Sidelink assisted position estimation procedure

Abstract

Techniques for wireless communications are disclosed. In one aspect, a location estimation entity (e.g., UE, gNB, LMF, etc.) identifies a pool of UEs for a SL-assisted location estimation procedure for a set of target UEs. SL SRS-Ps are communicated (e.g., transmitted and measured) among the pool of UEs (e.g., for relative SL ranging). UL SRS-Ps are communicated by at least some of the UEs in the pool of UEs. The location estimation entity obtains measurement data for both SL SRS-P and UL-SRS-P communications. The location estimation entity determines a location estimate for each UE in the set of UEs based on the measurement information.

Description

[Technical field]

[0001] Concerning sidelink assisted position estimation procedures. [Background technology]

[0002] 1. Field of disclosure Aspects of the present disclosure relate generally to wireless communications.

[0003] 2. Description of Related Technology Wireless communication systems have evolved through various generations, including first-generation analog wireless telephone service (1G), second-generation (2G) digital wireless telephone service (including interim 2.5G and 2.75G networks), third-generation (3G) high-speed data, Internet-enabled wireless service, and fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax). Currently, many different types of wireless communication systems are in use, including cellular systems and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog advanced mobile phone system (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), Global System for Mobile communications (GSM), and the like.

[0004] The fifth generation (5G) wireless standard, called New Radio (NR), calls for higher data rates, a larger number of connections, and better coverage, among other improvements. According to the Next Generation Mobile Network Alliance, the 5G standard is designed to provide data rates of tens of megabits per second to tens of thousands of users, providing 1 gigabit per second to a few dozen workers on an office floor. To support large-scale deployment of sensors, hundreds of thousands of simultaneous connections must be supported. Therefore, the spectral efficiency of 5G mobile communications should be significantly increased compared to the current 4G standard. Furthermore, signaling efficiency must be increased and latency significantly reduced compared to the current standard. Summary of the Invention [Means for solving the problem]

[0005] The following presents a simplified summary related to one or more aspects disclosed herein. As such, the following summary is not intended to be an extensive overview of all contemplated aspects, nor is it intended to identify key or critical elements of all contemplated aspects or to delineate the scope related to any particular aspect. Thus, the sole purpose of the following summary is to present certain concepts of one or more aspects of the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0006] In one aspect, a method of operating a position estimation entity includes identifying a pool of UEs for a sidelink (SL)-assisted position estimation procedure for a set of target user equipments (UEs); determining a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; determining a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs; transmitting a first indication of the first resource configuration to the pool of UEs; transmitting a second indication of the second resource configuration to the at least one UE; receiving first measurement information based on measurements of the at least one SL SRS-P in accordance with the first resource configuration; The method includes receiving second measurement information based on measurements of the SRS-P, and determining a location estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0007] In some aspects, each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is to be communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0008] In some aspects, one or more SL connections between UEs in a pool of UEs are set up with a SL-assisted position estimation procedure.

[0009] In some aspects, the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of at least one UL SRS-P.

[0010] In some aspects, the method includes selecting at least one UE in a pool of UEs for transmission of the at least one UL SRS-P based in part on the first measurement information.

[0011] In some aspects, the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0012] In some aspects, the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0013] In some aspects, the method includes determining to perform another SL-assisted position estimation procedure including some or all of the pool of UEs, where at least one UE designated to transmit at least one UL SRS-P is updated for the another SL-assisted position estimation procedure based on information obtained in connection with the SL-assisted position estimation procedure.

[0014] In some aspects the method includes transmitting an indication of the determined position estimate.

[0015] In some aspects, an indication of the determined location estimate is sent individually to each of the set of target UEs, or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UE.

[0016] In some aspects, one or more UEs in the pool of UEs are not part of the set of target UEs.

[0017] In some aspects, the one or more UEs correspond to anchor UEs associated with one or more known position estimates.

[0018] In some aspects, the pool of UEs includes two or more subsets of UEs, where each UE in each subset of UEs has an established SL connection to each other UE in the same subset of UEs, and where at least one UE in each subset of UEs has an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0019] In some aspects, the location estimation entity corresponds to a UE or a network component in a pool of UEs.

[0020] In some aspects, the first measurement data is received via individual reports from multiple UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by the multiple UEs is received via a lead UE of the pool of UEs.

[0021] In one aspect, a method of operating a user equipment (UE) includes receiving a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; receiving a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmitting the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration, measuring a second SL SRS-P from another UE in the pool of UEs, or both; and transmitting the UL SRS-P in accordance with the second resource configuration.

[0022] In some aspects, the UE further includes receiving a position estimate for the UE that is among the set of target UEs and associated with the SL-assisted position estimation procedure.

[0023] In some aspects, the position estimate is received from a position estimation entity or from another UE in a pool of UEs.

[0024] In some aspects, the UE has an established SL connection to each of one or more other UEs in the pool of UEs prior to receipt of the first indication.

[0025] In some aspects, one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up in conjunction with a SL-assisted position estimation procedure.

[0026] In some aspects, the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of the UL SRS-P.

[0027] In some aspects, the second set of resources precedes the first set of resources such that a UL SRS-P transmission occurs before at least one SL SRS-P is communicated.

[0028] In some aspects, the UEs in the pool of UEs are not part of the set of target UEs.

[0029] In some aspects, the UE corresponds to an anchor UE associated with a known position estimate.

[0030] In some aspects, the UE and one or more other UEs form a subset of UEs in the pool of UEs, each UE in the subset of UEs has an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs has an established SL connection to at least one other UE in at least one other subset of UEs.

[0031] In some aspects, the UE further includes measuring a second SL SRS-P from another UE and transmitting measurement data based on the measurement of the second SL SRS-P directly to a position estimation entity or a lead UE of the pool of UEs.

[0032] In one aspect, a location estimation entity includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: identify a pool of target user equipment (UE) for a sidelink (SL)-assisted location estimation procedure for a set of UEs; and determine a first resource configuration for the SL-assisted location estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs. the at least one transceiver; receiving, via the at least one transceiver, first measurement information based on measurements of the at least one SL SRS-P in accordance with the first resource configuration; receiving, via the at least one transceiver, second measurement information based on measurements of the at least one UL SRS-P in accordance with the second resource configuration; and determining a position estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0033] In some aspects, each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is to be communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0034] In some aspects, one or more SL connections between UEs in a pool of UEs are set up with a SL-assisted position estimation procedure.

[0035] In some aspects, the first set of resources precedes the second set of resources, with at least one SL SRS-P being communicated prior to the transmission of the at least one UL SRS-P.

[0036] In some aspects, the at least one processor is further configured to select at least one UE in the pool of UEs for transmission of the at least one UL SRS-P based in part on the first measurement information.

[0037] In some aspects, the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0038] In some aspects, the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0039] In some aspects, the at least one processor is further configured to determine to perform another SL-assisted position estimation procedure including some or all of the pool of UEs, and at least one UE designated to transmit the at least one UL SRS-P is updated for the another SL-assisted position estimation procedure based on information obtained in connection with the SL-assisted position estimation procedure.

[0040] In some aspects the at least one processor is further configured to transmit, via the at least one transceiver, an indication of the determined position estimate.

[0041] In some aspects, an indication of the determined location estimate is sent individually to each of the set of target UEs, or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UE.

[0042] In some aspects, one or more UEs in the pool of UEs are not part of the set of target UEs.

[0043] In some aspects, the one or more UEs correspond to anchor UEs associated with one or more known position estimates.

[0044] In some aspects, the pool of UEs includes two or more subsets of UEs, where each UE in each subset of UEs has an established SL connection to each other UE in the same subset of UEs, and where at least one UE in each subset of UEs has an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0045] In some aspects, the location estimation entity corresponds to a UE or a network component in a pool of UEs.

[0046] In some aspects, the first measurement data is received via individual reports from multiple UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by the multiple UEs is received via a lead UE of the pool of UEs.

[0047] In one aspect, a user equipment (UE) includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor including: receiving, via the at least one transceiver, a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; receiving, via the at least one transceiver, a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmitting, via the at least one transceiver, the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration; receiving, via the at least one transceiver, a second SL SRS-P from another UE in the pool of UEs in accordance with the first resource configuration; and / or transmitting, via the at least one transceiver, the UL SRS-P in accordance with the second resource configuration.

[0048] In some aspects, the UE is among the set of target UEs, and further includes: the at least one processor further configured to receive, via the at least one transceiver, a position estimate of the UE associated with the SL-assisted position estimation procedure.

[0049] In some aspects, the position estimate is received from a position estimation entity or from another UE in a pool of UEs.

[0050] In some aspects, the UE has an established SL connection to each of one or more other UEs in the pool of UEs prior to receipt of the first indication.

[0051] In some aspects, one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up in conjunction with a SL-assisted position estimation procedure.

[0052] In some aspects, the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of the UL SRS-P.

[0053] In some aspects, the second set of resources precedes the first set of resources such that transmission of a UL SRS-P occurs before at least one SL SRS-P is communicated.

[0054] In some aspects, the UEs in the pool of UEs are not part of the set of target UEs.

[0055] In some aspects, the UE corresponds to an anchor UE associated with a known position estimate.

[0056] In some aspects, the UE and one or more other UEs form a subset of UEs in the pool of UEs, each UE in the subset of UEs has an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs has an established SL connection to at least one other UE in at least one other subset of UEs.

[0057] In some aspects, the UE measures a second SL SRS-P from another UE, and the at least one processor is further configured to transmit, via the at least one transceiver, measurement data based on the measurement of the second SL SRS-P to a location estimation entity or directly to a lead UE of the pool of UEs.

[0058] In one aspect, a position estimation entity includes means for identifying a pool of UEs for a sidelink (SL)-assisted position estimation procedure of a set of target user equipments (UEs), means for determining a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs, means for determining a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs, means for transmitting a first indication of the first resource configuration to the pool of UEs, means for transmitting a second indication of the second resource configuration to the at least one UE, means for receiving first measurement information based on measurement of the at least one SL SRS-P in accordance with the first resource configuration, and means for receiving at least one UL SRS-P in accordance with the second resource configuration. The method includes: receiving second measurement information based on measurements of the SRS-P; and determining a position estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0059] In some aspects, each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is to be communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0060] In some aspects, one or more SL connections between UEs in a pool of UEs are set up with a SL-assisted position estimation procedure.

[0061] In some aspects, the first set of resources precedes the second set of resources such that the at least one SL SRS-P is communicated before transmission of the at least one UL SRS-P.

[0062] In some aspects, the method includes means for selecting at least one UE in a pool of UEs for transmission of the at least one UL SRS-P based in part on the first measurement information.

[0063] In some aspects, the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0064] In some aspects, the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0065] In some aspects, the method includes means for determining to perform another SL-assisted position estimation procedure including some or all of the pool of UEs, where at least one UE designated to transmit at least one UL SRS-P is updated for the another SL-assisted position estimation procedure based on information obtained in connection with the SL-assisted position estimation procedure.

[0066] In some aspects the method includes means for transmitting an indication of the determined position estimate.

[0067] In some aspects, an indication of the determined location estimate is sent individually to each of the set of target UEs, or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UE.

[0068] In some aspects, one or more UEs in the pool of UEs are not part of the set of target UEs.

[0069] In some aspects, the one or more UEs correspond to anchor UEs associated with one or more known position estimates.

[0070] In some aspects, the pool of UEs includes two or more subsets of UEs, where each UE in each subset of UEs has an established SL connection to each other UE in the same subset of UEs, and where at least one UE in each subset of UEs has an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0071] In some aspects, the location estimation entity corresponds to a UE or a network component in a pool of UEs.

[0072] In some aspects, the first measurement data is received via individual reports from multiple UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by the multiple UEs is received via a lead UE of the pool of UEs.

[0073] In one aspect, the user equipment includes means for receiving a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; means for receiving a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; means for transmitting the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration, measuring a second SL SRS-P from another UE in the pool of UEs, or both; and means for transmitting the UL SRS-P in accordance with the second resource configuration.

[0074] In some aspects, the UE further includes means for receiving a position estimate for a UE that is among the set of target UEs and associated with the SL-assisted position estimation procedure.

[0075] In some aspects, the position estimate is received from a position estimation entity or from another UE in a pool of UEs.

[0076] In some aspects, the UE has an established SL connection to each of one or more other UEs in the pool of UEs prior to receipt of the first indication.

[0077] In some aspects, one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up in conjunction with a SL-assisted position estimation procedure.

[0078] In some aspects, the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of a UL SRS-P.

[0079] In some aspects, the second set of resources precedes the first set of resources such that transmission of a UL SRS-P occurs before at least one SL SRS-P is communicated.

[0080] In some aspects, the UEs in the pool of UEs are not part of the set of target UEs.

[0081] In some aspects, the UE corresponds to an anchor UE associated with a known position estimate.

[0082] In some aspects, the UE and one or more other UEs form a subset of UEs in the pool of UEs, each UE in the subset of UEs has an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs has an established SL connection to at least one other UE in at least one other subset of UEs.

[0083] In some aspects, the UE further includes means for measuring a second SL SRS-P from another UE and transmitting measurement data based on the measurement of the second SL SRS-P directly to a location estimation entity or a lead UE of the pool of UEs.

[0084] In one aspect, when performed by a location estimation entity, the method includes: identifying a pool of target user equipment (UE) UEs for a sidelink (SL)-assisted location estimation procedure for a set of UEs; determining a first resource configuration for the SL-assisted location estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; determining a second resource configuration for the SL-assisted location estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs; transmitting a first indication of the first resource configuration to the pool of UEs; transmitting a second indication of the second resource configuration to the at least one UE; receiving first measurement information based on measurement of the at least one SL SRS-P in accordance with the first resource configuration; and transmitting at least one UL SRS-P in accordance with the second resource configuration. A non-transitory computer-readable medium storing computer-executable instructions to cause a device to receive second measurement information based on measurements of the SRS-P, and to determine a position estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0085] In some aspects, each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is to be communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0086] In some aspects, one or more SL connections between UEs in a pool of UEs are set up with a SL-assisted position estimation procedure.

[0087] In some aspects, the first set of resources precedes the second set of resources such that the at least one SL SRS-P is communicated before transmission of the at least one UL SRS-P.

[0088] In some aspects, the instructions when executed by the position estimation entity further cause the position estimation entity to: In some aspects, the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0089] In some aspects, the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0090] In some aspects, the instructions when executed by the position estimation entity further cause the position estimation entity to: In some aspects, the instructions when executed by the position estimation entity further cause the position estimation entity to: In some aspects, an indication of the determined location estimate is sent individually to each of the set of target UEs, or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UE.

[0091] In some aspects, one or more UEs in the pool of UEs are not part of the set of target UEs.

[0092] In some aspects, the one or more UEs correspond to anchor UEs associated with one or more known position estimates.

[0093] In some aspects, the pool of UEs includes two or more subsets of UEs, where each UE in each subset of UEs has an established SL connection to each other UE in the same subset of UEs, and where at least one UE in each subset of UEs has an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0094] In some aspects, the location estimation entity corresponds to a UE or a network component in a pool of UEs.

[0095] In some aspects, the first measurement data is received via individual reports from multiple UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by the multiple UEs is received via a lead UE of the pool of UEs.

[0096] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions that, when executed by a user equipment (UE), cause the UE to: receive a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; receive a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmit the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration, measure a second SL SRS-P from another UE in the pool of UEs, or both, and transmit the UL SRS-P in accordance with the second resource configuration.

[0097] In some aspects, the UE is among a set of target UEs, and the instructions further cause the UE to receive a position estimate for the UE associated with the SL-assisted position estimation procedure.

[0098] In some aspects, the position estimate is received from a position estimation entity or from another UE in a pool of UEs.

[0099] In some aspects, the UE has an established SL connection to each of one or more other UEs in the pool of UEs prior to receipt of the first indication.

[0100] In some aspects, one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up in conjunction with a SL-assisted position estimation procedure.

[0101] In some aspects, the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of a UL SRS-P.

[0102] In some aspects, the second set of resources precedes the first set of resources such that transmission of a UL SRS-P occurs before at least one SL SRS-P is communicated.

[0103] In some aspects, the UEs in the pool of UEs are not part of the set of target UEs.

[0104] In some aspects, the UE corresponds to an anchor UE associated with a known position estimate.

[0105] In some aspects, the UE and one or more other UEs form a subset of UEs in the pool of UEs, each UE in the subset of UEs has an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs has an established SL connection to at least one other UE in at least one other subset of UEs.

[0106] In some aspects, the UE measures a second SL SRS-P from another UE, further comprising: the instructions further causing the UE to transmit measurement data based on the measurement of the second SL SRS-P directly to a position estimation entity or a lead UE of a pool of UEs.

[0107] Other objects and advantages associated with the embodiments disclosed herein will become apparent to those skilled in the art based on the accompanying drawings and detailed description.

