Device positioning using distributed antenna coordination

Abstract

Various aspects of the present disclosure relate to device positioning using distributed antenna coordination. For instance, phase, frequency, and timing synchronization can be implemented between distributed unit (DU) to allow for coherent downlink positioning reference signal (DL PRS) transmission from different DU and enable target user equipment (UE) to efficiently estimate carrier phase. Further, geometry of distributed antennas can allow the resolution of integer ambiguities. Still further, assistance data signalling associated with different distributed antennas can be transmitted.

Description

Lenovo Docket No. SMM920230097-WO-PCT 1 DEVICE POSITIONING USING DISTRIBUTED ANTENNA COORDINATION RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application Serial No. 63 / 588,616 filed October 6, 2023, entitled “DEVICE POSITIONING USING DISTRIBUTED ANTENNA COORDINATION,” the disclosure of which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates to wireless communications, and more specifically to device positioning in wireless communications. BACKGROUND

[0003] A wireless communications system may include one or multiple network communication devices, such as base stations, which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like). Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G)). SUMMARY

[0004] An article “a” before an element is unrestricted and understood to refer to “at least one” of those elements or “one or more” of those elements. The terms “a,” “at least one,” “one or more,” and “at least one of one or more” may be interchangeable. As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 2 “one or more of” or “one or both of”) indicates inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on”. Further, as used herein, including in the claims, a “set” may include one or more elements.

[0005] Some implementations of the method and apparatuses described herein may further include to receive, from one or more distributed units (DU), signaling including downlink (DL) positioning reference signals (PRS) and estimate one or more carrier phase measurements; and generate position information for the UE based at least in part on the signaling.

[0006] In some implementations of the method and apparatuses described herein, the signaling further includes one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU; estimate the carrier phase of the received DL PRS; and resolve integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information; transmit the position information to a network entity

[0007] Some implementations of the method and apparatuses described herein may further include receiving, from one or more DU, signaling including DL PRS and estimate one or more carrier phase measurements; and generating position information for the UE based at least in part on the signaling.

[0008] In some implementations of the method and apparatuses described herein, the signaling further includes one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU; estimating the carrier phase of the received DL PRS; and resolving integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information; transmitting the position information to a network entity. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 3

[0009] Some implementations of the and apparatuses described herein may further include to receive, from one or more DU, signaling comprising DL PRS and estimate one or more carrier phase measurements; and generate position information for a user equipment (UE) based at least in part on the signaling.

[0010] In some implementations of the method and apparatuses described herein, the signaling further comprises one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU; estimate a carrier phase of the received DL PRS; and resolve integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information; transmit the position information to a network entity.

[0011] Some implementations of the method and apparatuses described herein may further include to receive, at a first apparatus and from a second apparatus, one or more first synchronization reference signals; transmit, to the second apparatus, one or more second synchronization reference signals; and transmit, based at least in part on one or more of the first synchronization reference signals or the second synchronization reference signals, one or more downlink PRS to a positioning target apparatus.

[0012] In some implementations of the method and apparatuses described herein, the first apparatus and the second apparatus include different DU, and the target apparatus includes a user equipment (UE); the first apparatus and the second apparatus are controlled by a same central unit (CU); or the first apparatus and the second apparatus are controlled by different CU; utilize the one or more of the first synchronization reference signals or the second synchronization reference signals to synchronize at least one of frequency configuration, phase configuration, or timing configuration of the first apparatus to generate the one or more PRS; utilize the one or more of the first synchronization reference signals or the second synchronization reference signals to mitigate at least one of frequency offset, phase offset, or timing offset between the first apparatus and the second apparatus to generate the one or more PRS; determine, based at least in part on the one or more first synchronization reference signals, synchronization reference signal information including one or more of angle of departure information, angle of arrival information, or distance information; and transmit the synchronization reference signal information to one or more of the positioning target apparatus or a network entity Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 4

[0013] In some implementations of the and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a distributed topology, and the first apparatus mitigates one or more phase errors in the one or more PRS based at least in part on the first synchronization reference signals or the second synchronization reference signals; the one or more phase errors are based at least in part on one or more of frequency offsets, initial phases, or timing synchronization errors; to mitigate the one or more phase errors, the at least one processor is configured to cause the first apparatus to: generate estimated frequency values and estimated phase values for the first apparatus and the second apparatus; average the estimated frequency values and the estimated phase values to generate averaged estimated frequency values and averaged estimated phase values; and synchronize the estimated frequency values and the estimated phase values with the averaged estimated frequency values and the averaged estimated phase values.

[0014] In some implementations of the method and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a centralized topology, and wherein the at least one processor is configured to cause the first apparatus to mitigate one or more phase errors in the one or more PRS based at least in part on locking one or more frequencies and one or more phases of the first apparatus to one or more frequencies and one or more phases of a primary node oscillator of the centralized topology; the at least one processor is configured to cause the first apparatus to generate the one or more PRS based at least in part on a resolved integer ambiguity determined based at least in part on one or more of angle information or distance information for the second apparatus; the at least one processor is configured to cause the first apparatus to determine the angle information based at least in part on one or more phase differences between the one or more first synchronization reference signals and one more third synchronization reference signals received from a third apparatus.

[0015] Some implementations of the method and apparatuses described herein may further include receiving, at a first apparatus and from a second apparatus, one or more first synchronization reference signals; transmitting, to the second apparatus, one or more second synchronization reference signals; and transmitting, based at least in part on one or more of the first synchronization reference signals or the second synchronization reference signals, one or more downlink PRS to a positioning target apparatus. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 5

[0016] In some implementations of the and apparatuses described herein, the first apparatus and the second apparatus include different DU, and the target apparatus includes a user equipment (UE); the first apparatus and the second apparatus are controlled by a same CU; or the first apparatus and the second apparatus are controlled by different CU; utilizing the one or more of the first synchronization reference signals or the second synchronization reference signals to synchronize at least one of frequency configuration, phase configuration, or timing configuration of the first apparatus to generate the one or more PRS; utilizing the one or more of the first synchronization reference signals or the second synchronization reference signals to mitigate at least one of frequency offset, phase offset, or timing offset between the first apparatus and the second apparatus to generate the one or more PRS; determining, based at least in part on the one or more first synchronization reference signals, synchronization reference signal information including one or more of angle of departure information, angle of arrival information, or distance information; and transmitting the synchronization reference signal information to one or more of the positioning target apparatus or a network entity.

[0017] In some implementations of the method and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a distributed topology, and wherein the method further includes mitigating one or more phase errors in the one or more PRS based at least in part on the first synchronization reference signals or the second synchronization reference signals; the one or more phase errors are based at least in part on one or more of frequency offsets, initial phases, or timing synchronization errors; mitigating the one or more phase errors includes: generating estimated frequency values and estimated phase values for the first apparatus and the second apparatus; averaging the estimated frequency values and the estimated phase values to generate averaged estimated frequency values and averaged estimated phase values; and synchronizing the estimated frequency values and the estimated phase values with the averaged estimated frequency values and the averaged estimated phase values.

[0018] In some implementations of the method and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a centralized topology, and wherein the method further includes mitigating one or more phase errors in the one or more PRS based at least in part on locking one or more frequencies and one or more phases of the first apparatus to one or more frequencies and one or more phases of a primary node oscillator of the centralized Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 6 topology; generating the one or more PRS at least in part on a resolved integer ambiguity determined based at least in part on one or more of angle information or distance information for the second apparatus; determining the angle information based at least in part on one or more phase differences between the one or more first synchronization reference signals and one more third synchronization reference signals received from a third apparatus.

[0019] Some implementations of the method and apparatuses described herein may further include to receive, from a network entity, location assistance data for a set of DU; and signal at least some of the location assistance data to one or more DU of the set of DU.

[0020] In some implementations of the method and apparatuses described herein, the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; the at least one processor is configured to cause the CU to signal one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF).

[0021] Some implementations of the method and apparatuses described herein may further include receiving, from a network entity, location assistance data for a set of DU; and signaling at least some of the location assistance data to one or more DU of the set of DU.

[0022] In some implementations of the method and apparatuses described herein, the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; signaling one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF).

[0023] Some implementations of the method and apparatuses described herein may further include to generate location assistance data for a set of DU; and signal at least some of the location assistance data to a CU.

[0024] In some implementations of the method and apparatuses described herein, the location assistance data includes DL positioning reference signal (PRS) information; the location assistance Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 7 data includes one or more identifiers for DU of set of DU; the at least one processor is configured to cause the network entity to receive, from the CU, one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF).

