a unicast connection with UE 304 via a sidelink, which may be a V2X sidelink between UE 302 and UE 304. As a specific example, the established sidelink connection may correspond to Figure 1 The sidelinks 162 and / or 168 or Figure 2A and 2B The sidelink connection may be established in an omni frequency range (e.g., FR1) and / or in a mmW frequency range (e.g., FR2). In some cases, UE 302 may be referred to as an initiating UE that initiates a sidelink connection procedure, and UE 304 may be referred to as a target UE that is the target of the sidelink connection procedure for the initiating UE.

[0077] In order to establish a unicast connection, access stratum (AS) (a functional layer in the UMTS and LTE protocol stacks between the RAN and the UE, which is responsible for delivering data over a wireless link and managing radio resources, and is part of layer 2) parameters may be configured and negotiated between UE 302 and UE 304. For example, a transmit and receive capability match may be negotiated between UE 302 and UE 304. Each UE may have different capabilities (e.g., transmit and receive, 64 quadrature amplitude modulation (QAM), transmit diversity, carrier aggregation (CA), supported communication bands, etc.). In some cases, different services may be supported in the upper layers of the corresponding protocol stacks of UE 302 and UE 304. In addition, a security association may be established between UE 302 and UE 304 for a unicast connection. Unicast services may benefit from security protection (e.g., integrity protection) at the link layer. Security requirements may be different for different wireless communication systems. For example, V2X and Uu systems may have different security requirements (e.g., Uu security does not include confidentiality protection). Additionally, IP configuration (eg, IP version, address, etc.) may be negotiated for a unicast connection between UE 302 and UE 304 .

[0078] In some cases, UE 304 may create a service announcement (e.g., a service capability message) to be sent over a cellular network (e.g., cV2X) to assist in the establishment of a sidelink connection. Conventionally, UE 302 may identify and locate candidates for sidelink communication based on a basic service message (BSM) broadcasted unencrypted by a nearby UE (e.g., UE 304). The BSM may include location information, security and identity information, and vehicle information (e.g., speed, maneuvering, size, etc.) of the corresponding UE. However, for different wireless communication systems (e.g., D2D or V2X communication), the discovery channel may not be configured to enable UE 302 to detect the BSM. Therefore, the service announcement (e.g., discovery signal) sent by UE 304 and other nearby UEs may be an upper layer signal and broadcast (e.g., in an NR sidelink broadcast). In some cases, UE 304 may include one or more parameters of itself in the service announcement, including connection parameters and / or the capabilities it possesses. Then, UE 302 may monitor and receive the broadcasted service announcement to identify potential UEs for corresponding sidelink connections. In some cases, UE 302 may identify potential UEs based on the capabilities indicated by each UE in its corresponding service announcement.

[0079] The service announcement may include assisting UE 302 (eg, or any initiating UE) to identify the UE ( Figure 3 304 in the example of ). For example, the service announcement may include channel information on which the direct communication request may be sent. In some cases, the channel information may be RAT-specific (e.g., LTE or NR-specific) and may include a resource pool in which the UE 302 sends the communication request. In addition, if the destination address is different from the current address (e.g., the address of the stream provider or UE that sends the service announcement), the service announcement may include a specific destination address of the UE (e.g., a layer 2 destination address). The service announcement may also include a network or transport layer for the UE 302 to send the communication request on. For example, the network layer (also referred to as "layer 3" or "L3") or the transport layer (also referred to as "layer 4" or "L4") may indicate the port number of the application for the UE that sends the service announcement. In some cases, IP addressing may not be required if the signaling (e.g., PC5 signaling) directly carries a protocol (e.g., a real-time transport protocol (RTP)) or gives a locally generated random protocol. In addition, the service announcement may include a protocol type for credential establishment and QoS-related parameters.

[0080] After identifying potential sidelink connection targets ( Figure 3 After that, the initiator UE ( Figure 3304) can send a connection request 315 to the identified target UE 304. In some cases, the connection request 315 can be a first RRC message (e.g., an "RRCDirectConnectionSetupRequest" message) sent by the UE 302 to request a unicast connection with the UE 304. For example, the unicast connection can utilize the PC5 interface of the sidelink, and the connection request 315 can be an RRC connection establishment request message. In addition, the UE 302 can use the sidelink signaling radio bearer 305 to transmit the connection request 315.

[0081] After receiving the connection request 315, the UE 304 may determine whether to accept or reject the connection request 315. The UE 304 may make this determination based on the transmit / receive capabilities, the ability to accommodate unicast connections via the sidelink, the specific services indicated for the unicast connection, the content to be sent via the unicast connection, or a combination thereof. For example, if the UE 302 wants to use the first RAT to send or receive data, but the UE 304 does not support the first RAT, the UE 304 may reject the connection request 315. Additionally or alternatively, the UE 304 may reject the connection request 315 based on the inability to accommodate the unicast connection via the sidelink due to limited radio resources, scheduling issues, etc. Therefore, the UE 304 may send an indication of whether the request is accepted or rejected in the connection response 320. Similar to the UE 302 and the connection request 315, the UE 304 may use the sidelink signaling radio bearer 310 to convey the connection response 320. Additionally, the connection response 320 may be a second RRC message (eg, a “RRCDirectConnectionResponse” message) sent by the UE 304 in response to the connection request 315 .

[0082] In some cases, the sidelink signaling radio bearers 305 and 310 may be the same sidelink signaling radio bearer, or may be independent sidelink signaling radio bearers. Thus, a radio link control (RLC) layer acknowledgement mode (AM) may be used for the sidelink signaling radio bearers 305 and 310. A UE supporting unicast connections may monitor on a logical channel associated with the sidelink signaling radio bearer. In some cases, the AS layer (i.e., Layer 2) may deliver information directly through RRC signaling (e.g., control plane) rather than the V2X layer (e.g., data plane).

[0083] If the connection response 320 indicates that the UE 304 accepts the connection request 315, the UE 302 may send a connection setup 325 message on the sidelink signaling radio bearer 305 to indicate that the unicast connection setup is complete. In some cases, the connection setup 325 may be a third RRC message (e.g., an "RRCDirectConnectionSetupComplete" message). Each of the connection request 315, the connection response 320, and the connection setup 325 may use basic capabilities when transmitted from one UE to another UE to enable each UE to receive and decode the corresponding transmission (e.g., RRC message).

[0084] In addition, an identifier may be used for each of the connection request 315, the connection response 320, and the connection establishment 325. For example, the identifier may indicate which UE 302 / 304 is sending which message and / or which UE 302 / 304 the message is for. For physical (PHY) layer channels, RRC signaling and any subsequent data transmission may use the same identifier (e.g., layer 2 ID). However, for logical channels, the identifier may be separate for RRC signaling and data transmission. For example, on logical channels, RRC signaling and data transmission may be treated differently and have different confirmation (ACK) feedback message transmissions. In some cases, for RRC message transmissions, a physical layer ACK may be used to ensure that the corresponding message is correctly sent and received.

[0085] One or more information elements may be included in the connection request 315 and / or the connection response 320 of the UE 302 and / or the UE 304, respectively, to enable negotiation of the corresponding AS layer parameters of the unicast connection. For example, the UE 302 and / or the UE 304 may include a packet data convergence protocol (PDCP) parameter in the corresponding unicast connection establishment message to set the PDCP context of the unicast connection. In some cases, the PDCP context may indicate whether PDCP duplication is used for the unicast connection. In addition, the UE 302 and / or the UE 304 may include an RLC parameter when establishing the unicast connection to set the RLC context of the unicast connection. For example, the RLC context may indicate whether the RLC layer for unicast communication uses AM (e.g., using a reordering timer (reordering timer (t-reordering))) or an unacknowledged mode (UM).

[0086] In addition, UE 302 and / or UE 304 may include media access control (MAC) parameters to set the MAC context of the unicast connection. In some cases, the MAC context may enable a resource selection algorithm for the unicast connection, a hybrid automatic repeat request (HARQ) feedback scheme (e.g., ACK or negative ACK (NACK) feedback), parameters of the HARQ feedback scheme, carrier aggregation, or a combination thereof. In addition, UE 302 and / or UE 304 may include PHY layer parameters when establishing a unicast connection to set the PHY layer context of the unicast connection. For example, the PHY layer context may indicate a transmission format for the unicast connection (unless a transmission profile is included for each UE 302 / 304) and a radio resource configuration (e.g., bandwidth part (BWP), numerology, etc.). These information elements may support different frequency range configurations (e.g., FR1 and FR2).