[0108] The accompanying drawings are presented to aid in the explanation of various aspects of the present disclosure and are provided only to illustrate, not limit, the aspects. [Brief description of the drawings]

[0109] [Figure 1] 1 illustrates an example wireless communication system according to an aspect of the present disclosure. [Figure 2A] 1 illustrates an exemplary wireless network structure according to an aspect of the present disclosure. [Figure 2B] 1 illustrates an exemplary wireless network structure according to an aspect of the present disclosure. [Figure 3A] 1 is a simplified block diagram of several sample aspects of components that may be employed in a user equipment (UE) and configured to support communications as taught herein; [Figure 3B] 1 is a simplified block diagram of several sample aspects of components that may be employed in a base station and configured to support communications as taught herein. [Figure 3C] 1 is a simplified block diagram of several sample aspects of components that may be employed in a network entity and configured to support communications as taught herein. [Figure 4] FIG. 2 is a block diagram illustrating various components of an exemplary user equipment (UE) in accordance with aspects of the present disclosure. [Diagram 5] 1 illustrates an example of a wireless communication system supporting unicast sidelink establishment in accordance with an aspect of the present disclosure. [Figure 6] FIG. 2 illustrates an example frame structure according to an aspect of the present disclosure. [Figure 7] FIG. 1 illustrates various uplink channels in an example uplink slot, in accordance with an aspect of the disclosure. [Figure 8] 1 illustrates examples of various positioning methods according to aspects of the present disclosure. [Figure 9] 1 illustrates a sidelink communication scheduling (or resource allocation) scheme according to an aspect of the present disclosure. [Figure 10] 1 illustrates an example wireless communication system in which a vehicle user equipment (V-UE) is exchanging ranging signals with a roadside unit (RSU) and another V-UE, in accordance with an aspect of the present disclosure. [Figure 11] 1 illustrates another sidelink positioning scheme according to an aspect of the present disclosure. [Figure 12] 1 illustrates another UE distribution scenario for sidelink positioning, in accordance with an aspect of the present disclosure. [Figure 13] 1 illustrates an example process for wireless communication according to an aspect of the present disclosure. [Figure 14] 1 illustrates an example process for wireless communication according to an aspect of the present disclosure. [Figure 15] 15 illustrates an example implementation of the process of FIGS. 13-14, respectively, according to one embodiment of the present disclosure. [Figure 16] 15 illustrates an exemplary implementation of the process of FIGS. 13-14, respectively, according to another aspect of the disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0110] Aspects of the present disclosure are provided in the following description and associated drawings directed to various examples provided for illustrative purposes. Alternative aspects may be devised without departing from the scope of the present disclosure. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the present disclosure.

[0111] The words "exemplary" and / or "example" are used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" and / or "example" is not necessarily to be construed as preferred or advantageous over other aspects. Similarly, the term "aspects of the present disclosure" does not require that all aspects of the present disclosure include the discussed feature, advantage or mode of operation.

[0112] Those skilled in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the following description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, desired design, corresponding technology, etc.

[0113] Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be appreciated that various actions described herein may be performed by specific circuitry (e.g., an application specific integrated circuit (ASIC), by program instructions executed by one or more processors, or by a combination of both. In addition, a sequence of actions described herein may be considered to be embodied entirely in any form of non-transitory computer-readable storage medium storing a corresponding set of computer instructions that, when executed, cause or instruct an associated processor of a device to perform the functionality described herein. Thus, various aspects of the present disclosure may be embodied in a number of different forms, all of which are contemplated to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspect may be described herein, for example, as "logic configured to" perform the described actions.

[0114] The terms "user equipment" (UE) and "base station" as used herein are not intended to be specific or otherwise limited to any particular radio access technology (RAT) unless otherwise specified. In general, a UE may be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, a consumer location device, a wearable (e.g., a smart watch, glasses, augmented reality (AR) / virtual reality (VR) headset, etc.), a vehicle (e.g., a car, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. A UE may be mobile or stationary (e.g., at a given time) and may communicate with a radio access network (RAN). As used herein, the term "UE" may be referred to interchangeably as an "access terminal" or "AT", "client device", "wireless device", "subscriber device", "subscriber terminal", "subscriber station", "user terminal" or "UT", "mobile device", "mobile terminal", "mobile station", or variations thereof. In general, a UE may communicate with a core network via a RAN, through which the UE may be connected to external networks, such as the Internet, and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for a UE, such as via a wired access network, a wireless local area network (WLAN) network (e.g., based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 specifications, etc.).

[0115] A base station may operate according to one of several RATs in communication with UEs depending on the network in which the base station is deployed and may alternatively be referred to as an access point (AP), network node, Node B, evolved Node B (eNB), next generation eNB (ng-eNB), New Radio (NR) Node B (also referred to as gNB or gNodeB), etc. A base station may be primarily used to support wireless access by UEs, including supporting data, voice, and / or signaling connections for supported UEs. In some systems, a base station may provide only edge node signaling functionality, while in other systems, a base station may provide additional control and / or network management functionality. A communication link through which a UE may send signals to a base station is referred to as an uplink (UL) channel (e.g., reverse traffic channel, reverse control channel, access channel, etc.). A communication link through which a base station may send signals to a UE is referred to as a downlink (DL) channel or a forward link channel (e.g., paging channel, control channel, broadcast channel, forward traffic channel, etc.). As used herein, the term traffic channel (TCH) can refer to either an uplink / reverse traffic channel or a downlink / forward traffic channel.

[0116] The term "base station" may refer to a single physical transmission-reception point (TRP) or multiple physical TRPs that may or may not be collocated. For example, when the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station that corresponds to a cell (or several cell sectors) of the base station. When the term "base station" refers to multiple collocated physical TRPs, the physical TRP may be an array of antennas of the base station (e.g., as in the case of a multiple-input multiple-output (MIMO) system or when the base station employs beamforming). When the term "base station" refers to multiple non-collocated physical TRPs, the physical TRP may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, non-co-located physical TRPs may be serving base stations that receive measurement reports from the UE and neighboring base stations whose reference radio frequency (RF) signals the UE is measuring. Since a TRP is a point from which a base station transmits and receives wireless signals, as used herein, references to transmission from or reception at a base station should be understood as referring to a particular TRP of the base station.

[0117] In some implementations that support positioning of UEs, a base station may not support wireless access by the UE (e.g., may not support data, voice, and / or signaling connections for the UE) but may instead transmit reference signals to the UE to be measured by the UE and / or receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., when it transmits signals to the UE) and / or a location measurement unit (e.g., when it receives and measures signals from the UE).

[0118] An "RF signal" includes electromagnetic waves of a given frequency that transport information through space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels. The same transmitted RF signal on different paths between a transmitter and a receiver may be referred to as a "multipath" RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply a "signal" when it is clear from the context that the term "signal" refers to a wireless signal or an RF signal.

[0119] 1 illustrates an example wireless communication system 100 according to aspects of the disclosure. The wireless communication system 100 (sometimes referred to as a wireless wide area network, WWAN) may include various base stations 102 (labeled "BS") and various UEs 104. The base stations 102 may include macrocell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). In an aspect, the macrocell base stations may include eNBs and / or ng-eNBs where the wireless communication system 100 corresponds to an LTE network, or gNBs where the wireless communication system 100 corresponds to an NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0120] The base stations 102 may collectively form a RAN and may interface with a core network 170 (e.g., evolved packet core (EPC) or 5G core (5GC)) through the backhaul links 122 and with one or more location servers 172 (e.g., a location management function (LMF) or a secure user plane location (SUPL) location platform (SLP)) through the core network 170. The location server 172 may be part of the core network 170 or may be external to the core network 170. The location server 172 may be integrated with the base station 102. The UE 104 may communicate with the location server 172 directly or indirectly. For example, the UE 104 may communicate with the location server 172 through the base station 102 currently serving the UE 104. The UE 104 may also communicate with the location server 172 through another path, such as through an application server (not shown), through another network, such as through a wireless local area network (WLAN) access point (AP) (e.g., AP 150 described below), etc. For purposes of signaling, communication between the UE 104 and the location server 172 may be represented as an indirect connection (e.g., through a core network 170, etc.) or a direct connection (e.g., as shown via direct connection 128), with intervening nodes (if any) omitted from the signaling diagrams for clarity.

[0121] In addition to other functions, the base stations 102 may perform functions related to one or more of forwarding user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracing, RAN information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through EPC / 5GC) via backhaul links 134, which may be wired or wireless.

[0122] The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage to a respective geographic coverage area 110. In an aspect, one or more cells may be supported by the base stations 102 in each geographic coverage area 110. A "cell" is a logical communication entity used for communication with a base station (e.g., over some frequency resources, referred to as a carrier frequency, component carrier, carrier, band, etc.) and may be associated with an identifier (e.g., a physical cell identifier (PCI), an enhanced cell identifier (ECI), a virtual cell identifier (VCI), a cell global identifier (CGI), etc.) to distinguish cells operating over the same or different carrier frequencies. In some cases, different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of UEs. Since a cell is supported by a particular base station, the term "cell" may refer to one or both of the logical communication entity and the base station that supports it, depending on the context. In addition, since a TRP is typically a physical transmission point of a cell, the terms "cell" and "TRP" may be used interchangeably. In some cases, the term "cell" may also refer to the geographic coverage area (e.g., sector) of a base station, as long as the carrier frequency can be detected and used for communication within a portion of the geographic coverage area 110.

[0123] The geographic coverage areas 110 of neighboring macrocell base stations 102 may overlap partially (e.g., in handover regions), and some of the geographic coverage areas 110 may be substantially overlapped by larger geographic coverage areas 110. For example, a small cell base station 102' (labeled "SC" instead of "small cell") may have a geographic coverage area 110' that significantly overlaps with the geographic coverage area 110 of one or more macrocell base stations 102. A network that includes both small cell base stations and macrocell base stations may be known as a heterogeneous network. A heterogeneous network may also include home eNBs (HeNBs), which may serve closed groups known as closed subscriber groups (CSGs).

[0124] The communication link 120 between the base station 102 and the UE 104 may include uplink (also referred to as reverse link) transmissions from the UE 104 to the base station 102, and / or downlink (DL) (also referred to as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna techniques, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be through one or more carrier frequencies. The allocation of carriers may be asymmetric with respect to the downlink and uplink (e.g., more or fewer carriers may be allocated for the downlink than for the uplink).

[0125] The wireless communication system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with a WLAN station (STA) 152 over a communication link 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in the unlicensed frequency spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure before communicating to determine if a channel is available.

[0126] The small cell base station 102' may operate in a licensed and / or unlicensed frequency spectrum. When operating in the unlicensed frequency spectrum, the small cell base station 102' may utilize LTE or NR technology and use the same 5 GHz unlicensed frequency spectrum used by the WLAN AP 150. A small cell base station 102' employing LTE / 5G in the unlicensed frequency spectrum may extend coverage to and / or increase capacity of the access network. NR in the unlicensed spectrum may be referred to as NR-U. LTE in the unlicensed spectrum may be referred to as LTE-U, licensed assisted access (LAA), or MulteFire.

[0127] The wireless communication system 100 may further include a millimeter wave (mmW) base station 180 that may operate in mmW and / or sub-mmW frequencies in communication with the UE 182. Extremely high frequency (EHF) is a part of RF in the electromagnetic spectrum. EHF ranges from 30 GHz to 300 GHz and has a wavelength between 1 and 10 millimeters. Radio waves in this band may be referred to as millimeter waves. Sub-mmW may extend down to frequencies of 3 GHz with wavelengths of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communications using the mmW / sub-mmW radio frequency bands have high path losses and relatively short distances. The mmW base station 180 and the UE 182 may utilize beamforming (transmit and / or receive) over the mmW communication link 184 to compensate for the extremely large path losses and short distances. It will be further appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or quasi-mmW and beamforming. Thus, it will be appreciated that the above illustrations are merely examples and should not be construed as limiting various aspects disclosed herein.

[0128] Transmit beamforming is a technique for focusing an RF signal in a particular direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omnidirectionally). With transmit beamforming, the network node determines where a given target device (e.g., UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that particular direction, thereby providing a faster and more powerful RF signal (in terms of data rate) to the receiving device. To vary the directionality of the RF signal when transmitting, the network node can control the phase and relative amplitude of the RF signal at each of one or more transmitters broadcasting the RF signal. For example, the network node can use an array of antennas (also called a "phased array" or "antenna array") that creates beams of RF waves that can be "steered" to point in different directions without actually moving the antennas. In particular, RF current from a transmitter is fed to each antenna with the correct phase relationship so that the radio waves from the separate antennas combine together to enhance radiation in the desired direction while suppressing and canceling radiation in undesirable directions.

[0129] A transmit beam may be quasi-co-located, meaning that the transmit beam appears to a receiver (e.g., UE) to have the same parameters, regardless of whether the network node's own transmit antennas are physically co-located or not. In NR, there are four types of quasi-co-location (QCL) relationships. Specifically, a QCL relationship of a given type means that certain parameters for a second reference RF signal on a second beam can be derived from information about a source reference RF signal on a source beam. Thus, if the source reference RF signal is QCL type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type D, the receiver can use the source reference RF signal to estimate spatial reception parameters of a second reference RF signal transmitted on the same channel.

[0130] In receive beamforming, a receiver uses a receive beam to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting and / or adjust the phase setting of an array of antennas in a particular direction to amplify (e.g., increase the gain level) RF signals received from that direction. Thus, when a receiver is said to beamform in a particular direction, it means that the beam gain in that direction is higher than the beam gains along other directions, or that the beam gain in that direction is the highest compared to the beam gains in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) of RF signals received from that direction.

[0131] The transmit beam and the receive beam may be spatially related. The spatial relationship means that the parameters for the second beam (e.g., transmit beam or receive beam) for the second reference signal may be derived from information about the first beam (e.g., receive beam or transmit beam) for the first reference signal. For example, the UE may use a particular receive beam to receive a reference downlink reference signal (e.g., synchronization signal block (SSB)) from a base station. The UE may then form a transmit beam for transmitting an uplink reference signal (e.g., sounding reference signal (SRS)) to that base station based on the parameters of the receive beam.

[0132] Note that a "downlink" beam can be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station forms a downlink beam to transmit a reference signal to the UE, then the downlink beam is a transmit beam. However, if the UE forms a downlink beam, then it is a receive beam to receive a downlink reference signal. Similarly, an "uplink" beam can be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if the base station forms an uplink beam, then it is an uplink receive beam, and if the UE forms an uplink beam, then it is an uplink transmit beam.

[0133] In 5G, the frequency spectrum in which wireless nodes (e.g., base stations 102 / 180, UEs 104 / 182) operate is divided into multiple frequency ranges: FR1 (450-6000 MHz), FR2 (24250-52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). The mmW frequency band generally includes the FR2, FR3, and FR4 frequency ranges. Thus, the terms "mmW" and "FR2" or "FR3" or "FR4" may generally be used interchangeably.

[0134] In a multi-carrier system such as 5G, one of the carrier frequencies is called the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell" and the remaining carrier frequencies are called the "secondary carrier" or "secondary serving cell" or "SCell". In carrier aggregation, the anchor carrier is a carrier operating on the primary frequency (e.g., FR1) utilized by the UE 104 / 182 and on the cell in which the UE 104 / 182 either performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure. The primary carrier carries all common control channels and UE-specific control channels and may (but is not always) be a carrier among licensed frequencies. The secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once an RRC connection is established between the UE 104 and the anchor carrier and may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier in unlicensed frequencies. Since both the primary uplink carrier and the primary downlink carrier are typically UE specific, the secondary carrier may contain only the necessary signaling information and signals, e.g., the signaling information and signals that are UE specific may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same applies to the uplink primary carrier. The network may change the primary carrier of any UE 104 / 182 at any time. This is done, for example, to distribute the load on different carriers. Since a "serving cell" (whether PCell or SCell) corresponds to a carrier frequency / component carrier over which several base stations are communicating, terms such as "cell", "serving cell", "component carrier", "carrier frequency", etc. may be used interchangeably.

[0135] For example, still referring to FIG. 1, one of the frequencies utilized by the macrocell base station 102 may be an anchor carrier (or "PCell"), and the other frequencies utilized by the macrocell base station 102 and / or the mmW base station 180 may be secondary carriers ("SCells"). Simultaneous transmission and / or reception of multiple carriers allows the UE 104 / 182 to significantly increase its data transmission and / or data reception rates. For example, two aggregated 20 MHz carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz) compared to the data rate achieved by a single 20 MHz carrier.

[0136] The wireless communications system 100 may further include a UE 164, which may communicate with the macrocell base station 102 via communications link 120 and / or with the mmW base station 180 via an mmW communications link 184. For example, the macrocell base station 102 may support a PCell and one or more SCells for the UE 164, and the mmW base station 180 may support one or more SCells for the UE 164.

[0137] In the example of FIG. 1, any of the illustrated UEs (shown in FIG. 1 as a single UE 104 for simplicity) may receive signals 124 from one or more Earth-orbiting space vehicles (SVs) 112 (e.g., satellites). In one aspect, the SVs 112 may be part of a satellite positioning system that the UEs 104 may use as an independent source of location information. A satellite positioning system typically includes a system of transmitters (e.g., SVs 112) positioned to enable receivers (e.g., UEs 104) to determine their location on or above the Earth based at least in part on positioning signals (e.g., signals 124) received from the transmitters. Such transmitters typically transmit signals marked with a repeating pseudo-random noise (PN) code of a set number of chips. Although typically located within the SVs 112, transmitters may sometimes be located on ground-based control stations, base stations 102, and / or other UEs 104. The UE 104 may include one or more dedicated receivers specifically designed to receive the signals 124 from the SV 112 to derive geolocation information.

[0138] In a satellite positioning system, the use of the signals 124 may be augmented by various satellite-based augmentation systems (SBAS) that may be associated with or otherwise enabled for use with one or more global and / or regional navigation satellite systems. For example, the SBAS may include augmentation systems that provide integrity information, differential corrections, and the like, such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multi-functional Satellite Augmentation System (MSAS), the Global Positioning System (GPS)-aided Geo-augmented Navigation, or the GPS and Geo Augmented Navigation system (GAGAN). Thus, as used herein, a satellite positioning system may include any combination of one or more global and / or regional navigation satellites associated with one or more such satellite positioning systems.

