5G network side link positioning initialization

Abstract

A mechanism is disclosed for performing sidelink positioning between a target user equipment (UE) and an anchor UE, in which there is or is not interacted with a fifth generation radio access network (5G) base station (gNB), in which there is a mechanism for performing sidelink positioning between the target UE and the anchor UE. The mechanism includes sending a positioning request from a target UE to one or more anchor UEs over sidelink communication. A positioning signal is received from the one or more anchor UEs over the sidelink communication. Positioning measurements are performed based on the positioning signals.

Description

[0001] Cross-reference to related applications

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 336,046, filed on April 28, 2022, entitled “Method and Apparatus of Sidelink Positioning,” which is incorporated herein by reference. Technical Field

[0003] The present disclosure generally relates to fifth generation wireless access network (5G) network technologies, and specifically to the initialization of sidelink communications between an anchor user equipment (UE) and a target UE to support sidelink positioning, regardless of whether or not reliance is placed on a 5G network for resource communication allocation. Background Art

[0004] Some features associated with the fifth generation (5G) new radio access technology are being developed and standardized by the third-generation partnership project (3GPP). For example, one work item includes a request for 5G new radio (NR) vehicle-to-everything (V2X) wireless communication mechanisms, with the goal of providing 5G-compatible high-speed, reliable connections for vehicle communications. Summary of the invention

[0005] In one embodiment, the present disclosure includes a method implemented by a target user equipment (UE). The method includes sending a positioning request to one or more anchor UEs via sidelink communication. The method also includes receiving a positioning signal from one or more anchor UEs via sidelink communication. The method also includes performing positioning measurements based on the positioning signal. A UE (e.g., a vehicle, a phone, a computer, a tablet, an industrial device, or other wireless network-based computing device) may wish to determine a current location / positioning. In addition, these devices may move out of the network range, making it impossible for the network to provide a location / positioning to the UE using a positioning system. This aspect includes a mechanism for initiating sidelink positioning between an anchor UE and a target UE. Sidelink positioning is a mechanism that supports an anchor UE or a target UE to determine the location of a target UE relative to an anchor UE via sidelink communication between the target UE and the anchor UE, for example, without the need for direct interaction with a corresponding 5G network. One or more anchor UEs may indicate the willingness and ability of each UE to be an anchor UE via signaling. Then, the target UE may select one or more anchor UEs. The target UE and the anchor UE may reserve time and frequency communication resources for signaling via an opportunistic mechanism or via allocation by the 5G network. Then a positioning request is sent. The request may be sent by the target UE to one or more anchor UEs. In another example, the request may be sent by the anchor UE to the target UE. In another example, the anchor UE may act as a serving anchor UE and may send a request to the target UE and the coordinating anchor UE, or to the target UE to further communicate with the coordinating anchor UE. The anchor UE responds with positioning information upon receiving the request. In one example, the request is triggered by a condition. In other examples, the positioning information is sent based on the condition without the need for a request. Once the positioning information is sent, the target UE may measure the location of the target UE, or send the positioning information back to the anchor UE (e.g., the serving anchor UE) to support the anchor UE in measuring the location of the target UE. The positioning information from the coordinating UE may also be sent directly or via the target UE to the serving anchor UE. By using one or more of these mechanisms, the exchange of positioning information is triggered by sidelink communication (e.g., directly between UEs without the need for interaction with the 5G network). The UE can then determine the location of the target UE by measuring the positioning information without relying on the positioning system in the 5G network. Thus, the present mechanism enables the UE to perform beneficial functions, such as enabling a UE (eg, a vehicle) to determine its location even when out of network coverage.

[0006] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the target UE communicates with one or more anchor UEs according to perception-based resource selection of sidelink resources.

[0007] Optionally, according to any of the above aspects, in another implementation of this aspect, the target UE communicates with one or more anchor UEs through resource reservation provided by a fifth generation (5G) base station (gNB).

[0008] Optionally, according to any of the above aspects, in another implementation of this aspect, the positioning signal includes a sidelink positioning reference signal (SL-Pos-RS).

[0009] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: before sending the positioning request to the anchor UE, selecting one or more anchor UEs.

[0010] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: estimating the position of the target UE based on the positioning measurement and the position of one or more anchor nodes.

[0011] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: before sending the positioning request to the anchor UE, receiving an initial positioning request from the serving anchor UE through sidelink communication.

[0012] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: sending positioning measurements to the service anchor UE through sidelink communication to estimate the position of the target UE.

[0013] Optionally, according to any of the above aspects, in another implementation manner of this aspect, sending the positioning request is triggered by a condition.

[0014] Optionally, according to any of the above aspects, in another implementation of this aspect, the conditions include reference signal received power (RSRP) relative to a first threshold, distance relative to a second threshold, number of UE anchor points relative to a third threshold, channel conditions relative to a fourth threshold, or a combination thereof.

[0015] Optionally, according to any of the above aspects, in another implementation manner of this aspect, one or more anchor UEs are selected based on a UE anchor indication and a UE anchor level.

[0016] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the UE anchor indication indicates whether the corresponding UE is capable of serving as an anchor UE, and indicates whether the corresponding UE is allowed to serve as an anchor UE.

[0017] Optionally, according to any of the above aspects, in another implementation of this aspect, the UE anchor point level is set based on synchronization source, priority, positioning accuracy, maximum bandwidth, coverage range indicator, sidelink synchronization signal identifier (SLSSID) or a combination thereof.

[0018] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes reselecting one or more anchor UEs after obtaining the anchor UE position, channel measurement, timing measurement or a combination thereof.

[0019] In one embodiment, the present disclosure includes a method implemented by an anchor user equipment (UE). The method includes sending a positioning request to a target UE via sidelink communication. The method also includes receiving a positioning signal from the target UE via sidelink communication. The method also includes performing positioning measurements on the target UE based on the positioning signal. A UE (e.g., a vehicle, a phone, a computer, a tablet, an industrial device, or other wireless network-based computing device) may wish to determine a current location / positioning. In addition, these devices may move out of the network range, making it impossible for the network to provide a location / positioning to the UE using a positioning system. This aspect includes a mechanism for initiating sidelink positioning between an anchor UE and a target UE. Sidelink positioning is a mechanism that supports an anchor UE or a target UE to determine the location of a target UE relative to an anchor UE via sidelink communication between the target UE and the anchor UE, for example, without the need for direct interaction with a corresponding 5G network. One or more anchor UEs may indicate the willingness and ability of each UE to be an anchor UE via signaling. Then, the target UE may select one or more anchor UEs. The target UE and the anchor UE may reserve time and frequency communication resources for signaling via an opportunistic mechanism or via allocation by a 5G network. Then a positioning request is sent. The request may be sent by the target UE to one or more anchor UEs. In another example, the request may be sent by the anchor UE to the target UE. In another example, the anchor UE may act as a serving anchor UE and may send a request to the target UE and the coordinating anchor UE, or to the target UE to further communicate with the coordinating anchor UE. The anchor UE responds with positioning information upon receiving the request. In one example, the request is triggered by a condition. In other examples, the positioning information is sent based on the condition without the need for a request. Once the positioning information is sent, the target UE may measure the location of the target UE, or send the positioning information back to the anchor UE (e.g., the serving anchor UE) to support the anchor UE in measuring the location of the target UE. The positioning information from the coordinating UE may also be sent directly or via the target UE to the serving anchor UE. By using one or more of these mechanisms, the exchange of positioning information is triggered by sidelink communication (e.g., directly between UEs without the need for interaction with the 5G network). The UE can then determine the location of the target UE by measuring the positioning information without relying on the positioning system in the 5G network. Thus, the present mechanism enables the UE to perform beneficial functions, such as enabling a UE (eg, a vehicle) to determine its location even when out of network coverage.

[0020] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the anchor UE communicates with the target UE according to perception-based resource selection of the sidelink resources.

[0021] Optionally, according to any of the above aspects, in another implementation of this aspect, the anchor UE communicates with the target UE through resource reservation provided by a fifth generation (5G) base station (gNB).

[0022] Optionally, according to any of the above aspects, in another implementation of this aspect, the positioning signal includes a sidelink positioning reference signal (SL-Pos-RS).

[0023] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: estimating the position of the target UE based on positioning measurements.

[0024] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the positioning request indicates that the target UE sends one or more second positioning requests to one or more coordination anchor point UEs.

[0025] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the positioning signal from the target UE includes location information from one or more coordination anchor point UEs.

[0026] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: receiving location information from one or more coordination anchor UEs.

[0027] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: sending one or more second positioning requests to one or more coordination anchor point UEs.

[0028] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the positioning request is triggered by a condition.

[0029] Optionally, according to any of the above aspects, in another implementation of this aspect, the conditions include reference signal received power (RSRP) relative to a first threshold, distance relative to a second threshold, number of UE anchor points relative to a third threshold, channel conditions relative to a fourth threshold, or a combination thereof.

[0030] Optionally, according to any of the above aspects, in another implementation manner of this aspect, it also includes: sending a UE anchor indication, the UE anchor indication indicating whether the anchor UE is capable of acting as an anchor UE, and indicating whether the anchor UE is allowed to act as an anchor UE.

[0031] Optionally, according to any of the above aspects, in another implementation of this aspect, it also includes sending a UE anchor point level, and the UE anchor point level is set based on a synchronization source, priority, positioning accuracy, maximum bandwidth, coverage range indicator, sidelink synchronization signal identifier (sidelink synchronization signal identifier, SLSSID) or a combination thereof.

[0032] Optionally, according to any of the above aspects, in another implementation manner of the aspect, one or more anchor UEs are selected based on a line-of-sight (LOS) / non-line-of-sight (NLOS) indicator.

[0033] Optionally, according to any of the above aspects, in another implementation of this aspect, the sidelink positioning measurement report includes a line-of-sight (LOS) / non-line-of-sight (NLOS) indicator.

[0034] In one embodiment, the present disclosure includes a UE, which includes one or more processors, a transmitter coupled to the one or more processors, and a receiver coupled to the one or more processors, wherein the one or more processors, the transmitter, and the receiver are used to perform the method of any one of the above aspects.

[0035] In one embodiment, the present disclosure includes a non-transitory computer-readable medium, including a computer program product for use by a UE, the computer program product including computer executable instructions stored in the non-transitory computer-readable medium, and the computer executable instructions, when executed by one or more processors, cause the UE to perform any of the methods described above.

[0036] In one embodiment, the present disclosure includes a UE, the UE including a sending component for sending a positioning request to one or more anchor UEs via sidelink communication. The UE also includes a receiving component for receiving a positioning signal from one or more anchor UEs via sidelink communication. The UE also includes a measuring component for performing positioning measurements based on the positioning signal.

[0037] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the UE is also used to execute a method according to any of the above aspects.

[0038] In one embodiment, the present disclosure includes a UE, the UE including a sending component for sending a positioning request to a target UE via a sidelink communication. The UE also includes a receiving component for receiving a positioning signal from the target UE via the sidelink communication. The UE also includes a measuring component for performing positioning measurements on the target UE based on the positioning signal.

[0039] Optionally, according to any of the above aspects, in another implementation manner of this aspect, the UE is also used to execute a method according to any of the above aspects.

[0040] For clarity, any of the embodiments described above may be combined with any one or more of the other embodiments described above to create new embodiments within the scope of the present disclosure.

[0041] These and other features will become more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] For a more complete understanding of the present disclosure, reference is made to the following brief description, taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0043] Figure 1 is a schematic diagram of examples of within-network coverage operation and outside-network coverage operation using 5G network-compatible technology.

[0044] Figure 2 is a schematic diagram of exemplary resource pools in a resource grid for sidelink communications.

[0045] Figure 3 is a schematic diagram of an exemplary resource grid having physical sidelink control channel (PSCCH), physical sidelink shared channel (PSSCH) and physical sidelink feedback channel (PSFCH) resources.

[0046] Figure 4 It is a schematic diagram of an exemplary structure of a sidelink synchronization signal block (S-SSB).

[0047] Figure 5 is a schematic diagram of an exemplary uplink (UL) sounding reference signal (SRS).

[0048] Figure 6 is a schematic diagram of an exemplary downlink (DL) positioning reference signal (PRS).

[0049] Figure 7 is a schematic diagram of an exemplary perception and resource selection window.

[0050] Figure 8 is a schematic diagram of sidelink positioning.

[0051] Fig. 9 It is a schematic diagram of sidelink positioning triggered by the target UE.

[0052] Fig.10 It is a schematic diagram of sidelink positioning triggered by anchor UE.

[0053] Fig.11 is a flow chart of an exemplary method for request-triggered positioning at a target UE.

[0054] Fig.12 is a flow chart of an exemplary method for a hybrid process for positioning at an anchor UE.

[0055] Fig.13 is a flow chart of an exemplary method for a UE to determine and indicate an anchor point level to support UE anchor point selection.

[0056] Fig.14 is a flow chart of an exemplary method for anchor UE selection.

[0057] Fig.15 It is a schematic diagram of the anchor UE broadcasting a sidelink positioning reference signal (SL-Pos-RS) and location information.

[0058] Fig.16 is a schematic diagram of examples of line-of-sight (LOS) and non-line-of-sight (NLOS) sidelink positioning.

[0059] Fig.17 is a schematic diagram of an example of a positioning reference signal (PRS) resource set.

[0060] Fig.18 is a schematic diagram of an exemplary UL PRS resource configuration.

[0061] Fig.19is a schematic diagram of an exemplary sidelink synchronization signal block (S-SSB).

[0062] Fig. 20 is a schematic diagram of an exemplary UE for sidelink communication.

[0063] Fig.21 is a schematic diagram of an exemplary embodiment of a UE for sidelink positioning.

[0064] Fig. 22 is a flow chart of an exemplary method for performing sidelink based positioning in a target UE.

[0065] Fig.23 is a flow chart of an exemplary method for performing sidelink based positioning in an anchor UE. DETAILED DESCRIPTION

[0066] First, it should be understood that although illustrative implementations of one or more embodiments are provided below, the disclosed systems and / or methods can be implemented using any number of techniques, whether currently known or existing. The present disclosure is in no way limited to the illustrative implementations, drawings, and techniques described below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims and the full scope of their equivalents.

[0067] 3GPP provides the basis for NR sidelink communication for applications such as safety systems and autonomous driving. High data rate, low latency and high reliability are some of the areas of research and standardization. 3GPP also provides a sidelink enhancement work item to further enhance the capabilities and performance of sidelink communication. One of the goals of this work item is to introduce an inter-UE coordination mechanism where one UE shares preferred or non-preferred resources for another UE to use in its resource selection or sends a conflict indication to other UEs when there is a conflict on the reserved resources.