[0087] In some cases, a security context may also be set for the unicast connection (e.g., after sending the connection establishment 325 message). Before a security association (e.g., a security context) is established between UE 302 and UE 304, the sidelink signaling radio bearers 305 and 310 may not be protected. After the security association is established, the sidelink signaling radio bearers 305 and 310 may be protected. Therefore, the security context may enable secure data transmission over the unicast connection and the sidelink signaling radio bearers 305 and 310. In addition, IP layer parameters (e.g., link-local IPv4 or IPv6 addresses) may also be negotiated. In some cases, the IP layer parameters may be negotiated by an upper layer control protocol running after establishing RRC signaling (e.g., establishing a unicast connection). As described above, UE 304 may decide whether to accept or reject the connection request 315 based on a specific service indicated for the unicast connection and / or content to be sent over the unicast connection (e.g., upper layer information). Specific services and / or content may also be indicated by an upper layer control protocol running after the RRC signaling is established.

[0088] After establishing the unicast connection, UE 302 and UE 304 may communicate via sidelink 330 using the unicast connection, wherein sidelink data 335 is sent between the two UEs 302 and 304. Sidelink 330 may correspond to Figure 1 The sidelinks 162 and / or 168 and / or Figure 2A and 2B242 in the sidelink. In some cases, the sidelink data 335 may include RRC messages sent between the two UEs 302 and 304. In order to maintain the unicast connection on the sidelink 330, UE 302 and / or UE 304 may send a keep-alive message (e.g., an "RRCDirectLinkAlive" message, a fourth RRC message, etc.). In some cases, the keep-alive message may be triggered periodically or on demand (e.g., event triggered). Therefore, the triggering and sending of the keep-alive message may be initiated by UE 302 or by both UE 302 and UE 304. In addition or alternatively, a MAC control element (MAC-CE) (e.g., defined by the sidelink 330) may be used to monitor the state of the unicast connection on the sidelink 330 and maintain the connection. When the unicast connection is no longer needed (e.g., when UE 302 travels far enough away from UE 304), UE 302 and / or UE 304 may initiate a release procedure to drop the unicast connection over sidelink 330. Therefore, subsequent RRC messages may not be sent between UE 302 and UE 304 over the unicast connection.

[0089] Figure 4 400 is a block diagram illustrating various components of an example UE 400 according to aspects of the present disclosure. In one aspect, UE 400 may correspond to any UE described herein. As a specific example, UE 400 may be a V-UE, such as Figure 1 For simplicity, Figure 4 The various features and functions illustrated in the block diagram of the present invention are connected together using a common data bus, which means that these various features and functions are operably coupled together. Those skilled in the art will recognize that other connections, mechanisms, features, functions, etc. can be provided and adapted as needed to operably couple and configure the actual UE. In addition, it is also recognized that Figure 4 One or more features or functions described in the examples may be further subdivided, or Figure 4 Two or more features or functions described in the accompanying drawings may be combined.

[0090] The UE 400 may include at least one transceiver 404 connected to one or more antennas 402 and providing means (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for suppressing transmission, etc.) for communicating with other network nodes (such as V-UE (e.g., V-UE 160), infrastructure access points (e.g., roadside access points 164), P-UE (e.g., UE 104), base stations (e.g., base station 102), etc.) via at least one designated RAT (e.g., cV2X or IEEE 802.11p) through one or more communication links (e.g., communication link 120, sidelinks 162, 166, 168, mmW communication link 184). The transceiver 404 may be configured differently to transmit and encode signals (e.g., messages, indications, information, etc.) according to the designated RAT, and conversely, to receive and decode signals (e.g., messages, indications, information, pilots, etc.).

[0091] As used herein, a "transceiver" may include at least one transmitter and at least one receiver in an integrated device (e.g., embodied as transmitter circuitry and receiver circuitry of a single communication device) in some implementations, may include separate transmitter devices and separate receiver devices in some implementations, or may be embodied in other ways in other implementations. In one aspect, the transmitter may include or be coupled to multiple antennas (e.g., antennas 402), such as an antenna array, that allow the UE 400 to perform transmit "beamforming", as described herein. Similarly, the receiver may include or be coupled to multiple antennas (e.g., antennas 402), such as an antenna array, that allow the UE 400 to perform receive beamforming, as described herein. In one aspect, the transmitter and receiver may share the same multiple antennas (e.g., antennas 402), such that the UE 400 can only receive or transmit at a given time, but not simultaneously. In some cases, the transceiver may not provide transmit and receive functionality simultaneously. For example, in some designs, when full communications need not be provided, a low-functionality receiver circuit may be employed to reduce cost (eg, a receiver chip or similar circuit simply provides low-level sniffing).

[0092] UE 400 may also include a satellite positioning service (SPS) receiver 406. SPS receiver 406 may be connected to one or more antennas 402 and may provide components for receiving and / or measuring satellite signals. SPS receiver 406 may include any suitable hardware and / or software for receiving and processing SPS signals, such as global positioning system (GPS) signals. SPS receiver 406 requests appropriate information and operations from other systems and uses measurements obtained by any suitable SPS algorithm to perform calculations necessary to determine the location of UE 400.

[0093] One or more sensors 408 may be coupled to the processing system 410 and may provide means for sensing or detecting information related to the state and / or environment of the UE 400, such as speed, heading (e.g., compass heading), headlight status, gas mileage, etc. For example, the one or more sensors 408 may include a speedometer, a tachometer, an accelerometer (e.g., a micro-electromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), etc.

[0094] The processing system 410 may include one or more microprocessors, microcontrollers, ASICs, processing cores, digital signal processors, etc. that provide processing functions and other computing and control functionality. Thus, the processing system 410 may provide means for processing, such as means for determining, means for calculating, means for receiving, means for sending, means for indicating, etc. The processing system 410 may include any form of logic suitable for performing or causing the components of the UE 400 to perform at least the techniques described herein.

[0095] The processing system 410 may also be coupled to a memory 414, which provides means for storing data and software instructions (including means for retrieval, means for maintenance, etc.) for performing programmed functionality within the UE 400. The memory 414 may be on the processing system 410 (e.g., within the same integrated circuit (IC) package), and / or the memory 414 may be external to the processing system 410 and functionally coupled via a data bus.

[0096] UE 400 may include a user interface 450 that provides any suitable interface system that allows a user to interact with UE 400, such as microphone / speaker 452, keyboard 454, and display 456. Microphone / speaker 452 may provide voice communication services with UE 400. Keyboard 454 may include any suitable buttons for user input to UE 400. Display 456 may include any suitable display, such as, for example, a backlit liquid crystal display (LCD), and may also include a touch screen display for additional user input modes. Therefore, user interface 450 may be a component for providing indications (e.g., auditory and / or visual indications) to a user and / or for receiving user input (e.g., via user actuation of sensing devices such as a keypad, a touch screen, a microphone, etc.).

[0097] In one aspect, UE 400 may include a sidelink manager 470 coupled to processing system 410. Sidelink manager 470 may be a hardware, software, or firmware component that, when executed, causes UE 400 to perform operations described herein. For example, sidelink manager 470 may be a software module stored in memory 414 and executable by processing system 410. As another example, sidelink manager 470 may be a hardware circuit (e.g., an ASIC, a field programmable gate array (FPGA), etc.) within UE 400.

[0098] The link-level ranging signal may be used to estimate the distance between a V-UE pair or between a V-UE and a roadside unit (RSU). Figure 5 An example wireless communication system 500 is illustrated in accordance with aspects of the present disclosure, wherein a V-UE 504 is exchanging ranging signals with an RSU 510 and another V-UE 506. Figure 5 As illustrated, a wideband (e.g., FR1) ranging signal (e.g., a Zadoff Chu sequence) is sent by two endpoints (e.g., V-UE 504 and RSU 510, and V-UE 504 and V-UE 506). In one aspect, the ranging signal can be a sidelink positioning reference signal (SL-PRS), which is a reference signal sent via a sidelink specifically configured for positioning purposes. Upon receiving the ranging signal from a transmitter (e.g., V-UE 504), a receiver (e.g., RSU 510 and / or V-UE 506) uses channel estimation to estimate the time of arrival (ToA) of the first multipath of the ranging signal. The receiver then responds by sending a ranging signal including the calculated ToA to the transmitter. The transmitter calculates the ToA of the response signal and uses the two estimated ToAs to estimate the distance between the transmitter and the receiver. It should be noted that this positioning process assumes that the V-UE involved is time synchronized (i.e., its system frame time is the same as other V-UEs, or is a known offset relative to other V-UEs). In addition, despite Figure 5 Two V-UEs are illustrated, but it should be understood that they need not be V-UEs, but may be any other type of UE capable of sidelink communication.

[0099] It should be understood that ranging accuracy increases with the bandwidth of the ranging signal. Specifically, a higher bandwidth can better separate different multipaths of the ranging signal.

[0100] The three-phase protocol may be used to send ranging signals (eg, SL-PRS) for positioning. Figure 6 6 is a timeline 600 illustrating a three-phase protocol according to aspects of the present disclosure. Figure 6As shown, the three-phase protocol occurs periodically, such as every second. In the first phase 610, the transmitter (e.g., V-UE 504, RSU 510) broadcasts the relative position of its antenna (compared to the center position of the transmitter), the identifier (ID) of the sequence to be transmitted by the antenna in the second phase 620, and the time / frequency resource in which the sequence will be transmitted in the second phase 620.