[0025] Some implementations of the method and apparatuses described herein may further include generating location assistance data for a set of DU; and signaling at least some of the location assistance data to a CU.

[0026] In some implementations of the method and apparatuses described herein, the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; receiving, from the CU, one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present disclosure.

[0028] Figure 2 illustrates example scenarios 200 for absolute and relative positioning scenarios.

[0029] Figure 3 illustrates an example multi-cell round trip time (RTT) procedure 300.

[0030] Figure 4 illustrates an example relative range estimation system 400 using an existing single gNB RTT positioning framework.

[0031] Figure 5 illustrates an example NR beam-based positioning system 500.

[0032] Figure 6 illustrates an example of function split options of a distributed antenna system (DAS) 600. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 8

[0033] Figure 7 illustrates an example of a DAS 700 with distributed units at a vehicles front and rear bumpers.

[0034] Figure 8 illustrates an example of a double-differential system 800 for error mitigation in GNSS.

[0035] Figure 9 illustrates a system 900 for inter-node coordination for coherent DL PRS transmission.

[0036] Figure 10 illustrates an example system 1000 for centralized frequency, phase, and time synchronization between distributed antennas in accordance with aspects of the present disclosure.

[0037] Figure 11 illustrates an example system 1100 for integer ambiguity resolution using DAS geometries.

[0038] Figure 12 illustrates an example message 1200 in accordance with aspects of the present disclosure.

[0039] Figure 13 illustrates an example of a UE 1300 in accordance with aspects of the present disclosure.

[0040] Figure 14 illustrates an example of a processor 1400 in accordance with aspects of the present disclosure.

[0041] Figure 15 illustrates an example of a network entity (NE) 1500 in accordance with aspects of the present disclosure.

[0042] Figure 16 illustrates a flowchart of a method 1600 in accordance with aspects of the present disclosure.

[0043] Figure 17 illustrates a flowchart of a method 1700 in accordance with aspects of the present disclosure.

[0044] Figure 18 illustrates a flowchart of a method 1800 in accordance with aspects of the present disclosure.

[0045] Figure 19 illustrates a flowchart of a method 1900 in accordance with aspects of the present disclosure. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 9

[0046] Carrier phase measurement-based positioning represent RAT-dependent positioning techniques that have been used in GNSS (e.g., GPS, GLONASS) for centimetre-level accuracy. Positioning horizontal and vertical stringent accuracy requirements can be met using carrier phase- based positioning. Although there exists a GPS / GNSS carrier phase positioning framework, there is currently a lack of support for RAT-dependent carrier phase-based positioning procedures in the 3GPP specifications.

[0047] Centimetre-level accuracy for certain scenarios can be met using carrier phase-based positioning techniques. However, certain conditions apply. For instance, phase error sources (e.g., initial phase offset, time and frequency synchronization errors, carrier frequency offset (CFO), antenna reference points (ARP), Doppler shift, etc.) are to be correctly mitigated. These phase errors can impact the carrier phase measurement performance and several techniques have been proposed to mitigate them. The use of double differential method has been discussed as a potential technique to mitigate part of the error sources, particularly phase related errors. Double differential techniques rely on the existence of positioning reference units (PRUs) with well-known positions with centimetre-level accuracy, high PRU deployment density and good channel conditions (e.g., line of sight (LOS) link) between TRP and PRU and / or TRP and target UE. Thus, it has been discussed to use and deploy PRU for carrier phase positioning similar to GNSS reference stations to correct for the aforementioned challenges. PRU can perform measurements over DL PRS transmitted from different TRPs with the goal of providing assistance data to target UE allowing phase errors mitigation. However, in order to have accurate error compensation, double-differential techniques require a high deployment density of PRU and might cause a high signalling overhead and high deployment costs.

[0048] Distributed Antenna systems (DAS) is an important technology to increase communication capabilities such as antenna coverage. A goal of the antenna distribution technique is to leverage DAS and improve the positioning performance such as accuracy, reliability and availability. Instead of using different TRP to locate a UE, different distributed antennas (e.g., DU) controlled by the same CU can be used for UE positioning. Additionally, distributed antennas allow for more LOS links with target UE. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 10

[0049] Accordingly, aspects of the are directed to leveraging distributed antenna system characteristics to enhance positioning accuracies such as when carrier phase positioning is used. For instance, phase, frequency, and timing synchronization is implemented between distributed nodes in order to allow for coherent DL PRS transmission from different distributed units and enable target UE to efficiently estimate carrier phase without having to mitigate the phase errors coming from the unsynchronized transmitters. Further, a known geometry of distributed antennas can allow the resolution of integer ambiguities. This geometry can include known distances between antennas as well as angular information (e.g., AoD) that can be determined during the synchronization phase by applying phase differences of received signals. Further, assistance data signalling associated with different distributed antennas can be transmitted to one central unit (a central unit that controls multiple DU) and each configuration can be associated with a DU-ID. Thus, different phase measurements can be signalled within a same report and DU-ID can be associated with each of the phase measurements.

[0050] Accordingly, by utilizing the described techniques distributed antennas can coordinate to mitigate phase errors of their DL PRS signals and thus can transmit RF coherent DL PRS signals to target UE. Reliance on PRU can thus be reduced and / or eliminated. Accordingly, the described techniques can reduce deployment cost and signalling overhead in wireless communications systems and implementations. Aspects of the present disclosure are described in the context of a wireless communications system.

[0051] Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more NE 102, one or more UE 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20. The wireless communications system 100 may support radio access technologies Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 11 beyond 5G, for example, 6G. Additionally, the communications system 100 may support technologies, such as time division multiple access (TDMA), frequency division multiple access (FDMA), or code division multiple access (CDMA), etc.

[0052] The one or more NE 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NE 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN), a NodeB, an eNodeB (eNB), a next- generation NodeB (gNB), or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

[0053] An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc.) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN). In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NE 102.

[0054] The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (IoT) device, an Internet-of- Everything (IoE) device, or machine-type communication (MTC) device, among other examples.

[0055] A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 12 such as vehicle-to-vehicle (V2V) deployments, to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

[0056] An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g., S1, N2, N6, or other network interface). In some implementations, the NE 102 may communicate with each other directly. In some other implementations, the NE 102 may communicate with each other indirectly (e.g., via the CN 106). In some implementations, one or more NE 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC). An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as a radio heads, smart radio heads, or transmission-reception points (TRPs).

[0057] The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC), or a 5G core (5GC), which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management functions (AMF)) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc.) for the one or more UEs 104 served by the one or more NE 102 associated with the CN 106.

[0058] The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an S1, N2, N6, or other network interface). The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session). The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106). Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 13

[0059] In the wireless communications 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers)) to perform various operations (e.g., wireless communications). In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0060] One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., ^=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., ^=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., ^=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., ^=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., ^=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., ^=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0061] A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames). Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

[0062] Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 14 numerologies supported in the wireless system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., ^=0, ^=1, ^=2, ^=3, ^=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., OFDM symbols). In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing), a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., ^=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0063] In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz – 7.125 GHz), FR2 (24.25 GHz – 52.6 GHz), FR3 (7.125 GHz – 24.25 GHz), FR4 (52.6 GHz – 114.25 GHz), FR4a or FR4-1 (52.6 GHz – 71 GHz), and FR5 (114.25 GHz – 300 GHz). In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data). In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0064] FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies). For example, FR1 may be associated with a first numerology (e.g., ^=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., ^=1), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., ^=2), which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies). For example, FR2 may be associated with a third numerology (e.g., ^=2), which includes 60 kHz Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 15 subcarrier spacing; and a fourth numerology ^=3), which includes 120 kHz subcarrier spacing.

[0065] According to implementations, one or more of the NE 102 and the UE 104 are operable to implement various aspects of the techniques described with reference to the present disclosure. For example, a set of NE 102 (e.g., a set of DU) can inter-coordinate to mitigate phase errors in DL PRS and thus can transmit coherent DL PRS to different UE 104 to enable the UE 104 to accurately determine position information for the UE 104.