[0139] In one aspect, the SV 112 may additionally or alternatively be part of one or more non-terrestrial networks (NTNs). In an NTN, the SV 112 is connected to an earth station (also called a ground station, NTN gateway, or gateway), which in turn is connected to an element in a 5G network, such as a modified base station 102 (without a terrestrial antenna) or a network node in a 5G network. This element will then provide access to other elements in the 5G network and ultimately to entities outside the 5G network, such as Internet web servers and other user devices. In this way, the UE 104 may receive communication signals (e.g., signal 124) from the SV 112 instead of or in addition to communication signals from the terrestrial base station 102.

[0140] The wireless communication system 100 may further include one or more UEs, such as UE 190, that indirectly connect to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links (referred to as "sidelinks"). In the example of FIG. 1, the UE 190 has a D2D P2P link 192 (e.g., through which the UE 190 may indirectly obtain cellular connectivity) with one of the UEs 104 connected to one of the base stations 102, and a D2D P2P link 194 (through which the UE 190 may indirectly obtain WLAN-based Internet connectivity) with a WLAN STA 152 connected to a WLAN AP 150. In one example, the D2D P2P links 192 and 194 may be supported using any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth, etc.

[0141] 2A illustrates an exemplary wireless network structure 200. For example, a 5GC 210 (also referred to as Next Generation Core (NGC)) may be considered functionally as control plane (C-plane) functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane (U-plane) functions 212 (e.g., UE gateway functions, access to data networks, IP routing, etc.) that operate cooperatively to form a core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect the gNB 222 to the 5GC 210, specifically to the user plane function 212 and the control plane function 214, respectively. In an additional configuration, the ng-eNB 224 may also be connected to the 5GC 210 via the NG-C 215 to the control plane function 214 and the NG-U 213 to the user plane function 212. Additionally, the ng-eNB 224 may communicate directly with the gNB 222 via a backhaul connection 223. In some configurations, the Next Generation RAN (NG-RAN) 220 may have one or more gNBs 222, while other configurations include one or more of both the ng-eNB 224 and the gNB 222. Either the gNB 222 or the ng-eNB 224 (or both) may communicate with one or more UEs 204 (e.g., any of the UEs described herein).

[0142] Another optional aspect may include a location server 230, which may be in communication with the 5GC 210 to provide location assistance to the UE 204. The location servers 230 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The location servers 230 may be configured to support one or more location services for the UE 204 that may connect to the location server 230 via the core network 5GC 210 and / or via the Internet (not shown). Furthermore, the location server 230 may be integrated into a component of the core network, or alternatively, may be external to the core network (e.g., a third-party server, such as an original equipment manufacturer (OEM) server or a service server).

[0143] 2B illustrates another example wireless network structure 250. 5GC 260 (which may correspond to 5GC 210 in FIG. 2A) may be viewed functionally as a control plane function provided by an access and mobility management function (AMF) 264 and a user plane function provided by a user plane function (UPF) 262, which operate cooperatively to form a core network (i.e., 5GC 260). The functions of the AMF 264 include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between one or more UEs 204 (e.g., any of the UEs described herein) and a session management function (SMF) 266, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and a short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF 264 also interacts with an authentication server function (AUSF) (not shown) and the UE 204 to receive intermediate keys established as a result of the UE 204 authentication process. In case of authentication based on a UMTS (universal mobile telecommunications system) subscriber identity module (USIM), the AMF 264 retrieves security material from the AUSF. AMF264 functionality also includes security context management (SCM).The SCM receives keys from the SEAF that the SCM uses to derive access network specific keys. The functionality of the AMF 264 also includes location service management for regulated services, transport for location service messages between the UE 204 and the Location Management Function (LMF) 270 (acting as the location server 230), transport for location service messages between the NG-RAN 220 and the LMF 270, EPS bearer identifier allocation for interworking with evolved packet system (EPS), and UE 204 mobility event notification. In addition, the AMF 264 also supports functions for non-3GPP (Third Generation Partnership Project) access networks.

[0144] The functions of the UPF 262 include acting as an anchor point for intra / inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point for interconnection to a data network (not shown), packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) processing for the user plane (e.g., uplink / downlink rate enforcement, reflective QoS marking in the downlink), uplink traffic validation (service data flow (SDF) to QoS flow mapping), transport level packet marking in the uplink and downlink, downlink packet buffering and downlink data notification triggering, as well as sending and forwarding one or more "end markers" to the source RAN node. The UPF 262 may also support forwarding of location service messages on the user plane between the UE 204 and a location server, such as the SLP 272.

[0145] The functions of the SMF 266 include session management, UE Internet protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering in the UPF 262 to route traffic to the appropriate destination, policy enforcement and control of part of QoS, and downlink data notification. The interface through which the SMF 266 communicates with the AMF 264 is called the N11 interface.

[0146] Another optional aspect may include an LMF 270, which may be in communication with the 5GC 260 to provide location assistance to the UE 204. The LMF 270 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The LMF 270 may be configured to support one or more location services for UEs 204 that may connect to the LMF 270 via a core network, the 5GC 260, and / or via the Internet (not shown). The SLP 272 may support similar functions as the LMF 270, except that the LMF 270 may communicate with the AMF 264, the NG-RAN 220, and the UE 204 on the control plane (e.g., using interfaces and protocols intended to carry signaling messages rather than voice or data) and the SLP 272 may communicate with the UE 204 and external clients (not shown in FIG. 2B ) on the user plane (e.g., using protocols intended to carry voice and / or data, such as the transmission control protocol (TCP) and / or IP).

[0147] The user plane interface 263 and the control plane interface 265 connect the 5GC 260, in particular the UPF 262 and the AMF 264, to one or more gNBs 222 and / or ng-eNBs 224 in the NG-RAN 220, respectively. The interface between the gNBs 222 and / or ng-eNBs 224 and the AMF 264 is referred to as the "N2" interface, and the interface between the gNBs 222 and / or ng-eNBs 224 and the UPF 262 is referred to as the "N3" interface. The gNBs 222 and / or ng-eNBs 224 of the NG-RAN 220 may communicate directly with each other via a backhaul connection 223 referred to as the "Xn-C" interface. One or more of the gNBs 222 and / or ng-eNBs 224 may communicate with one or more UEs 204 via a wireless interface referred to as the "Uu" interface.

[0148] The functionality of the gNB 222 is divided between a gNB Central Unit (gNB-CU) 226 and one or more gNB Distributed Units (gNB-DU) 228. The interface 232 between the gNB-CU 226 and one or more gNB-DUs 228 is called the "F1" interface. The gNB-CU 226 is a logical node that includes base station functions such as user data forwarding, mobility control, radio access network sharing, positioning, session management, etc., except for those functions exclusively allocated to the gNB-DU 228. More specifically, the gNB-CU 226 hosts the Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP) protocols of the gNB 222. The gNB-DU 228 is a logical node that hosts the Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers of the gNB 222. Its operation is controlled by the gNB-CU 226. One gNB-DU 228 can support one or more cells, and one cell is supported by only one gNB-DU 228. Thus, the UE 204 communicates with the gNB-CU 226 via the RRC, SDAP, and PDCP layers, and with the gNB-DU 228 via the RLC, MAC, and PHY layers.

[0149] 3A, 3B, and 3C illustrate several example components (represented by corresponding blocks) that may be incorporated in a UE 302 (which may correspond to any of the UEs described herein), a base station 304 (which may correspond to any of the base stations described herein), and a network entity 306 (which may correspond to or embody any of the network functions described herein, including a location server 230 and an LMF 270, or alternatively, may be independent of the NG-RAN 220 and / or 5GC 210 / 260 infrastructure depicted in FIGS. 2A and 2B, such as a private network) to support file transmission operations taught herein. It will be understood that these components may be implemented in different types of devices in different implementations (e.g., in an ASIC, in a system on chip (SoC), etc.). The illustrated components may also be incorporated in other devices in a communication system. For example, other devices in the system may include components similar to the illustrated components to provide similar functionality. Also, a given device may include one or more of the components. For example, a device may contain multiple transceiver components that enable the device to operate on multiple carriers and / or communicate via different technologies.

[0150] The UE 302 and base station 304 each include one or more wireless wide area network (WWAN) transceivers 310 and 350, respectively, and provide means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for ceasing transmission, etc.) over one or more wireless communications networks (not shown), such as an NR network, an LTE network, a GSM network, etc. The WWAN transceivers 310 and 350 may each be connected to one or more antennas 316 and 356, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc., over at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communications medium of interest (e.g., some set of time / frequency resources in a particular frequency spectrum). The WWAN transceivers 310 and 350 may be variously configured to transmit and encode signals 318 and 358, respectively (e.g., messages, instructions, information, etc.), and conversely, to receive and decode signals 318 and 358, respectively (e.g., messages, instructions, information, pilots, etc.), in accordance with a designated RAT. In particular, the WWAN transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, to transmit and encode signals 318 and 358, respectively, and include one or more receivers 312 and 352, respectively, to receive and decode signals 318 and 358, respectively.

[0151] The UE 302 and base station 304 also each, in at least some cases, include one or more short-range wireless transceivers 320 and 360, respectively. The short-range wireless transceivers 320 and 360 may be connected to one or more antennas 326 and 366, respectively, and may provide means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for ceasing transmission, etc.) with other network nodes, such as other UEs, access points, base stations, etc., via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth, Zigbee, Z-Wave, PC5, Dedicated Short-Range Communications (DSRC), wireless access for vehicular environments (WAVE), Near Field Communication (NFC), etc.) over a wireless communication medium of interest. The short-range wireless transceivers 320 and 360 may be variously configured for transmitting and encoding signals 328 and 368, respectively (e.g., messages, instructions, information, etc.), and conversely, for receiving and decoding signals 328 and 368, respectively (e.g., messages, instructions, information, pilots, etc.), in accordance with a specified RAT. In particular, the short-range wireless transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and include one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively. As specific examples, the short-range wireless transceivers 320 and 360 may be WiFi transceivers, Bluetooth® transceivers, Zigbee® and / or Z-Wave® transceivers, NFC transceivers, or Vehicle-to-Vehicle (V2V) and / or Vehicle-to-Everything (V2X) transceivers.

[0152] The UE 302 and the base station 304 also, at least in some cases, include satellite signal receivers 330 and 370. The satellite signal receivers 330 and 370 may be connected to one or more antennas 336 and 376, respectively, and may provide means for receiving and / or measuring satellite positioning / communication signals 338 and 378, respectively. If the satellite signal receivers 330 and 370 are satellite positioning system receivers, the satellite positioning / communication signals 338 and 378 may be Global Positioning System (GPS) signals, Global Navigation Satellite System (GLONASS) signals, Galileo signals, Beidou signals, Navigation Satellite System of India (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. If the satellite signal receivers 330 and 370 are non-terrestrial network (NTN) receivers, the satellite positioning / communication signals 338 and 378 may be communication signals (e.g., carrying control and / or user data) originating from a 5G network. Satellite signal receivers 330 and 370 may comprise any suitable hardware and / or software for receiving and processing satellite positioning / communications signals 338 and 378, respectively. Satellite signal receivers 330 and 370 may request information and action from other systems as appropriate and, at least in some cases, perform calculations to determine the location of UE 302 and base station 304, respectively, using the acquired measurements according to any suitable satellite positioning system algorithms.

[0153] The base station 304 and the network entity 306 each include one or more network transceivers 380 and 390, respectively, that provide a means for communicating (e.g., a means for transmitting, a means for receiving, etc.) with other network entities (e.g., other base stations 304, other network entities 306). For example, the base station 304 may employ one or more network transceivers 380 to communicate with other base stations 304 or network entities 306 over one or more wired or wireless backhaul links. As another example, the network entity 306 may employ one or more network transceivers 390 to communicate with one or more base stations 304 over one or more wired or wireless backhaul links or with other network entities 306 over one or more wired or wireless core network interfaces.

[0154] A transceiver may be configured to communicate over a wired or wireless link. A transceiver (whether a wired or wireless transceiver) includes transmitter circuitry (e.g., transmitters 314, 324, 354, 364) and receiver circuitry (e.g., receivers 312, 322, 352, 362). A transceiver may be an integrated device (e.g., embodying transmitter and receiver circuitry in a single device) in some implementations, may comprise separate transmitter circuitry and separate receiver circuitry in some implementations, or may be embodied in other ways in other implementations. The transmitter and receiver circuitry of a wired transceiver (e.g., network transceivers 380 and 390 in some implementations) may be coupled to one or more wired network interface ports. The wireless transmitter circuitry (e.g., transmitters 314, 324, 354, 364) may include or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array that enables an individual device (e.g., UE 302, base station 304) to perform transmit "beamforming" as described herein. Similarly, the wireless receiver circuitry (e.g., receivers 312, 322, 352, 362) may include or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array that enables an individual device (e.g., UE 302, base station 304) to perform receive beamforming as described herein. In an aspect, the transmitter circuitry and the receiver circuitry may share multiple identical antennas (e.g., antennas 316, 326, 356, 366), such that an individual device can only receive or transmit at a given time, but not both at the same time. The wireless transceivers (eg, WWAN transceivers 310 and 350, short range wireless transceivers 320 and 360) may also include network listen modules (NLMs) and the like for performing various measurements.

[0155] As used herein, various wireless transceivers (e.g., transceivers 310, 320, 350, and 360, and network transceivers 380 and 390, in some implementations) and wired transceivers (e.g., network transceivers 380 and 390, in some implementations) may be generally characterized as a "transceiver," "at least one transceiver," or "one or more transceivers." Thus, whether a particular transceiver is a wired or wireless transceiver may be inferred from the type of communication being performed. For example, backhaul communications between network devices or servers generally involve signaling via wired transceivers, while wireless communications between a UE (e.g., UE 302) and a base station (e.g., base station 304) generally involve signaling via wireless transceivers.

[0156] The UE 302, base station 304, and network entity 306 also include other components that may be used in conjunction with operations as disclosed herein. The UE 302, base station 304, and network entity 306 each include one or more processors 332, 384, and 394, for example, to provide functionality related to wireless communications and to provide other processing functionality. Thus, the processors 332, 384, and 394 may comprise processing means, such as means for determining, means for calculating, means for receiving, means for transmitting, means for indicating, etc. In one aspect, the processors 332, 384, and 394 may include, for example, one or more general purpose processors, multi-core processors, central processing units (CPUs), ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGAs), other programmable logic devices or processing circuits, or various combinations thereof.

[0157] The UE 302, the base station 304, and the network entity 306 include memory circuitry implementing memories 340, 386, and 396, respectively (e.g., each including a memory device) for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, etc.). Thus, the memories 340, 386, and 396 may comprise storage means, retrieval means, maintaining means, etc. In some cases, the UE 302, the base station 304, and the network entity 306 may include SRS components 342, 388, and 398, respectively. The SRS components 342, 388, and 398 may be hardware circuits that are part of or coupled to the processors 332, 384, and 394, respectively, and that, when executed, cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein. In other aspects, the SRS components 342, 388, and 398 may be external to the processors 332, 384, and 394 (e.g., part of a modem processing system, integrated with another processing system, etc.). Alternatively, the SRS components 342, 388, and 398 may be memory modules stored in the memories 340, 386, and 396, respectively, and when executed by the processors 332, 384, and 394 (or a modem processing system, another processing system, etc.), cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein. FIG. 3A illustrates possible locations of the SRS component 342, which may be part of, for example, one or more WWAN transceivers 310, the memory 340, one or more processors 332, or any combination thereof, or may be a stand-alone component. FIG. 3B shows possible locations for an SRS component 388, which may be, for example, part of one or more WWAN transceivers 350, memory 386, one or more processors 384, or any combination thereof, or may be a stand-alone component.FIG. 3C illustrates possible locations for an SRS component 398, which may be, for example, part of one or more network transceivers 390, memory 396, one or more processors 394, or any combination thereof, or may be a stand-alone component.

[0158] The UE 302 may include one or more sensors 344 coupled to the one or more processors 332 to provide a means for sensing or detecting movement and / or orientation information that is independent of movement data derived from signals received by the one or more WWAN transceivers 310, the one or more short-range wireless transceivers 320, and / or the satellite signal receiver 330. By way of example, the sensors 344 may include an accelerometer (e.g., a microelectromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), and / or any other type of movement detection sensor. Additionally, the sensors 344 may include multiple different types of devices and combine their outputs to provide movement information. For example, the sensors 344 may use a combination of a multi-axis accelerometer and an orientation sensor to provide the ability to calculate a position in a two-dimensional (2D) and / or three-dimensional (3D) coordinate system.

[0159] Additionally, the UE 302 includes a user interface 346 that provides a means for providing indications to a user (e.g., audio and / or visual indications) and / or receiving user input (e.g., upon user actuation of a sensing device, such as a keypad, touch screen, microphone, etc.). Although not shown, the base station 304 and the network entity 306 may also include user interfaces.