[0101] In the second phase 620, the transmitter transmits a wideband sequence (e.g., SL-PRS) with a determined sequence ID on a determined time / frequency resource. In the third phase 630, the transmitter broadcasts its own GPS position, pseudoranges to one or more satellites, and / or its orientation during the second phase. The transmitter also broadcasts the ToA from the second phase 620. That is, the transmitter broadcasts the ToA of any SL-PRS received during the second phase 620. It should be noted that for V2I positioning, only the RSU needs to perform the third phase 630.

[0102] In one aspect, all V-UEs and RSUs may be configured (e.g., by an applicable standard) to follow the three-phase protocol. Thus, during each phase, the transmitter may also receive signals from other V-UEs / RSUs that contain the same type of information as the transmitter. In this way, both the transmitter and the receiver may estimate the distance between themselves and other V-UEs / RSUs.

[0103] Figure 7 Two resource allocation modes for transmission on the NR sidelink according to aspects of the present disclosure are illustrated. In the first mode 710 (labeled as "Mode 1"), the base station 702 (e.g., gNB) allocates time / frequency resources for sidelink communications between the V-UEs involved. Figure 7 In the example of FIG. 7 , base station 702 allocates time / frequency resources for the sidelink between V-UE 704 and 706. The transmitter (eg, V-UE 704) receives the time / frequency resource from the sidelink between V-UE 704 and 706 according to the above reference. Figure 6 The three-phase protocol described uses allocated resources to transmit ranging signals (e.g., SL-PRS). That is, the transmitter transmits the first, second, and third phase signals on the resources allocated by the base station 702. In the second mode 720 (labeled as "Mode 2"), the UEs 704 and 706 involved autonomously select sidelink resources for the transmission of the three-phase ranging signals. If the V-UE has a cellular coverage area, the V-UE can only use the first mode, and regardless of whether the V-UE has a cellular coverage area, the V-UE can use the second mode. It should be noted that although Figure 7 Two V-UEs are illustrated, but it should be understood that they need not be V-UEs, but may be any other type of UE capable of sidelink communication.

[0104] The signaling on the sidelink is the same between the two resource allocation modes. From the perspective of the receiver (e.g., V-UE 706), there is no difference between the modes. That is, it does not matter to the receiver whether the resources for the ranging signal are allocated by the base station 702 or by the transmitter UE.

[0105] In addition, as mentioned above Figure 3 As described above, the NR sidelink supports HARQ retransmission. In a first mode, a base station (e.g., base station 702) provides a dynamic grant for HARQ feedback, or activates a configured sidelink grant. A sending UE (e.g., V-UE 704) can report the sidelink feedback back to the base station.

[0106] Each established sidelink includes a physical sidelink control channel (PSCCH) carrying sidelink control information (SCI). The first level of control (referred to as "SCI-1") is sent on the PSCCH and contains information for resource allocation and decoding the second level of control (referred to as "SCI-2"). The second level of control is sent on the physical sidelink shared channel (PSSCH) and contains information for decoding data to be sent on the shared channel (SCH) of the sidelink. The first stage control information can be decoded by all UEs, while the second stage control information may include a format that can only be decoded by certain UEs. This ensures that new features can be introduced in the second stage control while maintaining backward compatibility of resource reservation in the first stage control.

[0107] Both the first and second level control use the physical downlink control channel (PDCCH) polar coding chain, such as Figure 8 As described. Figure 8 800 is a diagram illustrating how to establish a SCH on a sidelink between two or more UEs according to aspects of the present disclosure. Specifically, information in SCI-1 802 is used for resource allocation 804 (performed by the network or the UEs involved) for SCI-2 806 and SCH 808. In addition, information in SCI-1 802 is used to determine / decode the content of SCI-2 806 sent on the allocated resources. Therefore, the receiving UE needs both resource allocation 804 and SCI-1 802 to decode SCI-2 806. Then, information in SCI-2 806 is used to determine / decode SCH 808.

[0108] The UE may use a round trip time (RTT) positioning technique with multiple other UEs or RSUs to determine its position based on ranging signals to / from the other involved UEs / RSUs and the known positions of the other involved UEs / RSUs. It should be noted that the term "position" may refer to an absolute position or a relative position, depending on the context.

[0109] Fig. 9 900 is a diagram illustrating example timing of RTT signals between a target UE 904 (labeled as “UE2”) and two auxiliary UEs 902 (labeled as “UE1”) and 906 (labeled as “UE3”) according to aspects of the present disclosure. UEs 902 to 906 may correspond to any UE described herein, and in particular, may be V-UEs. Fig. 9 In FIG. 8 , the target UE 904 is trying to estimate its location, and the assisting UEs 902 and 906 have known locations (eg, from GPS).

[0110] exist Fig. 9 In the example of , the target UE 904 receives a ranging signal (eg, SL-PRS) from the assisting UE 902 and responds with its own ranging signal (eg, SL-PRS). Figure 7 As described, the ranging signal may be sent on a time / frequency resource allocated by the network (e.g., a base station or location server) or one of the UEs involved. This enables the receiver UE to know at what frequency and at what time to measure the ranging signal. Fig. 9 In the example of FIG. 1 , the received ranging signal has some propagation time between the assisting UE 902 and the target UE 904, referred to as T prop,UE1-UE2 The length of time between receiving the ranging signal from the assisting UE 902 and sending the response ranging signal by the target UE 904 is referred to as “T UE2,Rx-Tx ” or “UE2 Rx-Tx”, where “Rx-Tx” stands for “receive-transmit”. The response ranging signal may include T UE2,Rx-Tx The measurement report of the value of , and there is some propagation time between the target UE 904 and the auxiliary UE 902, referred to as T prop,UE2-UE1 (Assume that it is equal to T prop,UE1-UE2 ).

[0111] The response ranging signal from the target UE 904 may also be transmitted over a propagation time (referred to as T prop,UE2-UE3 ) is received by the second assisting UE 906 after . Alternatively, this may be received by the target UE 904 at about the same time as the response ranging signal to the assisting UE 902 (at Fig. 9 In the example of FIG. 1 , different ranging signals are sent by the second assisting UE 906. Some delay (referred to as “T UE3,Rx-Tx ” or “UE3 Rx-Tx”), the second assisting UE 906 sends a response ranging signal to the target UE 904. The response ranging signal may include T UE3,Rx-TxThe measurement report of the value of and there is some propagation time between the assisting UE 906 and the target UE 904, referred to as T prop,UE3-UE2 (Assume that it is equal to T prop,UE2-UE3 ).

[0112] Based on the sending and receiving time of the ranging signal and T UE2,Rx-Tx and T UE3,Rx-Tx The value of , the positioning entity (eg, the target UE 904) can calculate the flight time between the target UE 904 and the auxiliary UEs 902 and 906 (ie, Fig. 9 In the example of prop,UE1-UE2 and / or T prop,UE2-UE1 and T prop,UE2-UE3 and / or T prop,UE3-UE2 ). Based on the flight time and the speed of light, the positioning entity can calculate the distance between the target UE 904 and the assisting UEs 902 and 906. Based on these distances, the positioning entity can estimate the relative position of the target UE 904 with respect to the assisting UEs 902 and 906. If the assisting UEs 902 and 906 have known locations (e.g., GPS coordinates received from the assisting UEs 902 and 906), the positioning entity can estimate the absolute position of the target UE 904 based on the distance between the target UE 904 and the assisting UEs 902 and 906 and the known positions of the assisting UEs 902 and 906. In the case where the assisting UEs 902 and 906 provide their positions, the assisting UEs 902 and 906 can also provide the uncertainty or accuracy level associated with the position.

[0113] Fig.10 1 is a diagram 1000 showing example timing of RTT signals exchanged between a target UE 1004 (labeled as “UE2”) and two auxiliary UEs 1002 (labeled as “UE1”) and 1006 (labeled as “UE3”) according to aspects of the present disclosure. UEs 1002 to 1006 may correspond to any UE described herein, and in particular, may be V-UEs. Fig.10 In the example, target UE 1004 attempts to estimate its location, and assisting UEs 1002 and 1006 have known locations (eg, from GPS).

[0114] exist Fig.10 In the example of FIG. 1 , the first assisting UE 1002 sends a ranging signal (eg, SL-PRS) which is transmitted at a certain propagation time T prop,UE1-UE2 It is then received at the target UE 1004. At a certain propagation time T prop,UE1-UE3 Afterwards, the ranging signal is also received / measured at the second assisting UE 1006. Fig.10In the example of , this is a known propagation time, or can be derived because the locations of the assisting UEs 1002 and 1006 are known.