[0066] With reference to positioning requirements, NR positioning based on NR Uu signals and stand-alone (SA) architecture (e.g., beam-based transmissions) was first specified in Release 16. The targeted use cases also included commercial and regulatory (emergency services) scenarios as in Release 15. The performance requirements are the following: Positioning Error Indoor Outdoor Horizontal Positioning < 3m for 80% of UEs < 10m for 80% of UEs Vertical Positioning < 3m for 80% of UEs < 3m for 80% of UEs

[0067] Currently 3GPP Release 17 positioning has defined the positioning performance requirements for commercial and IIoT use cases as follows: Positioning Error Commercial IIoT Horizontal Positioning (< 1 m) for 90% of UEs (< 0.2 m) for 90% of UEs; Vertical Positioning (< 3 m) for 90% of UEs (< 1 m) for 90% of UEs Physical layer latency for (< 10 ms) (< 10 ms) position estimation of UE End-to-End Latency for (<100 ms) (< 100 ms, in the order of position estimation of UE 10 ms is desired) Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 16

[0068] Figure 2 illustrates example scenarios 200 for absolute and relative positioning scenarios. The scenarios 200, for instance, as defined in the system architectural (stage 1) study reported in technical report (TR) 22.832 using three different coordinate systems including Absolute Positioning (e.g., fixed coordinate systems), Relative Positioning (e.g., variable and moving coordinate systems), and Relative Positioning, e.g., variable coordinate systems.

[0069] The following are some example RAT-dependent positioning techniques:

[0070] DL-TDoA: The DL-time difference of arrival (TDOA) positioning method makes use of the DL RSTD (and optionally DL PRS reference signal received power (RSRP)) of downlink signals received from multiple TPs, at the UE. The UE measures the DL RSTD (and optionally DL PRS RSRP) of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to locate the UE in relation to the neighboring TPs.

[0071] DL-AoD: The DL AoD positioning method makes use of the measured DL PRS RSRP of downlink signals received from multiple TPs, at the UE. The UE measures the DL PRS RSRP of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to locate the UE in relation to the neighboring TPs.

[0072] Multi-RTT: The Multi-RTT positioning method makes use of the UE Rx-Tx measurements and DL PRS RSRP of downlink signals received from multiple TRPs, measured by the UE and the measured gNB Rx-Tx measurements and uplink (UL) sounding reference signal (SRS) RSRP at multiple TRPs of uplink signals transmitted from UE. The UE measures the UE Rx- Tx measurements (and optionally DL PRS RSRP of the received signals) using assistance data received from the positioning server, and the TRPs measure the gNB Rx-Tx measurements (and optionally UL SRS-RSRP of the received signals) using assistance data received from the positioning server. The measurements are used to determine the RTT at the positioning server which are used to estimate the location of the UE. Figure 3 illustrates an example multi-cell RTT procedure 300. Figure 4 illustrates an example relative range estimation system 400 using an existing single gNB RTT positioning framework. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 17

[0073] Carrier Phase Based Positioning : Supported in Rel.16 [Technical Specification (TS) 38.855]: NR carrier-phase based positioning technique refers to a positioning method where the transmitter (either the gNB or the UE) transmits the positioning reference signals at the pre- configured carrier frequency, and the receiver (either the UE or the gNB) obtains the carrier phase measurements by tracking reference signals. Phase measurements can be derived from the complex correlations at the receiver side. The measurements combined with TDOA are used to estimate user position.

[0074] E-CID / NR E-CID: In an Enhanced Cell ID (CID) positioning method, the position of an UE is estimated with the knowledge of its serving ng-eNB, gNB and cell and is based on LTE signals. The information about the serving ng-eNB, gNB and cell may be obtained by paging, registration, or other methods. NR Enhanced Cell ID (NR E CID) positioning refers to techniques which use additional UE measurements and / or NR radio resource and other measurements to improve the UE location estimate using NR signals. Although NR E-CID positioning may utilize some of the same measurements as the measurement control system in the radio resource control (RRC) protocol, the UE generally is not expected to make additional measurements for the sole purpose of positioning; e.g., the positioning procedures do not supply a measurement configuration or measurement control message, and the UE reports the measurements that it has available rather than being required to take additional measurement actions.

[0075] UL-TDoA: The UL TDOA positioning method makes use of the UL TDOA (and optionally UL SRS-RSRP) at multiple RPs of uplink signals transmitted from UE. The RPs measure the UL TDOA (and optionally UL SRS-RSRP) of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to estimate the location of the UE.

[0076] UL-AoA: The UL AoA positioning method makes use of the measured azimuth and the zenith of arrival at multiple RPs of uplink signals transmitted from UE. The RPs measure A-AoA and Z-AoA of the received signals using assistance data received from the positioning server, and the resulting measurements are used along with other configuration information to estimate the location of the UE. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 18

[0077] Figure 5 illustrates an example NR based positioning system 500. According to Rel-16, the PRS can be transmitted by different base stations (serving and neighboring) using narrow beams over FR1 and FR2, which is relatively different when compared to LTE where the PRS was transmitted across the whole cell. The PRS can be locally associated with a PRS Resource ID and Resource Set ID for a base station (TRP). Similarly, UE positioning measurements such as Reference Signal Time Difference (RSTD) and PRS RSRP measurements are made between beams (e.g., between a different pair of DL PRS resources or DL PRS resource sets) as opposed to different cells as was the case in LTE. In addition, there are additional UL positioning methods for the network to exploit in order to compute the target UE’s location. Table 1 and Table 2 below show the reference signal to measurements mapping required for each of the supported RAT- dependent positioning techniques at the UE and gNB, respectively. RAT-dependent positioning techniques involve the 3GPP RAT and core network entities to perform the position estimation of the UE, which are differentiated from RAT-independent positioning techniques which rely on GNSS, IMU sensor, WLAN and Bluetooth technologies for performing target device (UE) positioning. Table 1: UE Measurements to enable RAT-dependent positioning techniques To facilitate support DL / UL Reference UE Measurements of the following Signals positioning techniques Rel.16 DL PRSDL RSTD DL-TDOADL-TDOA, Rel.16 DL PRSDL PRS RSRPDL-AoD, Multi-RTT Multi-RTT Rel.16 DL PRS UE Rx-Tx time / Rel.16 SRS difference for positioning Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 19 E-CID RSRP(RSRP for RRM), SS- RSRQ(for Rel. 15 SSB / RRM), CSI- CSI-RS for RSRP (for RRM RRM), CSI- RSRQ (for RRM), SS- RSRPB (for RRM) Table 2: gNB Measurements to enable RAT-dependent positioning techniques To facilitate support DL / UL Reference of the following gNB Measurements Signals positioning techniques UL-TDOA Rel.16 SRS UL RTOA for positioning UL-TDOA, Rel.16 SRS UL SRS- UL-AoA, for positioning RSRP Multi-RTT Multi-RTT Rel.16 SRS for gNB Rx-Tx positioning, time Rel.16 DL difference PRS Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 20 UL-AoA, Rel.16 SRS AoA Multi-RTT for and ZoA positioning,

[0078] Figure 6 illustrates an example of function split options of a DAS 600. Figure 7 illustrates an example of a vehicular DAS 700 with distributed units at a vehicle front and rear bumpers. A DAS is a network of spatially separated antenna nodes connected to a common source via a transport medium that provides wireless service within a geographic area or structure.

[0079] In a simple form a DAS has two basic components: (1) A signal source: A Distributed Antenna System, as the name implies, “distributes” signal. But it generally doesn’t generate the cellular signal itself. A DAS needs to be fed signal from somewhere. Whether it's 4G LTE or 5G, there are four typical signal sources: off-air (via an antenna on the roof), an on-site BTS (Base Transceiver Station), and finally the newest approach: small cells. (2) Distribution system: Once received, the cellular signal can be distributed throughout the building. There are four main types of distribution systems: active (using fiber optic or ethernet cable), passive, hybrid, and digital.

[0080] Figure 8 illustrates an example of a double-differential system 800 for error mitigation in GNSS. In differential GNSS, the position of a fixed GNSS receiver, referred to as a base station, is determined to a high degree of accuracy using conventional surveying techniques. Then, the base station determines ranges to the GNSS satellites in view using the location of the satellites determined from the precisely known orbit ephemerides and satellite time. The base station compares the surveyed position to the position calculated from the satellite ranges. Differences between the positions can be attributed to satellite ephemeris and clock errors, but mostly to errors associated with atmospheric delay. The base station sends these errors to other receivers (rovers), which incorporate the corrections into their position calculations.

