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Title:
INTEGER AMBIGUITY RESOLUTION FOR CARRIER PHASE-BASED POSITIONING
Document Type and Number:
WIPO Patent Application WO/2024/033799
Kind Code:
A1
Abstract:
Various aspects of the present disclosure relate to a user equipment (UE) and method for wireless communication. The method includes receiving, from a first base station, a reference signal transmitted over a known carrier frequency, with an unknown integer number, N, of cycles between the first base station and the UE. The method includes receiving, from a location server, a message with assistance information corresponding to a plurality of positioning reference units (PRUs) having known locations in proximity to the UE. The method further includes calculating and reporting a substantially precise location of the UE by performing carrier phase measurement that integrates the received assistance information to resolve a value of N, where integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the UE.

Inventors:
BEN HADJ FREDJ ABIR (DE)
THOMAS ROBIN RAJAN (DE)
GANESAN KARTHIKEYAN (DE)
EDLER VON ELBWART ALEXANDER GOLITSCHEK (DE)
Application Number:
PCT/IB2023/057988
Publication Date:
February 15, 2024
Filing Date:
August 08, 2023
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
LENOVO SINGAPORE PTE LTD (SG)
International Classes:
H04W64/00; G01S19/04; G01S19/44; G01S19/55
Domestic Patent References:
WO2021227821A12021-11-18
Foreign References:
EP3910364A12021-11-17
US20220043099A12022-02-10
US197262633710P
Other References:
NOKIA ET AL: "Initial Views on improved accuracy based on NR carrier phase measurement", vol. RAN WG1, no. e-Meeting; 20220509 - 20220520, 29 April 2022 (2022-04-29), XP052152860, Retrieved from the Internet [retrieved on 20220429]
XIAOMI: "Improved accuracy based on NR carrier phase measurement", vol. RAN WG1, no. e-Meeting; 20220509 - 20220520, 29 April 2022 (2022-04-29), XP052153206, Retrieved from the Internet [retrieved on 20220429]
CATT: "NR RAT-dependent DL Positioning", vol. RAN WG1, no. Taipei; 20190121 - 20190125, 12 January 2019 (2019-01-12), XP051575919, Retrieved from the Internet [retrieved on 20190112]
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Claims:
CLAIMS

What is claimed is:

1. A user equipment (UE) for wireless communication, the user equipment comprising: a memory comprising program code for integer ambiguity resolution; at least one transceiver that enables the user equipment to communicate with other network entities, including at least a first base station and at least one network device; and a controller communicatively coupled to the memory and to the at least one transceiver and which: receives, from the first base station, a reference signal transmitted over a known carrier frequency with an unknown integer number, N, of cycles between the first base station and the user equipment; receives, from the at least one network device, a message comprising assistance information corresponding to a plurality of neighboring network apparatuses having known locations in proximity to the user equipment; and calculates and reports a substantially precise location of the user equipment by performing carrier phase measurement that integrates the received assistance information to resolve a value of N, wherein integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the user equipment.

2. The user equipment of claim 1, wherein: the assistance information is received from a location server performing a location management function, the location server receiving the assistance information from at least two of the plurality of neighboring network apparatuses; and the plurality of neighboring network apparatuses are positioning reference units (PRUs) deployed in a neighborhood of the UE and selected by the location server based on proximity to the UE.

3. The user equipment of claim 1, wherein: the reference signal is transmitted via a transmission beam from the first base station, the reference signal used for determining a location of the user equipment relative to the first base station; each of the plurality of neighboring network apparatuses is co-located within a propagation area of the transmission beam and receive a similar reference signal for each of at least one positioning reference signal carrier frequency; each neighboring network apparatus computes a respective value of number of cycles for the similar reference signal for each of at least one positioning reference signal carrier frequency, based on a known distance of the neighboring network apparatus to the first base station; and at least two of the plurality of neighboring network apparatuses are selected by the network device for respective integer reference data included within the assistance information, based on the at least two neighboring network apparatuses being in a physical location that is proximate to the user equipment and within the propagation area of the transmission beam.