[0115] Some UE processing time (referred to as T UE2,Rx-Tx ), the target UE 1004 sends a response ranging signal, after a propagation delay T prop,UE2-UE1 Afterwards, the response ranging signal is received / measured at the first assisting UE 1002. The second assisting UE 1006 also receives / measures the response ranging signal at a certain propagation delay T prop,UE2-UE3 Then, a response ranging signal is received / measured. As described above, the response ranging signal may include a measurement report including the UE processing time T at the target UE 1004. UE2,Rx-Tx .

[0116] The second assisting UE 1006 determines the time difference between the ToA of the ranging signal sent by the first assisting UE 1002 and the ToA of the response ranging signal sent by the target UE 1004, referred to as T UE-Rx-UE-Rx , or more simply called T Rx-Rx The second assisting UE 1006 sends a measurement report to the positioning entity (eg, the target UE 1004), thereby reporting T UE-Rx-UE-Rx Measurement.

[0117] Then, the distance between the second assisting UE 1006 and the target UE 1004 may be calculated based on the following observations:

[0118] T prop,uE1-uE2 +T Rx-Tx +T Prop,uE2-uE3 =T uE Rx-UE Rx +T Prop,uE1-uE3

[0119] Based on these distances, the positioning entity can estimate the relative position of the target UE 1004 with respect to the assisting UEs 1002 and 1006. If the assisting UEs 1002 and 1006 have known positions (e.g., GPS coordinates received from the assisting UEs 1002 and 1006), the positioning entity can estimate the absolute position of the target UE 1004 based on the distances between the target UE 1004 and the assisting UEs 1002 and 1006 and the known positions of the assisting UEs 1002 and 1006. In the event that the assisting UEs 1002 and 1006 provide their positions, the assisting UEs 1002 and 1006 may also provide an uncertainty or level of accuracy associated with the positions.

[0120] It should be noted that although Fig. 9 and 10Explaining the RTT timing between the target UE and two assisting UEs, it should be understood that there may be more or less than two assisting UEs.

[0121] The present disclosure provides a technique for sidelink assisted positioning. In a first scenario of sidelink assisted positioning, an assisting UE (e.g., assisting UEs 1002 and 1006) may have a cellular coverage area (i.e., cellular connectivity to a base station), while a target UE (e.g., target UE 1004) may not have a coverage area (i.e., no cellular connectivity to a base station). Alternatively, the target UE may have a coverage area, but it may be very poor, such that the UE still cannot receive transmissions from a base station.

[0122] In this scenario, the target UE may initiate a location request by sending a request to each of any nearby (assistant) UEs over a sidelink established with those UEs. The sidelink may be established at the time of the location request, or may have been pre-established for other reasons. The assistant UE receives the location request and forwards the location request to the network (e.g., a serving base station or location server). In response, the network allocates time / frequency resources (e.g., resource allocation 804) to each assistant UE over a Uu interface for ranging signals (e.g., SL-PRS) to be used for the corresponding positioning process. However, the target UE does not receive the Uu link and resource allocation information. Instead, the assistant UE sends a sidelink transmission to the target UE, the sidelink transmission including a ranging signal configuration in a selected subchannel. Specifically, the assistant UE sends an SCI-2 including the ranging signal configuration received from the network. However, the assistant UE first sends an SCI-1 that enables the target UE to decode the subsequent SCI-2, as described above with reference to Figure 8 Once the target UE has the allocated ranging signal configuration for use in the positioning process with each assisting UE, the target UE may send and receive ranging signals on those resources, as described above with reference to Fig. 9 and 10 discussed.

[0123] In the second scenario of sidelink assisted positioning, neither the target UE nor the assisting UE has a cellular coverage area. In this case, the target UE sends a location request to the assisting UE via a sidelink established with the corresponding assisting UE, and the assisting UE can select a ranging signal (e.g., SL-PRS) time / frequency resource without coordinating with the network. The assisting UE then sends a sidelink transmission to the target UE, which includes the selected ranging signal configuration in the selected subchannel. Specifically, unlike the first option, the assisting UE sends an SCI-2 including the selected ranging signal configuration without network participation. In addition, the assisting UE first sends an SCI-1 that enables the target UE to decode the subsequent SCI-2, as described above with reference to Figure 8Once the target UE has the allocated ranging signal configuration for use in the positioning process with each assisting UE, the target UE may send and receive ranging signals on those resources, as described above with reference to Fig. 9 and 10 discussed.

[0124] Referring to the first scenario in more detail, there should be at least two auxiliary UEs with known locations (e.g., auxiliary UEs 902, 906, 1002, 1006) and a target UE (e.g., target UEs 904, 1004) that initiate sidelink assisted positioning by sending a request to be positioned. The request can be sent to each auxiliary UE via a sidelink with the UE. The sidelink may have been previously established, or may be established for the target UE to send a location request. The location request may have different forms. In a first alternative aspect, the location request may be a new format for SCI-2, in which one or more additional bits are added to SCI-2, indicating that SCI-2 is or includes a location request. SCI-1 should be able to point to SCI-2 with the new format.

[0125] In a second alternative aspect, the location request may be part of the PSSCH data (e.g., MAC-CE). That is, the target UE may send the location request via the PSSCH in the MAC-CE. In either alternative, the target UE may send a ranging signal (e.g., SL-PRS) together with (i.e., simultaneously with) the location request, whether in SCI-1 / SCI-2 or on the PSSCH. In this case, a demodulation reference signal (DMRS) sent with the location request via the PSSCH may be used as a ranging signal.

[0126] More specifically, like other transmissions over the PSSCH, the target UE transmits DMRS on the PSSCH simultaneously or at least in association with a MAC-CE containing a location request. The DMRS enables the receiver to estimate the channel conditions of the sidelink in order to better transmit and receive over the sidelink. The DMRS associated with the location request can be used as a ranging signal by the auxiliary UE. At the physical layer, because the auxiliary UE does not know whether the DMRS is associated with the location request until after the MAC-CE is decoded at the MAC layer, the auxiliary UE should measure the DMRS as a positioning signal (e.g., ToA, signal strength, etc.) and store the measurement values. The auxiliary UE can then decode the MAC-CE, determine that it includes a location request, and return to retrieve the stored DMRS measurements. The auxiliary UE can then treat the DMRS as a ranging signal for the requested positioning process.

[0127] It should be appreciated that the second alternative may add a significant amount of overhead since the assisting UE always has to perform and store positioning measurements of the DMRS. Therefore, in one aspect, the first and second alternatives may be combined. In this case, as in the first alternative, a flag (e.g., a one-bit field) in the SCI-2 (decodable at the physical layer) indicates that the SCI-2 includes a location request that alerts the assisting UE that it should treat the associated DMRS as a ranging signal for positioning purposes. In this way, the assisting UE only needs to perform and store positioning measurements of the DMRS of the DMRS associated with the location request.

[0128] In one aspect, a location request (whether in SCI-2 or MAC-CE) can be associated with a specific group of UEs by using a given destination ID. The destination ID is a specific scrambling of the SCI-1 that only the group members know. More specifically, a group of UEs can be created by a higher layer application. The grouped UEs are given the same destination ID, and they also have their own source ID. In this way, when the UEs in the group transmit, all UEs in the group and only the UEs in the group can read the SCI-1, and therefore decode the subsequent SCI-2 and corresponding data. Therefore, when the target UE sends a location request scrambled by a specific destination ID, only the UE associated with that destination ID can decode the location request.

[0129] In an alternative aspect, the target UE may instead broadcast a location request to all nearby UEs, not just those in a specific group. More specifically, each SCI-1 is scrambled with a destination ID. For the broadcast to be read by any receiving UE, the sending UE scrambles the SCI-1 with one of several destination IDs known to all UEs in the network. In this way, any receiving UE will be able to decode the SCI-1 on the PSCCH, and thereby decode the SCI-2.

[0130] The location request may also include additional information. In one aspect, the location request may include an indication of whether, where (in time and frequency), and / or how many ranging signals (e.g., SL-PRS, DMRS) are sent along with the location request (e.g., simultaneously). The location request may also include various expectations of the assisting UE. For example, the location request may indicate that the assisting UE is expected to perform an RTT procedure with the target UE, or in other words, send a response ranging signal (e.g., SL-PRS). In this case, the assisting UE may also need to report the "Rx-Tx" between receiving the ranging signal and sending the response ranging signal, as described above with reference to Fig. 9 The auxiliary UEs 902 and 906 and Fig.10 As described in the auxiliary UE 1002.

[0131] As another example, the location request may indicate that the assisting UE is expected to measure only the ranging signal associated with the location request and any other ranging signals that may be sent by other assisting UEs. In this case, the assisting UE may report "Rx-Rx" measurements between receiving ranging signals from the target UE and receiving ranging signals from other assisting UEs, as described above with reference to Fig.10 As described in the auxiliary UE 1006.

[0132] In one aspect, by associating different destination IDs with different methods, the location request may identify whether the receiving UE is expected to perform the first or second alternative described above (sending a response ranging signal and an Rx-Tx report or only reporting Rx-Rx).