[0081] Differential positioning requires a data link between the base station and rovers, if corrections need to be applied in real-time, and at least four GNSS satellites in view at both the base station and the rovers. The absolute accuracy of the rover’s computed position will depend on the absolute accuracy of the base station’s position. Since GNSS satellites orbit high above the earth, Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 21 the propagation paths from the satellites to the stations and rovers pass through similar atmospheric conditions, as long as the base station and rovers are not too far apart. Differential GNSS works very well with base station-to-rover separations of up to tens of kilometers.

[0082] The use of the positioning reference unit (PRU) to facilitate NR carrier phase positioning has been studied. • For DL NR carrier phase positioning, the PRU works as a UE to receive the DL PRS reference signals and provide the DL carrier phase measurements to the LMF, where the double differential measurements can be obtained by the difference of the DL carrier phase measurements from the target UE and those from the PRU for eliminating the measurement errors. • For UL NR carrier phase positioning, the PRU works as a UE to transmit the UL SRS signals for positioning purpose. The TRPs provides the UL carrier phase measurements obtained from the UL SRS signals of the target UE and of the PRU to the LMF, where the double differential measurements can be obtained by the difference of these UL carrier phase measurements for eliminating the measurement errors. Agreement Add the following note to the previous agreement on error modelling of the initial phase: • Note: The initial phases of a transmitter for different carriers can be assumed to be independent of each other. Similarly, the initial phases of a receiver for different carriers can be assumed to be independent of each other. • It has been concluded that it is feasible to use existing DL PRS and SRS signals to obtain the carrier phase measurements for achieving a horizontal accuracy of up to a few centimeters at least at 50% under certain conditions, including the PRU(s) being located in LOS with TRP(s), and the locations of the PRU(s) and TRPs known with centimeter-level accuracy, in the agreed evaluation assumptions.

[0083] For RAT-dependent positioning measurements, examples of different DL measurements including DL PRS-RSRP, DL RSTD and UE Rx-Tx Time Difference required for the supported RAT-dependent positioning techniques such as shown in Table 3 below. The following measurement configurations are specified [TS38.215]: Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 22 • 4 Pair of DL RSTD measurements can performed per pair of cells. Each measurement is performed between a different pair of DL PRS Resources / Resource Sets with a single reference timing. • 8 DL PRS RSRP measurements can be performed on different DL PRS resources from the same cell. Table 3: DL Measurements required for DL-based positioning methods DL PRS reference signal received power (DL PRS-RSRP) DefinitionDL PRS reference signal received power (DL PRS-RSRP), is defined as thelinear average over the power contributions (in [W]) of the resource elements that carry DL PRS reference signals configured for RSRP measurements within the considered measurement frequency bandwidth. For frequency range 1, the reference point for the DL PRS-RSRP shall be the antenna connector of the UE. For frequency range 2, DL PRS-RSRP shall be measured based on the combined signal from antenna elements corresponding to a given receiver branch. For frequency range 1 and 2, if receiver diversity is in use by the UE, the reported DL PRS-RSRP value shall not be lower than the corresponding DL PRS-RSRP of any of the individual receiver branches. Applicable forRRC_CONNECTED intra-frequency,RRC_CONNECTED inter-frequency DL reference signal time difference (DL RSTD) Definition DL reference signal time difference (DL RSTD) is the DL relative timing difference between the positioning node j and the reference positioning node i, defined as TSubframeRxj – TSubframeRxi, Where: Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 23 TSubframeRxj is the time UE receives the start of one subframe from positioning node j. TSubframeRxiis the time when the UE receives the corresponding start of one subframe from positioning node i that is closest in time to the subframe received from positioning node j. Multiple DL PRS resources can be used to determine the start of one subframe from a positioning node. For frequency range 1, the reference point for the DL RSTD shall be the antenna connector of the UE. For frequency range 2, the reference point for the DL RSTD shall be the antenna of the UE. Applicable for RRC_CONNECTED intra-frequency RRC_CONNECTED inter-frequency UE Rx – Tx time difference Definition The UE Rx – Tx time difference is defined as TUE-RX – TUE-TX Where: TUE-RX is the UE received timing of downlink subframe #i from a positioning node, defined by the first detected path in time. TUE-TXis the UE transmit timing of uplink subframe #j that is closest in time to the subframe #i received from the positioning node. Multiple DL PRS resources can be used to determine the start of one subframe of the first arrival path of the positioning node. For frequency range 1, the reference point for TUE-RXmeasurement shall be the Rx antenna connector of the UE and the reference point for TUE- TX measurement shall be the Tx antenna connector of the UE. For frequency range 2, the reference point for TUE-RXmeasurement shall be Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 24 the Rx antenna of UE and the reference point for TUE-TX measurement shall be the Tx antenna of the UE. Applicable for RRC_CONNECTED intra-frequency RRC_CONNECTED inter-frequency

[0084] Accordingly, the present disclosure details solutions to carrier phase positioning error sources mitigation using DAS. Prior to transmitting DL PRS to target UE, distributed antennas coordinate by locally transmitting reference signals to synchronize their phase, frequency and time. Consequently, DL PRS signals transmitted to target UE would be RF-coherent. Angular information (e.g., DL-AoD) determined using phase differences between distributed antenna can serve to resolve unknown number of cycles between transmitter and receiver, known as integer ambiguity.

[0085] The described techniques do not exhibit the deployment of high density PRUs to allow for high accuracy position estimation using carrier phase measurements. Thus, carrier phase can be efficiently estimated without using PRUs and double differential techniques. It is also beneficial for reducing signalling overhead by reducing the PRS configuration and phase estimates and errors reporting from PRUs to LMF or from PRU to target UE.

[0086] Phase errors at transmitters can be mitigated when distributed antennas used for target UE positioning coordinate to synchronize their frequency, phase and time before transmitting positioning reference signals to target UE. AoA and AoD from different antennas are used along with known antennas positions to determine the integer ambiguity value. The methods described in this disclosure can be summarized as follows: • Distributed antennas are configured by LMF or gNB to transmit DL PRS to target UE in order to enable target UE to determine its location using carrier phase measurements. To mitigate phase errors at transmitters, distributed antennas synchronize their frequency, phase and time errors by iteratively transmitting reference signals between each other. This can be done in a centralized and / or distributed manner such as described below. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 25 • The PRS signals received by target UE the different distributed antennas are coherent, in the sense that frequency and phase errors such as frequency offsets, initial phases at transmitters, and timing synchronization errors are mitigated at transmitters. In this case, carrier phases of received DL PRS signals can be correctly estimated. • Integer ambiguity can be resolved using the geometry of distributed antennas as well as different angle of departures (AoD) and angles of arrival (AoA) determined using phase differences between distributed nodes. The integer ambiguity resolution method can use the geometry of the distributed nodes as well as the known inter-nodes distances and angles of departures and arrivals. • Carrier phase estimates of received signals from different distributed antennas can be reported by UE to LMF in a network-assisted scenario.

[0087] As discussed in this disclosure, a positioning-related reference signal may be referred to as a reference signal used for positioning procedures / purposes in order to estimate a target-UE’s location, e.g., PRS, or based on existing reference signals such as channel state information (CSI) reference signals (RS) or SRS or a new RS for carrier phase positioning. A target UE may be referred to as a device / entity to be localized / positioned. In various implementations the term ‘PRS’ may refer to any signal such as a reference signal, which may or may not be used primarily for positioning.

[0088] Figure 9 illustrates a system 900 for inter-node coordination for coherent DL PRS transmission. Implementations described herein, for instance, enable phase, frequency, and time synchronization of transmitters. For example, prior to transmitting positioning reference signals to a target UE, distributed antennas (e.g., as illustrated in the system 900) synchronize their frequency, phase, and time by locally broadcasting signals to share their frequencies and phase with other nodes and use consensus to align these parameters. In the system 900 each node has its own local oscillator in its transceiver chain, and thus synchronizing the transceivers of the nodes implies synchronizing the frequencies and phases of the signals generated by these oscillators. The stability of the local oscillator is the primary factor that affects the synchronization of these transceivers. Due to the manufacturing tolerances and temperature variations, these oscillators undergo random Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 26 frequency drift and phase jitters over the time offsets the frequency and phases of their generated signals.