[0160] Referring to the one or more processors 384 in more detail, on the downlink, IP packets from the network entity 306 may be provided to the processor 384. The one or more processors 384 may implement functionality for an RRC layer, a Packet Data Convergence Protocol (PDCP) layer, a Radio Link Control (RLC) layer, and a Medium Access Control (MAC) layer. The one or more processors 384 may provide RRC layer functionality associated with system information (e.g., master information block (MIB), system information block (SIB)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and broadcasting of measurement configurations for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with forwarding of higher layer PDUs, error correction with automatic repeat request (ARQ), concatenation, segmentation and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0161] The transmitter 354 and receiver 352 may implement Layer 1 (L1) functionality related to various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on transport channels, forward error correction (FEC) encoding / decoding of transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The transmitter 354 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-ary quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with reference signals (e.g., pilots) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM symbol stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the UE 302. Each spatial stream may then be provided to one or more different antennas 356. The transmitter 354 may modulate an RF carrier with the individual spatial streams for transmission.

[0162] At the UE 302, the receiver 312 receives the signal through its respective antenna 316. The receiver 312 recovers the information modulated onto the RF carriers and provides the information to one or more processors 332. The transmitter 314 and the receiver 312 implement layer 1 functionality associated with various signal processing functions. The receiver 312 may perform spatial processing on the information to recover any spatial streams destined for the UE 302. If multiple spatial streams are destined for the UE 302, they may be combined by the receiver 312 into a single OFDM symbol stream. The receiver 312 then converts the OFDM symbol stream from the time domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the most likely signal constellation point transmitted by the base station 304. These soft decisions may be based on channel estimates calculated by a channel estimator. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 304. The data and control signals are then provided to one or more processors 332 that implement Layer 3 (L3) and Layer 2 (L2) functionality.

[0163] In the uplink, the one or more processors 332 provide demultiplexing between transport and logical channels, packet reassembly, decryption, header recovery, and control signal processing to recover IP packets from the core network. The one or more processors 332 are also responsible for error detection.

[0164] Similar to the functionality described in connection with downlink transmissions by the base station 304, the one or more processors 332 provide RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with forwarding of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

[0165] Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 304 may be used by the transmitter 314 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the transmitter 314 may be provided to different antennas 316. The transmitter 314 may modulate an RF carrier with the individual spatial streams for transmission.

[0166] Uplink transmissions are processed at the base station 304 in a manner similar to that described with respect to the receiver functions at the UE 302. The receiver 352 receives the signal through its respective antenna 356. The receiver 352 recovers the information modulated onto the RF carrier and provides the information to one or more processors 384.

[0167] In the uplink, the one or more processors 384 provide demultiplexing between transport and logical channels, packet reassembly, decryption, header recovery, and control signal processing to recover IP packets from the UE 302. The IP packets from the one or more processors 384 may be provided to a core network. The one or more processors 384 are also responsible for error detection.

[0168] For convenience, the UE 302, base station 304, and / or network entity 306 are illustrated in Figures 3A, 3B, and 3C as including various components that may be configured according to various examples described herein. However, it will be understood that the illustrated components may have different functionality in different designs. In particular, various components in Figures 3A-3C are optional in alternative configurations, and various aspects include configurations that may vary due to design choice, cost, device use, or other considerations. For example, in the case of Figure 3A, a particular implementation of the UE 302 may omit the WWAN transceiver 310 (e.g., a wearable device or tablet computer or PC or laptop may have Wi-Fi and / or Bluetooth capabilities without cellular capabilities), or may omit the short-range wireless transceiver 320 (e.g., cellular only, etc.), or may omit the satellite signal receiver 330, or may omit the sensor 344, etc. 3B, a particular implementation of base station 304 may omit WWAN transceiver 350 (e.g., a Wi-Fi "hotspot" access point without cellular capability), or may omit short-range wireless transceiver 360 (e.g., cellular only), or may omit satellite receiver 370, etc. For brevity, examples of various alternative configurations are not provided herein, but should be readily apparent to one of ordinary skill in the art.

[0169] The various components of the UE 302, base station 304, and network entity 306 may be communicatively coupled to one another via data buses 334, 382, ​​and 392, respectively. In an aspect, the data buses 334, 382, ​​and 392 may form or be part of communication interfaces of the UE 302, base station 304, and network entity 306, respectively. For example, when various logical entities are embodied within the same device (e.g., gNB and location server functionality integrated within the same base station 304), the data buses 334, 382, ​​and 392 may provide communication therebetween.

[0170] The components of Figures 3A, 3B, and 3C may be implemented in a variety of ways. In some implementations, the components of Figures 3A, 3B, and 3C may be implemented in one or more circuits, such as, for example, one or more processors and / or one or more ASICs (which may include one or more processors), where each circuit may use and / or incorporate at least one memory component for storing information or executable code used by the circuit to provide its functionality. For example, some or all of the functionality represented by blocks 310-346 may be implemented by the processor and memory components of the UE 302 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Similarly, some or all of the functionality represented by blocks 350-388 may be implemented by the processor and memory components of the base station 304 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Also, some or all of the functionality represented by blocks 390-398 may be implemented by the processor and memory components of the network entity 306 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). For simplicity, various operations, actions, and / or functions are described herein as being performed "by the UE," "by the base station," "by the network entity," etc. However, it will be understood that such operations, actions, and / or functions may actually be performed by particular components or combinations of components of the UE 302, base station 304, network entity 306, etc., such as the processors 332, 384, 394, transceivers 310, 320, 350, and 360, memories 340, 386, and 396, SRS components 342, 388, and 398, etc.

[0171] In some designs, the network entity 306 may be implemented as a core network component. In other designs, the network entity 306 may be separate from the network operator or operation of the cellular network infrastructure (e.g., the NG RAN 220 and / or the 5GC 210 / 260). For example, the network entity 306 may be a component of a private network that may be configured to communicate with the UE 302 via the base station 304 or independently of the base station 304 (e.g., via a non-cellular communication link such as WiFi).

[0172] FIG. 4 is a block diagram illustrating various components of an exemplary UE 400 according to aspects of the disclosure. In an aspect, the UE 400 may correspond to any of the UEs described herein. As a specific example, the UE 400 may be a V-UE, such as the V-UE 160 in FIG. 1. For simplicity, the various features and functions illustrated in the block diagram of FIG. 4 are connected together using a common data bus, which is intended to represent that these various features and functions are operatively coupled together. Those skilled in the art will recognize that other connections, mechanisms, features, functions, etc. may be provided and adapted as necessary to operatively couple and configure an actual UE. It is further recognized that one or more of the features or functions illustrated in the example of FIG. 4 may be further subdivided, or two or more of the features or functions illustrated in FIG. 4 may be combined.

[0173] The UE 400 may include at least one transceiver 404 coupled to one or more antennas 402, which provides means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for ceasing transmission, etc.) with other network nodes, such as a V-UE (e.g., V-UE 160), an infrastructure access point (e.g., roadside access point 164), a P-UE (e.g., UE 104), a base station (e.g., base station 102), etc., via at least one designated RAT (e.g., cV2X or IEEE 802.11p) via one or more communication links (e.g., communication link 120, sidelinks 162, 166, 168, mmW communication link 184). The at least one transceiver 404 may be variously configured for transmitting and encoding signals (e.g., messages, instructions, information, etc.) and conversely for receiving and decoding signals (e.g., messages, instructions, information, pilots, etc.) in accordance with the designated RAT. In one aspect, the at least one transceiver 404 and the antenna 402 may form a (wireless) communication interface of the UE 400.

[0174] A "transceiver" as used herein may in some implementations include at least one transmitter and at least one receiver in an integrated device (e.g., implemented as transmitter and receiver circuits in a single communications device), in some implementations may comprise separate transmitter and receiver devices, or in other implementations may be implemented in other ways. In one aspect, the transmitter may include or be coupled to multiple antennas, such as an antenna array (e.g., antenna 402), that enable the UE 400 to perform transmit "beamforming" as described herein. Similarly, the receiver may include or be coupled to multiple antennas, such as an antenna array (e.g., antenna 402), that enable the UE 400 to perform receive beamforming as described herein. In one aspect, the transmitter and receiver may share the same multiple antennas (e.g., antenna 402) such that the UE 400 can only receive or transmit at a given time, rather than both receive and transmit at the same time. In some cases, a transceiver may not provide both transmit and receive functionality. For example, in some designs, a low functionality receiver circuit (e.g., a receiver chip or similar circuitry that merely provides low level sniffing) may be employed to reduce cost when it is not necessary to provide full communication.

[0175] The UE 400 may also include a Satellite Positioning Service (SPS) receiver 406. The SPS receiver 406 may be connected to one or more antennas 403 and may provide a means for receiving and / or measuring satellite signals. The SPS receiver 406 may comprise any suitable hardware and / or software for receiving and processing SPS signals, such as Global Positioning System (GPS) signals. The SPS receiver 406 requests information and actions from other systems as appropriate, and performs the calculations necessary to determine the position of the UE 400 using measurements obtained by any suitable SPS algorithms.

[0176] One or more sensors 408 may be coupled to the at least one processor 410 and may provide a means for sensing or detecting information regarding the state and / or environment of the UE 400, such as speed, heading (e.g., compass heading), headlight status, gas mileage, etc. By way of example, the one or more sensors 408 may include a speedometer, a tachometer, an accelerometer (e.g., a micro-electromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), etc.

[0177] The at least one processor 410 may include one or more central processing units (CPUs), microprocessors, microcontrollers, ASICs, processing cores, digital signal processors (DSPs), field programmable gate arrays (FPGAs), etc. that provide processing functions and other computational and control functionality. Thus, the at least one processor 410 may provide means for processing, such as means for determining, means for calculating, means for receiving, means for transmitting, means for indicating, etc. The at least one processor 410 may include any form of logic suitable for implementing or causing components of the UE 400 to implement at least the techniques described herein.

[0178] The at least one processor 410 may also be coupled to a memory 414 that provides a means for storing (including a means for retrieving, a means for maintaining, etc.) data and software instructions for executing programmed functionality within the UE 400. The memory 414 may be on-board the at least one processor 410 (e.g., within the same integrated circuit (IC) package) and / or the memory 414 may be external to the at least one processor 410 and operatively coupled thereto via a data bus.

[0179] The UE 400 may include a user interface 450 providing any suitable interface system, such as a microphone / speaker 452, a keypad 454, and a display 456, to enable user interaction with the UE 400. The microphone / speaker 452 may provide voice communication services with the UE 400. The keypad 454 may comprise any suitable buttons for user input to the UE 400. The display 456 may comprise any suitable display, such as, for example, a backlit liquid crystal display (LCD), and may further include a touch screen display for additional user input modes. The user interface 450 may thus be a means for providing instructions (e.g., audible and / or visual instructions) to a user and / or for receiving user input (e.g., via user actuation of a sensing device, such as a keypad, touch screen, microphone, etc.).

[0180] In one aspect, the UE 400 may include a sidelink manager 470 coupled to the at least one processor 410. The sidelink manager 470 may be a hardware, software, or firmware component that, when executed, causes the UE 400 to perform the operations described herein. For example, the sidelink manager 470 may be a software module stored in the memory 414 and executable by the at least one processor 410. As another example, the sidelink manager 470 may be a hardware circuit (e.g., an ASIC, a field programmable gate array (FPGA), etc.) within the UE 400.

[0181] 5 illustrates an example of a wireless communication system 500 supporting wireless unicast sidelink establishment according to aspects of the disclosure. In some examples, the wireless communication system 500 may implement aspects of the wireless communication systems 100, 200, and 250. The wireless communication system 500 may include a first UE 502 and a second UE 504, which may be examples of any of the UEs described herein. As specific examples, the UEs 502 and 504 may correspond to the V-UE 160 in FIG. 1, the UE 190 and the UE 104 in FIG. 1 connected via the D2D P2P link 192, or the UE 204 in FIG. 2A and FIG. 2B.

[0182] In the example of Fig. 5, UE 502 may attempt to establish a unicast connection with UE 504 over a sidelink, which may be a V2X sidelink between UE 502 and UE 504. As a specific example, the established sidelink connection may correspond to sidelinks 162 and / or 168 in Fig. 1. The sidelink connection may be established in an omnidirectional frequency range (e.g., FR1) and / or a mmW frequency range (e.g., FR2). In some cases, UE 502 may be referred to as an initiating UE that initiates a sidelink connection procedure, and UE 504 may be referred to as a target UE that is targeted for the sidelink connection procedure by the initiating UE.

[0183] To establish a unicast connection, Access Stratum (AS) (a functional layer in the UMTS and LTE protocol stacks, and part of Layer 2, between the RAN and the UE responsible for transporting data over the wireless link and managing radio resources) parameters may be configured and negotiated between the UE 502 and the UE 504. For example, transmit and receive capability matching may be negotiated between the UE 502 and the UE 504. Each UE may have different capabilities (e.g., transmit and receive, 64 quadrature amplitude modulation (QAM), transmit diversity, carrier aggregation (CA), supported communication frequency bands, etc.). In some cases, different services may be supported at higher layers of the corresponding protocol stacks for the UE 502 and the UE 504. Additionally, a security association may be established between the UE 502 and the UE 504 for the unicast connection. Unicast traffic may benefit from security protection (e.g., integrity protection) at the link level. Security requirements may differ for different wireless communication systems. For example, V2X and Uu systems may have different security requirements (e.g., Uu security does not include confidentiality protection). Additionally, IP configurations (e.g., IP version, addresses, etc.) may be negotiated for unicast connections between UE 502 and UE 504.

[0184] In some cases, the UE 504 may create a service announcement (e.g., a service capability message) for transmission over a cellular network (e.g., cV2X) to assist in sidelink connection establishment. Conventionally, the UE 502 may identify and locate candidates for sidelink communication based on a broadcasted basic service message (BSM) that is decrypted by nearby UEs (e.g., the UE 504). The BSM may include location information, security and identification information, and vehicle information (e.g., speed, operation, size, etc.) for the corresponding UE. However, in the case of a different wireless communication system (e.g., D2D or V2X communication), the discovery channel may not be configured to allow the UE 502 to detect the BSM. Thus, the service announcement (e.g., discovery signal) transmitted by the UE 504 and other nearby UEs may be a higher layer signal and may be broadcast (e.g., in an NR sidelink broadcast). In some cases, the UE 504 may include one or more parameters for itself, including connection parameters and / or capabilities it possesses, in the service announcement. The UE 502 may then monitor for and receive the broadcasted service announcements to identify possible UEs for a corresponding sidelink connection. In some cases, the UE 502 may identify possible UEs based on the capabilities that each UE indicates in their respective service announcements.

[0185] The service announcement may include information to assist the UE 502 (e.g., or any initiating UE) in identifying the UE (UE 504 in the example of FIG. 5) that is sending the service announcement. For example, the service announcement may include channel information in which the direct communication request may be sent. In some cases, the channel information may be RAT-specific (e.g., specific to LTE or NR) and may include a resource pool in which the UE 502 sends the communication request. Additionally, the service announcement may include a specific destination address (e.g., Layer 2 destination address) for the UE if the destination address is different from the current address (e.g., the address of the streaming provider or the UE sending the service announcement). The service announcement may also include a network layer or transport layer for the UE 502 to send the communication request. For example, the network layer (also referred to as "Layer 3" or "L3") or transport layer (also referred to as "Layer 4" or "L4") may indicate a port number of the application for the UE sending the service announcement. In some cases, IP addressing may not be required if the signaling (e.g., PC5 signaling) directly carries a protocol (e.g., Real-time Transport Protocol (RTP)) or provides a locally generated random protocol. Additionally, the service announcement may include the type of protocol for certificate establishment and QoS related parameters.

[0186] After identifying a possible sidelink connection target (UE 504 in the example of FIG. 5), the initiating UE (UE 502 in the example of FIG. 5) may send a connection request 515 to the identified target UE 504. In some cases, the connection request 515 may be a first RRC message (e.g., an "RRC Setup Request" message) sent by the UE 502 to request a unicast connection with the UE 504. For example, the unicast connection may utilize a PC5 interface for sidelink, and the connection request 515 may be an RRC Connection Setup Request message. Additionally, the UE 502 may use a sidelink signaling radio bearer 505 to transport the connection request 515.

[0187] After receiving the connection request 515, the UE 504 may decide whether to accept or reject the connection request 515. The UE 504 may base this decision on transmit / receive capabilities, the ability to accommodate a unicast connection over the sidelink, the particular service indicated for the unicast connection, the content to be transmitted over the unicast connection, or a combination thereof. For example, if the UE 502 desires to use a first RAT to transmit or receive data, but the UE 504 does not support the first RAT, the UE 504 may reject the connection request 515. Additionally or alternatively, the UE 504 may reject the connection request 515 based on an inability to accommodate a unicast connection over the sidelink due to limited radio resources, scheduling issues, etc. Thus, the UE 504 may transmit an indication of whether the request was accepted or rejected in the connection response 520. Similar to the UE 502 and the connection request 515, the UE 504 may use the sidelink signaling radio bearer 510 to transport the connection response 520. Additionally, the connection response 520 may be a second RRC message sent by the UE 504 in response to the connection request 515 (eg, an “RRCResponse” message).

[0188] In some cases, the sidelink signaling radio bearers 505 and 510 may be the same sidelink signaling radio bearer or may be separate sidelink signaling radio bearers. Thus, a radio link control (RLC) layer acknowledged mode (AM) may be used for the sidelink signaling radio bearers 505 and 510. UEs supporting unicast connections may listen on a logical channel associated with the sidelink signaling radio bearer. In some cases, the AS layer (i.e., Layer 2) may pass information directly through RRC signaling (e.g., control plane) instead of the V2X layer (e.g., data plane).