[0068] Another work item requests NR positioning support, which provides positioning support in 5G NR, including DL and UL reference signals for various positioning techniques (DL-TDOA, DL-AoD, UL-TDOA, UL-AoA, multi-cell RTT and E-CID), and UE and gNB measurements for NR positioning. Another work item requests NR positioning enhancements, with the goal of supporting high accuracy, low latency, network efficiency, and device efficiency requirements for commercial use cases. This work item involves methods, measurements, signaling, and procedures to improve positioning accuracy compared to other exemplary positioning methods. Research projects on extended and improved NR positioning include research on sidelink positioning schemes. This disclosure describes techniques and signaling to achieve sidelink positioning.

[0069] Figure 1 1 is a schematic diagram of an example 100 of in-coverage operation and out-of-coverage operation using 5G network compatible technology. Sidelink communication can be in-coverage communication or out-of-coverage communication. In in-coverage (IC) operation, there is a central node 101 such as a 5G base station (gNB) or a fourth-generation evolved Node B base station (eNB), and can be used to manage sidelink communications 103 between UEs 105. This is referred to as mode 1. In mode 2 operation, system operation is fully distributed, and UEs 105 select resources on their own to support sidelink communications 103 between UEs 105. In the present disclosure, some UEs may also be facilitated / assisted in selecting their resources. In mode 2, the UE may be in coverage or out-of-coverage (OOC).

[0070] Figure 2 2 is a schematic diagram of an exemplary resource pool 200 in a resource grid for sidelink communication. Resource pool 200 is a set of resources that can be used for sidelink communication. Resources in resource pool 200 are used for different channels, including control channels, shared channels, feedback channels, synchronization signals, reference signals, broadcast channels (e.g., master information blocks), etc.

[0071] The resource pool 200 of the side link can be configured in units of time slots in the time domain and in units of physical resource blocks (PRBs) or subchannels in the frequency domain. A subchannel includes one or more PRBs. Figure 2 An example of a resource pool 200 in a time-frequency resource grid is shown.

[0072] For NR mobile broadband (MBB), each PRB in the grid is defined as a slot of 14 consecutive orthogonal frequency division multiplexing (OFDM) symbols in the time domain and 12 consecutive subcarriers in the frequency domain. Accordingly, each resource block includes 12×14 resource elements (RE). When used as a frequency domain unit, a PRB is 12 consecutive subcarriers. When a normal cyclic prefix (CP) is used, a slot has 14 symbols, and when an extended cyclic prefix (ECP) is used, a slot has 12 symbols. The duration of a symbol is inversely proportional to the subcarrier spacing (SCS). For SCSs of {15, 30, 60, 120} kilohertz (kHz), the duration of the slot is {1, 0.5, 0.25, 0.125} milliseconds (ms), respectively. Each PRB can be allocated to a combination of a control channel (CCH), a shared channel (SCH), a feedback channel, a reference signal (RS), etc. In addition, some REs of a PRB can be reserved. Communication resources can occupy PRBs, PRB sets, and use codes (if code division multiple access (CDMA) is used, as in the physical uplink control channel (PUCCH)), physical sequences, RE sets, etc.

[0073] Figure 3300 is a schematic diagram of an exemplary resource grid 300 with PSCCH 301, PSSCH 303, and PSFCH 305 resources. PSCCH 301 carries sidelink control information (SCI). The source UE uses SCI to schedule data transmission on PSSCH 303. SCI can convey the time and frequency resources of PSSCH 303, parameters of the hybrid automatic repeat request (HARQ) process, such as redundancy version, process identifier (identifier, ID), new data indicator, and resources for PFSCH 305. PFSCH 305 can carry an indication of whether the receiving / destination UE correctly decoded the payload carried on PSSCH 303, such as HarQ positive acknowledgement (HARQ-ACK) (e.g., positive acknowledgement (ACK) or negative acknowledgement (NACK)). SCI can also carry a bit field indicating the representation of the identity of the source UE. In addition, the SCI may also carry a bit field indicating the representation of the identity of one or more destination UEs. Other fields include the modulation coding scheme (MCS) used to encode the payload and modulate the encoded payload bits; the demodulation reference signal (DMRS) mode, antenna port, and the priority of the payload (transmission).

[0074] NR sidelink control information (SCI) can be transmitted in the first-level SCI and the second-level SCI. The first-level SCI uses SCI format 1-A. The second level uses SCI format 2-A, SCI format 2-B or SCI format 2-C. The first-level SCI indicates the resources used for the second-level SCI.

[0075] SCI format 1-A is used to schedule PSSCH and the second level SCI on PSSCH. The following information is transmitted using SCI format 1-A:

[0076] – Priority - 3 bits

[0077] – Frequency resource allocation- When the value of the high-level parameter sl-MaxNumPerReserve is configured to 2 bit; otherwise, when the value of the higher-level parameter sl-MaxNumPerReserve is configured as 3, Bit.

[0078] – Time Resource Allocation - 5 bits when the value of the higher-layer parameter sl-MaxNumPerReserve is configured as 2; otherwise, 9 bits when the value of the higher-layer parameter sl-MaxNumPerReserve is configured as 3.

[0079] – Resource reservation period - If the higher-level parameter sl-MultiReserveResource is configured, bits, where N rsv_period is the number of entries in the higher-level parameter sl-ResourceReservePeriodList; otherwise, it is 0 bit.

[0080] –DMRS Mode- bits, where N pattern It is the number of DMRS patterns configured by the higher-level parameter sl-PSSCH-DMRS-TimePatternList; if sl-PSSCH-DMRS-TimePatternList is not configured, it is 0 bit.

[0081] – Second level SCI format - 2 bits.

[0082] – Beta_offset indicator - 2 bits, provided by the higher layer parameter sl-BetaOffsets2ndSCI.

[0083] –DMRS port number - 1 bit.

[0084] – Modulation and coding scheme – 5 bits.

[0085] – Additional MCS table indicator -: 1 bit if the higher-layer parameter sl-Additional-MCS-Table configures one MCS table; 2 bits if the higher-layer parameter sl-Additional-MCS-Table configures two MCS tables; otherwise, 0 bit.

[0086] –PSFCH Overhead Indication - 1 bit if higher layer parameter sl-PSFCH-Period = 2 or 4; otherwise 0 bit.

[0087] – Reserved - The number of bits determined by the higher layer parameter sl-NumReservedBits, whose value is set to zero.

[0088] SCI format 2-A is used to decode PSSCH and use HARQ operation when HARQ-ACK information includes ACK or NACK, or when no HARQ-ACK information is fed back. The following information is transmitted through SCI format 2-A:

[0089] –HARQ process number-

[0090] – New data indicator - 1 bit.

[0091] – Redundancy version - 2 bits.

[0092] – Source ID - 8 bits.

[0093] – Destination ID - 16 bits.

[0094] – HARQ feedback enable / disable indicator - 1 bit.

[0095] – Broadcast type indicator - 2 bits, as defined in Table 8.4.1.1-1.

[0096] – CSI request - 1 bit.

[0097] Table 8.4.1.1-1: Broadcast type indicator

[0098] The value of the broadcast type indicator Broadcast Type 00 broadcast 01 Multicast 10 Unicast 11 Reserve

[0099] SCI format 2-B is used to decode PSSCH and use HARQ operation when HARQ-ACK information includes only NACK or when no HARQ-ACK information is fed back. The following information is transmitted via SCI format 2-B:

[0100] –HARQ process number- Bit.

[0101] – New data indicator - 1 bit.

[0102] – Redundancy version - 2 bits.

[0103] – Source ID - 8 bits.

[0104] – Destination ID - 16 bits.

[0105] – HARQ feedback enable / disable indicator - 1 bit.

[0106] – Area ID - 12 bits.

[0107] – Communication range requirement - 4 bits.

[0108] SCI format 2-C is used to decode PSSCH and provide or request inter-UE coordination information. The following information is transmitted via SCI format 2-C:

[0109] –HARQ process number - 4 bits

[0110] – New data indicator - 1 bit

[0111] – Redundancy version - 2 bits.

[0112] – Source ID - 8 bits.

[0113] – Destination ID - 16 bits.

[0114] – HARQ feedback enable / disable indicator - 1 bit.

[0115] – CSI request - 1 bit.

[0116] – Provide / request indication - 1 bit, where a value of 0 indicates that SCI format 2-C is used to provide inter-UE coordination information, and a value of 1 indicates that SCI format 2-C is used to request inter-UE coordination information

[0117] High-level news

[0118] SL-PSCCH-Config-r16::=SEQUENCE{

[0119] sl-TimeResourcePSCCH-r16 ENUMERATED{n2,n3}OPTIONAL,--Need M

[0120] sl-FreqResourcePSCCH-r16 ENUMERATED{n10,n12,n15,n20,n25}OPTIONAL,--Need M

[0121] sl-DMRS-ScrambleID-r16 INTEGER(0..65535)OPTIONAL,--Need M

[0122] sl-NumReservedBits-r16 INTEGER(2..4)OPTIONAL,--Need M

[0123] …………

[0124] }

[0125]

[0126] If the Offer / Request Indicator field is set to 0, all remaining fields are set as follows:

[0127] – Resource combination – Bit, where

[0128] – If the high-level parameter sl-MultiReserveResource is configured, then and Nrsv_period is the number of entries in the higher-level parameter sl-ResourceReservePeriodList; otherwise Y = 0

[0129] – 38.214 is the number of subchannels in the resource pool provided by the higher-level parameter sl-NumSubchannel

[0130] - First resource position - 8 bits.

[0131] – Reference time slot position – Bit.

[0132] - Resource set type - 1 bit, where a value of 0 indicates a preferred resource set and a value of 1 indicates a non-preferred resource set.

[0133] – Lowest Subchannel Index – Bit.

[0134] If the Offer / Request Indicator field is set to 1, all remaining fields are set as follows:

[0135] - Priority - 3 bits. A value of "000" in the "Priority" field corresponds to a priority value of "1".

[0136] "001" corresponds to a priority value of "2", and so on.

[0137] –Number of sub-channels- Bit.

[0138] – Resource reservation period - If the higher-level parameter sl-MultiReserveResource is configured, bits, where N rsv_period is the number of entries in the higher-level parameter sl-ResourceReservePeriodList; otherwise, it is 0 bit.

[0139] – Resource selection window location – Bit.

[0140] – Resource set type - If the higher layer parameter determineResourceSetTypeScheme1 is configured as “UE-B’s request”, it is 1 bit, where the value 0 indicates a request to provide inter-UE coordination information of a preferred resource set, and the value 1 indicates a request to provide inter-UE coordination information of a non-preferred resource set, otherwise it is 0 bit.

[0141] – Padding bits.

[0142] The purpose of sidelink inter-UE coordination (IUC) is to improve the reliability of Mode 2 and overcome the problems of hidden nodes, exposed nodes, half-duplex, etc. that affect the sidelink performance. Specifically, two IUC schemes are defined, namely,

[0143] Solution 1: Inter-UE coordination information signaling from UE-A to UE-B

[0144] o Preferred resource set for UE-B transmission

[0145] o Non-preferred resource set for UE-B transmission

[0146] Solution 2: Inter-UE coordination information signaling from UE-A to UE-B

[0147] o There is an expected / potential resource conflict on the resources indicated by UE-B's SCI

[0148] In IUC Scheme 1, two IUC triggering scenarios are considered and specified. These scenarios include: (1) coordination triggered by explicit request, in which UE-B sends an explicit request to UE-A, and UE-A generates coordination information based on the request and sends the coordination information (sending a preferred resource set or a non-preferred resource set to UE-B); (2) coordination triggered by conditions other than explicit request, in which a UE (UE-A) that meets certain conditions generates coordination information and sends the coordination information to UE-B.

[0149] Conditions for both IUC triggering scenarios are specified. For IUC triggered by explicit request, one of two conditions is configured for resource pool level. These conditions include: Option 1 - until UE-B is implemented; Option 2 - the request can be triggered only when UE-B has data to transmit to UE-A. Similarly, for IUC triggered by condition, two conditions are used, one of which is enabled by resource pool level (pre-)configuration. These conditions include: Option 1 - until UE-A is implemented; Option 2 - coordination can be triggered only when UE-A has data to transmit to UE-B together with coordination information.

[0150] The generation standard of coordination information, where the preferred resource set and the non-preferred resource set are defined as follows:

[0151] ·Preferred resource set:

[0152] o Condition 1-A-1: The reference signal received power (RSRP) of one or more resources of other UEs, excluding one or more overlapping reserved resources, is greater than a threshold.

[0153] o Condition 1-A-2: When UE-A (as Rx of UE-B) does not expect to perform SL reception from UE-B, one or more resources other than time slots.

[0154] Non-preferred resource set:

[0155] o Condition 1-B-1: One or more reserved resources and RSRP measurements of other identified UEs.

[0156] ■ Option 1: One or more reserved resources of one or more other UEs identified by UE-A, the RSRP measurement of UE-A being greater than a (pre-)configured RSRP threshold.

[0157] ■ Option 2: When UE-A is the destination of a TB sent by one or more UEs, one or more reserved resources of other UEs identified by UE-A, the RSRP measurement of UE-A is less than a (pre-)configured RSRP threshold.

[0158] o Condition 1-B-2: One or more resources (e.g., one or more time slots) where SL reception is not expected from UE-B when UE-A is the intended recipient of UE-B.

[0159] To send explicit request and coordination information, the Medium Access Control Protocol (MAC) Explicit Request and Coordination Information (MAC-CE) is used as a container. If configured, the second level SCI (SCI-2C) is also used for explicit request or coordination information.

[0160] For coordination triggered by explicit request, the transmission of explicit request and coordination information only supports unicast. For coordination triggered by condition, the transmission of both coordination information supports unicast. Non-preferred resource sets only support broadcast and multicast.

[0161] Coordination information and explicit requests can be multiplexed with data transmission only if the source / destination ID pair is the same.

[0162] Figure 4 4 is a schematic diagram of an exemplary structure of an S-SSB block 400. The synchronization slot in the sidelink is represented as S-SSB 400 and is designated for one UE to synchronize with another UE. Figure 4As shown, the first OFDM symbol is used for PSBCH. But as in a regular sidelink slot, the first symbol is used for the establishment of automatic gain control (AGC). After that, there are 2 symbols for S-PSS and 2 symbols for S-SSS. 8 of the remaining 9 symbols are used for PSBCH transmission. The last symbol is the guard period (GP), the same as in a regular sidelink slot. PSBCH carries the SL master information block (SL-MIB).