[0089] In the considered network setup a DAS can be split according to functional splits option 1 or option 2 as presented in Table 4 below. RF chains are, according to this setup, contained within the distributed unit (DU) along with antennas. Table 4: DAS Functional Split Options Option 0 (Antenna-RF Split) Only antennas are in the DU and the other functionalities are in the central units (CU) Extending the (copper) cabling between the antenna and RF unit is the most common solution when the antenna and RF unit are not in the same place. Option 1 (RF-PHY Split)Antennas and RF are in the DU and theother functionalities are in the CU The cable loss can be reduced when the RF signal is converted to intermediate frequency band, however cable length remains a limitation in the system design. Antennas, RF and ADC / DAC are in the Option 2 (RF+ADC / DAC- PHY DU and the other functionalities are in Split) the CU Time-domain I / Q samples are transmitted via the interface between CU and DU

[0090] In some scenarios carrier phase measurements can be subject to multiple phase errors that are to be efficiently mitigated to correctly estimate carrier phase and the location of a target UE with a centimeter-level accuracy. These phase errors include carrier frequency offset (CFO), initial Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 27 phase offsets at transmitter and receiver, shift, antenna reference point (ARP) errors, timing synchronization errors between transmitters, oscillator drifts and center phase offsets.

[0091] Without phase, frequency and timing synchronization at transmitters, the ^^^symbol at the ^^^subcarrier received from the ^^^node at the target UE can be given by: ^^,^,^= ^^,^,^^^(^^^^(^^^^^)^ ^^^^ ^^^, ,^)+ "^,^(1) Where ^^,^,^is the referencewavelength, &^is the propagation delay from node ^ to target UE. '()is the initial phase at receiver / target UE, *^is the timing offset between transmitters, and the phase error +,^,^,^defined as: +,^,^,^= 2.+#^,^,^ / + +#^,^,^+ '^0,^,^+ +'^,^,^(2)Where 2.+#^,^,^ / is the phase error due to the frequency offset +#^,^,^of the oscillator in the l-th node at the update time T; '^0,^,^is a constant phase term assumed herein to be uniformly distributed between 0 to 2π andfor the estimation error in the distance and orientation angle of the l-th node, any residual phase error due to the timing misalignment, any hardware or channel induced phase delay, and any phase error due to the mismatch of antennas radiation pattern, etc.; +#^,^,^represents the phase error due to the time variation of the frequency of the oscillator within the update interval; +'^,^,^is the error due to the random phase jitter of the oscillator in the i-th node.

[0092] According to implementations frequency, phase, and timing offsets between transmitters can be mitigated if distributed antennas (also referred as distributed nodes) are configured to synchronize their oscillator’s frequency and phase as well as the timing errors prior to transmitting DL reference signals to target UE. According to a first implementation, the nodes’ coordination architecture can be fully distributed, requiring no centralization. In this case, the distributed nodes enable a local broadcast of their signals to share their frequencies and phases with the neighbouring nodes and align these parameters. Each distributed node iteratively updates its frequency and phase by computing an average of the frequencies and phases of the other nodes. It can be assumed that Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 28 each node can estimate the frequencies and of its neighbouring nodes from the received signals, for instance, by using the fast Fourier transform based maximum likelihood estimator.

[0093] The algorithm converges and can align the frequencies and phases of all the nodes up to a residual phase error that is governed by the oscillators and the estimation errors. To reduce this residual phase error and thus improve the synchronization between the nodes, other techniques for example Kalman filtering can be used. The nodes align their transceivers within the fraction of the wavelength of wireless operation in such a way that their signals add up coherently at the destination. The distributed nodes coordinate with each other to synchronize their transceivers without using any feedback from the destination / target UE. Consider a network of N nodes spatially separated by multiples of wavelength and coordinating with each other to synchronize their frequency, phase, and timing offsets. Each node has a local oscillator and we consider a signal model where intrinsic frequency and phase errors of the local oscillators on each node caused by the frequency drift and phase jitter as well as the frequency and phase estimation errors at the nodes are included and modelled using practical statistics.

[0094] The nodes can be chosen by LMF to have a line-of-sight (LOS) path with a target UE. Without phase, frequency and timing synchronization at transmitters, the ^^^symbol at the ^^^subcarrier received from the ^^^node at the target UE can be given by: ^^,^,^= ^^,^,^^^(^^^^(^^^^^)^ ^^^^ ^^^, ,^)+ "^,^(3) Where ^^,^,^is theis the carrier wavelength, &^is the propagation delay from node ^ to target UE. '()is the initial phase at receiver / target UE, *^is the timing offset between transmitters, and the phase error +,^,^,^defined as: +,^,^,^= 2.+#^,^,^ / + 2.1^ / + +#^,^,^+ '^0,^,^+ +'^,^,^+ 1^(4)Where 2.+#^,^,^ / is the phase error due to the frequency offset +#^,^,^of the oscillator in the l-th node at the update time T; the term 2.1^ / represents the phase due to frequency estimation error 1^at the l-th node assuming that the nodes need to estimate their oscillator frequency in the update Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 29 interval to synchronizing it with the other,^,^is a constant phase term assumed herein to be uniformly distributed between 0 to 2π and accounting for the estimation error in the distance and orientation angle of the l-th node, any residual phase error due to the timing misalignment, any hardware or channel induced phase delay, and any phase error due to the mismatch of antennas radiation pattern, etc.; +#^,^,^represents the phase error due to the time variation of the frequency of the oscillator within the update interval; +'^,^,^is the error due to the random phase jitter of the oscillator in the i-th node; and 1^is the phase estimation error at the l-th node assuming that the nodes must estimate their oscillator phase in the update interval to synchronize it with the other nodes.

[0095] The nodes in the network are declared to have reached a consensus (synchronization in frequency and phase) when the standard deviation of the total phase errors {+,^,^,^} is less than or equal to some pre-set threshold 2.

[0096] Figure 10 illustrates an example system 1000 for centralized frequency, phase, and time synchronization between distributed antennas in accordance with aspects of the present disclosure. For instance, a centralized topology-based transceiver synchronization method is proposed in which a primary node transmits a reference signal to one or more secondary nodes and the secondary nodes use a frequency locking circuit with the phase-locked loops to synchronize with the primary node such as illustrated in the system 1000. In such scenarios the master node broadcasts reference signals to secondary nodes and upon reception, secondary nodes lock their PLLs to the master node’s oscillator phase and frequency. Time synchronization can also be utilized so that all the nodes can perform the coherent operations within the same coordinated interval of the clock.

[0097] At a target UE, after phase frequency and clock synchronization, the carrier phase of the received signals from different nodes (here three different nodes are used for target UE positioning) can be written as follows: ^^9 =:− 2.=8Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 30 Where 7^is the phase of the received signal node ^, A^is the distance between node ^ and target UE and =^is the unknown number of cycles between node ^ and target UE.

[0098] It can be assumed that phase errors at target UE mainly Doppler shift and initial phase at receiver are mitigated using other techniques such as double differential techniques. Using the synchronization methods described above, the phases of the received signals (considering only LOS links) can be correctly estimated since phase errors are mitigated at transmitters before sidelink (SL) PRS transmission.

[0099] In an alternate or additional implementation for a centralized-topology, phase and frequency synchronization can be valid during a time span / window whose duration is denoted by T. Upon the expiry of T, master node should broadcast reference signals to secondary nodes to synchronize their frequencies and phases.

[0100] Figure 11 illustrates an example system 1100 for integer ambiguity resolution using DAS geometries. Implementations described herein, for example, also enable integer ambiguity resolution using DAS phase difference information. For instance, carrier phase differences between different distributed antennas can be used for integer ambiguity resolution without the need for receiving DL PRS over different frequencies and for virtual wavelength technique. High precision relative positioning can be based on the very precise carrier phase measurements. In order to achieve high precision results within a short observation time span, the integer nature of the ambiguities has to be exploited.

[0101] According to implementations the distance between distributed antennas can be of the order of multiple wavelengths and distributed antenna positions are known with a high certainty level (uncertainty less than the half of signal wavelength such as illustrated in the system 1100. In addition, at each antenna phase differences between the received signal from other antennas can be determined along with the frequency and phase synchronization procedure such as described above. These phase differences can allow the computation of AoAs and AoDs at each antenna. In such scenarios and knowing the distance between different nodes of the distributed antenna system, integer ambiguity can be resolved. For instance, integer ambiguity can be resolved using a modified LAMBDA algorithm as described below. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 31

[0102] The linearized phase difference equations are collected in the following linear system, B. B = CD + EF + ^ (6) Where: B is the vector of observed computed double difference carrier phase measurements F the vector that contains the increments of different target UE- distributed antennas distance or alternatively the unknown coordinates (2-d position) of target UE E denotes the design matrix for target UE coordinates / position. C denotes the design matrix for the ambiguity terms. ^ vector of unmodelled effects and measurement noise

[0103] To locate a target UE, at least three different distributed antennas transmit DL PRS to target UE. In this case, UE calculated the different carrier phases of the antennas. The system of equations can be written as follows: ^^9 ì78 =:;^− 2.=8

[0104] Insystem 1100 and using different angles of arrival and angles of departure as well as known distributed antenna distances, =^and =?can be written as functions of =8, F8, F^and F?as well as the different angles AoA and AoD. This can result in a less complex system resolution using equation (6) by reducing the number of unknown variables.