[0189] If the connection response 520 indicates that the UE 504 accepted the connection request 515, the UE 502 may then send a connection establishment 525 message on the sidelink signaling radio bearer 505 to indicate that the unicast connection setup is complete. In some cases, the connection establishment 525 may be a third RRC message (e.g., an "RRC Setup Complete" message). Each of the connection request 515, the connection response 520, and the connection establishment 525 may use basic capabilities when in transport from one UE to the other UE to enable each UE to receive and decode the corresponding transmission (e.g., an RRC message).

[0190] Additionally, an identifier may be used for each of the connection request 515, the connection response 520, and the connection establishment 525. For example, the identifier may indicate which UE 502 / 504 is sending which message and / or which UE 502 / 504 the message is intended for. For physical (PHY) layer channels, the RRC signaling and any subsequent data transmissions may use the same identifier (e.g., Layer 2 ID). However, for logical channels, the identifiers may be separate for the RRC signaling and for the data transmissions. For example, on logical channels, the RRC signaling and the data transmissions may be treated differently and may have different acknowledgement (ACK) feedback messaging. In some cases, for RRC messaging, a physical layer ACK may be used to ensure that the corresponding message is transmitted and received correctly.

[0191] One or more information elements may be included in the connection request 515 and / or connection response 520 for the UE 502 and / or UE 504, respectively, to enable negotiation of corresponding AS layer parameters for the unicast connection. For example, the UE 502 and / or UE 504 may include Packet Data Convergence Protocol (PDCP) parameters in the corresponding unicast connection setup message to set up a PDCP context for the unicast connection. In some cases, the PDCP context may indicate whether PDCP duplication is utilized for the unicast connection. Additionally, the UE 502 and / or UE 504 may include RLC parameters when establishing the unicast connection to set up an RLC context for the unicast connection. For example, the RLC context may indicate whether AM (e.g., reordering timer (t-reordering) is used) or unacknowledged mode (UM) is used for the RLC layer of the unicast communication.

[0192] Additionally, the UE 502 and / or UE 504 may include medium access control (MAC) parameters to set up a MAC context for the unicast connection. In some cases, the MAC context may enable a resource selection algorithm, a hybrid automatic repeat request (HARQ) feedback scheme (e.g., ACK or negative ACK (NACK) feedback), parameters for the HARQ feedback scheme, carrier aggregation, or a combination thereof, for the unicast connection. Additionally, the UE 502 and / or UE 504 may include PHY layer parameters when establishing a unicast connection to set up a PHY layer context for the unicast connection. For example, the PHY layer context may indicate a transmission format (unless a transmission profile is included per UE 502 / 504) and a radio resource configuration (e.g., bandwidth portion (BWP), numerology, etc.) for the unicast connection. These information elements may be supported for different frequency range configurations (e.g., FR1 and FR2).

[0193] In some cases, a security context may also be set for the unicast connection (e.g., after the connection establishment 525 message is sent). Before a security association (e.g., security context) is established between the UE 502 and the UE 504, the sidelink signaling radio bearers 505 and 510 may not be protected. After the security association is established, the sidelink signaling radio bearers 505 and 510 may be protected. Thus, the security context may enable secure data transmission over the unicast connection as well as the sidelink signaling radio bearers 505 and 510. Furthermore, IP layer parameters (e.g., link-local IPv4 or IPv6 addresses) may also be negotiated. In some cases, the IP layer parameters may be negotiated by a higher layer control protocol operating after the RRC signaling is established (e.g., the unicast connection is established). As mentioned above, the UE 504 may base its decision on whether to accept or reject the connection request 515 for a particular service indicated for a unicast connection and / or content (e.g., higher layer information) to be transmitted over the unicast connection. The particular service and / or content may also be indicated by a higher layer control protocol operating after the RRC signaling is established.

[0194] After the unicast connection is established, the UE 502 and the UE 504 may communicate using a unicast connection over a sidelink 530, where sidelink data 535 is transmitted between the two UEs 502 and 504. The sidelink 530 may correspond to the sidelinks 162 and / or 168 in FIG. 1. In some cases, the sidelink data 535 may include RRC messages transmitted between the two UEs 502 and 504. To maintain this unicast connection over the sidelink 530, the UE 502 and / or the UE 504 may transmit keep alive messages (e.g., "RRCLinkAlive" messages, fourth RRC messages, etc.). In some cases, the keep alive messages may be triggered (e.g., event triggered) periodically or on demand. Thus, the triggering and transmission of the keep alive messages may be invoked by the UE 502 or by both the UE 502 and the UE 504. Additionally or alternatively, a MAC Control Element (CE) (e.g., defined over sidelink 530) may be used to monitor the status of the unicast connection on sidelink 530 and maintain the connection. When the unicast connection is no longer needed (e.g., when UE 502 moves far enough away from UE 504), either UE 502 and / or UE 504 may initiate a release procedure to delete the unicast connection over sidelink 530. Thus, no subsequent RRC messages may be sent between UE 502 and UE 504 over the unicast connection.

[0195] Various frame structures may be used to support downlink and uplink transmissions between network nodes (e.g., base stations and UEs). Figure 6 is a diagram 600 illustrating example frame structures according to aspects of the disclosure. The frame structure may be a downlink or uplink frame structure. Other wireless communication technologies may have different frame structures and / or different channels.

[0196] LTE and in some instances NR utilize OFDM on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. However, unlike LTE, NR also has the option of using OFDM on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. Generally, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, or the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the subcarrier spacing may be 15 kilohertz (kHz), and the minimum resource allocation (resource block) may be 12 subcarriers (i.e., 180 kHz). Thus, the nominal FFT size may be equal to 128, 256, 512, 1024, or 2048 for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0197] LTE supports a single numerology (subcarrier spacing (SCS), symbol length, etc.). In contrast, NR may support multiple numerologies (μ), e.g., subcarrier spacings of 15 kHz (μ=0), 30 kHz (μ=1), 60 kHz (μ=2), 120 kHz (μ=3), and 240 kHz (μ=4) or more may be available. At each subcarrier spacing, there are 14 symbols per slot. For a 15 kHz SCS (μ=0), there is one slot per subframe, i.e., 10 slots per frame, the slot duration is 1 millisecond (ms), the symbol duration is 66.7 microseconds (μs), and the maximum nominal system bandwidth (in MHz) with an FFT size of 4K is 50. For a 30 kHz SCS (μ=1), there are two slots per subframe, i.e., 20 slots per frame, the slot duration is 0.5 ms, the symbol duration is 33.3 μs, and the maximum nominal system bandwidth (in MHz) for a 4K FFT size is 100. For a 60 kHz SCS (μ=2), there are four slots per subframe, i.e., 40 slots per frame, the slot duration is 0.25 ms, the symbol duration is 16.7 μs, and the maximum nominal system bandwidth (in MHz) for a 4K FFT size is 200. For a 120 kHz SCS (μ=3), there are eight slots per subframe, i.e., 80 slots per frame, the slot duration is 0.125 ms, the symbol duration is 8.33 μs, and the maximum nominal system bandwidth (in MHz) for a 4K FFT size is 400. For a 240 kHz SCS (μ=4), there are 16 slots per subframe, i.e., 160 slots per frame, the slot duration is 0.0625 ms, the symbol duration is 4.17 μs, and the maximum nominal system bandwidth (in MHz) with an FFT size of 4K is 800.

[0198] In the example of Figure 6, a numerology of 15 kHz is used. Thus, in the time domain, a 10 ms frame is divided into 10 equally sized subframes of 1 ms each, with each subframe containing one time slot. In Figure 6, time is represented horizontally (on the X-axis), with time increasing from left to right, and frequency is represented vertically (on the Y-axis), with frequency increasing (or decreasing) from bottom to top.

[0199] A resource grid may be used to represent a time slot, with each time slot including one or more time-parallel resource blocks (RBs) (also called physical RBs (PRBs)) in the frequency domain. The resource grid is further divided into multiple resource elements (REs). An RE may correspond to one symbol length in the time domain and one subcarrier in the frequency domain. In the numerology of FIG. 6, for a normal cyclic prefix, an RB may include 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols in the time domain to obtain a total of 84 REs. For an extended cyclic prefix, an RB may include 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain to obtain a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

[0200] Some of the REs may carry reference (pilot) signals (RS). The reference signals may include positioning reference signals (PRS), tracking reference signals (TRS), phase tracking reference signals (PTRS), cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), primary synchronization signals (PSS), secondary synchronization signals (SSS), synchronization signal blocks (SSB), sounding reference signals (SRS), etc., depending on whether the illustrated frame structure is used for uplink or downlink communications. Figure 6 shows example locations of REs carrying reference signals (labeled "R").

[0201] In one aspect, the reference signal carried on the RE labeled "R" may be an SRS. The SRS transmitted by the UE may be used by the base station to obtain channel state information (CSI) for the transmitting UE. The CSI describes how the RF signal propagates from the UE to the base station and represents the combined effects of scattering, fading, and power attenuation with distance. The system uses the SRS for resource scheduling, link adaptation, massive MIMO, beam management, etc.

[0202] A set of REs used for transmission of an SRS is called an "SRS resource" and may be identified by a parameter "SRS-ResourceId". The set of resource elements may span multiple PRBs in the frequency domain and "N" (e.g., one or more) consecutive symbols within a slot in the time domain. Within a given OFDM symbol, an SRS resource occupies one or more consecutive PRBs. An "SRS resource set" is a set of SRS resources used for transmission of an SRS signal and is identified by an SRS resource set ID ("SRS-ResourceSetId").

[0203] The transmission of SRS resources within a given PRB has a particular comb size (also referred to as "comb density"). Comb size "N" represents the subcarrier spacing (or frequency / tone spacing) within each symbol of the SRS resource configuration. Specifically, for comb size "N", the SRS is transmitted in every Nth subcarrier of the symbols of the PRB. For example, for comb 4, for each symbol of the SRS resource configuration, the RE corresponding to every fourth subcarrier (such as subcarriers 0, 4, 8) is used to transmit the SRS of the SRS resource. In the example of FIG. 6, the illustrated SRS is comb 4 across four symbols. That is, the location of the shaded SRS RE indicates the comb 4 SRS resource configuration.

[0204] Currently, an SRS resource can span 1, 2, 4, 8, or 12 consecutive symbols within a slot with comb sizes Com 2, Com 4, or Com 8. Below are the symbol-to-symbol frequency offsets for the currently supported SRS comb patterns: 1 symbol comb2: {0}, 2 symbol comb2: {0,1}, 2 symbol comb4: {0,2}, 4 symbol comb2: {0,1,0,1}, 4 symbol comb4: {0,2,1,3} (for the example in Figure 6), 8 symbol comb4: {0,2,1,3,0,2,1,3}, 12 symbol comb4: {0,2,1,3,0,2,1,3,0,2,1,3}, 4 symbol comb8: {0,4,2,6}, 8 symbol comb8: {0,4,2,6,1,5,3,7}, and 12 symbol comb8: {0,4,2,6,1,5,3,7,0,4,2,6}.

[0205] Generally, as mentioned above, a UE transmits an SRS to enable a receiving base station (either a serving base station or a neighboring base station) to measure the channel quality (i.e., CSI) between the UE and the base station. However, the SRS may also be specifically configured as an uplink positioning reference signal for uplink-based positioning procedures such as uplink time difference of arrival (UL-TDOA), round-trip time (RTT), uplink angle-of-arrival (UL-AoA), etc. As used herein, the term "SRS" may refer to an SRS configured for channel quality measurement or an SRS configured for positioning purposes. When it is necessary to distinguish between the two types of SRS, the former may be referred to herein as a "communication SRS" and / or the latter may be referred to as a "positioning SRS" or a "positioning SRS".

[0206] Several extensions beyond the previous definition of SRS have been proposed for positioning SRS (also called "UL-PRS"), such as new staggered patterns in SRS resources (except single symbol / comb2), new comb types for SRS, new sequences for SRS, more SRS resource sets per component carrier, and more SRS resources per component carrier. In addition, the parameters "SpatialRelationInfo" and "PathLossReference" will be configured based on downlink reference signals or SSBs from neighboring TRPs. Still further, one SRS resource may be transmitted outside the active BWP and one SRS resource may span across multiple component carriers. Also, SRS may be configured in RRC connected state and may only be transmitted within the active BWP. Furthermore, there may be no frequency hopping, no repetition factor, there may be a single antenna port, and there may be new lengths for SRS (e.g., 8 and 12 symbols). Also, there may be open loop power control rather than closed loop power control, and Com8 (i.e., SRS transmitted on every 8th subcarrier in the same symbol) may be used. Finally, the UE may transmit from multiple SRS resources over the same transmit beam for UL-AoA. All of these are features added to the current SRS framework, configured (and potentially triggered) through RRC higher layer signaling, or activated through the MAC Control Element (MAC-CE) or DCI.

[0207] Figure 7 is a diagram 700 illustrating various uplink channels in an exemplary uplink slot. In Figure 7, time is represented horizontally (on the X-axis), with time increasing from left to right, and frequency is represented vertically (on the Y-axis), with frequency increasing (or decreasing) from bottom to top. In the example of Figure 7, a numerology of 15 kHz is used. Thus, in the time domain, the slot shown is 1 millisecond (ms) long and divided into 14 symbols.

[0208] A random access channel (RACH), also referred to as a physical random access channel (PRACH), may be in one or more slots in a frame based on a PRACH configuration. The PRACH may include six consecutive RB pairs in a slot. The PRACH allows a UE to perform initial system access and achieve uplink synchronization. A physical uplink control channel (PUCCH) may be located on the edge of the uplink system bandwidth. The PUCCH carries uplink control information (UCI), such as scheduling requests, CSI reports, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and HARQ ACK / NACK feedback. A physical uplink shared channel (PUSCH) carries data and may additionally be used to carry buffer status reports (BSR), power headroom reports (PHR), and / or UCI.

[0209] NR supports several cellular network-based positioning techniques, including downlink-based positioning methods, uplink-based positioning methods, and downlink- and uplink-based positioning methods. Downlink-based positioning methods include observed time difference of arrival (OTDOA) in LTE, downlink time difference of arrival (DL-TDOA) in NR, and downlink angle-of-departure (DL-AoD) in NR. FIG. 8 illustrates examples of various positioning methods according to aspects of the present disclosure. In an OTDOA or DL-TDOA positioning procedure illustrated by scenario 810, a UE measures the difference between times of arrival (ToA) of reference signals (e.g., positioning reference signals (PRS)) received from pairs of base stations, called reference signal time difference (RSTD) or time difference of arrival (TDOA) measurements, and reports them to a positioning entity. More specifically, the UE receives an identifier (ID) of a reference base station (e.g., a serving base station) and multiple non-reference base stations in the assistance data. The UE then measures the RSTD between the reference base station and each of the non-reference base stations. Based on the known locations of the involved base stations and the RSTD measurements, the positioning entity can estimate the location of the UE.

[0210] For DL-AoD positioning, illustrated by scenario 820, the positioning entity uses beam reports from the UE of received signal strength measurements of multiple downlink transmit beams to determine the angle between the UE and the transmitting base station. The positioning entity can then estimate the location of the UE based on the determined angles and the known locations of the transmitting base stations.

[0211] Uplink-based positioning methods include uplink time difference of arrival (UL-TDOA) and uplink angle-of-arrival (UL-AoA). UL-TDOA is similar to DL-TDOA, but is based on an uplink reference signal (e.g., Sounding Reference Signal (SRS)) transmitted by the UE. For UL-AoA positioning, one or more base stations measure the received signal strength of one or more uplink reference signals (e.g., SRS) received from the UE on one or more uplink receive beams. The positioning entity uses the signal strength measurements and the angles of the receive beams to determine the angle between the UE and the base station. Based on the determined angle and the known location of the base station, the positioning entity can then estimate the location of the UE.

[0212] Downlink and uplink based positioning methods include enhanced cell-ID (E-CID) positioning, and multi-round-trip-time (RTT) positioning (also called "multi-cell RTT"). In the RTT procedure, an initiator (base station or UE) transmits an RTT measurement signal (e.g., PRS or SRS) to a responder (UE or base station), and the responder transmits an RTT response signal (e.g., SRS or PRS) back to the initiator. The RTT response signal includes the difference between the ToA of the RTT measurement signal and the transmission time of the RTT response signal, called the receive-transmit (Rx-Tx) time difference. The initiator calculates the difference between the transmission time of the RTT measurement signal and the ToA of the RTT response signal, called the transmit-receive (Tx-Rx) time difference. The propagation time (also called "time of flight") between the initiator and the responder can be calculated from the Tx-Rx and Rx-Tx time differences. Based on the propagation time and the known speed of light, the distance between the initiator and the responder can be determined. For multi-RTT positioning, as illustrated by scenario 830, the UE performs RTT procedures with multiple base stations to enable its location to be determined based on the known locations of the base stations (e.g., using multilateration). RTT and multi-RTT methods may be combined with other positioning techniques, such as UL-AoA and DL-AoD, as illustrated by scenario 840, to improve location accuracy.

[0213] The E-CID positioning method is based on Radio Resource Management (RRM) measurements. In E-CID, the UE reports the serving cell ID, timing advance (TA), identifier, estimated timing, and signal strength of the identifiers of detected neighboring base stations. The location of the UE is then estimated based on this information and the known locations of the base stations.

[0214] To assist the positioning operation, a location server (e.g., location server 230, LMF 270, SLP 272) may provide assistance data to the UE. For example, the assistance data may include an identifier of the base station (or cell / TRP of the base station) from which to measure the reference signal, reference signal configuration parameters (e.g., number of consecutive positioning subframes, periodicity of the positioning subframes, muting sequence, frequency hopping sequence, reference signal identifier, reference signal bandwidth, etc.), and / or other parameters applicable to a particular positioning method. Alternatively, the assistance data may be obtained directly from the base station itself (e.g., in periodically broadcasted overhead messages, etc.). In some cases, the UE may be able to detect neighboring network nodes itself without using the assistance data.