[0133] It should be noted that although the above has generally described the communication between the target UE and the auxiliary UE according to beamforming (e.g., communicating via a sidelink using transmit and receive beams, sending and receiving ranging signals using transmit and receive beams, etc.), the various UEs can also communicate with each other in FR1 using omnidirectional signals. For example, each UE can send identifiers of other nearby UEs that it can detect. The UE can detect other UEs based on ranging signals and / or discovery processes with other UEs. The UE can then send these identifiers along with the ranging signals, or the UE can send these identifiers in separate reports. In this way, the target UE can determine how the other UEs are related to each other.

[0134] Fig.11 An exemplary method 1100 for wireless communication according to aspects of the present disclosure is illustrated. In one aspect, the method 1100 may be performed by a first UE (eg, any UE described herein). As a specific example, the first UE may correspond to UE 904 or UE 1004.

[0135] At 1110, the first UE sends a request to perform a positioning procedure to at least one second UE (e.g., any UE described herein) via a sidelink between the first UE and the at least one second UE. As a specific example, the at least one second UE may correspond to UE 902 and / or 906 or UE 1002 and / or 1006. In an aspect, operation 1110 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0136] At 1120, the first UE receives an indication of a set of time resources, frequency resources, or both allocated for a positioning process from at least one second UE via a sidelink. In one aspect, operation 1120 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0137] At 1130, the first UE transmits at least one positioning reference signal (e.g., at least one ranging signal, such as SL-PRS) on a set of time resources, frequency resources, or both allocated for the positioning process. In an aspect, operation 1130 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0138] Fig.12 An exemplary method 1200 for wireless communication according to aspects of the present disclosure is described. In one aspect, the method 1200 may be performed by a second UE (e.g., any UE described herein). As a specific example, the at least one second UE may correspond to UE 902 and / or 906 or UE 1002 and / or 1006.

[0139] At 1210, the second UE receives a request to perform a positioning procedure from a first UE (e.g., any UE described herein) via a sidelink between the second UE and the first UE. As specific examples, the first UE may correspond to UE 904 or UE 1004. In an aspect, operation 1210 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0140] At 1220, the second UE sends a request to the first network entity (e.g., any base station or location server described herein) to perform a positioning process. In an aspect, operation 1220 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0141] At 1230, the second UE receives an indication of a set of time resources, frequency resources, or both allocated for the positioning process from a second network entity (e.g., any base station or location server or second entity described herein). In one aspect, operation 1230 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0142] At 1240, the second UE sends an indication of a set of time resources, frequency resources, or both allocated for the positioning process to the first UE via the sidelink. In one aspect, operation 1240 may be performed by transceiver 404, processing system 410, memory 414, and / or sidelink manager 470, any or all of which may be considered as means for performing the operation.

[0143] It should be appreciated that a technical advantage of methods 1100 and 1200 is the performance of cooperative positioning between sidelink UEs.

[0144] In the above detailed description, it can be seen that different features are grouped together in the examples. This disclosure should not be understood as an example clause having more features than those explicitly mentioned in each clause. On the contrary, various aspects of the present disclosure may include less than all the features of the disclosed single example clause. Therefore, the following clauses should be deemed to be included in the specification, where each clause itself can serve as a separate example. Although each dependent clause may refer to a specific combination with one of the other clauses in the clause, the aspects of the dependent clause are not limited to a specific combination. It should be understood that other example clauses may also include a combination of the dependent clause aspects with the subject matter of any other dependent clause or independent clause or any feature with other dependent and independent clauses. Unless it is explicitly expressed or it can be easily inferred that a specific combination is not intended (for example, contradictory aspects, such as defining an element as an insulator and a conductor), the various aspects disclosed herein explicitly include these combinations. In addition, it is also intended that various aspects of the clause may be included in any other independent clause, even if the clause is not directly dependent on the independent clause.

[0145] Implementation examples are described in the following numbered clauses:

[0146] Clause 1. A method for wireless communication performed at a first user equipment (UE), comprising: sending a request to perform a positioning process to at least one second UE via a sidelink between the first UE and at least one second UE; receiving an indication of time resources, frequency resources, or a set of both allocated for the positioning process from at least one second UE via the sidelink; and sending at least one positioning reference signal on the time resources, frequency resources, or a set of both allocated for the positioning process.

[0147] Clause 2. A method according to clause 1, wherein sending a request comprises: sending a first sidelink control information (SCI-1) message via a physical sidelink control channel (PSCCH) of a sidelink, SCI-1 being associated with a second sidelink control information (SCI-2), SCI-2 comprising a request to perform a positioning process; and sending an SCI-2 message via the PSCCH of the sidelink.

[0148] Clause 3. The method of clause 2, wherein the SCI-2 includes a one-bit field indicating that the SCI-2 includes a request to perform a positioning process.

[0149] Clause 4. A method according to any of clauses 2 to 3, wherein: SCI-1 is scrambled by a destination identifier, or the destination identifier is a field within SCI-2.

[0150] Clause 5. The method of clause 4, wherein the destination identifier identifies a group of UEs including at least one second UE.

[0151] Clause 6. The method of clause 4, wherein the destination identifier indicates that the request to perform the positioning procedure is a broadcast to all UEs within wireless communication range of the first UE.

[0152] Clause 7. A method according to clause 1, wherein sending the request comprises sending a medium access control element (MAC-CE) on a physical sidelink shared channel (PSSCH) of the sidelink, the MAC-CE comprising a request to perform a positioning procedure.

[0153] Clause 8. The method according to any one of clauses 1 to 7 further comprises: sending a demodulation reference signal (DMRS) associated with a request to perform a positioning procedure via a physical sidelink shared channel (PSSCH) of the sidelink.

[0154] Clause 9. The method of clause 8, wherein the request to perform the positioning procedure includes an indication that DMRS is to be used for the positioning procedure.

[0155] Clause 10. A method according to any of clauses 1 to 9, wherein the request to perform a positioning procedure comprises an indication of whether at least one reference signal associated with the request to perform a positioning procedure is to be used for positioning.

[0156] Clause 11. The method of clause 10, wherein the indication further indicates a number of at least one reference signal; a time position, a frequency position, or both of at least one reference signal; or both.

[0157] Clause 12. A method according to any of clauses 1 to 11, wherein the request to perform a positioning procedure comprises an indication that at least one second UE is expected to perform a positioning procedure with the first UE.

[0158] Clause 13. The method of clause 12, wherein the positioning procedure comprises a round trip time (RTT) positioning procedure.

[0159] Clause 14. The method of clause 13, further comprising: receiving from at least one second UE a second reference signal and a parameter indicating a time difference between a reception of a first reference signal transmitted by a first UE at the second UE and a transmission time of the second reference signal.

[0160] Clause 15. The method of clause 14, wherein the first reference signal sent by the first UE is at least one positioning reference signal.

[0161] Clause 16. A method according to any of clauses 14 to 15, wherein the first reference signal sent by the first UE is a demodulation reference signal (DMRS) associated with a request to perform a positioning procedure.

[0162] Clause 17. The method according to any one of clauses 14 to 16 also includes: estimating the absolute position of the first UE based at least on the time difference between the sending of the first reference signal and the receiving of the second reference signal, a parameter indicating the time difference between the reception time of the first reference signal at at least one second UE and the sending time of the second reference signal, and the known position of at least one second UE, wherein the at least one second UE includes multiple UEs.

[0163] Clause 18. The method according to any one of clauses 14 to 17 further includes: estimating the relative position of the first UE based at least on the time difference between the sending of the first reference signal and the receiving of the second reference signal, and a parameter indicating the time difference between the reception of the first reference signal at at least one second UE and the sending time of the second reference signal.

[0164] Clause 19. A method according to any one of clauses 14 to 18, wherein: a first reference signal is sent by a first UE on a transmit beam, a second reference signal is sent by at least one second UE on a transmit beam and received by the first UE on a receive beam, or any combination thereof.

[0165] Clause 20. A method according to any of clauses 14 to 18, wherein: the second reference signal is sent by at least one second UE in the omni-directional frequency range and received by the first UE, and the first UE sends the reference signal in the omni-directional frequency range.

[0166] Clause 21. A method according to any of clauses 12 to 20, wherein the destination identifier in the request to perform the positioning procedure indicates that at least one second UE is expected to perform the positioning procedure with the first UE.

[0167] Clause 22. A method according to any one of clauses 1 to 21, wherein the request to perform a positioning process includes an indication that at least one second UE is expected to report to the first UE an indication of the time difference between reception of a reference signal sent by the first UE at the second UE and reception of a reference signal sent by a third UE at the second UE, the third UE participating in the positioning process together with the first UE.

[0168] Clause 23. A method according to any of clauses 20 to 22, wherein a destination identifier in a request to perform a positioning procedure indicates that at least one second UE is expected to report a time difference between reception of a reference signal sent by a first UE at the second UE and reception of a reference signal sent by a third UE at the second UE.