[0105] Implementations described herein also enable signaling of PRS configuration and phase measurement reports. For instance, using DAS can enable the reduction of signaling overhead. LMF can configure CU of distributed antenna systems (DAS) with different DL PRS configurations corresponding to each node (distributed unit DU) of the distributed system. Compared with legacy DL PRS configurations where at least three TRPs are involved in the positioning of a target UE as well as PRU configuration, such solutions allow for largely reduced configuration signaling. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 32

[0106] Figure 12 illustrates an example 1200 in accordance with aspects of the present disclosure. In the message 1200, for instance, a “ProvideAssistanceData” LTE positioning protocol (LPP) message transmitted to the CU can provide DL PRS configurations associated with different DU. An LPP assistance data such as illustrated in the message 1200 can be transmitted to a central unit and can provide DL PRS configuration for different distributed units controlled by the CU. Different signaled DL PRS configurations can include an integer indicating the dl-PRS-DU-ID associated with the DL PRS configuration.

[0107] The reporting of the carrier phase measurements in a network-assisted positioning framework can also be done using the DU_IDs. In such scenarios carrier phase measurements can be grouped within the same reporting signaling and each measurement is associated with a DU_ID. An LMF can use these measurements along with information about precise location of DU to determine target UE position.

[0108] Figure 13 illustrates an example of a UE 1300 in accordance with aspects of the present disclosure. The UE 1300 may include a processor 1302, a memory 1304, a controller 1306, and a transceiver 1308. The processor 1302, the memory 1304, the controller 1306, or the transceiver 1308, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

[0109] The processor 1302, the memory 1304, the controller 1306, or the transceiver 1308, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0110] The processor 1302 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 1302 may be configured to operate the memory 1304. In some other implementations, the memory 1304 may be integrated into the processor 1302. The processor 1302 Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 33 may be configured to execute computer- instructions stored in the memory 1304 to cause the UE 1300 to perform various functions of the present disclosure.

[0111] The memory 1304 may include volatile or non-volatile memory. The memory 1304 may store computer-readable, computer-executable code including instructions when executed by the processor 1302 cause the UE 1300 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 1304 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0112] In some implementations, the processor 1302 and the memory 1304 coupled with the processor 1302 may be configured to cause the UE 1300 to perform one or more of the functions described herein (e.g., executing, by the processor 1302, instructions stored in the memory 1304). For example, the processor 1302 may support wireless communication at the UE 1300 in accordance with examples as disclosed herein. The UE 1300 may be configured to or operable to support a means for receiving, from one or more DU, signaling including DL PRS and estimate one or more carrier phase measurements; and generating position information for the UE based at least in part on the signaling.

[0113] Additionally, the UE 1300 may be configured to support any one or combination of where the signaling further includes one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU; estimating the carrier phase of the received DL PRS; and resolving integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information; transmitting the position information to a network entity.

[0114] Additionally, or alternatively, the UE 1300 may support functionality to receive, from one or more DU, signaling including DL PRS and estimate one or more carrier phase measurements; and generate position information for the UE based at least in part on the signaling.

[0115] Additionally, the UE 1300 may be configured to support any one or combination of the signaling further includes one or more of angle of arrival information, angle of departure Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 34 information, or distance information for DU of the one or more DU; estimate the carrier phase of the received DL PRS; and resolve integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information; transmit the position information to a network entity.

[0116] The controller 1306 may manage input and output signals for the UE 1300. The controller 1306 may also manage peripherals not integrated into the UE 1300. In some implementations, the controller 1306 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 1306 may be implemented as part of the processor 1302.

[0117] In some implementations, the UE 1300 may include at least one transceiver 1308. In some other implementations, the UE 1300 may have more than one transceiver 1308. The transceiver 1308 may represent a wireless transceiver. The transceiver 1308 may include one or more receiver chains 1310, one or more transmitter chains 1312, or a combination thereof.

[0118] A receiver chain 1310 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 1310 may include one or more antennas to receive a signal over the air or wireless medium. The receiver chain 1310 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 1310 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1310 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0119] A transmitter chain 1312 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 1312 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM). The transmitter chain 1312 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 35 chain 1312 may also include one or more for transmitting the amplified signal into the air or wireless medium.

[0120] Figure 14 illustrates an example of a processor 1400 in accordance with aspects of the present disclosure. The processor 1400 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 1400 may include a controller 1402 configured to perform various operations in accordance with examples as described herein. The processor 1400 may optionally include at least one memory 1404, which may be, for example, an L1 / L2 / L3 cache. Additionally, or alternatively, the processor 1400 may optionally include one or more arithmetic-logic units (ALUs) 1406. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses).

[0121] The processor 1400 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 1400) or other memory (e.g., random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous dynamic RAM (SDRAM), static RAM (SRAM), ferroelectric RAM (FeRAM), magnetic RAM (MRAM), resistive RAM (RRAM), flash memory, phase change memory (PCM), and others).

[0122] The controller 1402 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 1400 to cause the processor 1400 to support various operations in accordance with examples as described herein. For example, the controller 1402 may operate as a control unit of the processor 1400, generating control signals that manage the operation of various components of the processor 1400. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 36

[0123] The controller 1402 may be to fetch (e.g., obtain, retrieve, receive) instructions from the memory 1404 and determine subsequent instruction(s) to be executed to cause the processor 1400 to support various operations in accordance with examples as described herein. The controller 1402 may be configured to track memory addresses of instructions associated with the memory 1404. The controller 1402 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 1402 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 1400 to cause the processor 1400 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 1402 may be configured to manage flow of data within the processor 1400. The controller 1402 may be configured to control transfer of data between registers, ALUs 1406, and other functional units of the processor 1400.

[0124] The memory 1404 may include one or more caches (e.g., memory local to or included in the processor 1400 or other memory, such as RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. In some implementations, the memory 1404 may reside within or on a processor chipset (e.g., local to the processor 1400). In some other implementations, the memory 1404 may reside external to the processor chipset (e.g., remote to the processor 1400).

[0125] The memory 1404 may store computer-readable, computer-executable code including instructions that, when executed by the processor 1400, cause the processor 1400 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 1402 and / or the processor 1400 may be configured to execute computer-readable instructions stored in the memory 1404 to cause the processor 1400 to perform various functions. For example, the processor 1400 and / or the controller 1402 may be coupled with or to the memory 1404, the processor 1400, and the controller 1402, and may be configured to perform various functions described herein. In some examples, the processor 1400 may include multiple processors and the memory 1404 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 37

[0126] The one or more ALUs 1406 may to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 1406 may reside within or on a processor chipset (e.g., the processor 1400). In some other implementations, the one or more ALUs 1406 may reside external to the processor chipset (e.g., the processor 1400). One or more ALUs 1406 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 1406 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 1406 may be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 1406 may support logical operations such as AND, OR, exclusive-OR (XOR), not-OR (NOR), and not-AND (NAND), enabling the one or more ALUs 1406 to handle conditional operations, comparisons, and bitwise operations.

[0127] The processor 1400 may support wireless communication in accordance with examples as disclosed herein. The processor 1400 may be configured to or operable to receive, from one or more DU, signaling comprising DL PRS and estimate one or more carrier phase measurements; and generate position information for a user equipment (UE) based at least in part on the signaling.

[0128] Additionally, the processor 1400 may be configured to support any one or combination of where the signaling further comprises one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU; estimate a carrier phase of the received DL PRS; and resolve integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information; transmit the position information to a network entity.

[0129] Figure 15 illustrates an example of a NE 1500 in accordance with aspects of the present disclosure. The NE 1500 may include a processor 1502, a memory 1504, a controller 1506, and a transceiver 1508. The processor 1502, the memory 1504, the controller 1506, or the transceiver 1508, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 38 coupled (e.g., operatively, communicatively, electronically, electrically) via one or more interfaces.