[0215] In the case of OTDOA or DL-TDOA positioning procedures, the assistance data may further include an expected RSTD value and an associated uncertainty around the expected RSTD, i.e., a search window. In some cases, the value range for the expected RSTD may be + / - 500 microseconds (μs). In some cases, the value range for the expected RSTD uncertainty may be + / - 32 μs when any of the resources used for positioning measurements are in FR1. In other cases, the value range for the expected RSTD uncertainty may be + / - 8 μs when all of the resources used for positioning measurements are in FR2.

[0216] A location estimate may be referred to by other names, such as a position estimate, location, position, position fix, fix, etc. A location estimate may be geodetic and comprise coordinates (e.g., latitude, longitude, and possibly altitude), or urban and comprise a street address, postal address, or some other linguistic description of a location. A location estimate may also be defined relative to some other known location, or defined absolutely (e.g., using latitude, longitude, and possibly altitude). A location estimate may include an expected error or uncertainty (e.g., by including an area or volume within which the location is expected to lie with some specified or default level of confidence).

[0217] 9 illustrates a sidelink communication scheduling (or resource allocation) scheme 900 according to an aspect of the disclosure. In some designs, resource allocation in V2X may be implemented via Mode 1, where the gNB assigns Tx resources for sidelink communication over DCI3_0. In other designs, resource allocation in V2X may be implemented via Mode 2, where the transmitting UE autonomously determines resources for sidelink communication. In some designs, the behavior of the receiving UE is the same in both Mode 1 and Mode 2.

[0218] Referring to FIG. 9, mode 1 supports dynamic grant (DG), configured grant (CG) type 1, and CG type 2. In some designs, CG type 1 is activated via RRC signaling from the gNB. DCI3_0 is sent by the gNB to the allocated time and frequency resources to indicate the transmission timing. In some designs, the modulation and coding scheme (MCS) MCS is left to the UE within the limits set by the gNB. In mode 2, the transmitting UE performs channel sensing by blind decoding all physical sidelink control channels (PSCCHs) to find resources reserved by other sidelink transmissions. The transmitting UE reports the available resources to higher layers, which decide the resource usage.

[0219] In some designs, in the Industrial Internet of Things (IIoT), sidelinks can enable direct programmable logic controller (PLC) and sensor / actuator (SA) communication. Wireless PLC is desirable for flexible and simple deployment. In some designs, each PLC controls 20 to 50 SAs. In some designs, the IIoT requires low latency of 1 ms to 2 ms and 10 ms. -6 It has ultra-reliability requirements for error rates. In some designs, communication over gNBs will require multiple OTAs, which will impact latency and reliability.

[0220] IIoT traffic is typically deterministic and has small packet sizes 32 bytes to 256 bytes. Therefore, the required bandwidth is low, e.g., 2 RBs may be sufficient in some cases. SA may have constraints on UE capabilities in terms of bandwidth and processing power. Overall bandwidth may be large for IIoT using dedicated frequency bands and / or unlicensed bands. In some designs, SA does not need to detect / monitor all transmissions. In some designs, PSCCH must meet stringent IIoT requirements. IIoT networks may also be associated with challenging RF environments due to blockages and interference.

[0221] In some designs, first stage sidelink control information (SCI) may be included in the PSCCH. The first stage SCI may alternatively be referred to as SCI 1-A. In some designs, SCI 1-A shall be decoded by the intended RX and other sidelink UEs (especially in mode 2) to enable channel sensing and avoid resource collisions. In some designs, SCI 1-A may be configured as follows: Priority 3 bits · Allocation of frequency resources, number of reserved slots and bits according to the number of subchannels Time resource allocation, 5 bits or 9 bits for 2 or 3 reservations Resource reservation period, bits according to the number of allowable periods DM-RS pattern, bits according to the number of configured patterns SCI 2 format, 2 bits Beta offset for SCI2 rate matching, 2 bits DM-RS port, 1 bit indicating 1 or 2 data layers MCS, 5-bit Additional MCS table, 0 to 2 bits PSFCH overhead indicator, 0 or 1 bit Reserved bits, bits up to higher layers

[0222] In some designs, the second stage SCI may be included in a physical sidelink shared channel (PSSCH). The second stage SCI may alternatively be referred to as SCI2. In some designs, SCI2 is intended to help a receiving UE decode the PSSCH. In some designs, SCI2 may be configured as follows: HARQ ID, bits according to the number of HARQ processes NDI, 1-bit RV-ID, 2 bits Source ID, 8 bits Destination ID, 16 bits HARQ enable / disable, 1 bit SCI2-A dedicated fields: Cast type, 2 bits, broadcast, groupcast, unicast, CSI request, 1 bit SCI2-B dedicated fields (NACK-only groupcast): Zone ID, 12 bits; communication range, 4 bits

[0223] In addition to downlink-based, uplink-based, and downlink-and-uplink-based positioning methods, NR supports various sidelink positioning techniques. For example, link-level ranging signals can be used to estimate the distance between a pair of V-UEs or between a V-UE and a roadside unit (RSU), similar to the round-trip-time (RTT) positioning procedure.

[0224] 10 illustrates an example wireless communication system 1000 in which a V-UE 1004 is exchanging ranging signals with an RSU 1010 and another V-UE 1006 according to an aspect of the disclosure. As illustrated in FIG. 10, wideband (e.g., FR1) ranging signals (e.g., Zadoff Chu sequences) are transmitted by both endpoints (e.g., the V-UE 1004 and the RSU 1010, and the V-UE 1004 and the V-UE 1006). In one aspect, the ranging signals may be sidelink positioning reference signals (SL-PRS) transmitted by the participating V-UE 1004 and V-UE 1006 on uplink resources. Upon receiving a ranging signal from a transmitter (e.g., V-UE 1004), the receiver (e.g., RSU 1010 and / or V-UE 1006) responds by sending a ranging signal that includes a measurement of the difference between the reception time of the ranging signal and the transmission time of the response ranging signal, referred to as the receiver's receive-transmit (Rx-Tx) time difference measurement.

[0225] Upon receiving the reply ranging signal, the transmitter (or other positioning entity) can calculate the RTT between the transmitter and the receiver based on the receiver's Rx-Tx time difference measurement and a measurement of the difference between the transmission time of the first ranging signal and the reception time of the reply ranging signal (referred to as the transmitter's transmit-receive (Tx-Rx) time difference measurement). The transmitter (or other positioning entity) uses the RTT and the speed of light to estimate the distance between the transmitter and the receiver. If one or both of the transmitter and the receiver are beamforming capable, it may also be possible to determine the angle between V-UE 904 and V-UE 906. Additionally, if the receiver provides its Global Positioning System (GPS) location in the reply ranging signal, the transmitter (or other positioning entity) may be able to determine the absolute location of the transmitter as opposed to the relative location of the transmitter with respect to the receiver.

[0226] As can be seen, the ranging accuracy improves with the bandwidth of the ranging signal. In particular, a higher bandwidth can better separate different multipaths of the ranging signal.

[0227] Note that this positioning procedure assumes that the V-UEs involved are time synchronized (i.e., their system frame time is the same as the other V-UEs or has a known offset relative to the other V-UEs). Furthermore, although Figure 10 shows two V-UEs, it will be appreciated that they do not have to be V-UEs, but instead may be any other type of UE capable of sidelink communication.

[0228] 11 illustrates another sidelink positioning scheme 1100 according to an aspect of the disclosure. In FIG. 11, each positioning scheme includes a target UE (in this case, a VR headset), at least one gNB, and at least one reference UE (e.g., a UE with a known location from a recent positioning fix, where such location generally has a lower variance than a typical error estimate of the UE position).

[0229] Referring to Figure 11, scenario 1110 illustrates a UE with a known location improving Uu positioning by providing an additional anchor (e.g., RTT-based or TDOA-based). Scenario 1120 illustrates positioning of a low-tier UE (e.g., a VR headset) via assistance from a premium UE (i.e., positioning / ranging based on SL only). Scenario 1130 illustrates a relay or reference UE (with a known location) participating in position estimation of a remote UE (e.g., a VR headset) without UL PRS transmission in Uu. Each of scenarios 1110-1130 may be generally characterized as an SL-aided positioning scheme.

[0230] The SL UE assisting the target UE in estimating its position may affect various aspects associated with SL-assisted positioning, such as power consumption and / or position estimation accuracy.

[0231] 12 illustrates another UE distributed scenario 1200 for sidelink positioning according to an aspect of the disclosure. In the UE distributed scenario 1210, a large number of UEs participate in the SL-aided positioning, which is good for position estimation accuracy but also increases power consumption significantly. In the UE distributed scenario 1220, only two UEs participate in the SL-aided positioning, which is good for power consumption but also reduces position estimation accuracy. In the UE distributed scenario 1230, there is a reasonable number of UEs (i.e., four) participating in the SL-aided positioning, so power consumption is not too high and the UEs are also spaced well apart in sufficient numbers for good position estimation accuracy.

[0232] In NR, it is generally assumed that each UE position estimate is calculated individually at the LMF ("UE-assisted" technique) or that each UE calculates its own position ("UE-based" technique). As described above with respect to FIG. 8, NR RAT-based position estimation may be facilitated over the Uu link. In other implementations described above with respect to FIG. 9-FIG. 12, NR position estimation may be facilitated over the SL (PC5) link, or a combination of Uu and SL links. For example, SL-aided position estimation may be based on at least one non-gNB type transmitter (e.g., another UE), whose location may be known (for absolute position) or unknown (still useful for relative positioning).

[0233] In some legacy systems, SL-aided position estimation is primarily used for DL-based position estimation (e.g., based on DL-PRS). Aspects of the present disclosure are directed to uplink-based sidelink-aided position estimation procedures (e.g., based at least in part on UL SRS-P and SL SRS-P transmissions). In some designs, such aspects may be leveraged to limit the range of SRS-P transmissions or, alternatively, to improve position estimation accuracy. In the former case, such aspects may provide technical advantages such as reducing power consumption, limiting SRS pollution, serving more users simultaneously (e.g., SRS multiplexing capacity is limited by restricted SRS sequences and configurations), etc. Such aspects may be implemented in various technology environments (e.g., IIoT factory environments with many low-tier sensors, such as AGVs, robotic arms, etc.) where UEs may have limited computational capabilities and / or power.

[0234] 13 illustrates an example process 1300 for wireless communication according to an aspect of the disclosure. In an aspect, the process 1300 may be performed by a location estimation entity, which may correspond to a UE 302 (e.g., in the case of UE-based location estimation) or a network component such as a BS 304 (e.g., in the case of a location server or LMF integrated into the RAN) or a network entity 306 (e.g., a core network component or an external location server or LMF).

[0235] 13 , at 1310, a position estimation entity (e.g., processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc.) identifies a pool of UEs for a sidelink (SL)-assisted position estimation procedure for a set of target UEs. In some designs, the pool of UEs may include one or more additional UEs (e.g., anchor UEs whose locations are already known, etc.) in addition to the set of target UEs. In some designs, the means for performing the identification at 1310 may include processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc., depending on whether the position estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0236] 13 , at 1320, a position estimation entity (e.g., processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc.) determines a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal for positioning (SRS-P) among some or all of the pool of UEs. In some designs, the means for performing the determination at 1320 may include processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc., depending on whether the position estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0237] 13 , at 1330, a location estimation entity (e.g., processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc.) determines a second resource configuration for the SL-assisted location estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs. In some designs, the means for performing the determination at 1330 may include processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc., depending on whether the location estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0238] 13 , the location estimation entity (e.g., transmitter 314 or 324 or 354 or 364, network transceiver 380 or 390, etc.) transmits a first indication of the first resource configuration to the pool of UEs at 1340. In some designs, the means for performing transmission at 1340 may include the transmitter 314 or 324 or 354 or 364, the network transceiver 380 or 390, etc., depending on whether the location estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0239] 13, at 1350, the location estimation entity (e.g., transmitter 314 or 324 or 354 or 364, network transceiver 380 or 390, etc.) transmits a second indication of the second resource configuration to the at least one UE. In some designs, the second resource configuration may also be conveyed to one or more gNBs (or TRPs), which then measure the UL SRS-P on the second set of resources and report back to the location estimation entity. In some designs, the means for performing transmission at 1350 may include the transmitter 314 or 324 or 354 or 364, network transceiver 380 or 390, etc., depending on whether the location estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0240] 13, at 1360, a location estimation entity (e.g., receiver 312 or 322 or 352 or 362, network transceiver 380 or 390, etc.) receives first measurement information based on measurement of at least one SL SRS-P according to a first resource configuration. In some designs, the first measurement data may be based on multiple SL SRS-Ps (e.g., Rx-Tx measurements that correspond to delays from SL SRS-P reception time and SL SRS-P transmission time and may be used for RTT measurements, etc.). Alternatively, the first measurement data may include measured UL TOA and / or UL TDOA data. In some designs, the means for performing reception at 1360 may include receiver 312 or 322 or 352 or 362, network transceiver 380 or 390, etc., depending on whether the location estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0241] 13, at 1370, a location estimation entity (e.g., receiver 312 or 322 or 352 or 362, network transceiver 380 or 390, etc.) receives second measurement information based on measurement of at least one UL SRS-P according to a second resource configuration. In some designs, the second measurement data may be based on multiple SRS-Ps (e.g., Rx-Tx measurements corresponding to DL or UL SRS-P reception time and delays from DL or UL SRS-P transmission time, which may be used for RTT measurements, etc.). Alternatively, the second measurement data may include measured UL TOA and / or UL TDOA data. In some designs, the means for performing reception at 1370 may include receiver 312 or 322 or 352 or 362, network transceiver 380 or 390, etc., depending on whether the location estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0242] 13 , at 1370, a location estimation entity (e.g., processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc.) determines a location estimate for each UE in the set of UEs based on the first measurement information and the second measurement information. In some designs, the means for performing the determination at 1370 may include processor 332 or 384 or 394, SRS component 342 or 388 or 398, etc., depending on whether the location estimation entity is implemented in the UE 302, the BS 304, or the network entity 306.

[0243] 14 illustrates an example process 1400 for wireless communication according to an aspect of the disclosure. In one aspect, the process 1400 may be performed by a UE, such as the UE 302.

[0244] 14, at 1410, the UE 302 (e.g., receiver 312 or 322, etc.) receives a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs. In some designs, the pool of UEs may include one or more additional UEs (e.g., anchor UEs whose locations are already known, etc.) in addition to the set of target UEs for which a position estimate is desired. In some designs, the means for performing receiving at 1410 may include the receiver 312 or 322 of the UE 302.

[0245] 14, at 1420, the UE 302 (e.g., receiver 312 or 322, etc.) receives a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE. In some designs, the means for performing reception at 1420 may include the receiver 312 or 322 of the UE 302.

[0246] 14, at 1430, the UE 302 (e.g., receiver 312 or 322, transmitter 314 or 324, SRS component 342, etc.) transmits a first SL SRS-P to one or more other UEs in the pool of UEs, measures a second SL SRS-P from another UE in the pool of UEs, or both, according to the first resource configuration. In some designs, the means for performing the transmission and / or measurement at 1430 may include the receiver 312 or 322 or the transmitter 314 or 324 or the SRS component 342 of the UE 302.

[0247] 14, at 1430, the UE 302 (e.g., transmitter 314 or 324, etc.) transmits the UL SRS-P according to the second resource configuration. In some designs, fewer than all of the UEs in the pool of UEs may be designated to transmit the UL SRS-P (e.g., to conserve power, limit SRS pollution, etc.). Alternatively, if high accuracy is desired, more UEs in the pool of UEs (and theoretically all such UEs) may be designated to transmit the UL SRS-P according to the second resource configuration. Parameters that may be evaluated to select which UEs should transmit the UL SRS-P are described in more detail below. In some designs, the means for performing transmission at 1440 may include the transmitter 314 or 324 of the UE 302.

[0248] 13-14, in some designs, prior to transmission of the first indication, each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which the respective SL SRS-P will be communicated according to the first resource configuration. For example, the location estimation entity may want to add only SL-connected UEs to the pool of UEs to reduce location estimation latency (e.g., rather than pinging any unconnected UEs and then waiting for such UEs to form an SL connection). Alternatively, in other designs, one or more SL connections between UEs in the pool of UEs are set up in conjunction with the SL-assisted location estimation procedure. Thus, some or all of the SL connections may be set up on demand in some designs to facilitate, among other things, the SL-assisted location estimation procedure (e.g., increased location estimation latency as well as improved accuracy as additional UEs participate in the SL-assisted location estimation procedure). In some designs, the SL connection setup may be a one-time setup operation (e.g., there is long latency in the setup for the initial SL-assisted position estimation procedure, but then subsequent SL-assisted position estimation procedures can be performed without this setup latency).

[0249] 13-14, in some designs, communication of the UL SRS-P may be implemented either before or after communication of the SL SRS-P. In a first example, assume that a first set of resources precedes a second set of resources such that at least one SL SRS-P is communicated before transmission of at least one UL SRS-P.