[0163] In the frequency domain, S-SSB occupies 11 PRBs, a total of 132 subcarriers. PSBCH occupies all 11 PRBs, and the synchronization signal size is 127, so S-PSS and S-SSS occupy 127 subcarriers. The period of S-SSB is 160ms. The frequency position of S-SSB is preconfigured. For FR1, the number of S-SSB transmissions is set to 1, and for FR2, the number of S-SSB transmissions is configurable.

[0164] Figure 5 5 is a schematic diagram of an exemplary UL SRS 500. In NR, SRS resources for 1, 2, and 4 antenna ports are supported, and SRS resources can be mapped to Consecutive OFDM symbols. Supports each K in the frequency domain TC = 2 or 4 or 8 RE combined transmission. In addition, cyclic shift is supported. When the comb size is 2, 4 and 8, the maximum number of cyclic shifts is 8, 12 and 6 respectively. The SRS sequence ID is configured by high-level parameters. The starting OFDM symbol l0 in the time domain is offset by l relative to the end of the time slot. offset Definition, where l offset ∈{0,1,…,13} indicates that the starting position can be any OFDM symbol in the time slot. The frequency starting position is also specified. For positioning, an additional offset in the frequency domain is specified The offset also depends on the OFDM symbol configured for SRS transmission. SRS resources can be configured for periodic, semi-static or aperiodic SRS transmission. In the frequency domain, the SRS allocation is aligned with a 4PRB grid. Frequency hopping is supported, as is the case with long-term evolution (LTE). The NR SRS bandwidth and frequency hopping configuration are designed to cover a larger span of values ​​compared to LTE.

[0165] The SRS resource is configured by the SRS-Resource IE (for UL channel sounding) or by the SRS-PosResource IE (for positioning purposes). The UE can be configured with one or more SRS resource sets. For each SRS resource set, the UE can be configured with multiple SRS resources. The use cases of SRS resource sets are configured by high-level parameters. Such use cases may include beam management, codebook-based uplink MIMO and non-codebook-based uplink multiple input multiple output (MIMO), and antenna switching, which is actually used for general downlink CSI acquisition.

[0166] In the time domain at the time slot level, SRS resources can be periodically configured with a period (in units of time slots) (T SRS ) and time slot offset (T offset ).

[0167] Table 6.4.1.4.2-1: As K TC The maximum number of cyclic shifts of a function (TS 38.211)

[0168]

[0169] Table 6.4.1.4.3-2: As K TC SRS offset as a function of l′

[0170]

[0171] Figure 6 6 is a schematic diagram of an exemplary DL-PRS 600. A PRS is a downlink reference signal used for positioning. A PRS is also referred to as a DL-PRS 600, while an SRS configured for positioning is sometimes referred to as a UL-PRS 500.

[0172] DL-PRS 600 is designated with a start symbol The size of the PRS (the number of OFDM symbols) is L PRS ∈{2,4,6,12}, from The frequency domain spacing (comb tooth size) of two DL-PRS resource elements selected from a specified subset of combinations Initial frequency domain offset And similar to the UL-SRS used for positioning, an additional frequency domain offset k′ specified in the table (Table 7.4.1.7.3-1) varies from one OFDM symbol to another.

[0173] Table 7.4.1.7.3-1: As The frequency shift k′ of the function.

[0174]

[0175] In the time domain, at the time slot level, the DL-PRS 600 can be configured with a period and slot offset and additional slot offset The bandwidth of DL-PRS can be configured from 24 to 275 PRBs with a step size of 4 PRBs.

[0176] A 3GPP-based sidelink positioning solution is needed. Various use cases can benefit from SL positioning, such as vehicle to everything (V2x) and public safety use cases, ranging-based services, and industrial internet of things (IIoT) use cases.

[0177] The study project on extended and improved NR positioning includes the following objectives for SL positioning:

[0178] Study and evaluate the performance and feasibility of potential solutions for SL positioning, considering relative positioning, ranging and absolute positioning: [RAN1, RAN2]

[0179] o Evaluate the bandwidth requirements needed to meet the determined accuracy requirements [RAN1]

[0180] o Study positioning methods (e.g., TDOA, RTT, AOA / D, etc.), including the combination of SL positioning measurements with other RAT related positioning measurements (e.g., Uu based measurements) [RAN1]

[0181] o Study the sidelink reference signals for positioning purposes from the physical layer perspective, including signal design, resource allocation, measurement, association procedures, etc., and reuse existing reference signals and procedures in sidelink communication and positioning as much as possible [RAN1]

[0182] o Study the positioning architecture and signalling procedures (e.g. configuration, measurement reporting, etc.) to enable sidelink positioning, including UE-based positioning and network-based positioning [RAN2, including coordination and alignment with RAN3 and SA2 as required]

[0183] Now let's discuss the sidelink resource allocation. In NR V2X sidelink mode 1, the gNB performs scheduling for the sidelink. Accordingly, the gNB allocates SL resources for SL communication, which is sent to the UE via the NR Universal mobile telecommunications system terrestrial radio access network (UTRAN) to UE (Uu) interface. Therefore, sidelink mode 1 is applicable to UEs within the coverage of the gNB. The resources allocated by mode 1 can be on the same carrier as cellular NR or on a dedicated sidelink carrier.

[0184] There are three types of mode 1 resource allocation. They include dynamic allocation, type 1 configured grant (CG), and type 2 configured grant. In dynamic allocation, the UE first sends a scheduling request (SR) for each TB to the gNB through PUCCH. Then, the gNB sends the SL resource allocation to the UE through downlink control information (DCI) format 3_0 through the physical downlink control channel (PDCCH). In CG-based resource allocation, the UE first sends a message to the gNB including the expected SL traffic, including periodicity, traffic bandwidth (TB) maximum size, and quality of service (QoS) information. The gNB provides the resource allocation. The gNB provides the CG to the UE using radio resource control (RRC) signaling. In type 1 CG, the UE can use the resource allocation immediately. In type 2 CG, the UE uses the allocated resources after the gNB activates the allocated resources through DCI.

[0185] Figure 7 is a schematic diagram of an exemplary sensing and resource selection window 700. In sidelink mode 2, the UE can send and receive information without network management. The UE allocates resources from the resource pool for sidelink transmission. Resource allocation relies on the sensing and reservation process, such as Figure 7 As shown. During the sensing process, the monitoring UE detects the SCI sent in each time slot in the sensing window and measures the RSRP of the resources indicated in the SCI. The monitoring UE can also receive data transmissions and can therefore also be a receiving UE. For periodic traffic, resource reservation for sidelink transmissions can be used. When a UE occupies time slot s kWhen the UE uses the resources on the time slot s, the UE will also occupy the time slot s k +q*RRI k The resources on the k The interval is reserved for the resources of UE m detected by the sensing UE. Detecting SCI includes the steps of receiving and decoding PSCCH and processing SCI in PSCCH.

[0186] For aperiodic or dynamic transmissions, the transmitting UE reserves multiple resources and indicates the next resource in the SCI. Thus, based on the sensing results, the monitoring UE can determine which resources may be occupied in the future and avoid using these resources for its own transmission if the RSRP measured on the occupied resources during the sensing period is greater than the RSRP threshold in the resource exclusion process.

[0187] Figure 7 Figure 1 shows the timing information for sensing and resource selection of NR sidelink transmissions, referred to as full sensing. When resource selection is triggered on time slot n, the resource selection is triggered based on the sensing window (in time slots [n–T0, n–T proc,0 ]), the sending UE selects resources in the resource pool in the resource selection window (in time slot [n+T1, n+T2]), where

[0188] T0: time slot number with a value determined by the resource pool configuration;

[0189] T proc,0 : The time required for UE to complete the sensing process;

[0190] T1: The processing time required for candidate resource identification and resource selection, T1≤T proc,1 ;

[0191] T2: The last time slot of the resource pool used for resource selection, for UE implementation, but in [T 2min , PDB], where T 2min is the minimum value of T2, PDB represents the packet delay budget, i.e., the remaining time for the UE to send a data packet;

[0192] T proc,1 : The maximum time required for the UE to identify candidate resources and select new sidelink resources.

[0193] A variety of NP positioning methods can be used. NR positioning methods include DL-based schemes, UL-based schemes, and DL and UL-based schemes.

[0194] Now let’s discuss DL-based schemes. A timing-based technique called downlink time difference of arrival (DL-TDOA) can be used. Similar to observed time difference of arrival (OTDOA) in LTE, NR-specified DL-TDOA positioning measures the timing difference of DL-PRS on the line of sight (LOS) path from different gNBs. Downlink angle of departure (DL-AOD) is an example of an angle-based positioning technique used by the UE. In DL-AOD, the UE measures the received power based on the DL-PRS and estimates the angle of departure (AOD) from different gNBs based on the measured power difference between PRSs and / or beams from the same transmission and reception point (TRP).

[0195] Now let's discuss the UL based schemes. Uplink time difference of arrival (UL-TDOA) is an exemplary timing based technique. NR introduces UL positioning technology using UL positioning signal, which is configured through UL SRS. The gNB measures the UL timing difference from the UE. Uplink angle of arrival (UL-AOA) is an exemplary angle based technique. Similar to DL-AOD, the gNB measures the AOA of the UE using the UL SRS configured for positioning purposes. The gNB measures the zenith AOA and azimuth AOA to obtain a three-dimensional (3D) position.

[0196] Now let's discuss the DL-based scheme and the UL-based scheme. Multi-cell round trip time (multi-RTT) is an exemplary timing-based technique. In multi-RTT, the UE measures the UE receive-transmit (Rx-Tx) time difference, and the gNB measures the gNB Rx-Tx time difference. For each UE-gNB pair, two Rx-Tx time differences can be used to estimate the round trip time (RTT). For Rx-Tx time difference measurement, DL PRS and UL SRS are configured and sent by the gNB and UE, respectively. Enhanced cell-ID (E-CID) is a positioning technique based on radio resource management (RRM) measurements (such as RSRP and resource signal received quality (RSRQ)) through synchronization signals (such as SSB measurements and channel state information reference signal (CSI-RS)). UL AOA is also supported.

[0197] Positioning method selection, configuration of reference signals (SRS, PRS) and collection of measurements are orchestrated by the location management function (LMF) residing in the network. The LMF manages the target UE's support for different location services, including the positioning of the UE and the delivery of auxiliary data to the UE. The LMF can interact with the serving gNB or serving ng-eNB of the target UE to obtain positioning measurements for the UE. These positioning measurements include uplink measurements performed by the next generation radio access network (NG-RAN) and downlink measurements performed by the UE, which are provided to the NG-RAN as part of other functions (e.g., to support handover).

[0198] Figure 8 800 is a schematic diagram of sidelink positioning. Various procedures are used for radio access technology (RAT) related positioning in cellular systems. For NR positioning, the functions and procedures are similar to those used in LTE. NR introduces some techniques and UL reference signals. However, for SL positioning, the procedures and reference signaling are not yet defined.

[0199] like Figure 8As shown, the sidelink positioning 800 system may include multiple position reference UEs, represented as anchor UE 801 and target UE 803. The sidelink positioning 800 obtains the position of the target UE 803 based on the position information of the anchor UE 801 through reference signal measurement exchanged between the target UE 803 and the anchor UE 801. The reference signaling used for SL positioning measurement is represented as SL positioning reference signal (SL Pos-RS) 805.

[0200] In NR positioning, DL and UL positioning signaling are well synchronized and organized. The network can provide configuration and measurement reports of signaling (e.g. DL PRS or UL SRS) used for positioning. Unlike NR's Uu link, sidelink transmission is opportunistic and multiple transmit and receive links coexist in the same resource pool. Sidelink transmission is based on resource reservation to minimize the impact of resource allocation conflicts between different UE-to-UE links (resource allocation conflicts will cause interference). Resource reservation is centrally planned by the gNB under the coverage of the gNB (mode 1) or achieved through UE sensing in mode 2. Therefore, in the sidelink, the positioning process and resource allocation are different. In this article, the process and / or protocol design of SL positioning and reference signal configuration are provided.

[0201] This article discloses a mechanism for initiating sidelink positioning between an anchor UE and a target UE. Sidelink positioning is a mechanism that supports an anchor UE or a target UE to determine the position of a target UE relative to an anchor UE through sidelink communication between the target UE and the anchor UE, for example, without the need for direct interaction with the corresponding 5G network. One or more anchor UEs may indicate the willingness and ability of each UE to be an anchor UE through signaling. Then, the target UE may select one or more anchor UEs. The target UE and the anchor UE may reserve time and frequency communication resources for signaling through an opportunistic mechanism or through allocation of the 5G network. Then a positioning request is sent. The request may be sent by the target UE to one or more anchor UEs. In another example, the request may be sent by the anchor UE to the target UE. In another example, the anchor UE may act as a serving anchor UE and may send a request to the target UE and the coordinating anchor UE, or to the target UE, to further communicate with the coordinating anchor UE. Upon receiving the request, the anchor UE responds with positioning information. In one example, the request is triggered by a condition. In other examples, the positioning information is sent based on the condition without the need for a request. Once the positioning information is sent, the target UE can measure the position of the target UE, or send the positioning information back to the anchor UE (e.g., the serving anchor UE) to support the anchor UE in measuring the position of the target UE. The positioning information from the coordinating UE can also be sent to the serving anchor UE directly or through the target UE. By using one or more of these mechanisms, the exchange of positioning information is triggered by sidelink communication (e.g., directly between UEs without the need for interaction with the 5G network). The UE can then determine the position of the target UE by measuring the positioning information without relying on the positioning system in the 5G network. Therefore, the present mechanism enables the UE to perform beneficial functions, such as supporting a UE (e.g., a vehicle) to determine its position even when it is out of network coverage.

[0202] SL resources are required for SL Pos-RS, exchange of positioning information and measurement reports. In order to achieve a certain positioning accuracy, sufficient bandwidth should be allocated to SL Pos-RS, especially for timing-based positioning techniques. Therefore, SL positioning should be on-demand, or an on-demand process. Otherwise, the resource pool will be occupied by unnecessary reference signal transmission and information exchange, which will increase the system load and cause a large number of resource conflicts.

[0203] In addition, to reduce potential resource conflicts, sidelink inter-UE coordination is specified. In coordination scheme 1, UE (UE-A) provides coordination information, such as preferred resource sets or non-preferred resource sets, to help other UE (UE-B) select appropriate resources for its transmission. Coordination can be triggered by an explicit request from UE-B or when a certain condition is met at UE-A.