[0130] The processor 1502, the memory 1504, the controller 1506, or the transceiver 1508, or various combinations or components thereof may be implemented in hardware (e.g., circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

[0131] The processor 1502 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof). In some implementations, the processor 1502 may be configured to operate the memory 1504. In some other implementations, the memory 1504 may be integrated into the processor 1502. The processor 1502 may be configured to execute computer-readable instructions stored in the memory 1504 to cause the NE 1500 to perform various functions of the present disclosure.

[0132] The memory 1504 may include volatile or non-volatile memory. The memory 1504 may store computer-readable, computer-executable code including instructions when executed by the processor 1502 cause the NE 1500 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 1504 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

[0133] In some implementations, the processor 1502 and the memory 1504 coupled with the processor 1502 may be configured to cause the NE 1500 to perform one or more of the functions described herein (e.g., executing, by the processor 1502, instructions stored in the memory 1504). For example, the processor 1502 may support wireless communication at the NE 1500 in accordance with examples as disclosed herein.

[0134] The NE 1500 may be configured to or operable to support a means for receiving, at a first apparatus and from a second apparatus, one or more first synchronization reference signals; Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 39 transmitting, to the second apparatus, one or second synchronization reference signals; and transmitting, based at least in part on one or more of the first synchronization reference signals or the second synchronization reference signals, one or more downlink PRS to a positioning target apparatus.

[0135] Additionally, the NE 1500 may be configured to support any one or combination of where the first apparatus and the second apparatus include different DU, and the target apparatus includes a user equipment (UE); the first apparatus and the second apparatus are controlled by a same CU; or the first apparatus and the second apparatus are controlled by different CU; utilizing the one or more of the first synchronization reference signals or the second synchronization reference signals to synchronize at least one of frequency configuration, phase configuration, or timing configuration of the first apparatus to generate the one or more PRS; utilizing the one or more of the first synchronization reference signals or the second synchronization reference signals to mitigate at least one of frequency offset, phase offset, or timing offset between the first apparatus and the second apparatus to generate the one or more PRS; determining, based at least in part on the one or more first synchronization reference signals, synchronization reference signal information including one or more of angle of departure information, angle of arrival information, or distance information; and transmitting the synchronization reference signal information to one or more of the positioning target apparatus or a network entity.

[0136] In some implementations of the method and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a distributed topology, and wherein the method further includes mitigating one or more phase errors in the one or more PRS based at least in part on the first synchronization reference signals or the second synchronization reference signals; the one or more phase errors are based at least in part on one or more of frequency offsets, initial phases, or timing synchronization errors; mitigating the one or more phase errors includes: generating estimated frequency values and estimated phase values for the first apparatus and the second apparatus; averaging the estimated frequency values and the estimated phase values to generate averaged estimated frequency values and averaged estimated phase values; and synchronizing the estimated frequency values and the estimated phase values with the averaged estimated frequency values and the averaged estimated phase values. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 40 In some implementations of the method and described herein, the first apparatus and the second apparatus include at least a portion of a centralized topology, and wherein the method further includes mitigating one or more phase errors in the one or more PRS based at least in part on locking one or more frequencies and one or more phases of the first apparatus to one or more frequencies and one or more phases of a primary node oscillator of the centralized topology; generating the one or more PRS based at least in part on a resolved integer ambiguity determined based at least in part on one or more of angle information or distance information for the second apparatus; determining the angle information based at least in part on one or more phase differences between the one or more first synchronization reference signals and one more third synchronization reference signals received from a third apparatus.

[0137] Additionally, or alternatively, the NE 1500 may support to receive, at a first apparatus and from a second apparatus, one or more first synchronization reference signals; transmit, to the second apparatus, one or more second synchronization reference signals; and transmit, based at least in part on one or more of the first synchronization reference signals or the second synchronization reference signals, one or more downlink PRS to a positioning target apparatus.

[0138] Additionally, the NE 1500 may be configured to support any one or combination of where the first apparatus and the second apparatus include different DU, and the target apparatus includes a user equipment (UE); the first apparatus and the second apparatus are controlled by a same CU; or the first apparatus and the second apparatus are controlled by different CU; utilize the one or more of the first synchronization reference signals or the second synchronization reference signals to synchronize at least one of frequency configuration, phase configuration, or timing configuration of the first apparatus to generate the one or more PRS; utilize the one or more of the first synchronization reference signals or the second synchronization reference signals to mitigate at least one of frequency offset, phase offset, or timing offset between the first apparatus and the second apparatus to generate the one or more PRS; determine, based at least in part on the one or more first synchronization reference signals, synchronization reference signal information including one or more of angle of departure information, angle of arrival information, or distance information; and transmit the synchronization reference signal information to one or more of the positioning target apparatus or a network entity Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 41

[0139] In some implementations of the and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a distributed topology, and the first apparatus mitigates one or more phase errors in the one or more PRS based at least in part on the first synchronization reference signals or the second synchronization reference signals; the one or more phase errors are based at least in part on one or more of frequency offsets, initial phases, or timing synchronization errors; to mitigate the one or more phase errors, the at least one processor is configured to cause the first apparatus to: generate estimated frequency values and estimated phase values for the first apparatus and the second apparatus; average the estimated frequency values and the estimated phase values to generate averaged estimated frequency values and averaged estimated phase values; and synchronize the estimated frequency values and the estimated phase values with the averaged estimated frequency values and the averaged estimated phase values. In some implementations of the method and apparatuses described herein, the first apparatus and the second apparatus include at least a portion of a centralized topology, and wherein the at least one processor is configured to cause the first apparatus to mitigate one or more phase errors in the one or more PRS based at least in part on locking one or more frequencies and one or more phases of the first apparatus to one or more frequencies and one or more phases of a primary node oscillator of the centralized topology; the at least one processor is configured to cause the first apparatus to generate the one or more PRS based at least in part on a resolved integer ambiguity determined based at least in part on one or more of angle information or distance information for the second apparatus; the at least one processor is configured to cause the first apparatus to determine the angle information based at least in part on one or more phase differences between the one or more first synchronization reference signals and one more third synchronization reference signals received from a third apparatus.

[0140] The NE 1500 may be configured to or operable to support a means for receiving, from a network entity, location assistance data for a set of DU; and signaling at least some of the location assistance data to one or more DU of the set of DU.

[0141] Additionally, the NE 1500 may be configured to support any one or combination of the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; signaling one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 42 phase measurements is associated with a DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF).

[0142] Additionally, or alternatively, the NE 1500 may support to receive, from a network entity, location assistance data for a set of DU; and signal at least some of the location assistance data to one or more DU of the set of DU.

[0143] Additionally, the NE 1500 may be configured to support any one or combination of where the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; to signal one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF).

[0144] The NE 1500 may be configured to or operable to support a means for generating location assistance data for a set of DU; and signaling at least some of the location assistance data to a CU.

[0145] Additionally, the NE 1500 may be configured to support any one or combination of the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; receiving, from the CU, one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF).

[0146] Additionally, or alternatively, the NE 1500 may support to generate location assistance data for a set of DU; and signal at least some of the location assistance data to a CU.

[0147] Additionally, the NE 1500 may be configured to support any one or combination of where the location assistance data includes DL positioning reference signal (PRS) information; the location assistance data includes one or more identifiers for DU of the set of DU; the at least one processor is configured to cause the network entity to receive, from the CU, one or more phase measurements for each DU of the set of DU; each phase measurement of the one or more phase measurements is associated with a respective DU identifier for a DU of the set of DU; the network entity includes a location management function (LMF). Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 43

[0148] The controller 1506 may manage and output signals for the NE 1500. The controller 1506 may also manage peripherals not integrated into the NE 1500. In some implementations, the controller 1506 may utilize an operating system such as iOS®, ANDROID®, WINDOWS®, or other operating systems. In some implementations, the controller 1506 may be implemented as part of the processor 1502.

[0149] In some implementations, the NE 1500 may include at least one transceiver 1508. In some other implementations, the NE 1500 may have more than one transceiver 1508. The transceiver 1508 may represent a wireless transceiver. The transceiver 1508 may include one or more receiver chains 1510, one or more transmitter chains 1512, or a combination thereof.