[0250] In one example, to facilitate the SL SRS-P portion of the SL-aided position estimation procedure, the network (e.g., a position estimation entity) may provide assistance data for some or all UEs in the pool to other UEs in the pool. In some designs, the assistance data may include range and / or angle to another UE from the pool. In some designs, the assistance data may include an RSTD value of the UE for another set of UEs in the pool (e.g., some UEs may be synchronized by design, such as through a cable, or their clocks may be resynchronized at a very high frequency, especially in an indoor factory environment). In this case, RSTD makes sense (e.g., RSTD generally requires common synchronization (or a known synchronization offset) between receiving nodes).

[0251] 13-14 , in some designs, the first measurement data may be received at the location estimation entity via individual reports from multiple UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by the multiple UEs is received via a lead UE of the pool of UEs (e.g., for more compact reporting, fewer measurement reports, etc.). For example, the lead UE may collect the first measurement data from various UEs via SL signaling and then report the first measurement data to the location estimation entity via Uu signaling (e.g., at least in scenarios where the location estimation entity corresponds to a network component).

[0252] 13-14 , in some designs, the location estimation entity may select at least one UE in a pool of UEs for transmission of at least one UL SRS-P based in part on the first measurement information. In a particular example, the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographic parameter, or a combination thereof. For example, the selection criteria may be configured as follows: Minimize the number of UL SRS-P transmissions: In this case, the selected set is the minimum set of UL SRS-P transmissions needed to derive a position estimate for all target UEs in the pool using the first available measurement information (e.g. one UE transmits UL SRS-p and all other UEs in the pool know their relative position to the transmitting UE; all positions can be derived using just one UL SRS-P transmission). Maximize accuracy: In this case the set of transmitting UEs is selected such that the estimated accuracy of the positioning is maximized (e.g. all UEs in a pool of UEs may be requested to transmit UL SRS-P. In this case no UL SRS-P transmissions are saved, but the first measurement data can be used to improve the accuracy of the position estimate. For example, more equations input to the positioning engine can help reduce the uncertainty margin and constrain the set of acceptable solutions). · Trade-off between accuracy and network load: In this case, the network selects a subset of UEs from a pool of UEs such that a certain level of accuracy is provided while saving on overall SRS transmissions. UE capability / power considerations: In this case, the network will prioritize UL SRS-P transmission from UEs with more capability (e.g. more bandwidth such as 100 MHz for premium UEs as opposed to 20 MHz or even 5 MHz for some lower tier UEs) and / or more power (e.g. UEs with more transmit power may be selected, or UEs with more battery power may be selected, etc.), geographical parameters such as location (e.g. UEs located centrally in a pool of UEs may transmit while UEs located outliers or on the edge in a SL UE group may skip UL SRS-P transmission, one or more UEs may be designated per clique of UEs in a pool of UEs, etc.). · Quality of transmission: In one example, the network prioritizes transmissions from UEs with a higher probability of LOS.

[0253] 13-14, in some designs, the second set of resources precedes the first set of resources such that at least one transmission of a UL SRS-P occurs before at least one SL SRS-P is communicated. Thus, the UL SRS-P and SL SRS-P communications may occur in any order.

[0254] 13-14, in some designs, the UEs designated for UL SRS-P transmission may be modified by the positioning entity between SL-assisted positioning procedures. In other words, if the positioning entity decides to perform another SL-assisted positioning procedure involving some or all of the pool of UEs, the at least one UE designated to transmit at least one UL SRS-P may be optionally updated for another SL-assisted positioning procedure based on information obtained in association with the SL-assisted positioning procedure. For example, the positioning entity may determine that two UEs transmitting UL SRS-P are too close to each other and may select to shift the UEs transmitting UL SRS-P more geographically. In another example, the positioning entity may determine that more accuracy is needed and may select more UEs to transmit UL SRS-P for the next SL-assisted positioning procedure, and so on.

[0255] 13-14, in some designs, the position estimation entity may transmit an indication of the determined position estimate. In some designs, the indication of the determined position estimate may be transmitted individually to each of the set of target UEs (e.g., via a separate Uu communication in case of a network implementation of the position estimation entity, or via a separate SL communication in case of a UE implementation of the position estimation entity). Alternatively, at least one of the indications of the determined position estimate is transmitted to a lead UE for forwarding (e.g., SL-based forwarding) to the respective target UE (e.g., conveying all determined position estimates to the lead UE via Uu signaling, which then disseminates the determined position estimates to the target UEs via SL signaling).

[0256] 13-14, in some designs above, one or more UEs in the pool of UEs are not part of the set of target UEs. For example, one or more UEs may correspond to anchor UEs associated with one or more known position estimates. Alternatively, one or more UEs need not be anchor UEs (e.g., UEs that are not target UEs but at the same time are not anchor UEs can be added to the pool and used for relative position estimation or to corroborate or verify other positioning measurements associated with the SL-assisted position estimation procedure).

[0257] FIG. 15 illustrates an example implementation 1500 of the processes 1300-1400 of FIGS. 13-14, respectively, according to one aspect of the disclosure. With reference to FIG. 15, the SL connections between the pool of UEs to which the SL SRS-P is communicated are shown via dotted lines. As shown in FIG. 15, the pool of UEs is composed of UEs 1-8 and includes two "cliques" (which may alternatively be characterized as subgroups of a subset of the pool of UEs), whereby each UE in a clique has an established SL connection to each other UE in the same clique. In this case, UEs 1-4 form a first clique, and UEs 5-8 form a second clique. The first and second cliques are connected for the SL connection between UEs 1 and UE 5. Thus, in some designs, the pool of UEs includes two or more cliques, where each UE in each clique has an established SL connection to each other UE in the same clique, and at least one UE in each clique has an established SL connection to at least one other UE in at least one other respective clique.

[0258] FIG. 16 illustrates an example implementation 1600 of the processes 1300-1400 of FIG. 13-14, respectively, according to one aspect of the disclosure. Referring to FIG. 16, a UL or Uu connection from a selected UE is shown, with UL SRS-P being communicated to the range of TRP1, 2, 3, and 4. As shown in FIG. 16, a pool of UEs is comprised of UE1-8, and only UE1, 5, and 6 are designated for UL SRS-P transmission. As mentioned above, to reduce SRS pollution, fewer than all of the UEs in the pool of UEs may be designated for UL SRS-P transmission, and so on. In some designs, at least one UE per clique may be selected for UL SRS-P transmission.

[0259] 15-16, the first clique (or UEs 1-4) knows their pair-wise distances, and the second clique (or UEs 5-8) also knows their pair-wise distances. UE 1 also knows the range to UE 5. With this information, the network can configure the UEs in the pool of UEs with various options, such as: Option 1: UE1, UE2, UE3 transmit UL SRS-P. Knowledge of the locations of these UEs can be used to infer knowledge of UE4 position (e.g. from relative SL SRS-P ranging). UE5, 6 and 7 transmit UL SRS-P. Their locations infer the location of UE8 (e.g. from relative SL SRS-P ranging). Knowledge of the ranges of UE1 through UE5 can act as cross-validation for location estimates or as additional constraints in the formulation of the positioning problem. In this option there are 6 UL SRS-P transmissions. Option 2: The network may exploit channel correlation to reduce UL SRS-P transmissions. For example, the distance from UE1 to UE5 may be considered small enough to make a noticeable difference in terms of operational accuracy requirements, and the network may use one UL SRS-P transmission from UE1 that also serves as a "proxy" for the UL SRS-P signal from UE5.

[0260] Referring to Figures 15-16, in some designs, if there are cliques with N>3 nodes (e.g., all pairwise range distances are available for each clique), the locations of all nodes in each clique can be inferred from the positions of only three nodes (in 2D positioning).

[0261] In the above detailed description, it can be seen that various features are grouped together in each example. This manner of disclosure should not be understood as an intention that the exemplary clauses have more features than are expressly stated in each clause. Rather, various aspects of the disclosure may include fewer than all features of each disclosed exemplary clause. Thus, the following clauses should be considered to be incorporated in the description, and each clause may stand alone as a separate example. Although each dependent clause may refer to a specific combination with one of the other clauses in the clause, the aspects of that dependent clause are not limited to that specific combination. It will be understood that other exemplary clauses may also include combinations of aspects of the dependent clause with the subject matter of any other dependent clause or independent clause, or combinations of any features with other dependent clauses and independent clauses. Unless a specific combination is not intended (e.g., conflicting aspects such as defining an element as both an insulator and a conductor) is expressly expressed or can be easily inferred, the various aspects disclosed herein expressly include these combinations. It is further contemplated that aspects of a clause may be included in any other independent clause, even if the clause is not directly dependent on the independent clause.

[0262] The following numbered clauses describe example implementations.

[0263] Clause 1. A method of operating a position estimation entity, comprising: identifying a pool of UEs for a sidelink (SL)-assisted position estimation procedure of a set of target user equipments (UEs); determining a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; determining a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs; transmitting a first indication of the first resource configuration to the pool of UEs; transmitting a second indication of the second resource configuration to the at least one UE; receiving first measurement information based on measurement of the at least one SL SRS-P in accordance with the first resource configuration; and transmitting at least one UL SRS-P in accordance with the second resource configuration. A method comprising: receiving second measurement information based on measurements of the SRS-P; and determining a position estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0264] Clause 2. The method of clause 1, wherein each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is to be communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0265] Clause 3. The method according to any one of clauses 1 to 2, wherein one or more SL connections between UEs in a pool of UEs are set up with a SL-assisted location estimation procedure.

[0266] Clause 4. The method of any one of clauses 1-3, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated before transmission of at least one UL SRS-P.

[0267] Clause 5. The method of clause 4, further comprising selecting at least one UE in the pool of UEs for transmission of the at least one UL SRS-P based in part on the first measurement information.

[0268] Clause 6. The method of clause 5, wherein the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0269] Clause 7. The method of any one of clauses 1 to 6, wherein the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0270] Clause 8. The method of any one of clauses 1 to 7, further comprising: determining to perform another SL-assisted location estimation procedure involving some or all of the pool of UEs, wherein at least one UE designated to transmit at least one UL SRS-P is updated for the another SL-assisted location estimation procedure based on information obtained in relation to the SL-assisted location estimation procedure.

[0271] Clause 9. The method of any one of clauses 1-8, further comprising transmitting an indication of the determined position estimate.

[0272] Clause 10. The method of clause 9, wherein an indication of the determined location estimate is sent individually to each of a set of target UEs or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UEs.

[0273] Clause 11. The method of any one of clauses 1 to 10, wherein one or more UEs in the pool of UEs are not part of the set of target UEs.

[0274] Clause 12. The method of clause 11, wherein the one or more UEs correspond to anchor UEs associated with one or more known position estimates.

[0275] Clause 13. The method of any one of clauses 1 to 12, wherein the pool of UEs includes two or more subsets of UEs, each UE in each subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in each subset of UEs having an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0276] Clause 14. The method according to any one of clauses 1 to 13, wherein the location estimation entity corresponds to a UE in a pool of UEs or a network element.

[0277] Clause 15. The method according to any one of clauses 1 to 14, wherein the first measurement data is received via individual reports from a plurality of UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by a plurality of UEs is received via a lead UE of the pool of UEs.

[0278] Clause 16. A method of operating a user equipment (UE), the method including: receiving a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; receiving a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmitting the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration, measuring a second SL SRS-P from another UE in the pool of UEs, or both, and transmitting the UL SRS-P in accordance with the second resource configuration.

[0279] Clause 17. The method of clause 16, further comprising receiving a position estimate for the UE that is among a set of target UEs and associated with the SL-assisted position estimation procedure.

[0280] Clause 18. The method of clause 17, wherein the location estimate is received from a location estimation entity or from another UE in a pool of UEs.

[0281] Clause 19. The method of any one of clauses 16 to 18, wherein the UE has, prior to receipt of the first indication, an established SL connection to each of one or more other UEs in the pool of UEs.

[0282] Clause 20. The method according to any one of clauses 16 to 19, wherein one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up with a SL assisted position estimation procedure.

[0283] Clause 21. The method of any one of clauses 16 to 20, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated before transmission of the UL SRS-P.

[0284] Clause 22. The method of any one of clauses 16 to 21, wherein the second set of resources precedes the first set of resources such that transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0285] Clause 23. The method according to any one of clauses 16 to 22, wherein the UEs in the pool of UEs are not part of the set of target UEs.

[0286] Clause 24. The method of clause 23, wherein the UE corresponds to an anchor UE associated with a known location estimate.

[0287] Clause 25. The method of any one of clauses 16 to 24, wherein the UE and the one or more other UEs form a subset of UEs in a pool of UEs, each UE in the subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs having an established SL connection to at least one other UE in at least one other subset of UEs.

[0288] Clause 26. The method of any one of clauses 16 to 25, further comprising the UE measuring a second SL SRS-P from another UE and transmitting measurement data based on the measurement of the second SL SRS-P directly to a location estimation entity or a lead UE of the pool of UEs.

[0289] Article 27. and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor including: identifying a pool of target user equipment (UE) for a sidelink (SL)-assisted position estimation procedure of a set of UEs; determining a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; determining a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs; transmitting, via the at least one transceiver, a first indication of the first resource configuration to the pool of UEs; transmitting, via the at least one transceiver, a second indication of the second resource configuration to the at least one UE; and transmitting, via the at least one transceiver, a second indication of the second resource configuration to the at least one UE according to the first resource configuration. a location estimation entity configured to receive first measurement information based on measurements of the SRS-P, receive via the at least one transceiver second measurement information based on measurements of at least one UL SRS-P according to a second resource configuration, and determine a location estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0290] Clause 28. The location estimation entity of clause 27, wherein each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0291] Clause 29. The location estimation entity according to any one of clauses 27 to 28, wherein one or more SL connections between UEs in a pool of UEs are set up with a SL assisted location estimation procedure.

[0292] Clause 30. The location estimation entity of any one of clauses 27-29, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of at least one UL SRS-P.

[0293] Clause 31. The location estimation entity of clause 30, wherein the at least one processor is further configured to select at least one UE in the pool of UEs for transmission of the at least one UL SRS-P based in part on the first measurement information.

[0294] Clause 32. The location estimation entity of clause 31, wherein the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0295] Clause 33. The location estimation entity of any one of clauses 27 to 32, wherein the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0296] Clause 34. The location estimation entity of any one of clauses 27 to 33, wherein the at least one processor is further configured to determine to perform another SL-assisted location estimation procedure including some or all of the pool of UEs, and wherein at least one UE designated to transmit the at least one UL SRS-P is updated for the another SL-assisted location estimation procedure based on information obtained in relation to the SL-assisted location estimation procedure.

[0297] Clause 35. The position estimation entity of any one of clauses 27-34, wherein the at least one processor is further configured to transmit, via the at least one transceiver, an indication of the determined position estimate.

[0298] Clause 36. The location estimation entity of clause 35, wherein an indication of the determined location estimate is sent to each of a set of target UEs individually or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UE.

[0299] Clause 37. The location estimation entity of any one of clauses 27 to 36, wherein one or more UEs in the pool of UEs are not part of the set of target UEs.

[0300] Clause 38. The location estimation entity of clause 37, wherein the one or more UEs correspond to anchor UEs associated with one or more known location estimates.

[0301] Clause 39. The location estimation entity of any one of clauses 27 to 38, wherein the pool of UEs includes two or more subsets of UEs, each UE in each subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in each subset of UEs having an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0302] Clause 40. The location estimation entity of any one of clauses 27 to 39, wherein the location estimation entity corresponds to a UE or a network element in a pool of UEs.

[0303] Clause 41. The location estimation entity according to any one of clauses 27 to 40, wherein the first measurement data is received via individual reports from a plurality of UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by a plurality of UEs is received via a lead UE of the pool of UEs.

[0304] Clause 42. A user equipment (UE), comprising: a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor comprising: receiving, via the at least one transceiver, a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; receiving, via the at least one transceiver, a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmitting, via the at least one transceiver, the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration; receiving, via the at least one transceiver, a second SL SRS-P from another UE in the pool of UEs in accordance with the first resource configuration; and / or measuring the UL SRS-P and transmitting, via the at least one transceiver, the UE in accordance with the second resource configuration.

[0305] Clause 43. The UE of clause 42, wherein the UE is among a set of target UEs, further comprising: the at least one processor further configured to receive, via the at least one transceiver, a position estimate of the UE associated with the SL-assisted position estimation procedure.

[0306] Clause 44. The UE of clause 43, wherein the location estimate is received from a location estimation entity or from another UE in a pool of UEs.

[0307] Clause 45. The UE of any one of clauses 42 to 44, wherein the UE has, prior to receipt of the first indication, an established SL connection to each of one or more other UEs in the pool of UEs.

[0308] Clause 46. The UE of any one of clauses 42 to 45, wherein one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up with a SL assisted location estimation procedure.

[0309] Clause 47. The UE of any one of clauses 42-46, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of the UL SRS-P.

[0310] Clause 48. The UE of any one of clauses 42 to 47, wherein the second set of resources precedes the first set of resources such that transmission of a UL SRS-P occurs before at least one SL SRS-P is communicated.

[0311] Clause 49. The UE of any one of clauses 42 to 48, wherein the UEs in the pool of UEs are not part of the set of target UEs.

[0312] Clause 50. The UE of clause 49, wherein the UE corresponds to an anchor UE associated with a known location estimate.

[0313] Clause 51. The UE of any one of clauses 42 to 50, wherein the UE and the one or more other UEs form a subset of UEs in a pool of UEs, each UE in the subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs having an established SL connection to at least one other UE in at least one other subset of UEs.