[0169] Clause 24. A method according to any of clauses 1 to 23, wherein the indication of the set of time resources, frequency resources, or both allocated for the positioning process is encoded in an SCI-2 message.

[0170] Clause 25. A method for wireless communication performed at a second user equipment (UE), comprising: receiving a request to perform a positioning process from a first UE via a sidelink between the second UE and the first UE; sending a request to perform a positioning process to a first network entity; receiving an indication of time resources, frequency resources, or a set of both allocated for the positioning process from the second network entity; and sending an indication of time resources, frequency resources, or a set of both allocated for the positioning process to the first UE via a sidelink.

[0171] Clause 26. A method according to clause 25, wherein receiving a request comprises: receiving a first sidelink control information (SCI-1) message via a physical sidelink control channel (PSCCH) of a sidelink, SCI-1 being associated with a second sidelink control information (SCI-2), SCI-2 comprising a request to perform a positioning process; and receiving an SCI-2 message via the PSCCH of the sidelink.

[0172] Clause 27. The method of clause 26, wherein the SCI-2 includes a one-bit field indicating that the SCI-2 includes a request to perform a positioning process.

[0173] Clause 28. A method according to any of clauses 26 to 27, wherein: SCI-1 is scrambled by a destination identifier, or the destination identifier is a field within SCI-2.

[0174] Clause 29. The method of clause 28, wherein the destination identifier identifies a group of UEs including the second UE.

[0175] Clause 30. The method of clause 28, wherein the destination identifier indicates that the request to perform the positioning procedure is a broadcast to all UEs within wireless communication range of the first UE.

[0176] Clause 31. A method according to clause 25, wherein receiving the request comprises: receiving a medium access control element (MAC-CE) on a physical sidelink shared channel (PSSCH) of the sidelink, the MAC-CE comprising a request to perform a positioning procedure.

[0177] Clause 32. The method according to any one of clauses 25 to 31 further comprises: receiving a demodulation reference signal (DMRS) associated with a request to perform a positioning procedure via a physical sidelink shared channel (PSSCH) of the sidelink.

[0178] Clause 33. The method of clause 32, wherein the request to perform the positioning procedure includes an indication that DMRS is to be used for the positioning procedure.

[0179] Clause 34. The method of clause 33, further comprising: performing positioning measurements of the DMRS based on the indication that the DMRS is to be used for a positioning process.

[0180] Clause 35. A method as set forth in any of clauses 33 to 34, wherein the indication comprises a one-bit field in an SCI-1 received from the first UE via a sidelink.

[0181] Clause 36. A method according to any of clauses 25 to 35, wherein the request to perform a positioning procedure comprises an indication of whether at least one reference signal associated with the request to perform a positioning procedure is to be used for positioning.

[0182] Clause 37. The method of clause 36, wherein the indication further indicates a number of at least one reference signal; a time position, a frequency position, or both of at least one reference signal; or both.

[0183] Clause 38. A method according to any of clauses 25 to 37, wherein the request to perform a positioning procedure comprises an indication that the second UE is expected to perform a positioning procedure with the first UE.

[0184] Clause 39. The method of clause 38, wherein the positioning process comprises a round trip time (RTT) positioning process.

[0185] Clause 40. The method of clause 39, further comprising: sending a second reference signal and a parameter indicating a time difference between reception of the first reference signal sent by the first UE at the second UE and sending of the second reference signal to the first UE via a sidelink.

[0186] Clause 41. The method of clause 40, wherein the first reference signal sent by the first UE is at least one positioning reference signal.

[0187] Clause 42. The method of clause 41, wherein the first reference signal sent by the first UE is a demodulation reference signal (DMRS) associated with a request to perform a positioning procedure.

[0188] Clause 43. A method according to any of clauses 38 to 42, wherein the destination identifier in the request to perform the positioning procedure indicates that the second UE is expected to perform the positioning procedure with the first UE.

[0189] Clause 44. A method according to any of clauses 25 to 43, wherein the request to perform a positioning procedure includes an indication that the second UE is expected to report to the first UE an indication of the time difference between reception of a reference signal sent by the first UE at the second UE and reception of a reference signal sent by a third UE at the second UE, the third UE participating in the positioning procedure together with the first UE.

[0190] Clause 45. A method according to clause 44, wherein the destination identifier in the request to perform the positioning procedure indicates that the second UE is expected to report a time difference between reception of a reference signal sent by the first UE at the second UE and reception of a reference signal sent by a third UE at the second UE.

[0191] Clause 46. A method according to any of clauses 25 to 45, wherein the second UE encodes an indication of the set of time and / or frequency resources allocated for the positioning procedure in an SCI-2 message.

[0192] Clause 47. A method according to any of clauses 25 to 46, wherein: the first network entity is a base station or a location server, and the second network entity is a base station or a location server.

[0193] Clause 48. An apparatus comprising a memory and at least one processor communicatively coupled to the memory, the memory and the at least one processor configured to perform the method of any of clauses 1 to 47.

[0194] Clause 49. An apparatus comprising means for performing the method according to any one of clauses 1 to 47.

[0195] Clause 50. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising at least one instruction for causing a computer or a processor to perform a method according to any one of clauses 1 to 47.

[0196] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0197] In addition, it will be appreciated by those skilled in the art that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the aspects disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. In order to clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been generally described above in terms of their functionality. Whether this functionality is implemented as hardware or software depends on the specific application and the design constraints on the entire system. A skilled person may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0198] The various illustrative logical blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or performed using a general purpose processor, a digital signal processor (DSP), an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The 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 combined with a DSP core, or any other such configuration.

[0199] The methods, sequences and / or algorithms described in conjunction with the aspects disclosed herein may be directly embodied in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a random access memory (RAM), a flash memory, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a register, a 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 a processor so that the processor can read information from the storage medium and write information to the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0200] In one or more example aspects, the functions described can be implemented using hardware, software, firmware, or any combination thereof. If implemented using software, these functions can be stored on a computer-readable medium or sent via a computer-readable medium as one or more instructions or codes. Computer-readable media include computer storage media and communication media, which include any media that facilitates the transfer of a computer program from one place to another. Storage media can be any available media that can be accessed by a computer. As an example and not a limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM, or other optical disk storage devices, disk storage devices, or other magnetic storage devices, or any other media that can be used to carry or store desired program codes in the form of instructions or data structures and can be accessed by a computer. In addition, any connection is appropriately referred to as a computer-readable medium. For example, if software is sent from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are all included in the definition of medium. As used herein, disk and disc include 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 via lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0201] Although the foregoing disclosure shows illustrative aspects of the present disclosure, it should be noted that various changes and modifications may be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions, steps and / or actions of the method claims according to the aspects of the disclosure described herein do not need to be performed in any particular order. In addition, although the elements of the present disclosure may be described or claimed in singular form, plural forms are contemplated unless a limitation to the singular form is explicitly stated.

Claims

1. A method for wireless communication performed at a first user equipment (UE), comprising: Sending a request to perform a positioning procedure to at least one second UE via a sidelink between the first UE and at least one second UE, wherein the request is associated with at least one reference signal; receiving, from the at least one second UE via the sidelink, an indication of a set of time resources, frequency resources, or both allocated for the positioning procedure; and sending at least one positioning reference signal on the time resources, frequency resources, or a set of both resources allocated for the positioning process, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

2. The method according to claim 1, wherein: Sending the request includes: sending a first sidelink control information (SCI-1) message via a physical sidelink control channel (PSCCH) of the sidelink, the SCI-1 being associated with second sidelink control information (SCI-2), the SCI-2 including the request to perform the positioning procedure; and The SCI-2 message is sent via the PSCCH of the sidelink.

3. The method according to claim 2, wherein: The SCI-2 includes a one-bit field indicating that the SCI-2 includes the request to perform the positioning process.

4. The method according to claim 2, wherein: The SCI-1 is scrambled by the destination identifier, or The destination identifier is a field inside the SCI-2.

5. The method according to claim 4, wherein: The destination identifier identifies a group of UEs including the at least one second UE.

6. The method according to claim 4, wherein: The destination identifier indicates that the request to perform the positioning procedure is broadcast to all UEs within wireless communication range of the first UE.

7. The method according to claim 1, wherein: The sending the request comprises: A medium access control element (MAC-CE) is sent on a physical sidelink shared channel (PSSCH) of the sidelink, the MAC-CE including the request to perform the positioning procedure.

8. The method according to claim 1, further comprising: A demodulation reference signal (DMRS) associated with the request to perform the positioning procedure is transmitted through a physical sidelink shared channel (PSSCH) of the sidelink.

9. The method according to claim 8, wherein: The request to perform the positioning procedure includes an indication that the DMRS is to be used for the positioning procedure.

10. The method according to claim 1, wherein: The indication further indicates the number of the at least one reference signal; the time position, the frequency position, or both of the at least one reference signal; or both.