[0150] A receiver chain 1510 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 1510 may include one or more antennas to receive a signal over the air or wireless medium. The receiver chain 1510 may include at least one amplifier (e.g., a low-noise amplifier (LNA)) configured to amplify the received signal. The receiver chain 1510 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1510 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

[0151] A transmitter chain 1512 may be configured to generate and transmit signals (e.g., control information, data, packets). The transmitter chain 1512 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM), frequency modulation (FM), or digital modulation schemes like phase-shift keying (PSK) or QAM. The transmitter chain 1512 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1512 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

[0152] Figure 16 illustrates a flowchart of a method 1600 in accordance with aspects of the present disclosure. The operations of the method may be implemented by a UE as described herein. In some implementations, the UE may execute a set of instructions to control the function elements Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 44 of the UE to perform the described functions. be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0153] At 1602, the method may include receiving, from one or more DU, signaling comprising DL PRS and estimating one or more carrier phase measurements. The operations of 1602 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1602 may be performed by a UE as described with reference to Figure 13.

[0154] At 1604, the method may include generating position information for the UE based at least in part on the signaling. The operations of 1604 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1604 may be performed by a UE as described with reference to Figure 13.

[0155] Figure 17 illustrates a flowchart of a method 1700 in accordance with aspects of the present disclosure. The operations of the method may be implemented by a NE as described herein. In some implementations, the NE may execute a set of instructions to control the function elements of the NE to perform the described functions. It should be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0156] At 1702, the method may include receiving, at a first apparatus and from a second apparatus, one or more first synchronization reference signals. The operations of 1702 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1702 may be performed by a NE as described with reference to Figure 15.

[0157] At 1704, the method may include transmitting, to the second apparatus, one or more second synchronization reference signals. The operations of 1704 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1704 may be performed by a NE as described with reference to Figure 15.

[0158] At 1706, the method may include transmitting, based at least in part on one or more of the first synchronization reference signals or the second synchronization reference signals, one or more DL PRS to a positioning target apparatus. The operations of 1706 may be performed in Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 45 accordance with examples as described herein. some implementations, aspects of the operations of 1706 may be performed a NE as described with reference to Figure 15.

[0159] Figure 18 illustrates a flowchart of a method 1800 in accordance with aspects of the present disclosure. The operations of the method may be implemented by a NE as described herein. In some implementations, the NE may execute a set of instructions to control the function elements of the NE to perform the described functions. It should be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0160] At 1802, the method may include receiving, from a network entity, location assistance data for a set of DU. The operations of 1802 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1802 may be performed by a NE as described with reference to Figure 15.

[0161] At 1804, the method may include signaling at least some of the location assistance data to one or more DU of the set of DU. The operations of 1804 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1804 may be performed by a NE as described with reference to Figure 15.

[0162] Figure 19 illustrates a flowchart of a method 1900 in accordance with aspects of the present disclosure. The operations of the method may be implemented by a NE as described herein. In some implementations, the NE may execute a set of instructions to control the function elements of the NE to perform the described functions. It should be noted that the method described herein describes a possible implementation, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible.

[0163] At 1902, the method may include generating location assistance data for a set of DU. The operations of 1902 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1902 may be performed by a NE as described with reference to Figure 15.

[0164] At 1904, the method may include signaling at least some of the location assistance data to a CU. The operations of 1904 may be performed in accordance with examples as described Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 46 herein. In some implementations, aspects of of 1904 may be performed by a NE as described with reference to Figure 15.

[0165] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein. Attorney Docket No. SMM920230097-WO-PCT

Claims

Lenovo Docket No. SMM920230097-WO-PCT 47 What is claimed is:

1. A user equipment (UE) for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive, from one or more distributed units (DU), signaling comprising downlink (DL) positioning reference signals (PRS) and estimate one or more carrier phase measurements; and generate position information for the UE based at least in part on the signaling.

2. The UE of claim 1, wherein the signaling further comprises one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU.

3. The UE of claim 2, wherein the at least one processor is configured to cause the UE to: estimate the carrier phase of the received DL PRS; and resolve integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information.

4. The UE of claim 1, wherein the at least one processor is configured to cause the UE to transmit the position information to a network entity.

5. A processor for wireless communication, comprising: at least one controller coupled with at least one memory and configured to cause the processor to: Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 48 receive, from one or more units (DU), signaling comprising downlink (DL) positioning reference signals (PRS) and estimate one or more carrier phase measurements; and generate position information for a user equipment (UE) based at least in part on the signaling.

6. The processor of claim 5, wherein the signaling further comprises one or more of angle of arrival information, angle of departure information, or distance information for distance between DU of the one or more DU.

7. The processor of claim 6, wherein the at least one controller is configured to cause the processor to: estimate a carrier phase of the received DL PRS; and resolve integer ambiguity of the carrier phase using one or more of the angle of arrival information, angle of departure information, or distance information.

8. The processor of claim 5, wherein the at least one controller is configured to cause the processor to transmit the position information to a network entity.

9. A first apparatus for wireless communication, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the first apparatus to: receive, from a second apparatus, one or more first synchronization reference signals; transmit, to the second apparatus, one or more second synchronization reference signals; and transmit, based at least in part on one or more of the first synchronization reference signals or the second synchronization reference signals, one or more downlink positioning reference signals (PRS) to a positioning target apparatus. Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 49 10. The first apparatus of claim 9, the first apparatus and the second apparatus comprise different distributed units (DU), and the target apparatus comprises a user equipment (UE).

11. The first apparatus of claim 10, wherein: the first apparatus and the second apparatus are controlled by a same central unit (CU); or the first apparatus and the second apparatus are controlled by different CU.

12. The first apparatus of claim 9, wherein the at least one processor is configured to cause the first apparatus to utilize the one or more of the first synchronization reference signals or the second synchronization reference signals to synchronize at least one of frequency configuration, phase configuration, or timing configuration of the first apparatus to generate the one or more PRS.

13. The first apparatus of claim 9, wherein the at least one processor is configured to cause the first apparatus to utilize the one or more of the first synchronization reference signals or the second synchronization reference signals to mitigate at least one of frequency offset, phase offset, or timing offset between the first apparatus and the second apparatus to generate the one or more PRS.

14. The first apparatus of claim 9, wherein the at least one processor is configured to cause the first apparatus to: determine, based at least in part on the one or more first synchronization reference signals, synchronization reference signal information comprising one or more of angle of departure information, angle of arrival information, or distance information; and transmit the synchronization reference signal information to one or more of the positioning target apparatus or a network entity.

15. The first apparatus of claim 9, wherein the first apparatus and the second apparatus comprise at least a portion of a distributed topology, and wherein the at least one processor is configured to: cause the first apparatus to mitigate one or more phase errors in the one or more PRS based at least in part on the first synchronization reference signals or the second synchronization reference Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 50 signals, and wherein the one or more phase based at least in part on one or more of frequency offsets, initial phases, or timing synchronization errors.

16. The first apparatus of claim 15, wherein to mitigate the one or more phase errors, the at least one processor is configured to cause the first apparatus to: generate estimated frequency values and estimated phase values for the first apparatus and the second apparatus; average the estimated frequency values and the estimated phase values to generate averaged estimated frequency values and averaged estimated phase values; and synchronize the estimated frequency values and the estimated phase values with the averaged estimated frequency values and the averaged estimated phase values.

17. The first apparatus of claim 9, wherein the first apparatus and the second apparatus comprise at least a portion of a centralized topology, and wherein the at least one processor is configured to cause the first apparatus to mitigate one or more phase errors in the one or more PRS based at least in part on locking one or more frequencies and one or more phases of the first apparatus to one or more frequencies and one or more phases of a primary node oscillator of the centralized topology.

18. The first apparatus of claim 9, wherein the at least one processor is configured to cause the first apparatus to generate the one or more PRS based at least in part on a resolved integer ambiguity determined based at least in part on one or more of angle information or distance information for the second apparatus.

19. The first apparatus of claim 18, wherein the at least one processor is configured to cause the first apparatus to determine the angle information based at least in part on one or more phase differences between the one or more first synchronization reference signals and one more third synchronization reference signals received from a third apparatus.

20. A central unit (CU) for wireless communication, comprising: Attorney Docket No. SMM920230097-WO-PCTLenovo Docket No. SMM920230097-WO-PCT 51 at least one memory; and at least one processor coupled with the at least one memory and configured to cause the CU to: receive, from a network entity, location assistance data for a set of distributed units (DU); and signal at least some of the location assistance data to one or more DU of the set of DU. Attorney Docket No. SMM920230097-WO-PCT

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