[0314] Clause 52. The UE of any one of clauses 42 to 51, wherein the UE is configured to measure a second SL SRS-P from another UE, and wherein the at least one processor is further configured to transmit, via the at least one transceiver, measurement data based on the measurement of the second SL SRS-P directly to a location estimation entity or a lead UE of the pool of UEs.

[0315] Clause 53. The method includes: means for identifying a pool of UEs for a sidelink (SL)-assisted position estimation procedure of a set of target user equipments (UEs); means for determining a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; means for determining a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs; means for transmitting a first indication of the first resource configuration to the pool of UEs; means for transmitting a second indication of the second resource configuration to the at least one UE; means for receiving first measurement information based on measurement of at least one SL SRS-P in accordance with the first resource configuration; and means for receiving measurement information based on measurement of at least one SL SRS-P in accordance with the second resource configuration. A location estimation entity comprising: means for receiving second measurement information based on measurements of the SRS-P; and means for determining a location estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0316] Clause 54. The location estimation entity of clause 53, wherein each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0317] Clause 55. The location estimation entity according to any one of clauses 53 to 54, wherein one or more SL connections between UEs in a pool of UEs are set up with a SL assisted location estimation procedure.

[0318] Clause 56. The location estimation entity of any one of clauses 53-55, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of at least one UL SRS-P.

[0319] Clause 57. The location estimation entity of clause 56, further comprising means for selecting at least one UE in the pool of UEs for transmission of at least one UL SRS-P based in part on the first measurement information.

[0320] Clause 58. The location estimation entity of clause 57, wherein the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

[0321] Clause 59. The location estimation entity of any one of clauses 53 to 58, wherein the second set of resources precedes the first set of resources and at least one transmission of the UL SRS-P occurs before the at least one SL SRS-P is communicated.

[0322] Clause 60. The location estimation entity of any of clauses 53 to 59, further comprising means for determining to perform another SL-assisted location estimation procedure involving some or all of the pool of UEs, wherein at least one UE designated to transmit at least one UL SRS-P is updated for another SL-assisted location estimation procedure based on information obtained in relation to the SL-assisted location estimation procedure.

[0323] Clause 61. The location estimation entity of any of clauses 53-60, further comprising means for transmitting an indication of the determined location estimate.

[0324] Clause 62. The location estimation entity of clause 61, wherein an indication of the determined location estimate is sent to each of a set of target UEs individually or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to the respective target UE.

[0325] Clause 63. The location estimation entity according to any one of clauses 53 to 62, wherein one or more UEs in the pool of UEs are not part of the set of target UEs.

[0326] Clause 64. The location estimation entity of clause 63, wherein the one or more UEs correspond to anchor UEs associated with one or more known location estimates.

[0327] Clause 65. The location estimation entity of any one of clauses 53 to 64, wherein the pool of UEs includes two or more subsets of UEs, each UE in each subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in each subset of UEs having an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0328] Clause 66. The location estimation entity of any one of clauses 53 to 65, wherein the location estimation entity corresponds to a UE or a network element in a pool of UEs.

[0329] Clause 67. The location estimation entity according to any one of clauses 53 to 66, wherein the first measurement data is received via individual reports from a plurality of UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by a plurality of UEs is received via a lead UE of the pool of UEs.

[0330] Clause 68. A user equipment (UE) comprising: means for receiving a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; means for receiving a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; means for transmitting the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration, measuring a second SL SRS-P from another UE in the pool of UEs, or both; and means for transmitting the UL SRS-P in accordance with the second resource configuration.

[0331] Clause 69. The UE of clause 68, further comprising means for receiving a position estimate for a UE that is among a set of target UEs and associated with the SL-assisted position estimation procedure.

[0332] Clause 70. The UE of clause 69, wherein the location estimate is received from a location estimation entity or from another UE in a pool of UEs.

[0333] Clause 71. The UE of any one of clauses 68 to 70, wherein the UE has, prior to receipt of the first indication, an established SL connection to each of one or more other UEs in the pool of UEs.

[0334] Clause 72. The UE of any one of clauses 68 to 71, wherein one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up with a SL assisted location estimation procedure.

[0335] Clause 73. The UE of any one of clauses 68-72, wherein the first set of resources precedes the second set of resources and at least one SL SRS-P is communicated prior to transmission of the UL SRS-P.

[0336] Clause 74. The UE of any one of clauses 68 to 73, wherein the second set of resources precedes the first set of resources, and wherein transmission of the UL SRS-P occurs before communication of the at least one SL SRS-P.

[0337] Clause 75. The UE of any one of clauses 68 to 74, wherein the UEs in the pool of UEs are not part of the set of target UEs.

[0338] Clause 76. The UE of clause 75, wherein the UE corresponds to an anchor UE associated with a known location estimate.

[0339] Clause 77. The UE of any one of clauses 68 to 76, wherein the UE and the one or more other UEs form a subset of UEs in a pool of UEs, each UE in the subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs having an established SL connection to at least one other UE in at least one other subset of UEs.

[0340] Clause 78. The UE of any one of clauses 68 to 77, wherein the UE further comprises means for measuring a second SL SRS-P from another UE and transmitting measurement data based on the measurement of the second SL SRS-P directly to a location estimation entity or a lead UE of a pool of UEs.

[0341] Clause 79. When executed by the location estimation entity, the method includes: identifying a pool of UEs for a sidelink (SL)-assisted location estimation procedure for a set of target user equipments (UEs); determining a first resource configuration for the SL-assisted location estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; determining a second resource configuration for the SL-assisted location estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs; transmitting a first indication of the first resource configuration to the pool of UEs; transmitting a second indication of the second resource configuration to the at least one UE; receiving first measurement information based on measurement of the at least one SL SRS-P in accordance with the first resource configuration; and determining a second resource configuration for the SL-assisted location estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by at least one UE in the pool of UEs in accordance with the second resource configuration. A non-transitory computer-readable medium storing computer-executable instructions to cause a device to receive second measurement information based on measurements of the SRS-P, and to determine a position estimate for each UE in the set of UEs based on the first measurement information and the second measurement information.

[0342] Clause 80. The non-transitory computer-readable medium of clause 79, wherein each UE in the pool of UEs has an established SL connection to each other UE in the pool of UEs over which a respective SL SRS-P is to be communicated in accordance with the first resource configuration prior to transmission of the first indication.

[0343] Clause 81. The non-transitory computer-readable medium of any one of clauses 79-80, wherein one or more SL connections between UEs in a pool of UEs are set up with a SL-assisted position estimation procedure.

[0344] Clause 82. The non-transitory computer-readable medium of any one of clauses 79-81, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of at least one UL SRS-P.

[0345] Clause 83. The non-transitory computer-readable medium of clause 82, further comprising instructions that, when executed by the location estimation entity, cause the location estimation entity to select at least one UE in the pool of UEs for transmission of at least one UL SRS-P based in part on the first measurement information.

[0346] Clause 84. The non-transitory computer-readable medium of clause 83, wherein the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographic parameter, or a combination thereof.

[0347] Clause 85. The non-transitory computer-readable medium of any one of clauses 79-84, wherein the second set of resources precedes the first set of resources such that at least one transmission of the UL SRS-P occurs before at least one SL SRS-P is communicated.

[0348] Clause 86. The non-transitory computer-readable medium of any one of clauses 79-85, further comprising instructions that, when executed by the position estimation entity, cause the position estimation entity to determine to perform another SL-assisted position estimation procedure involving some or all of the pool of UEs, wherein at least one UE designated to transmit at least one UL SRS-P is updated for another SL-assisted position estimation procedure based on information obtained in connection with the SL-assisted position estimation procedure.

[0349] Clause 87. The non-transitory computer-readable medium of any one of clauses 79-86, further comprising instructions that, when executed by the position estimation entity, cause the position estimation entity to transmit an indication of the determined position estimate.

[0350] Clause 88. The non-transitory computer-readable medium of clause 87, wherein an indication of the determined location estimate is sent individually to each of a set of target UEs or at least one of the indications of the determined location estimate is sent to a lead UE for forwarding to a respective target UE.

[0351] Clause 89. The non-transitory computer-readable medium of any one of clauses 79-88, wherein one or more UEs in the pool of UEs are not part of the set of target UEs.

[0352] Clause 90. The non-transitory computer-readable medium of clause 89, wherein the one or more UEs correspond to anchor UEs associated with one or more known position estimates.

[0353] Clause 91. The non-transitory computer-readable medium of any one of clauses 79-90, wherein the pool of UEs includes two or more subsets of UEs, each UE in each subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in each subset of UEs having an established SL connection to at least one other UE in at least one other respective subset of UEs.

[0354] Clause 92. The non-transitory computer-readable medium of any one of clauses 79 to 91, wherein the location estimation entity corresponds to a UE or a network component in a pool of UEs.

[0355] Clause 93. The non-transitory computer-readable medium of any one of clauses 79-92, wherein the first measurement data is received via individual reports from multiple UEs in a pool of UEs measuring at least one SL SRS-P, or some or all of the first measurement data measured by the multiple UEs is received via a lead UE of the pool of UEs.

[0356] Clause 94. A non-transitory computer-readable medium storing computer-executable instructions that, when executed by a user equipment (UE), cause the UE to: receive a first indication of a first resource configuration for a sidelink (SL)-assisted position estimation procedure for a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of the pool of UEs; receive a second indication of a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmit the first SL SRS-P to one or more other UEs in the pool of UEs in accordance with the first resource configuration, measure a second SL SRS-P from another UE in the pool of UEs, or both, and transmit the UL SRS-P in accordance with the second resource configuration.

[0357] Clause 95. The non-transitory computer-readable medium of clause 94, wherein the UE is among a set of target UEs, the instructions further causing the UE to receive a position estimate for the UE associated with the SL-assisted position estimation procedure.

[0358] Clause 96. The non-transitory computer-readable medium of clause 95, wherein the location estimate is received from a location estimation entity or from another UE in a pool of UEs.

[0359] Clause 97. The non-transitory computer-readable medium of any one of clauses 94-96, wherein the UE has an established SL connection to each of one or more other UEs in the pool of UEs prior to receipt of the first indication.

[0360] Clause 98. The non-transitory computer-readable medium of any one of clauses 94-97, wherein one or more SL connections between the UE and one or more other UEs in a pool of UEs are set up with a SL-assisted position estimation procedure.

[0361] Clause 99. The non-transitory computer-readable medium of any one of clauses 94-98, wherein the first set of resources precedes the second set of resources such that at least one SL SRS-P is communicated prior to transmission of the UL SRS-P.

[0362] Clause 100. The non-transitory computer-readable medium of any one of clauses 94-99, wherein the second set of resources precedes the first set of resources such that transmission of a UL SRS-P occurs before at least one SL SRS-P is communicated.

[0363] Clause 101. The non-transitory computer-readable medium of any one of clauses 94-100, wherein a UE in the pool of UEs is not part of a set of target UEs.

[0364] Clause 102. The non-transitory computer-readable medium of clause 101, wherein the UE corresponds to an anchor UE associated with a known position estimate.

[0365] Clause 103. The non-transitory computer-readable medium of any one of clauses 94-102, wherein the UE and one or more other UEs form a subset of UEs in the pool of UEs, each UE in the subset of UEs having an established SL connection to each other UE in the same subset of UEs, and at least one UE in the subset of UEs having an established SL connection to at least one other UE in at least one other subset of UEs.

[0366] Clause 104. The non-transitory computer-readable medium of any one of clauses 94-103, wherein the UE measures a second SL SRS-P from another UE, further comprising: the instructions further causing the UE to transmit measurement data based on the measurement of the second SL SRS-P directly to a location estimation entity or a lead UE of a pool of UEs.

[0367] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0368] Moreover, those skilled in the art will appreciate that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, various exemplary components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0369] The various example logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using a general purpose processor, a digital signal processor (DSP), an ASIC, a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0370] The methods, sequences, and / or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a random access memory (RAM), a flash memory, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). Alternatively, the processor and the storage medium may reside as discrete components in a user terminal.

[0371] In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of media. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0372] Although the above disclosure illustrates exemplary aspects of the disclosure, it should be noted that various changes and modifications may be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps, and / or actions of the method claims according to the aspects of the disclosure described herein need not be performed in any particular order. Further, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. [Explanation of symbols]

[0373] 302UE 304 base station 306 Network Entities 318 Signal 316 Antenna 310 WWAN Transceiver 320 Short Range Wireless Transceiver 330 Satellite signal receiver 332 processor 334 Data Bus 340 Memory 344 Sensors 346 User Interface

Claims

**Claim 1** A method for operating a location estimation entity, comprising: identifying a pool of UEs for side link (SL) assisted location estimation procedures for a set of target user equipment (UE); determining a first resource configuration for the SL assisted location estimation procedure, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning between some or all of the pool of UEs; determining a second resource configuration for the SL assisted location estimation procedure, the second resource configuration including a second set of resources associated with transmission of uplink (UL) SRS-P by at least one UE within the pool of UEs; transmitting a first indication of the first resource configuration to the pool of UEs; transmitting a second indication of the second resource configuration to the at least one UE; receiving first measurement information based on measurements of the at least one SL SRS-P according to the first resource configuration; receiving second measurement information based on measurements of the at least one UL SRS-P according to the second resource configuration; and determining a location estimate for each UE within the set of UEs based on the first measurement information and the second measurement information. **Claim 2** The method according to claim 1, wherein each UE within the pool of UEs has an established SL connection to each other UE within the pool of UEs through which its respective SL SRS-P will be communicated according to the first resource configuration prior to the transmission of the first indication. **Claim 3** The method according to claim 1, wherein the first set of resources precedes the second set of resources such that the at least one SL SRS-P is communicated before the transmission of the at least one UL SRS-P. **Claim 4** The method according to claim 3, further comprising selecting the at least one UE within the pool of UEs for transmission of the at least one UL SRS-P, based in part on the first measurement information. **Claim 5** The method according to claim 4, wherein the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

6. further comprising determining to execute another SL assistance location estimation procedure including some or all of the UE pool, wherein at least one UE designated to transmit the at least one UL SRS-P is updated for the another SL assistance location estimation procedure based on information obtained in relation to the SL assistance location estimation procedure, the method according to claim 1.

7. A method of operating a user equipment (UE), comprising: receiving a first indication of a first resource configuration for a sidelink (SL) assistance location estimation procedure of a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning among some or all of a pool of UEs; receiving a second indication of a second resource configuration for the SL assistance location estimation procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE; transmitting a first SL SRS-P to one or more other UEs within the pool of UEs, measuring a second SL SRS-P from another UE within the pool of UEs, or both, according to the first resource configuration; and transmitting the UL SRS-P according to the second resource configuration.

8. The UE is within the set of target UEs, the method according to claim 7, further comprising receiving a location estimate of the UE associated with the SL assistance location estimation procedure.

9. The method according to claim 8, wherein the location estimate is received from a location estimation entity or from another UE within the pool of UEs.

10. a memory; at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor identifying a pool of UEs for a sidelink (SL) assistance location estimation procedure of a set of target user equipment (UEs). ​ Determining a first resource configuration for the SL-assisted position estimation procedure, the first resource configuration including a first set of resources associated with the communication of at least one SL sounding reference signal (SRS-P) for positioning between some or all of the UEs in the pool of the UEs, the determining; Determining a second resource configuration for the SL-assisted position estimation procedure, the second resource configuration including a second set of resources associated with the transmission of uplink (UL) SRS-P by at least one UE in the pool of the UEs, the determining; Transmitting a first indication of the first resource configuration to the pool of the UEs via the at least one transceiver; Transmitting a second indication of the second resource configuration to the at least one UE via the at least one transceiver; Receiving, via the at least one transceiver, first measurement information based on the measurement of the at least one SL SRS-P according to the first resource configuration; Receiving, via the at least one transceiver, second measurement information based on the measurement of the at least one UL SRS-P according to the second resource configuration; A position estimation entity configured to determine a position estimation value for each UE in the set of UEs based on the first measurement information and the second measurement information.

11. The at least one processor is further Configured to select the at least one UE in the pool of the UEs for the transmission of the at least one UL SRS-P, at least partially based on the first measurement information, the position estimation entity according to claim 10.

12. The position estimation entity according to claim 11, wherein the selection is based on an overhead parameter, an accuracy parameter, a UE capability parameter, a power parameter, a quality parameter, a geographical parameter, or a combination thereof.

13. The at least one processor is further Configured to determine to execute another SL-assisted position estimation procedure including some or all of the pool of the UEs. The positioning entity according to claim 10, wherein at least one UE designated to transmit the at least one UL SRS-P is updated for the another SL assistance positioning procedure based on information obtained in relation to the SL assistance positioning procedure.

14. A user equipment (UE), a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor being to receive, via the at least one transceiver, a first indication of a first resource configuration for a sidelink (SL) assistance positioning procedure of a set of target UEs, the first resource configuration including a first set of resources associated with communication of at least one SL sounding reference signal (SRS-P) for positioning between some or all of a pool of UEs, to receive, via the at least one transceiver, a second indication of a second resource configuration for the SL assistance positioning procedure, the second resource configuration including a second set of resources associated with transmission of an uplink (UL) SRS-P by the UE, to transmit, via the at least one transceiver, a first SL SRS-P to one or more other UEs within the pool of the UEs, measure a second SL SRS-P from another UE within the pool of the UEs, or both, according to the first resource configuration, and to transmit the UL SRS-P according to the second resource configuration via the at least one transceiver.

15. The UE is within the set of target UEs and further includes the at least one processor is further configured to receive, via the at least one transceiver, a positioning value of the UE associated with the SL assistance positioning procedure, the UE according to claim 14.

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