11. The method according to claim 1, wherein: The request to perform the positioning procedure comprises an indication that the at least one second UE is expected to perform the positioning procedure with the first UE.

12. The method according to claim 11, wherein: The positioning process includes a round trip time (RTT) positioning process.

13. The method according to claim 12, further comprising: A second reference signal and a parameter indicating a time difference between a reception of a first reference signal transmitted by the first UE at the second UE and a transmission time of the second reference signal are received from the at least one second UE.

14. The method according to claim 13, wherein: The first reference signal sent by the first UE is the at least one positioning reference signal.

15. The method according to claim 13, wherein: The first reference signal sent by the first UE is a demodulation reference signal (DMRS) associated with the request to perform the positioning procedure.

16. The method according to claim 13, further comprising: The absolute position of the first UE is estimated based at least on the time difference between the transmission of the first reference signal and the reception of the second reference signal, the parameter indicating the time difference between the reception of the first reference signal at the at least one second UE and the transmission time of the second reference signal, and the known position of the at least one second UE, wherein the at least one second UE includes multiple UEs.

17. The method according to claim 13, further comprising: The relative position of the first UE is estimated based at least on a time difference between transmission of the first reference signal and reception of the second reference signal, and the parameter indicating the time difference between reception of the first reference signal at the at least one second UE and the transmission time of the second reference signal.

18. The method of claim 13, wherein: The first UE sends the first reference signal on a transmit beam, The second reference signal is transmitted by the at least one second UE on a transmit beam and received by the first UE on a receive beam, or Any combination thereof.

19. The method of claim 13, wherein: The second reference signal is sent by the at least one second UE and received by the first UE in an omni-frequency range, and The first UE sends the reference signal in the omnidirectional frequency range.

20. The method according to claim 11, wherein: The destination identifier in the request to perform the positioning procedure indicates that the at least one second UE is expected to perform the positioning procedure with the first UE.

21. The method according to claim 1, wherein: The request to perform the positioning procedure includes an indication that the at least one second UE is expected to report to the first UE a time difference between reception of a reference signal sent by the first UE at the second UE and reception of a reference signal sent by a third UE at the second UE, the third UE participating in the positioning procedure together with the first UE.

22. The method according to claim 21, wherein: The destination identifier in the request to perform the positioning procedure indicates that the at least one second UE is expected to report the time difference between reception at the second UE of the reference signal sent by the first UE and reception at the second UE of the reference signal sent by the third UE.

23. The method according to claim 1, wherein: The indication of the set of time resources, frequency resources, or both allocated for the positioning process is encoded in an SCI-2 message.

24. A method for wireless communication performed at a second user equipment (UE), comprising: receiving a request to perform a positioning procedure from the first UE via a sidelink between the second UE and the first UE, wherein the request is associated with at least one reference signal; Sending the request to perform the positioning process to the first network entity; receiving from a second network entity an indication of a set of time resources, frequency resources, or both allocated for the positioning process; and sending, via the sidelink, to the first UE, the indication of the time resources, frequency resources, or a set of both resources allocated for the positioning process, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

25. The method according to claim 24, wherein: Receiving the request includes: receiving a first sidelink control information (SCI-1) message via a physical sidelink control channel (PSCCH) of the sidelink, the SCI-1 being associated with a second sidelink control information (SCI-2), the SCI-2 including the request to perform the positioning procedure; and The SCI-2 message is received via the PSCCH of the sidelink.

26. The method according to claim 25, wherein: The SCI-2 includes a one-bit field indicating that the SCI-2 includes the request to perform the positioning process.

27. The method of claim 25, wherein: The SCI-1 is scrambled by the destination identifier, or The destination identifier is a field inside the SCI-2.

28. The method according to claim 27, wherein: The destination identifier identifies a group of UEs including the second UE.

29. The method according to claim 27, wherein: The destination identifier indicates that the request to perform the positioning procedure is broadcast to all UEs within wireless communication range of the first UE.

30. The method of claim 24, wherein: The receiving the request comprises: A medium access control element (MAC-CE) is received on a physical sidelink shared channel (PSSCH) of the sidelink, the MAC-CE including the request to perform the positioning procedure.

31. The method of claim 24, further comprising: A demodulation reference signal (DMRS) associated with the request to perform the positioning procedure is received through a physical sidelink shared channel (PSSCH) of the sidelink.

32. The method according to claim 31, wherein: The request to perform the positioning procedure includes an indication that the DMRS is to be used for the positioning procedure.

33. The method of claim 32, further comprising: Positioning measurements of the DMRS are performed based on the indication that the DMRS is to be used for the positioning process.

34. The method of claim 32, wherein: The indication comprises a one-bit field in an SCI-1 received from the first UE via the sidelink.

35. The method of claim 24, wherein: The indication further indicates the number of the at least one reference signal; the time position, the frequency position, or both of the at least one reference signal; or both.

36. The method of claim 24, wherein: The request to perform the positioning procedure includes an indication that the second UE is expected to perform the positioning procedure with the first UE.

37. The method of claim 36, wherein: The positioning process includes a round trip time (RTT) positioning process.

38. The method of claim 37, further comprising: A second reference signal and a parameter indicating a time difference between reception of a first reference signal transmitted by the first UE and transmission of the second reference signal at the second UE are transmitted to the first UE through the sidelink.

39. The method of claim 38, wherein: The first reference signal sent by the first UE is at least one positioning reference signal.

40. The method of claim 39, wherein: The first reference signal sent by the first UE is a demodulation reference signal (DMRS) associated with the request to perform the positioning procedure.

41. The method of claim 36, wherein: The destination identifier in the request to perform the positioning procedure indicates that the second UE is expected to perform the positioning procedure with the first UE.

42. The method of claim 24, wherein: The request to perform the positioning procedure includes an indication that the second UE is expected to report to the first UE a time difference between reception at the second UE of a reference signal sent by the first UE and reception at the second UE of a reference signal sent by a third UE, the third UE participating in the positioning procedure together with the first UE.

43. The method of claim 42, wherein: The destination identifier in the request to perform the positioning procedure indicates that the second UE is expected to report the time difference between reception at the second UE of the reference signal sent by the first UE and reception at the second UE of the reference signal sent by the third UE.

44. The method of claim 24, wherein: The second UE encodes the indication of the time resources, frequency resources, or a set of both allocated for the positioning process in an SCI-2 message.

45. The method of claim 24, wherein: The first network entity is a base station or a location server, The second network entity is the base station or the location server.

46. ​​A first user equipment (UE), comprising: Memory; at least one transceiver; as well as at least one processor, communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: causing the at least one transceiver to send a request to perform a positioning procedure to the at least one second UE via a sidelink between the first UE and the at least one second UE, wherein the request is associated with at least one reference signal; receiving, from the at least one second UE via the sidelink, an indication of a set of time resources, frequency resources, or both allocated for the positioning procedure; and causing the at least one transceiver to send at least one positioning reference signal on the time resources, frequency resources, or a set of both allocated for the positioning process, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

47. The UE according to claim 46, wherein: The at least one processor being configured to cause the at least one transceiver to send the request includes the at least one processor being configured to cause the at least one transceiver to perform the following operations: sending a first sidelink control information (SCI-1) message via a physical sidelink control channel (PSCCH) of the sidelink, the SCI-1 being associated with second sidelink control information (SCI-2), the SCI-2 including the request to perform the positioning procedure; and The SCI-2 message is sent via the PSCCH of the sidelink.

48. The UE according to claim 47, wherein: The SCI-2 includes a one-bit field indicating that the SCI-2 includes the request to perform the positioning process.

49. The UE of claim 47, wherein: The SCI-1 is scrambled by the destination identifier, or The destination identifier is a field inside the SCI-2.

50. The UE according to claim 49, wherein: The destination identifier identifies a group of UEs including the at least one second UE.

51. The UE according to claim 49, wherein: The destination identifier indicates that the request to perform the positioning procedure is broadcast to all UEs within wireless communication range of the first UE.

52. The UE according to claim 46, wherein: The at least one processor being configured to cause the at least one transceiver to send the request includes the at least one processor being configured to cause the at least one transceiver to perform the following operations: A medium access control element (MAC-CE) is sent on a physical sidelink shared channel (PSSCH) of the sidelink, the MAC-CE including the request to perform the positioning procedure.

53. The UE according to claim 46, wherein: The at least one processor being configured to cause the at least one transceiver to send the request includes the at least one processor being configured to cause the at least one transceiver to perform the following operations: A demodulation reference signal (DMRS) associated with the request to perform the positioning procedure is transmitted through a physical sidelink shared channel (PSSCH) of the sidelink.

54. The UE according to claim 53, wherein: The request to perform the positioning procedure includes an indication that the DMRS is to be used for the positioning procedure.

55. The UE according to claim 46, wherein: The indication further indicates the number of the at least one reference signal; the time position, the frequency position, or both of the at least one reference signal; or both.