[0204] The following is an exemplary design of a sidelink positioning system that may be triggered by request or condition.

[0205] Six NR RAT-related positioning methods are used, namely DL-TDOA, DL-AOD, UL-TDOA, UL-AOA, multi-RTT, and E-CID. For sidelink communications, timing-based techniques can also be applied. Since there is no DL or UL, the sidelink DL-TDOA and UL-TDOA techniques can be summarized as SL time difference of arrival (SL-TDOA). However, as Figure 8 As shown, the location of the target UE may be requested and estimated at the target UE 803 and the anchor UE 801. Since the information exchange and positioning signals are in different directions, additional procedures will be described.

[0206] Multi-RTT is also an efficient positioning technology that needs to be considered for the sidelink. Since multi-RTT-based positioning does not require synchronization, multi-RTT-based positioning can facilitate sidelink positioning considering that no synchronization is required between anchor UEs.

[0207] E-CID is a positioning method that only requires signal strength measurements (such as RSRP and RSRQ). For the sidelink, a process based on RSRP measurements can be specified for SL positioning. For the purpose of description, this disclosure refers to this sidelink positioning technology as enhanced sidelink-ID (E-SID).

[0208] For angle-based techniques, the measurement and estimation of angles (i.e., AOD and AOA) may not be accurate enough for positioning because a maximum of two antenna ports are supported in the sidelink. Although angle-based positioning techniques may be associated with certain shortcomings in the sidelink supported by existing specifications based on the number of antenna ports, the design of the positioning process or protocol and positioning signaling can also be applied to angle-based positioning techniques.

[0209] Now let's discuss the sidelink positioning process. First, let's discuss the indication of the anchor UE 801. The anchor UE 801 serves as a reference UE with a known position. A UE that supports sidelink positioning and can serve as the anchor UE 801 for the positioning function may be the anchor UE 801. Since there may be multiple positioning technologies, the anchor UE may support one or more positioning technologies. The target UE 803 may request positioning reference signaling, location information, or measurement from the anchor UE 801. In one embodiment, the anchor UE 801 (or positioning reference UE) indicates to another UE that it may be the anchor UE 801.

[0210] If the UE is capable of acting as an anchor UE 801, the UE may not always wish to act as an anchor UE 801. For example, the UE may not meet certain conditions for becoming an anchor UE 801. Therefore, an indication of the anchor UE 801 may be used. For example, the UE may indicate whether it can be an anchor UE 801 for sidelink positioning through periodic, semi-static, or dynamic signaling. In order to achieve better positioning accuracy, the target UE 803 may be synchronized with the anchor UE 801. However, this is not necessary for some positioning methods such as multi-RTT. SL synchronization may be achieved through S-SSB. Since the S-SSB is sent periodically, the UE may indicate that it can be an anchor UE 801 or that it can be positioned as an anchor UE 801 through one or more reserved bits in the SL-MIB carried in the PSBCH transmitted in the S-SSB. For example, a reserved bit in the SL-MIB in the S-SSB may indicate whether the UE can be an anchor UE 801. Here, the indication can be used to indicate both cases, including whether the UE is able to become an anchor UE and whether the UE is willing to become an anchor UE. The effective duration of the indication in the S-SSB can be the S-SSB transmission period (e.g., 160ms), some other specified value (e.g., before the next S-SSB transmission), or a configured or preconfigured value. Alternatively, in order to achieve a more dynamic indication, the UE can use the reserved bits in SCI format 1-A. The indication can also be provided through RRC signaling.

[0211] The anchor indication can be enabled / disabled by (pre)configuration, which is mainly used for dynamic indication, for example, using reserved bits in S-SSB or PSCCH SCI-1A. This indication is complementary to the signaling of UE capabilities.

[0212] The anchor point availability indication and support for specific positioning methods / techniques can be indicated in a variety of ways. For example, the anchor point indication can be used for all supported SL positioning technologies. Alternatively, it can be specified as a subset of positioning technologies, such as timing-based and / or angle-based technologies. In E-SID positioning based on signal strength measurement (e.g., RSRP), dynamic indications may not be used. The capability signaling exchange of UE characteristics between the target UE 803 and the anchor UE 801 can be used for signaling as described above. RTT-based ranging or multi-RTT-based positioning can use more signaling interactions, such as Rx-Tx time difference measurement. RTT-based capabilities are different from timing-based technologies. The indication can be different. The indication may be different for different positioning technologies. If there is a separate indication, more bits should be specified. Examples of these indications can be bitmaps, table entry indications, each combination, etc.

[0213] The sidelink positioning process and SL Pos-RS transmission are now discussed. The positioning technique uses the transmission of a positioning reference signal. For the Uu link, the reference signal can be configured by the network and broadcast to each UE or gNB connected to the network. However, the reference signal in the SL may require resource reservation. For example, the SL CSI-RS transmitted together with the PSSCH and CSI-RS is only used for unicast communication. For positioning, the sidelink Pos-RS transmission may require SL resource reservation even if there is no data to be transmitted. Since the positioning request may be on-demand, this may require a trigger from the target UE or anchor UE, so the triggering process enhances the process for inter-UE coordination. The process of sidelink positioning is discussed below, for example based on SL Pos-RS transmission. The present disclosure describes a scenario where the positioning estimation is at the target UE 803. The proposed design and scheme can also be applied to the scenario where the positioning estimation is performed at the anchor UE 801.

[0214] Now let's discuss the triggering of the sidelink Pos-RS transmission. UE-B can trigger coordination by sending an explicit request to UE-A, and UE-A will provide UE-B with coordination information including a preferred resource set or a non-preferred resource set for resource selection of UE-B. Coordination can also be triggered by a condition at UE-A. When the condition is met, UE-A generates coordination information and sends the coordination information to UE-B. In SL positioning, the target UE 803 or the anchor UE 801 can trigger the SL positioning process, which initiates the transmission of SLPos-RS and the corresponding information exchange. The information exchange may include location information from the anchor UE 801 to the target UE 803, or measurements from the anchor UE 801 to the anchor UE 801 that performs position estimation of the target UE 803. Several examples of triggering the sidelink positioning process or specifically transmitting SL Pos-RS signaling are given below.

[0215] Fig. 9 is a schematic diagram of sidelink positioning 900 triggered by a target UE 903. Sidelink positioning and SL Pos-RS transmission may be triggered by an explicit request 905. The explicit request 905 may be sent from the target UE 903 or the anchor UE 901, depending on which device performs the positioning or timing / angle measurements.

[0216] like Fig. 9As shown, when the target UE performs positioning or measurement, the target UE 903 may send an explicit request 905 and an SL Pos-RS for positioning to the anchor UE 901. Through the indication of the presence of the anchor UE 901, the target UE 903 may know the availability of the anchor UE 901 and select a group of UEs as the anchor UE 901 for the positioning request of the target UE 903. Not all UEs indicated as anchor UEs 901 may or need to be selected by the target UE 903. The selection may be based on certain criteria. In order to achieve a certain positioning reliability, the synchronization (sync) source of the anchor UE 901 may be important. The UE may have certain requirements for the synchronization source or position accuracy, thereby supporting the UE to indicate whether the UE can be the anchor UE 901. The target UE 903 may have different or more stringent requirements for the selection of the anchor UE 901. In addition, the target UE 903 may select the anchor UE 901 based on the channel conditions between the target UE 903 and the anchor UE 901. For example, the target UE 903 may select a UE with a clear main LOS channel path as the anchor UE 901. For example, for a multipath channel, when one path is significantly stronger than all other paths, the anchor UE 901 may be selected. The threshold for LOS determination may use the power difference for path comparison and may be preconfigured. The non-line-of-sight (NLOS) channel of the target UE 903 may introduce errors in position determination, so a corresponding anchor UE 901 may be given a lower priority in anchor selection.

[0217] Fig.10 1000 is a schematic diagram of sidelink positioning 1000 triggered by an anchor UE 1002. In one example, the anchor UE may initiate a positioning process. The anchor UE may act as a serving anchor UE 1002, may send an explicit positioning request 1005 to a target UE 1003, and may request the transmission of an SL Pos-RS. At the same time, the anchor UE 1002 may send different requests 1007 to other anchor UEs 1001 to coordinate measurements. Such other anchor UEs 1001 may also be referred to as coordinating anchor UEs. This is not necessary when ranging is performed only between the anchor UE 1002 and the target UE 1003.

[0218] The request can be sent from the serving anchor UE 1002 to the target UE 1003 in one of the three alternative ways as described above. The 1-bit trigger request can be used to initiate a (pre-)configured S-SSB, SL CSI-RS transmission, a (pre-)configured SL PRS, or a (pre-)configured SL SRS (as SL-Pos-RS) from the target UE 1003. The request through the second-level SCI or MAC-CE can trigger SL Pos-RS transmission at the target UE 1003 through some settings (such as signaling options, SL Pos-RS configuration, bandwidth, SL Pos-RS power control, etc.). In the present disclosure, the term anchor UE can be equivalent to the term anchor node, because many devices, such as road side units (RSUs), can be used as anchors for position determination.

[0219] When performing position estimation at the serving anchor UE 1002, the serving anchor UE 1002 may send a request to another anchor UE 1001. The anchor UE 1002 that needs to estimate the position of the target UE 1003 may send a request in the capacity of the node as the serving anchor UE 1002.

[0220] The participating anchor UEs 1001 may then send their locations to the serving anchor UE 1002 and also report their measurements to the serving anchor UE 1001. When the anchor UE 1001 is a UE with a fixed location (e.g., an RSU), the location information may be exchanged only once, even if the UE indicates that it cannot act as an anchor UE 1001 at this time. For UEs with low mobility and slowly changing locations, location information may be exchanged semi-statically, for example, via a direct communication interface (PC5) RRC. For UEs with rapidly changing locations, location information should be exchanged or updated to / from the serving anchor UE 1002 dynamically or with a smaller period. In one example, the period of information exchange is related to the speed or Doppler spread of the RS. For example, when the RS has a large Doppler spread, frequent information exchange may be performed. The precise mapping between Doppler values ​​and periods may be (pre)configured and provided via a positioning request 1005 and / or a positioning coordination request 1007. In order to achieve positioning accuracy, location information should be acquired when the anchor UE 1001 performs measurements, and the location information should be sent to the serving anchor UE 1002 dynamically.

[0221] Fig.111 is a flow chart of an exemplary method 1100 for triggering positioning at a target UE by a request. In step 1101, the target UE selects one or more anchor UEs. In one example, there is a metric (e.g., a number between 0 and 1) to characterize the LOS / NLOS degree of the channel. The selection of the anchor point can be done by combining the RSRP of the positioning RS, the LOS / NLOS metric and other criteria (region, reference synchronization, mobile indicator, speed, Doppler spread, etc.).

[0222] Once the anchor UE is selected, the target UE may send a positioning request to one or more anchor UEs in step 1103. The request may be triggered simply by a 1-bit indication. A reserved bit of the first-level SCI (e.g., SCI 1A) may be used for such an indication, or a 1-bit in the second-level SCI may be used for such an indication. The request may also be sent by the second-level SCI to convey more information, such as SL Pos-RS signaling options and / or configurations. In another example, the MAC-CE may send a request to obtain more information, including SL Pos-RS signaling options and / or configurations, and / or preferred resources for SL Pos-RS transmissions. The request may be implemented via RRC signaling.

[0223] A 1-bit trigger request may be used for S-SSB or SL CSI-RS transmission preconfigured by the anchor UE, SL PRS or SLSRS (as SL Pos-RS), default SL Pos-RS configuration, or semi-static RRC configuration at the anchor UE. For the second level, SCI or MAC-CE may be used as a container for positioning requests and may carry more bits. Thus, SL Pos-RS signaling options, SL Pos-RS configuration, bandwidth, SL Pos-RS power control, etc. may be sent in the request.

[0224] The SL Pos-RS configuration can be dynamic or semi-static and can be sent by the target UE in the request or through RRC signaling. The trigger can be dynamic or semi-static. Typically, physical layer (PHY) signals, such as 1-bit request, second-level SCI, and MAC-CE, can be considered dynamic triggers, while RRC signaling is semi-static. A hybrid approach is that the configuration can be sent to the anchor UE through RRC signaling or MAC-CE. When the target UE determines that its position is to be estimated, the target UE sends an explicit request to the anchor UE.

[0225] In a different example, a trigger bit is sent to a group of UEs via multicast. In addition to the trigger bit, a response condition may also be provided. Potential anchor nodes will only participate if the provided conditions (e.g., conditions related to RSRP, synchronization source, area ID, etc.) are met.

[0226] In step 1105, all anchor UEs send SL Pos-RS signals in response to the positioning request sent in step 1103. Then, the target UE can perform positioning measurements based on the SL Pos-RS signals. Then, the target UE can estimate its position based on the measurements of step 1107.

[0227] Fig.12 1 is a flow chart of an exemplary method 1200 for a hybrid process for positioning at an anchor UE. A hybrid mode for positioning using an anchor UE is now described. In step 1201, the serving anchor UE may send a request to the target UE. In step 1203, the target UE first sends a request to other coordination anchor UEs. Then, in step 1205, the coordination anchor UE may participate and send SL Pos-RS to the target UE. The target UE may perform positioning measurements. Then, in step 1207, the target UE sends a measurement report to the serving anchor UE. In some examples, the coordination anchor UE may send its location information directly to the serving anchor UE. In other examples, the coordination anchor UE sends its location information to the target UE. Then, in step 1207, the target UE sends the location information of the coordination anchor to the serving anchor UE together with the measurement report in one or a separate transmission.

[0228] Now let's discuss the positioning conditions triggered by explicit requests. Certain conditions can be specified for the target UE or anchor UE to trigger the positioning procedure or SL-only Pos-RS transmission. One or more conditions triggering the explicit request can be set as a resource pool level (pre) configuration. One or more of the following alternatives can be enabled or disabled as conditions for triggering the explicit request.

[0229] In one example, an explicit request is triggered according to the implementation of the UE (target UE or anchor UE). In another example, the generation of the request can be triggered by one or more RSRP measurements greater than a threshold. RSRP measurements can be performed between the target UE and the serving anchor UE. In another example, the distance can trigger an explicit request. For example, the distance can be determined based on an area ID (e.g., included in SCI format 2-B) indicating the location of the target UE itself and the location of the anchor UE and / or its changes. The center or edge of the area can be estimated based on historical communications (e.g., based on the time the target UE stays in the same area). In another example, the number of possible anchor nodes can be greater than the threshold for triggering an explicit request. This condition indicates whether SL positioning is feasible or whether basic limitations on positioning accuracy are met. This can be a sufficient condition for SL positioning. It should be noted that these conditions depend on the positioning target, such as absolute positioning or ranging. Conditions related to the number of possible anchor nodes relative to the threshold can be applied to positioning. For example, one anchor UE is sufficient to support ranging.