56. The UE according to claim 46, wherein: The request to perform the positioning procedure comprises an indication that the at least one second UE is expected to perform the positioning procedure with the first UE.

57. The UE according to claim 56, wherein: The positioning process includes a round trip time (RTT) positioning process.

58. The UE according to claim 57, wherein: The at least one processor is further configured to: A second reference signal and a parameter indicating a time difference between a reception of a first reference signal transmitted by the first UE at the second UE and a transmission time of the second reference signal are received from the at least one second UE.

59. The UE according to claim 58, wherein: The first reference signal sent by the first UE is the at least one positioning reference signal.

60. The UE according to claim 58, wherein: The first reference signal sent by the first UE is a demodulation reference signal (DMRS) associated with the request to perform the positioning procedure.

61. The UE according to claim 58, wherein: The at least one processor is further configured to: The absolute position of the first UE is estimated based at least on the time difference between the transmission of the first reference signal and the reception of the second reference signal, the parameter indicating the time difference between the reception of the first reference signal at the at least one second UE and the transmission time of the second reference signal, and the known position of the at least one second UE, wherein the at least one second UE includes multiple UEs.

62. The UE according to claim 58, wherein: The at least one processor is further configured to: The relative position of the first UE is estimated based at least on a time difference between transmission of the first reference signal and reception of the second reference signal, and the parameter indicating the time difference between reception of the first reference signal at the at least one second UE and the transmission time of the second reference signal.

63. The UE of claim 58, wherein: The first UE sends the first reference signal on a transmit beam, The second reference signal is transmitted by the at least one second UE on a transmit beam and received by the first UE on a receive beam, or Any combination thereof.

64. The UE of claim 58, wherein: The second reference signal is sent by the at least one second UE and received by the first UE in an omni-frequency range, and The first UE sends the reference signal in the omnidirectional frequency range.

65. The UE according to claim 56, wherein: The destination identifier in the request to perform the positioning procedure indicates that the at least one second UE is expected to perform the positioning procedure with the first UE.

66. The UE according to claim 46, wherein: The request to perform the positioning procedure includes an indication that the at least one second UE is expected to report to the first UE a time difference between reception of a reference signal sent by the first UE at the second UE and reception of a reference signal sent by a third UE at the second UE, the third UE participating in the positioning procedure together with the first UE.

67. The UE according to claim 64, wherein: The destination identifier in the request to perform the positioning procedure indicates that the at least one second UE is expected to report the time difference between reception at the second UE of the reference signal sent by the first UE and reception at the second UE of the reference signal sent by a third UE.

68. The UE according to claim 46, wherein: The indication of the time resources, frequency resources, or a set of both allocated for the positioning process is encoded in an SCI-2 message.

69. A second user equipment (UE), comprising: Memory; at least one transceiver; as well as at least one processor, communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receiving a request to perform a positioning procedure from the first UE via a sidelink between the second UE and the first UE, wherein the request is associated with at least one reference signal; causing the at least one transceiver to send the request to perform the positioning procedure to a first network entity; receiving from a second network entity an indication of a set of time resources, frequency resources, or both allocated for the positioning process; and causing the at least one transceiver to send the indication of the set of the time resources, frequency resources, or both allocated for the positioning process to the first UE via the sidelink, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

70. The UE according to claim 69, wherein: The at least one processor being configured to receive the request comprises the at least one processor being configured to: receiving a first sidelink control information (SCI-1) message via a physical sidelink control channel (PSCCH) of the sidelink, the SCI-1 being associated with a second sidelink control information (SCI-2), the SCI-2 including the request to perform the positioning procedure; and The SCI-2 message is received via the PSCCH of the sidelink.

71. The UE according to claim 70, wherein: The SCI-2 includes a one-bit field indicating that the SCI-2 includes the request to perform the positioning process.

72. The UE of claim 70, wherein: The SCI-1 is scrambled by the destination identifier, or The destination identifier is a field inside the SCI-2.

73. The UE according to claim 72, wherein: The destination identifier identifies a group of UEs including the second UE.

74. The UE according to claim 72, wherein: The destination identifier indicates that the request to perform the positioning procedure is broadcast to all UEs within wireless communication range of the first UE.

75. The UE according to claim 69, wherein: The receiving the request comprises: A medium access control element (MAC-CE) is received on a physical sidelink shared channel (PSSCH) of the sidelink, the MAC-CE including the request to perform the positioning procedure.

76. The UE according to claim 69, wherein: The at least one processor is further configured to: A demodulation reference signal (DMRS) associated with the request to perform the positioning procedure is received through a physical sidelink shared channel (PSSCH) of the sidelink.

77. The UE according to claim 76, wherein: The request to perform the positioning procedure includes an indication that the DMRS is to be used for the positioning procedure.

78. The UE according to claim 77, wherein: The at least one processor is further configured to: Positioning measurements of the DMRS are performed based on the indication that the DMRS is to be used for the positioning process.

79. The UE according to claim 77, wherein: The indication comprises a one-bit field in an SCI-1 received from the first UE via the sidelink.

80. The UE according to claim 69, wherein: The indication further indicates the number of the at least one reference signal; the time position, the frequency position, or both of the at least one reference signal; or both.

81. The UE according to claim 69, wherein: The request to perform the positioning procedure includes an indication that the second UE is expected to perform the positioning procedure with the first UE.

82. The UE according to claim 81, wherein: The positioning process includes a round trip time (RTT) positioning process.

83. The UE according to claim 82, wherein: The at least one processor is further configured to: The at least one transceiver is caused to transmit, to the first UE through the sidelink, a second reference signal and a parameter indicating a time difference between reception of a first reference signal transmitted by the first UE and transmission of the second reference signal at the second UE.

84. The UE according to claim 83, wherein: The first reference signal sent by the first UE is the at least one positioning reference signal.

85. The UE according to claim 84, wherein: The first reference signal sent by the first UE is a demodulation reference signal (DMRS) associated with the request to perform the positioning procedure.

86. The UE according to claim 81, wherein: The destination identifier in the request to perform the positioning procedure indicates that the second UE is expected to perform the positioning procedure with the first UE.

87. The UE according to claim 69, wherein: The request to perform the positioning procedure includes an indication that at least one second UE is expected to report to the first UE an indication of a time difference between reception of a reference signal sent by the first UE at the second UE and reception of a reference signal sent by a third UE at the second UE, the third UE participating in the positioning procedure together with the first UE.

88. The UE according to claim 87, wherein: The destination identifier in the request to perform the positioning procedure indicates that the second UE is expected to report the time difference between reception at the second UE of the reference signal sent by the first UE and reception at the second UE of the reference signal sent by the third UE.

89. The UE according to claim 69, wherein: The second UE encodes the indication of the time resources, frequency resources, or a set of both allocated for the positioning process in an SCI-2 message.

90. The UE of claim 69, wherein: The first network entity is a base station or a location server, The second network entity is the base station or the location server.

91. A first user equipment (UE), comprising: means for sending a request to perform a positioning procedure to at least one second UE via a sidelink between the first UE and the at least one second UE, wherein the request is associated with at least one reference signal; means for receiving, from the at least one second UE via the sidelink, an indication of a set of time resources, frequency resources, or both allocated for the positioning procedure; as well as means for sending at least one positioning reference signal on said time resources, frequency resources, or a set of both allocated for said positioning process, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

92. A second user equipment (UE), comprising: means for receiving a request to perform a positioning procedure from the first UE via a sidelink between the second UE and the first UE, wherein the request is associated with at least one reference signal; means for sending said request to perform said positioning procedure to a first network entity; means for receiving from a second network entity an indication of a set of time resources, frequency resources, or both allocated for said positioning procedure; as well as means for sending, via the sidelink, to the first UE, the indication of the time resources, frequency resources, or a set of both allocated for the positioning procedure, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

93. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising: directing a first user equipment (UE) to send at least one instruction of a request to perform a positioning procedure to at least one second UE via a sidelink between the first UE and the at least one second UE, wherein the request is associated with at least one reference signal; at least one instruction directing the first UE to receive, from the at least one second UE via the sidelink, an indication of a set of time resources, frequency resources, or both allocated for the positioning process; and at least one instruction directing the first UE to send at least one positioning reference signal on the time resources, frequency resources, or a set of both allocated for the positioning process, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

94. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising: directing a second user equipment (UE) to receive at least one instruction of a request to perform a positioning procedure from the first UE via a sidelink between the second UE and the first UE, wherein the request is associated with at least one reference signal; Instructing the second UE to send at least one instruction of the request to perform the positioning process to the first base station; at least one instruction directing the second UE to receive, from a second network entity, an indication of time resources, frequency resources, or a set of both allocated for the positioning procedure; and at least one instruction directing the second UE to send the indication of the time resources, frequency resources, or a set of both allocated for the positioning process to the first UE via the sidelink, The request to perform the positioning process includes an indication of whether the at least one reference signal associated with the request to perform the positioning process is to be used for positioning.

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