[0230] Sidelink positioning can also be triggered based on conditions other than explicit requests. In some scenarios, the UE may perform positioning periodically or when some conditions are met. Therefore, the anchor UE or the target UE may send the SL Pos-RS when the condition is triggered. One example is that in some areas, the RSU may send the SL Pos-RS when the target UE appears or is within a certain range. Another example is network physical control in a smart factory. In some working areas or in order to perform a certain task, the target UE may need to estimate its position, or the anchor UE may need to estimate the position of the target UE. In these scenarios, it may not be necessary to trigger the SL positioning process by a request. In addition, sidelink positioning can also be triggered by conditions. For sidelink positioning triggered by conditions, the SL Pos-RS setting can be (pre) configured or determined by the UE implementation. The SL Pos-RS power control can be specified or determined by the UE sending the SL Pos-RS.

[0231] Similar to the conditions for SL positioning request, the conditions for SL Pos-RS transmission can be (pre-)configured at the resource pool level, which can enable and / or disable one or more of the conditions listed below.

[0232] In one example, the condition for triggering SL Pos-RS transmission depends on the implementation of the UE (target UE or anchor UE). In another example, SL Pos-RS transmission can be triggered by one or more RSRP measurements greater than a threshold. RSRP measurements can be performed between the target UE and the serving anchor UE. In another example, distance can trigger SL Pos-RS transmission. For example, the distance can be determined based on an area ID indicating the location of the target UE itself and the location of the anchor UE and / or its changes. In another example, the anchor UE may consider its position accuracy to be a key condition for the anchor UE to become an anchor UE. Position accuracy can be determined based on the synchronization source used by the anchor UE. Accordingly, changing the position accuracy can trigger or disable SL Pos-RS transmission. In another example, the channel condition between the anchor UE and the target UE can trigger or disable SL Pos-RS transmission. The channel condition between the anchor UE and the target UE can be determined based on a LOS channel with a main LOS path.

[0233] Once the enabling conditions are met, the anchor UE or target UE (as UE-A) sends the SL Pos-RS. The above conditions may also depend on the positioning scenario, such as absolute positioning, ranging and / or positioning technology. For RTT-based ranging used to determine the varying positioning accuracy, the positioning accuracy of the anchor UE or other reference UEs may not be necessary.

[0234] Now let's discuss a hybrid approach of request-based and condition-based. Instead of triggering SL positioning through explicit request or condition-based, a hybrid approach can be adopted. As described above, the target UE can send a positioning request including SL Pos-RS transmission to the anchor UE, or the serving anchor UE can send a positioning request to the target UE. However, the anchor UE or the target UE may not send the SL Pos-RS immediately. Instead, the anchor UE or the target UE can start sending the SL Pos-RS and / or sending measurement reports only when one or more conditions set for positioning are met.

[0235] The method or container of the request can be any of the methods discussed above.Similarly, one or more conditions of condition-based positioning can be applied in this hybrid approach.

[0236] Now let's discuss the location information of the anchor / reference UE. In NR positioning, the base station location information is sent to the UE through the system information block (SIB) message. But there is no SIB message for SL. The location information of the anchor UE should be delivered to the target UE or the serving anchor UE by other means. The anchor UE can reserve resources independently and send its location information to other UEs through unicast, multicast or broadcast. The location information can be multiplexed with the SL Pos-RS transmission.

[0237] The location information of the UE may be private information. The UE may need approval to share the location information with other UEs. This may be used as an indication of an anchor UE. If necessary, approval for the UE to share its location may be a prerequisite for the UE to become an anchor UE. Only when the UE agrees to share its location information can the UE indicate to other UEs that it may be an anchor UE.

[0238] Now let's discuss the sidelink positioning reference source (SLPos-RS). SL Pos-RS can be used to represent a general positioning reference signal. Each technology can use a different positioning signal. Several reference signals are specified. Among them, suitable reference signals for positioning can be synchronization signals or general S-SSB and SL CSI-RS. In the E-SID positioning technology, these two reference signals are sufficient for RSRP or RSSI measurements. For timing or angle estimation, additional positioning signals for SL may be useful. These reference signals and potential configurations are now discussed.

[0239] As described above, the period of the S-SSB with the SL synchronization signal can be set to 160ms. The number of S-SSB transmissions per period is (pre)configured. The following number of S-SSB transmissions within a period has been specified for (pre)configuration, which is related to the SCS and related to the frequency band.

[0240] For FR1:

[0241] oFor 15kHz SCS, {1}

[0242] oFor 30kHz SCS, {1, 2}

[0243] oFor 60kHz SCS, {1, 2, 4}

[0244] For FR2:

[0245] oFor 60kHz SCS, {1, 2, 4, 8, 16, 32}

[0246] oFor 120kHz SCS, {1, 2, 4, 8, 16, 32, 64}

[0247] In addition to the number of transmissions within a 160ms period, the transmission of an S-SSB is based on two settings, the offset slot of the first S-SSB and the slot interval between two consecutive S-SSBs, which can be (pre)configured. In addition to these settings, the number of periods in which the S-SSB is transmitted can also be configured. In summary, the following is a list of configuration parameters, one or more of which can be considered for SL positioning.

[0248] Number of transmissions

[0249] The time slot offset of the first S-SSB transmission in a cycle

[0250] The interval between two consecutive S-SSBs

[0251] Transmission cycle

[0252] In addition, for the purpose of SL positioning, the following contents can also be introduced.

[0253] Time domain repetition: repeated S-SSB transmissions, for example, multiple S-SSB transmissions within each S-SSB transmission.

[0254] Frequency domain repetition: Multiple S-SSB transmissions are performed on different PRB sets in the configured S-SSB slot.

[0255] Typically, the configuration of S-SSB cannot be changed dynamically. For positioning purposes, the following methods can be used for the configuration of S-SSB transmissions.

[0256] These configurations are provided in the request message.

[0257] Two pre-configured sets of S-SSBs. Once positioning is triggered, the S-SSBs configured for positioning are sent.

[0258] oS-SSB for synchronization and PSBCH

[0259] o S-SSB is used for other purposes, such as positioning

[0260] Various (pre-) configurations of S-SSB. When positioning is triggered, S-SSB is sent according to a (pre-) configuration used for positioning.

[0261] This configuration can be selected by request or by the UE itself.

[0262] o Various configurations can mitigate S-SSB collisions because for positioning, S-SSBs are sent from multiple anchor UEs in a short period (e.g., within a 160ms period).

[0263] Now let's discuss SL CSI-RS. In order to improve the transmission efficiency of SL, the Rx UE uses the CSI-RS signal to measure the sidelink channel quality to achieve link adaptation. The CSI-RS of the sidelink is the same as the CSI-RS of the Uu link, such as the CSI-RS pattern. However, in the sidelink, the CSI-RS is sent on the resources of the scheduled PSSCH. Therefore, it is multiplexed with the coded transport block. Since the transmission of SL data is based on resource reservation, the multiplexed CSI-RS transmission can avoid conflict with the CSI-RS transmission of other UEs.

[0264] In SL, the number of antenna ports used for CSI-RS is a maximum of 2. For SL positioning, only one antenna port is used for SL Pos-RS transmission, unless the two antenna ports are not considered to be co-located. In this case, both can be used as positioning references. The transmission and configuration of SL PRS can modify the existing positioning configuration / process described below.

[0265] Now let's discuss SL Pos-RS based on DL SRS or UL SRS for positioning (SL PRS or SL SRS). Since S-SSB has a smaller bandwidth and CSI-RS has a lower density, they may not be suitable as SL Pos-RS for timing-based or angle-based positioning measurements. A different SL Pos-RS may be needed. UL SRS can extend more signals for positioning purposes. Since UL SRS is designed for UE transmission, UL SRS can be used for NR positioning for SL positioning, which is one of the SL Pos-RS.

[0266] The following can be configured on the UL SRS for positioning:

[0267] Comb tooth size K TC : 2, 4, 8

[0268] Number of UL SRS OFDM symbols

[0269] ·By offset l offset Define the starting OFDM symbol

[0270] Frequency domain offset

[0271] SRS sequence ID

[0272] Time domain period T SRS and offset T offset

[0273] SRS BW or number of PRBs

[0274] The SRS as SL Pos-RS can be configured by one of the following alternative methods.

[0275] • The SRS configuration is provided in the request message.

[0276] Various (pre)configurations of SRS for positioning, for example in SL-SRS-PosResourceSet. When SL positioning is triggered, a (pre-)configured SL SRS for positioning is sent. This configuration can be selected by request or by the UE itself (positioning / SL Pos-RS transmission triggered by conditions).

[0277] Since the bandwidth (BW) of the reference signal may be critical to the positioning accuracy of timing-based positioning techniques, the configuration of the SRS BW or the number of PRBs for SRS as SL Pos-RS may be important. Since SRS is transmitted on 4 consecutive PRBs, the subchannels used for SRS transmission in the sidelink as SL Pos-RS transmission should be a multiple of 4 consecutive PRBs. The number of subchannels for SL SRS transmission can be (pre)configured. For SL positioning, the number of subchannels used for SRS can be specified within the lower limit of the minimum number of subchannels (or the minimum number of PRBs) and the upper limit of the maximum number of subchannels (or the maximum number of PRBs). The upper limit can be the total number of subchannels or PRBs in the SL resource pool. The anchor UE can reserve resources for transmitting the SL Pos-RS. For efficient transmission, the configuration of the BW and / or the number of PRBs for the SL Pos-RS can be within a range or can be the minimum number of subchannels. The anchor UE can decide the actual number of subchannels used for SL Pos-RS transmission.

[0278] It should be noted that, for positioning, the configuration and transmission of SL Pos-RS may not be limited to one type of SL Pos-RS. Multiple SL Pos-RSs may be configured and transmitted, such as S-SSB and SL PRS.

[0279] Now let's discuss the behavior of positioning / target UEs and the hierarchy of anchor / reference UEs. For these two types of UEs in the SL positioning system, the UE that provides the location reference is called the anchor UE, and the UE whose location is to be estimated (either at the UE itself or at the anchor UE) is called the target UE. The following terms can also be used for these two types of UEs. The UE with the location reference can be called the anchor UE, reference UE, location reference UE, responding UE and / or source UE. The UE whose location is to be estimated can be called the positioning UE, target UE, location requesting UE, requesting UE and / or initiating UE.

[0280] Although the UE whose position is to be estimated may be referred to as a requesting UE or an initiating UE, the positioning request or initiation may not always be initiated at the UE. The anchor UE may also request or initiate a positioning procedure including a SL Pos-RS transmission at the target UE. In addition, the anchor UEs may have different positioning accuracies depending on their synchronization signal / source, which may be converted into a priority based on whether the original source is a global navigation satellite system (GNSS) or a gNB / eNB.

[0281] Now let's discuss the sidelink synchronization references, priorities, and hierarchy for the SL positioning anchor. In the sidelink, the UE has four possible synchronization sources, which include GNSS, gNB / eNB, synchronization reference (SyncRef) UE via S-SSB, and the UE's own internal clock. Among these synchronization sources, GNSS or eNB / gNB are considered to be the highest quality sources. SyncRef can be distinguished by the number of steps (hops) away from GNSS or gNB / eNB. For example, a SyncRef directly synchronized to GNSS or gNB / eNB differs from GNSS or gNB / eNB by 1 step. The sidelink synchronization process defines a hierarchy or a set of priorities between these synchronization references and encourages all UEs to continuously search this hierarchy for the highest quality synchronization reference they can find. The synchronization priority order is described in the following hierarchical priority, where lower numbers indicate higher priority.

[0282] Level 1. GNSS or eNB / gNB, depending on (pre-)configuration.

[0283] Level 2. SyncRef The UE synchronizes directly to a Level 1 source.

[0284] Level 3. SyncRef UE synchronized to a Level 2 source, i.e. indirectly synchronized to a Level 1 source.

[0285] Level 4. Neither GNSS nor eNB / gNB is (pre-)configured as a Level 1 source.

[0286] Level 5. SyncRef The UE synchronizes directly to a level 4 source.

[0287] Level 6. SyncRef UE synchronized to a level 5 source, i.e. indirectly synchronized to a level 4 source.

[0288] Level 7. Any other SyncRef UE.

[0289] Level 8. UE's internal clock.

[0290] Based on different synchronization references, the qualification of a UE as a positioning anchor can have multiple levels of hierarchy due to different timing and positioning accuracy. A SL UE can obtain / derive its own location information from sources other than the synchronization source. There can also be different levels. For example, gNB and GNSS as synchronization sources are considered to be at the same level. However, in terms of positioning performance, they may not be the same. In addition, a SL UE connected to a gNB can obtain / derive its position from SL positioning, which can be used as an anchor with a lower priority / accuracy. A SL UE can broadcast or indicate to a target UE its one or more levels as an anchor UE for SL positioning.

[0291] On the other hand, the sidelink data traffic has 8 priorities, which are represented by a 3-bit number in the priority field in SCI 1-A, p = 0...7. The smaller the number, the higher the priority. The lowest level represents the highest priority. The priority is set by the application layer and provided to the physical layer. The level of the anchor UE and the corresponding SL Pos-RS transmission can be converted and indicated by the 8 PHY priorities.

[0292] Therefore, the synchronization source or priority can be used as a condition for a UE to act as an anchor UE or for a target UE to select an anchor UE. In addition, the positioning accuracy of the UE based on the positioning source (which may be different from its synchronization source) can also set the UE's qualification as an anchor UE. Based on the coverage indicator I sent in the S-SSB and SL-MIB IC The SLSSID and Sync source or priority range can be roughly estimated. Correspondingly, the location information during transmission can be assigned a certain priority based on the Sync reference source level. It should be noted that the mapping may not be an exact one-to-one match, because location information is usually a high-priority information in SL positioning.

[0293] Fig.13 is a flow chart of an exemplary method 1300 of a UE determining and indicating an anchor point level to support UE anchor point selection.

[0294] In step 1301, as an anchor point, the UE may determine pre-configured or specified requirements for synchronization source, positioning accuracy and / or maximum bandwidth. Given one or more hierarchical level structures of anchor UEs, the UE may determine in step 1303 whether it can be an anchor UE. The determination may be made based on one or more (pre) configured requirements for the anchor level as an anchor UE, based on the synchronization source and / or priority, positioning source or positioning accuracy, and / or maximum BW of the UE. Through the hierarchical level structure, the UE may determine its own anchor level. The UE may then set an anchor level for itself based on the hierarchical level defined for the anchor UE. The anchor level may be a single-level metric that may be converted or mapped to a SL PHY priority. The anchor level may also be a list of each metric with different associated anchor levels, such as the synchronization source of the UE, the positioning source of the UE, and the like. When the UE is eligible to be an anchor UE, the UE may send a signal for an anchor indication in step 1305. The UE may also send one or more anchor levels of the UE. In some examples, in step 1305, the UE may send a signal indicating that the UE is not and / or no longer eligible to be an anchor UE. The target UE receives the anchor indication and one or more anchor levels of the anchor UE. In step 1307, the target UE then selects an anchor UE according to one or more requirements of the target UE itself based on the indication, metric and / or anchor level of the anchor UE received from the anchor UE.

[0295] Fig.14 14 is a flow chart of an exemplary method 1400 for anchor UE selection. In step 1401, when certain requirements / conditions are met, the UE may indicate that it can be an anchor UE. These requirements / conditions may include synchronization source requirements, location accuracy, and / or any other conditions discussed herein. In step 1403, the target UE selects the anchor UE based on certain conditions. These conditions may include synchronization source requirements, channel conditions (LOS / NLOS), and / or any other conditions discussed herein. In step 1405, the target UE may reselect the anchor UE for positioning after acquiring the anchor UE position, and / or after acquiring channel and timing measurements, for example based on synchronization source requirements, corrected channel measurements-LOS / NLOS, the actual position of the anchor UE, the BW of the SL Pos-RS (e.g., SL PRS), and / or any other conditions discussed herein.

[0296] In addition to the conditions set for the UE to select an anchor UE as an anchor UE or a target UE, the target UE may also reselect an anchor UE and exclude the SL Pos-RS and positioning information of some UEs used for positioning according to step 1405. This may occur after the SL Pos-RS is transmitted and is based on the synchronization source and / or priority of the anchor UE and other conditions, such as the BW of the SL Pos-RS signaling and the location information of the anchor UE. Since the target UE does not know the location of the anchor UE, a location-based selection may be made after the location of the anchor UE is transmitted. For example, the target UE may select one or more anchor UEs from a group of UEs that may be very close to each other.

[0297] Therefore, given the hierarchical levels of eligibility of a UE as an anchor point, several hierarchical structures for selecting anchor point UEs can be adopted. For example, these hierarchical levels can also include the channel quality when triggering SL positioning.

[0298] Similarly, when positioning is performed at the serving anchor UE, the serving anchor UE may select additional anchor UEs after acquiring location information and / or use measurement reports from a subset of coordinating anchor UEs.The behavior of the target UE may also be scenario-dependent, such as absolute positioning or ranging.

[0299] Now let's discuss the broadcast type of transmissions in the SL positioning process. In many cases or scenarios, S-SSB transmissions are broadcast. For the case of SL positioning or SL Pos-RS transmissions, the following broadcast types of different types of transmissions may be supported.

[0300] If the SL Pos-RS is triggered by a request, an explicit request is transmitted:

[0301] oUnicast: The target UE sends a request to each anchor UE independently.

[0302] o Multicast: After the anchor UE is selected, a group of anchor UEs is formed by the upper layer. The target UE multicasts the request to the group of anchor UEs.

[0303] SL CSI-RS transmission:

[0304] o Reuse rel-16 behavior, support unicast.

[0305] SL Pos-RS (e.g., SL PRS) transmission:

[0306] o Unicast: Each anchor UE reserves resources and sends the SL Pos-RS to the target UE via unicast.

[0307] o Broadcast: The anchor UE or target UE (if positioning is done at the serving anchor UE) broadcasts the SL Pos-RS.

[0308] o Multicast: The target UE can multicast the SL Pos-RS to the selected anchor UEs.

[0309] For SL positioning or SL Pos-RS transmission triggered by conditions, broadcast or multicast may be preferred.

[0310] Fig.15 1500 is a schematic diagram of an anchor UE broadcasting SL-Pos-RS and location / positioning information. It should be noted that location information and positioning information can be used interchangeably in this article. In some scenarios, such as when the RSU acts as an anchor UE, the broadcast technology is more useful. Therefore, the interaction between the anchor UE and the target UE can preferably be very limited. The location information of the anchor UE can also be broadcast to each UE by multiplexing with the SL Pos-RS transmission or in a separate transmission. By broadcasting the SL Pos-RS and the location information of the anchor UE, the UEs within the range of these anchor UEs will benefit from the positioning information. Figure 1500 shows an exemplary case of V2x in which the anchor UE 1501 is an RSU. The anchor UE 1501 broadcasts (1505) the SL Pos-RS and their location information. For the E-SID SL positioning technology, the SL S-SSB may only need to be the SL Pos-RS. The target UE 1503 can measure the RSRP on the DMRS in the PSBCH and / or the S-PSS or S-SSS in the S-SSB.

[0311] Although positioning based on timing measurements uses a large bandwidth SL Pos-RS to achieve high accuracy, broadcasting may still be preferred for some scenarios / areas in V2X, public safety and / or IIoT applications. Resource allocation may not be as critical as in these scenarios. Therefore, more positioning and less communication may be required. Whenever positioning information is triggered by a request or condition described in this document, each anchor UE 1501 can reserve resources for broadcasting SL Pos-RS and the position of the anchor UE within a certain time period.

[0312] Now let's discuss SL resource allocation.During the SL positioning procedure, resources are allocated for various transmissions, such as transmission of explicit requests, transmission of SL Pos-RS, transmission of measurement reports and / or transmission of location information of anchor UE.

[0313] Typically, each Tx UE can select resources for its own transmission based on (pre) configured transmission settings (e.g., periodicity, etc.). In one example, the transmission of SL reference signals for positioning purposes can also employ resource reservation. In some SL scenarios, the anchor UE may be mobile and may also be dynamically deployed. In one example, the anchor UE may indicate that the location of the anchor UE may change frequently. Therefore, the anchor UEs may update and transmit their locations to the target UE. In addition, measurements between the anchor UE and the target UE may be exchanged based on the location at which the location of the target UE is estimated. These transmissions also use resource allocation.

[0314] The positioning process involves information exchange between the two parties. IUC solution 1 can be modified as follows to assist other UEs in SL positioning transmission:

[0315] In addition to the request, the target UE as UE-A sends each anchor UE (as UE B) the preferred resource set for its SLPos-RS transmission. Through such coordination, collision of SL Pos-RS can be avoided.

[0316] • The target UE as UE-A also sends the preferred resource set to each anchor UE (as UE-B) to communicate its position.

[0317] The (serving) anchor UE as UE-A sends the preferred resource set for the target UE (as UE-B) to transmit the SL Pos-

[0318] RS.

[0319] The (serving) anchor UE as UE-A sends a preferred resource set for the target UE (as UE-B) to send a measurement report.

[0320] Now let's discuss data multiplexing. Transmissions of explicit requests and SL Pos-RS can be multiplexed with other data. In one example, for explicit requests, transmissions can be multiplexed with data only if the source / destination ID pair is the same. In one example, for explicit requests, retransmissions of transmissions are supported.

[0321] For SL Pos-RS transmission, the following can be specified:

[0322] S-SSB: In the current frame structure, S-SSB is not multiplexed with data.

[0323] SL CSI-RS: Based on Rel-16 specification, it can be multiplexed with data

[0324] SL PRS (SL SRS):

[0325] o For unicast: If the same behavior as CSI-RS, it should be included with data (e.g., location information or measurement reports)

[0326] Reuse.

[0327] o For multicast / unicast, it can be multiplexed with data (e.g., location information or measurement report). It should be noted that for SL PRS transmission, the source / destination ID pair may not need to be the same as the source / destination ID pair of the data, because SL PRS does not require a destination ID, even if it is triggered by a specific UE and / or for a specific target UE.

[0328] o For broadcast, it can also be multiplexed with data if necessary (e.g., location information of anchor UE or measurement report from target UE to anchor UE or from coordinating anchor UE to serving anchor UE)

[0329] For the transmission of location information, retransmission may not be needed because the location may change during the retransmission. For example, if the change in location is greater than a threshold or the speed of the UE is greater than a threshold, retransmission may be discarded or disabled based on the quality of the location information.

[0330] For PSSCH RE mapping of multiplexed data, SL can modify the NR positioning DL PRS RE mapping rules. In order to support legacy UEs that do not recognize SL Pos-RS, data modulation symbols are punctured on SL Pos-RS (SL PRS, SL SRS) REs to support backward compatibility.

[0331] Since the bandwidth of each SL Pos-RS transmission is large, it is also preferred that multiple UEs transmit different SL Pos-RS on the same resources in the same time slot, but are orthogonal in time and frequency in the same RB. The UL SRS of different UEs can be sent on the same resources as long as they are on different REs. For the sidelink, when the SL Pos-RS signals of multiple anchor UEs are sent on the same resources, inter-symbol interference may occur due to the different reception times of the UEs. This can be alleviated by configuring the SL Pos-RS to have SL Pos-RS REs that do not appear on the same subcarrier of two consecutive OFDM symbols. Alternatively, this problem can be solved by configuring each PRS / SRS to have a different offset so that there are one or more guard symbols between any two PRS / SRS in the time domain. In this case, the number of OFDM symbols for each PRS / SRS is 4 or less.

[0332] For SL Pos-RS signals from different UEs on the same resources, additional control signaling support is adopted. For example, only one UE can send PSSCH for resource reservation, or PSCCH can be supported to indicate overlapping resources for SL Pos-RS transmission without multiplexing with data.

[0333] Therefore, the present disclosure focuses on the first artificial intelligence (AI) of SL positioning for potential solutions of SL positioning, and considers relative positioning, ranging and absolute positioning. For this purpose, it is necessary to consider reference signals for positioning, including signal design, measurement and association processes, while reusing reference signals and processes in sidelink communication and positioning as much as possible.

[0334] Now let’s discuss signal bandwidth and signal to noise ratio (SNR). Channel bandwidth and received SNR determine the positioning accuracy of methods based on time-of-flight (TOF) / time of arrival (TOA) distance measurement. According to the Cramer-Rao lower bound (CRLB) analysis, the variance of TOA measurement in LOS channel is approximately the lower bound:

[0335]

[0336] Where β is the effective signal bandwidth,

[0337]

[0338] Where SNR is the signal-to-noise ratio, f is the frequency, and S(f) is the Fourier transform of the transmitted signal. The above inequality means that higher signal bandwidth can improve TOA measurement accuracy. Studies on the impact of bandwidth on positioning accuracy can indicate whether SL positioning schemes should be extended to unlicensed spectrum.

[0339] Fig.16 A schematic diagram 1600 of an example of LOS and NLOS sidelink positioning is shown. If there is a direct LOS path 1611 between the anchor UE 1601 and the target UE 1603 node, the larger positioning signal bandwidth supports better multipath component resolution, which improves the accuracy of finding the first path, thereby reducing the error caused by multipath bias in TOA, RTT and TDOA based methods. However, if there is no such direct LOS path 1611 and the communication between the anchor UE 1601 and the target UE 1603 node is completed by NLOS reflection 1613, the range between the anchor UE 1601 and the target UE 1603 node is overestimated due to the increased TOF. The angle of arrival (AOA) and angle of departure (AOD) estimates may also be affected by NLOS propagation, which results in a lower accuracy of the position estimate.

[0340] Now let's discuss time synchronization. When using a positioning method based on TOF and / or TOA, the receiver can use the timestamp from the transmitter to estimate the TOF and thus the distance between the transmitter and the receiver. However, even when the channel is LOS, if the clocks of the transmitter and receiver are not synchronized, additional errors will be introduced, affecting the ranging and position estimates. The network synchronization error is defined as a truncated Gaussian distribution of the root mean square (rms) value (expressed as (T1) in nanoseconds (ns)) between the anchor node and the timing reference source assumed to have perfect timing, subject to a maximum timing difference of T2ns, where T2=2*T1. That is, the range of the timing error is [-T2, T2]. Two exemplary values ​​of T1 include 0ns (perfect synchronization) and 50ns.

[0341] Some positioning methods (e.g., multi-RTT) are robust in terms of time synchronization, provided that the clock drift is negligible during the period of measuring the difference between the reception time and the transmission time of the positioning signal, while other methods are more sensitive to synchronization errors (e.g., TOA). Therefore, when studying SL positioning schemes, the synchronization error between the target node and the anchor node should be considered.

[0342] In one example, SL positioning research should study the impact of BW size, non-ideal synchronization and NLOS propagation on SL positioning accuracy. The position determination method is now discussed.

[0343] RAT-related positioning methods are based on the exchange of reference signals (RS) between an anchor node (gNB) and a target node (UE). In the present disclosure, a target UE is a UE that requests to determine the positioning / position, and anchor nodes are those nodes that can be considered as references for relative or absolute positioning of the target UE, such as UE, gNB, RSU. RAT-related positioning methods are methods other than RAT-independent methods for positioning such as GNSS, Wi-Fi, Bluetooth, terrestrial beacon systems (TBS), and motion-based sensors. The RAT-related methods are:

[0344] NR Enhanced Cell ID method based on NR signal (NR E-CID)

[0345] Multi-round-trip time positioning (multi-RTT based on NR signals)

[0346] Downlink angle-of-departure (DL-AoD) based on NR signals

[0347] Downlink time difference of arrival (DL-TDOA) based on NR signals

[0348] Uplink time difference of arrival (UL-TDOA) based on NR signals;

[0349] Uplink angle-of-arrival (UL-AoA), including A-AoA and Z-AoA based on NR signals.

[0350] It also supports mixed positioning using multiple methods in the above positioning method list

[0351] The measurements supporting the above method are as follows.

[0352] Downlink PRS reference signal received power (DL PRS RSRP)

[0353] Downlink PRS reference signal received path power (DL PRS RSRPP)

[0354] Downlink PRS reference signal time difference (DL PRS RSTD)

[0355] UE Rx-Tx time difference

[0356] For sidelink positioning scenarios, at least one positioning reference signal is provided via the sidelink (PC5), so the SLUE can combine and measure the sidelink Pos-RS and DL PRS, and send the sidelink Pos-RS and UL PRS. For sidelink mode 2 (intended for out-of-coverage scenarios), the reference node (anchor node) may be less reliable than the in-coverage anchor nodes such as the gNB. In these scenarios, it is better to use positioning methods such as multi-RTT, which are more robust for clock synchronization between the anchor node and the target node.

[0357] For sidelink Mode 2 operation, robust positioning methods (e.g., multi-RTT) may be preferred. The physical layer standard may be changed to support SL UE positioning methods and measurements. For position determination, SL UE should support aggregation of DL PRS resources with SL positioning resources.

[0358] In 5G services, a basic scenario for positioning is to support positioning in OOC scenarios when all devices involved in SL positioning are out of the coverage of LMF. OOC scenario positioning is part of the study item description (SID). The 5G system should provide positioning information for UEs out of the coverage of the network with a positioning accuracy of < [1m] relative to other UEs that are nearby and within the coverage of the network. This positioning support data is available to the UE, which makes UE-based positioning and positioning in OOC scenarios possible.

[0359] The 5G system should be able to make location-related data available to applications or application servers within the 5G network, outside the 5G network or in the user equipment. In the OOC case, it is unclear whether an entity similar to the LMF is still needed, and if so, where it should be located. The target UE should support the function of calculating its position estimate. This function and complexity may depend on the scenario covered by the OOC, such as ranging, relative positioning or absolute positioning.

[0360] The SL positioning solution for OOC scenarios should be able to select a positioning method to: configure and enable sidelink reference signal transmission per request or triggered by an event; select an anchor node and enable an RRC connection when necessary; obtain location information or request SL Pos-RS transmission; provide or exchange location information (if requested); configure and enable a set of SL positioning measurements to estimate relative or absolute position.

[0361] Some positioning methods involve an exchange between the target node and the anchor node. For example, in UE-based positioning multi-RTT, the anchor node should provide Rx-Tx measurements to the SL UE target node, which will be combined with the Rx-Tx measurements at the target node to obtain the final position estimate. Another example of data exchange between the target node and the anchor node can be the absolute position coordinates provided by the anchor node to the target node. This exchange can only be performed after an RRC connection is established between the target node and the anchor node, which can enable data encryption and thus privacy.

[0362] The SL positioning scheme should support the configuration and control of OOC SL positioning. These scenarios of the OOC SL positioning scheme can be implemented by two possible approaches. One option is to start from scratch and define the protocol and signaling to support the SL positioning method. The other option is to build on the SL design and extend the protocol with signaling that implements the SL positioning method. The inter UE coordination (IUC) feature is a candidate that can be considered and extended to support the SL positioning scheme for OOC scenarios. The IUC feature provides the framework to request and respond to measurements and location information, configure and trigger the necessary signaling, and coordinate the transmission of anchor nodes. In addition, the use of the IUC feature can minimize the specification impact.

[0363] The IUC framework of the OOC SL positioning scheme can be extended and / or used.

[0364] Now let's discuss positioning reference signals. RAT-dependent positioning methods are based on the exchange of reference signals (RS) between the anchor node (gNB) and the target UE. More precisely, the gNB sends the DL positioning RS (DL PRS) signal. The UE sends the UL sounding reference signal (UL PRS) based on the configuration provided by SRS-PosResourceSet, which is different from the SRS used for UL channel estimation based on the configuration given by SRS-ResourceSet.

[0365] The DL PRS signal is a length-31 Gold QPSK sequence, where the pseudo-random sequence generator is based on the time slot number, the DL PRS sequence ID, The PRS sequence ID is initialized with the OFDM symbol index in the time slot to which the sequence is mapped. The PRS sequence ID supports frequency reuse, while the time slot and symbol index supports TOF, TOA, TDOA, and RTT determination.

[0366] In the time domain, the size of the DL PRS resource is L PRS ∈{2, 4, 6, 12} symbols, given by the higher-layer parameter dl-PRS-NumSymbols.

[0367] In the frequency domain, the PRS resource has a comb-tooth distribution (eg, the resource element (RE) spacing in each symbol of the DL-PRS resource), where the comb-tooth size K is comb PRS ∈{2, 4, 6, 12} is given by the higher-level parameter dl-PRS-CombSizeN-AndReOffset of the downlink PRS resource configured for RTT-based propagation delay compensation, otherwise it is given by the higher-level parameter dl-PRS-CombSizeN, so that the combination {LL PRS , K comb PRS} is one of {2,2}, {4,2}, {6,2}, {12,2}, {4,4}, {12,4}, {6,6}, {12,6} and {12,12}.

[0368] The comb distribution supports RS signals with wider bandwidth and thus better accuracy for TOA estimation. However, the gaps in frequency produce aliasing in time, which can be compensated by repetition and coherent combination of PRS in time. For example, if two symbols with comb-4 are coherently combined, the result is equivalent to a PRS signal with comb-2.

[0369] The symbol-to-symbol frequency offset is chosen so that there is no step pattern. This has the main advantage of improving robustness (e.g., against Doppler shift) when only the first symbol is used for coherent combining. In addition, the comb design and the frequency offset between consecutive symbols increase robustness to wideband fading, as well as orthogonality with respect to other PRS signals from other TRPs.

[0370] PRS resources are defined by ID, sequence ID {0...4095}, comb size {2, 4, 6, 12} and RE offset of remaining symbols, resource slot offset, resource symbol offset and QCL information. DL PRS resource set is configured by NR-DL-PRS-ResourceSet, including one or more DL PRS resources, each of which has an associated spatial transmission filter (transmission direction).

[0371] Fig.17 Schematic diagram of an example of a positioning reference signal (PRS) resource set 1700. The PRS resource set 1700 is characterized by: ID, subcarrier spacing, periodicity (of resource set transmission), resource list, resource repetition factor (number of times each resource is repeated during an instance of the resource set), resource time gap (number of time slots between consecutive repetitions of a resource), comb size, resource bandwidth (between 24 PRBs and 272 PRBs in increments of 4 PRBs), PRB index start, number of resource symbols in a PRS time slot. The PRS resource set 1700 can be located anywhere in the frequency grid by the PRB index start, which is an offset relative to the reference frequency point A.

[0372] The PRS resource set is sent by the gNB with a period of T per PRS ∈2 μ {4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320, 640, 1280, 2560, 5120, 10240} time slots.

[0373] The PRS resource repetition factor defines the number of times each DL-PRS resource is repeated for a single instance of the DL-PRS resource set and can take the value T rep PRS ∈{1, 2, 4, 6, 8, 16, 32}. All DL PRS resources in a resource set have the same resource repetition factor.

[0374] In order to reduce the interference of weak PRS signals, strong PRS signals can be muted. The muting mode is specified by a bit string of {2, 4, 8, 16, 32} bits in each cell, where one bit indicates whether the PRS transmission in the corresponding time slot is muted.

[0375] A UE in RRC connected state only needs to measure DLPRS on the active bandwidth part (BWP) with the same parameter set as the active BWP. The UE can request the serving gNB to measure gaps, which can be used to measure DL PRS outside the active BWP and with a different parameter set.

[0376] For a 15kHz SCS, the minimum DL PRS is about 5 megahertz (MHz) and the maximum is about 50MHz. For a 120kilohertz (kHz) SCS, the minimum DL PRS bandwidth is about 34Mhz and the maximum bandwidth is about 400MHz.

[0377] Fig.18 It is a schematic diagram of an exemplary UL PRS1800 resource configuration. UL PRS1800 is based on sounding RS (SRS), called positioning SRS. The UL PRS1800 sequence is a 31-bit Zadoff-Chu, which provides a good peak-to-average ratio. UL PRS1800 can span {1, 2, 4, 8, 12} consecutive OFDM symbols in time, and these symbols can be located anywhere in the time slot. Similar to DL PRS, UL PRS1800 has a comb-N pattern in frequency, and the comb size is {2, 4, 8}. Similar to UL PRS1800, DL PRS also has a comb offset, which defines the relative frequency offset between consecutive OFDM symbols. The offset has similar advantages to DL PRS. Through coherent combining, only the first few symbols can be considered for TOA measurement. Similar to DL PRS, UL PRS1800 can be sent periodically with a certain period and time slot offset. However, the semi-static configuration is activated and deactivated through MAC-CE signaling. Aperiodic UL PRS 1800 is sent only when the gNB instructs the UE through downlink control information (DCI). UL PRS 1800 supports spatial relationships, where the spatial relationship can be a DL reference signal (SSB, CSI-RS or DL-PRS) or a previously transmitted SRS or UL-PRS 1800. UL PRS 1800 can also have a spatial relationship with an adjacent transmit receive point (TRP).

[0378] Another attribute of UL PRS1800 is power transmission control, where the UE estimates the UL path loss of the serving and neighboring TRPs based on DL measurements and sets the UL PRS1800 power accordingly. A UL PRS1800 resource set consists of one or more UL PRS resources and is defined by a resource set ID, resource type (aperiodic, semi-persistent, periodic), a value α that characterizes fractional power control, the expected received power p0 at the TRP, a path loss reference RS, and a UL PRS resource list.

[0379] The UL resources are described by ID, transmission comb, resource mapping (symbol position in UL PRS1800 time slot), frequency domain offset, bandwidth indication (as part of frequency hopping, for SRS case, frequency hopping is not used for frequency hopping indication), resource type (periodic, semi-static, non-periodic), corresponding period, sequence ID for initializing pseudo-random group, sequence hopping, and spatial relationship information.

[0380] Similar to DL PRS, a UE may be configured with multiple UL PRS resource sets.

[0381] Reference signals for sidelink positioning are now discussed.

[0382] Fig.19 is a schematic diagram of an exemplary S-SSB 1900. The S-SSB 1900 is a broadcast signal for synchronization purposes, consisting of a sidelink primary synchronization signal (S-PSS), a sidelink secondary synchronization signal (S-SSS) and a physical sidelink broadcast channel (PSBCH). There are 672 unique physical layer sidelink synchronization identifiers, which are divided into two sets {0, 1...335} and {336...671}. The sidelink synchronization signal ID (SLSSID) indicates the source of the time reference (GNSS, gNB or another SL UE (SyncRef UE)), and therefore gives accuracy information of the time reference. Before starting to send the S-SSB 1900, the SLUE must select its own time reference and announce it via the SLSSID.

[0383] In the frequency domain, S-SSB 1900 occupies 11 physical resource blocks (PRBs), i.e., 132 subcarriers, of which S-PSS and S-SSS each occupy 127 subcarriers and are repeated twice during the S-SSB time slot. PSBCH occupies 132 subcarriers for a duration of eight symbols ( Figure 5 ). The first PSBCH symbol is used for automatic gain control (AGC) purposes. Each S-SSB transmission is repeated once or several times in each 16-subframe period. The frequency position of the S-SSB is fixed.

[0384] S-SSB 1900 can be mainly used by a receiver SL UE to acquire synchronization with a transmitter SL device, or by a target SL UE to measure the time difference of arrival (TDOA) between two SyncRef UEs synchronized with the same reference time. Therefore, the target SL UE can estimate the relative position with the SyncRef UE.

[0385] S-SSB can be used to estimate TDOA between anchor SL devices. When the S-SSB initiators have the same reference time (SLSSID), the accuracy of TDOA estimation is improved. Using S-SSB for positioning can achieve SL UE positioning in RRC_INACTIVE state. The network can support SL position determination based on S-SSB.

[0386] Now let's discuss the Sidelink Positioning Signal (SL Pos-RS). One of the topics of this research project involves studying the sidelink reference signal for positioning purposes from a physical layer perspective, including signal design, resource allocation, measurement, association procedures, etc., to make the best use of reference signals, procedures, etc. in sidelink communication and positioning.

[0387] In out-of-coverage (OOC) scenarios, the target SL UE may rely on the sidelink (PC5) reference signals received from other SL devices (SL UE, RSU) to determine the range or position. The signal bandwidth plays a role in the estimation accuracy. The bandwidth of the S-SSB may not be sufficient. In addition, the S-SSB period (160ms) may add additional latency to the position determination. Therefore, RAN1 may define SL Pos-RS that share some common features of DL and UL PRS, such as

[0388] Flexible bandwidth size

[0389] Comb-N distribution in frequency

[0390] · Repetition of frequency offsets in consecutive symbols

[0391] Different time lengths and cycles of resource sets

[0392] Aperiodic, semi-static and periodic transmission

[0393] The Zadoff-Chu (ZC) sequence for uplink PRS provides better PAPR characteristics (smaller power variation in time and frequency) than the Gold sequence for DL ​​PRS. For SL UE, such PAPR characteristics may be required to avoid nonlinear signal distortion.

[0394] RAN1 may consider UL PRS design as a starting point for SL Pos-RS design. SL UEs at the edge of network coverage may participate in SL positioning exchanges with other SL UEs in partial coverage. Therefore, the serving gNB should be able to control and configure SL Pos-RS UE transmissions within its coverage to minimize interference and maximize capacity. SL Pos-RS configuration may be controlled by the gNB when the SL UE is in coverage or in partial coverage.

[0395] Now let's discuss the SL positioning architecture.

[0396] UE positioning can be performed in NG-RAN. Positioning methods, positioning architecture, signaling protocols and interfaces are defined. The positioning solution relies on the LTE positioning protocol (LPP) and location management function (LMF). Specifically, LMF is used to orchestrate positioning methods and protocols.

[0397] For the positioning of the target UE, the LMF decides the positioning method to be used based on factors that may include LCS client type, required QoS, UE positioning capabilities, gNB positioning capabilities and ng-eNB positioning capabilities. The LMF then invokes these positioning methods in the UE, serving gNB and / or serving ng-eNB. These positioning methods can produce a position estimate for UE-based positioning methods and / or positioning measurements for UE-assisted and network-based positioning methods. The LMF can combine all received results and determine a single position estimate for the target UE (hybrid positioning).

[0398] When the SL UE participating in the positioning exchange is within the coverage of the gNB, the positioning protocol (LTE positioning protocol) should still be supported. The LMF through the Uu connection and SL relay should be able to coordinate and process measurements for positioning. At the same time, the gNB can forward measurements from the SL UE to the LMF to estimate the position of the SL UE in partial coverage.

[0399] Fig. 20 is a schematic diagram of an exemplary UE 2000 for sidelink communication. UE 2000 can be used as a target UE, an anchor UE, or any other UE described herein. Accordingly, UE 2000 can be used to implement or support the schemes / features / methods described herein. For example, the features / methods in the present disclosure can be implemented using hardware, firmware, and / or software installed and running on hardware. Those skilled in the art will recognize that the term UE includes a wide range of devices, of which UE 2000 is only an example. For the purpose of clarity of discussion, UE 2000 is included, but it is by no means intended to limit the application of the present disclosure to a specific network device embodiment or a class of network device embodiments.

[0400] UE 2000 may be a device that transmits electrical signals, wireless signals and / or optical signals through a network. Fig. 20As shown, UE 2000 may include a transceiver (Tx / Rx) 2010, which may be a transmitter, a receiver, or a combination thereof. Respectively, one Tx / Rx 2010 may be coupled to multiple downlink ports 2020 (e.g., downlink interfaces) to send and / or receive frames from other nodes, and one Tx / Rx 2010 may be coupled to multiple uplink ports 2050 (e.g., uplink interfaces) to send and / or receive frames from other nodes. A processor 2030 may be coupled to Tx / Rx 2010 to process data signals and / or determine which nodes to send data signals to. The processor 2030 may include one or more multi-core processors and / or a memory device 2032, which may be used as a data memory, a buffer, etc. The processor 2030 may be implemented as a general-purpose processor, or may be part of one or more application specific integrated circuits (ASICs) and / or digital signal processors (DSPs). UE 2000 may include a SL positioning module 2014, which may be used to employ sidelink communications to initialize the SL-based positioning mechanism described herein. SL positioning module 2014 may be implemented in a general purpose processor, a field programmable gate array (FPGA), an ASIC, a DSP, a microcontroller, etc. In an alternative embodiment, SL positioning module 2014 may be implemented in processor 2030 as computer executable instructions stored in memory device 2032 (e.g., as a computer program product stored in a non-transitory computer-readable medium), which may be executed by processor 2030 and / or implemented partially in processor 2030 and partially in memory device 2032. According to an embodiment, downlink port 2020 and / or uplink port 2050 may include wireless, electrical, and / or optical transmission and / or reception components.

[0401] Fig.21 2 is a schematic diagram of an exemplary embodiment of a UE 2100 for sidelink positioning. UE 2100 can be used as a target UE and an anchor UE or any other UE described herein. UE 2100 includes a receiver 2101, a measurement module 2103, and a transmitter 2107. In one example, the transmitter 2107 acts as a sending component for sending a positioning request to one or more anchor UEs via sidelink communication. In addition, the receiver 2101 acts as a receiving component for receiving a positioning signal from one or more anchor UEs via sidelink communication. In addition, the measurement module 2103 acts as a measurement component for performing positioning measurements based on the positioning signal.

[0402] In another example, the transmitter 2107 acts as a transmitting component for sending a positioning request to the target UE via a sidelink communication. In addition, the receiver 2101 acts as a receiving component for receiving a positioning signal from the target UE via a sidelink communication. In addition, the measurement module 2103 acts as a measurement component for performing positioning measurements on the target UE based on the positioning signal.

[0403] Fig. 22 22 is a flow chart of an exemplary method 2200 for performing sidelink-based positioning in a target UE. In step 2201, the target UE selects one or more anchor UEs. In one example, the one or more anchor UEs are selected based on a UE anchor indication and a UE anchor level. For example, the UE anchor indication may indicate whether the corresponding UE is capable of acting as an anchor UE, and whether the corresponding UE is allowed to act as an anchor UE. In one example, the UE anchor level may be set based on a synchronization source, a priority, a positioning accuracy, a maximum bandwidth, an in-coverage indicator, an SLSSID, or a combination thereof.

[0404] Positioning may be managed jointly by the target UE, the anchor UE and / or the serving anchor UE and the coordinating anchor UE. In step 2203, the target UE may optionally receive an initial positioning request from the serving anchor UE via sidelink communication. This may occur when the serving anchor UE manages positioning.

[0405] In step 2205, the target UE sends a positioning request to one or more anchor UEs via sidelink communication. In one example, the positioning request may be triggered by the target UE. In other examples, at step 2203, the positioning request may be triggered by an initial positioning request from a serving anchor UE, in which case the one or more anchor UEs are coordinating anchor UEs. In some examples, the positioning request is triggered by a condition. For example, the condition may include a comparison of RSRP relative to a first threshold, a comparison of a distance relative to a second threshold, a comparison of the number of UE anchors relative to a third threshold, a comparison of a channel condition relative to a fourth threshold, or a combination thereof.

[0406] It should be noted that the target UE can communicate with the anchor UE according to mode 1 or mode 2. In mode 1, the target UE is within the 5G network range. In this case, the target UE can communicate with one or more anchor UEs through resource reservation provided by the gNB. In mode 2, the target UE is not within the network range. In this case, the target UE communicates with one or more anchor UEs based on the perception-based resource selection of the sidelink resources. This method can use opportunistic signaling to select communication resources without communicating with the 5G network.

[0407] In step 2207, the target UE receives a positioning signal from one or more anchor UEs through sidelink communication. The positioning signal may include SL-Pos-RS.

[0408] In step 2209, the UE may perform positioning measurements based on the positioning signal. For example, the target UE may estimate the position of the target UE based on the positioning measurements and the positions of one or more anchor nodes.

[0409] In step 2211, the target UE may optionally send positioning measurements to the serving anchor UE via sidelink communications to estimate the position of the target UE. In some examples, the target UE alternatively sends a report indicating the position of the target UE to the serving anchor UE based on step 2209. In some examples, the target UE may also send a report related to the positioning signal received from the coordinating anchor UE to the serving anchor UE.

[0410] In step 2213, the target UE may optionally reselect one or more anchor UEs after acquiring the anchor UE location, channel measurement, timing measurement, or a combination thereof.

[0411] Fig.23 2300 is a flow chart of an exemplary method 2300 for performing sidelink-based positioning in an anchor UE. In optional step 2301, the anchor UE may send a UE anchor indication, which indicates whether the anchor UE is capable of acting as an anchor UE and whether the anchor UE is allowed to act as (e.g., wants to act as) an anchor UE. In step 2303, the anchor UE may optionally send a UE anchor level, which is set based on a synchronization source, priority, positioning accuracy, maximum bandwidth, coverage indicator, sidelink synchronization signal identifier (SLSSID), or a combination thereof. Optional steps 2301 and 2303 support the anchor UE to indicate to a potential target UE whether the anchor UE can be selected as an anchor UE for positioning purposes, and also support the target UE to determine which anchor UEs should be selected to obtain the best results.

[0412] In step 2305, the anchor UE sends a positioning request to the target UE via sidelink communication. In some cases, the anchor node acts as a serving anchor node. In some examples, the positioning request may instruct the target UE to send one or more second positioning requests to one or more coordinating anchor UEs. In some examples, the positioning request is triggered by a condition. For example, the condition may include RSRP relative to a first threshold, distance relative to a second threshold, number of UE anchors relative to a third threshold, channel conditions relative to a fourth threshold, or a combination thereof.

[0413] It should be noted that the anchor UE can communicate with the target UE according to mode 1 or mode 2. In mode 1, the anchor UE is within the 5G network range. In this case, the anchor UE can communicate with the target UE through resource reservation provided by the gNB. In mode 2, the anchor UE is not within the network range. In this case, the anchor UE communicates with the target UE based on the perception-based resource selection of the sidelink resources. This method can use opportunistic signaling to select communication resources without communicating with the 5G network.

[0414] In optional step 2307, the anchor node may act as a serving anchor node and may send one or more second positioning requests to one or more coordinating anchor UEs instead of delegating such transmission to the target UE.

[0415] In step 2309, the anchor node receives a positioning signal from the target UE via sidelink communication. For example, the positioning signal may include SL-Pos-RS. In some examples, the positioning signal from the target UE also includes location information from one or more coordinating anchor UEs.

[0416] In step 2311, the anchor UE may optionally receive location information from one or more coordinating anchor UEs instead of receiving the information through the target UE.

[0417] In step 2313, the anchor UE performs positioning measurement on the target UE based on the positioning signal.

[0418] In step 2315, the anchor UE may estimate the location of the target UE based on positioning measurements from the target UE and / or location information from one or more coordinating anchor UEs. In some examples, the target UE may instead estimate its own location. In this case, the anchor UE may receive a report from the target UE indicating the location of the target UE.

[0419] Although the present disclosure provides several embodiments, it should be understood that the disclosed systems and methods may be embodied in other various specific forms without departing from the spirit or scope of the present disclosure. The current examples are considered to be illustrative rather than restrictive, and are not intended to be limited to the details given herein. For example, various elements or components may be combined or integrated in another system, or some features may be omitted or not implemented.

[0420] In addition, without departing from the scope of the present disclosure, the techniques, systems, subsystems and methods described and illustrated as discrete or separate in the various embodiments may be combined or integrated with other systems, modules, techniques or methods. Other items shown or discussed as coupled or directly coupled or communicating with each other may also be indirectly coupled or communicated through an interface, device or intermediate component using electrical, mechanical or other means. Other examples of changes, substitutions, and alterations may be determined by those skilled in the art and may be exemplified without departing from the spirit and scope disclosed herein.

Claims

1. A method implemented by a target user equipment (UE), characterized in that: The method comprises: sending a positioning request to one or more anchor UEs via sidelink communication; receiving a positioning signal from the one or more anchor UEs via the sidelink communication; Positioning measurements are performed based on the positioning signal.

2. The method according to claim 1, characterized in that The target UE communicates with the one or more anchor UEs according to perception-based resource selection of sidelink resources.

3. The method according to claim 1 or 2, characterized in that: The target UE communicates with the one or more anchor UEs through resource reservation provided by a fifth generation (5G) base station (gNB).

4. The method according to any one of claims 1 to 3, characterized in that The positioning signal includes a sidelink positioning reference signal (SL Pos-RS).

5. The method according to claim 4, characterized in that The positioning request includes at least one of a SL Pos-RS signaling option or a SL Pos-RS signaling configuration.

6. The method according to any one of claims 1 to 5, characterized in that Also includes: Before sending the positioning request to the anchor UE, the one or more anchor UEs are selected from a plurality of additional anchor UEs.

7. The method according to any one of claims 1 to 6, characterized in that Also includes: The position of the target UE is estimated based on the positioning measurements and the positions of the one or more anchor UEs.

8. The method according to any one of claims 1 to 7, characterized in that Also includes: Prior to sending the positioning request to the one or more anchor UEs, an initial positioning request is received from a serving anchor UE through the sidelink communication.

9. The method according to any one of claims 1 to 8, characterized in that Also includes: The positioning measurements are sent to a serving anchor UE via the sidelink communication to estimate a position of the target UE.

10. The method according to any one of claims 1 to 9, characterized in that Sending the positioning request is triggered by a condition, wherein the condition includes at least one of a reference signal received power (RSRP) relative to a first threshold, a distance relative to a second threshold, a number of UE anchor points relative to a third threshold, or a channel condition relative to a fourth threshold.

11. The method according to any one of claims 1 to 10, characterized in that The one or more anchor UEs are selected based on a UE anchor indication and a UE anchor level.

12. The method according to any one of claims 1 to 11, characterized in that The UE anchor indication indicates whether the corresponding UE is capable of serving as an anchor UE, and indicates whether the corresponding UE is allowed to serve as an anchor UE.

13. The method according to any one of claims 1 to 12, characterized in that The UE anchor level is set based on at least one of a synchronization source, a priority, a positioning accuracy, a maximum bandwidth, a coverage indicator, or a sidelink synchronization signal identifier (SLSSID).

14. The method according to any one of claims 1 to 13, characterized in that Also includes: After obtaining at least one of an anchor UE location, a channel measurement, or a timing measurement, the one or more anchor UEs are reselected.

15. A method implemented by an anchor user equipment (UE), characterized in that: The method comprises: sending a positioning request to a target UE via a sidelink communication; receiving a positioning signal from the target UE via the sidelink communication; Performing positioning measurements on the target UE based on the positioning signal.

16. The method according to claim 15, characterized in that The anchor UE communicates with the target UE according to perception-based resource selection of sidelink resources.

17. The method according to claim 15 or 16, characterized in that The anchor UE communicates with the target UE through resource reservation provided by a fifth generation (5G) base station (gNB).

18. The method according to any one of claims 15 to 17, characterized in that The positioning signal includes a sidelink positioning reference signal (SL Pos-RS).

19. The method according to any one of claims 15 to 18, characterized in that Also includes: A position of the target UE is estimated based on the positioning measurements.

20. The method according to any one of claims 15 to 19, characterized in that The positioning request triggers the target UE to send one or more second positioning requests to one or more coordination anchor UEs.

21. The method according to any one of claims 15 to 20, characterized in that The positioning signal from the target UE includes location information from one or more coordination anchor UEs.

22. The method according to any one of claims 15 to 20, characterized in that Also includes: The location information is received from one or more coordination anchor UEs.

23. The method according to any one of claims 15 to 22, characterized in that Also includes: One or more second positioning requests are sent to one or more coordination anchor UEs.

24. The method according to any one of claims 15 to 23, characterized in that The positioning request is triggered by a condition, wherein the condition includes at least one of a reference signal received power (RSRP) relative to a first threshold, a distance relative to a second threshold, a number of UE anchor points relative to a third threshold, or a channel condition relative to a fourth threshold.

25. The method according to any one of claims 15 to 24, characterized in that Also includes: A UE anchor indication is sent, wherein the UE anchor indication indicates whether the anchor UE is capable of acting as an anchor UE and whether the anchor UE is allowed to act as the anchor UE.

26. The method according to any one of claims 15 to 25, characterized in that Also includes: A UE anchor level is sent, where the UE anchor level is set based on at least one of a synchronization source, a priority, a positioning accuracy, a maximum bandwidth, a coverage indicator, or a sidelink synchronization signal identifier (SLSSID).

27. The method according to any one of claims 1 to 27, characterized in that The one or more anchor UEs are selected according to a line-of-sight (LOS) / non line-of-sight (NLOS) indicator.

28. A user equipment (UE), characterized in that: include: one or more processors; a transmitter coupled to the one or more processors; A receiver coupled to the one or more processors, wherein the one or more processors, the transmitter and the receiver are configured to perform the method according to any one of claims 1 to 27.

29. A non-transitory computer readable medium, characterized in that A computer program product for use with a user equipment (UE), the computer program product comprising computer executable instructions stored in the non-transitory computer readable medium, wherein the computer executable instructions, when executed by one or more processors, cause the UE to perform a method according to any one of claims 1 to 27.

30. A target user equipment (UE), characterized in that: Comprising one or more means for performing the method according to any one of claims 1 to 14.

31. An anchor user equipment (UE), characterized in that: Comprising one or more means for performing a method according to any one of claims 15 to 27.

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