4. The user equipment of claim 1, wherein: the assistance information comprises exact coordinates of each of the plurality of neighboring network apparatuses and associated reference carrier phase measurements comprising a calculated value of integer cycles for that neighboring network entity using a similar reference signal for each of at least one positioning reference signal carrier frequency; and the controller: identifies an approximate location of the user equipment relative to the first base station; selects, as a lower bound for calculating an accurate value of N, a first N 1 value corresponding to received data from a first neighboring network entity that is a smaller distance away from the first base station than the user equipment; selects, as an upper bound for calculating an accurate value of N, a second N2 value corresponding to received data from a second neighboring network entity that is a greater distance away from the first base station than the user equipment; and performs the carrier phase measurement using the upper bound and lower bound to more efficiently compute a precise value of N and compute the more precise location of the user equipment in terms of distance from the base station.

5. The user equipment of claim 1, wherein the at least one network device is a location server and the plurality of neighboring network apparatuses are second user equipments that are configured by a downlink message from the location server to generate and communicate respective carrier phase measurement data as the assistance information via a sidelink channel established with the user equipment.

6. The user equipment of claim 1 , wherein the controller: receives within the assistance information at least a first value of N 1 cycles for a first neighboring network apparatus that is closer to the base station than the user equipment and a second value of N2 cycles for a second neighboring network apparatus that is further away from the base station than the user equipment, the N 1 cycles and N2 cycles computed for a similar reference signal for at least one positioning reference signal carrier frequency, based on a known distance of the first and second neighboring network apparatuses, respectively; and calculates an actual value of N cycles using the N 1 cycles as a lower bound and the N2 cycles as an upper bound within the carrier phase measurement for the apparatus.

7. The user equipment of claim 1, wherein: the first base station is one of at least three base stations, each having a known physical location and each transmitting a respective reference signal to the apparatus over different frequencies; and the controller: receives, from each of the at least three base stations, the respective reference signal of each base station; and performs carrier phase measurements via a calculation that comprises triangulation over different frequencies to generate a final value of N and an absolute position of the user equipment.

8. The user equipment of claim 7, wherein, in performing the carrier phase measurements, the controller: estimates a distance of the user equipment to each of the at least three base stations; computes at least three integer ambiguities respectively associated with each of the at least three base stations, in part based on the assistance information from the neighboring network apparatuses; resolves the value of N for the user equipment using an upper bound and a lower bound of integer ambiguity from the at least three integer ambiguities computed; and computes location coordinates of the user equipment based on the value of N.

9. A network apparatus supporting wireless communication, the network apparatus comprising: at least one transceiver that enables the network apparatus to communicate with at least one base station and to provide data to at least one network device that provides a location management function; a memory comprising program code for generating and providing data used for integer ambiguity resolution; and a controller communicatively coupled to the at least one transceiver and the memory and which: performs an exploration session to generate a table of data to be used for integer ambiguity computations by a user equipment located within a neighboring area of the network apparatus; and transmits, to at least one of the at least one network device and the user equipment, frequency-based integer ambiguity values to enable the user equipment to accurately calculate a location of the user equipment relative to the base station.

10. The network apparatus of claim 9, wherein: the network apparatus is a positioning reference unit having a fixed location within a communication network; and in performing the exploration session, the controller: communicatively connects with each surrounding base station via different reference signals transmitted at a plurality of different frequencies; evaluates, for each of the plurality of different frequencies, a value of an integer number of cycles in a corresponding reference signal; and generates the table of data comprising the integer number of cycles associated with a specific frequency at a known distance of the network apparatus from a corresponding base station.

11. The network apparatus of claim 9, wherein the controller: receives, from the at least one network device via the transceiver, a request for transmission of frequency-based integer ambiguity values corresponding to a location of the network apparatus relative to a specific base station; and transmits, to the network device, the table of data for that specific base station.

12. The network apparatus of claim 9, wherein: the network apparatus is a static user equipment with a known location coordinate; and the controller: receives from the at least one network device, a message comprising an indication for the static user equipment to be configured to operate as a temporary positioning reference unit; configures the static user equipment with capabilities enabling the static user equipment to switch from device positioning operations to perform carrier phase measurements and other functions of an actual positioning reference unit; and forwards data, including distance, frequency, and integer value of cycles derived from the carrier phase measurements to one of (i) the network device via a connection through the base station and (ii) the user equipment via a direct sidelink to the apparatus.

13. A network device supporting wireless communication, the network device comprising: at least one network interface that enables the network device to communicate with at least one base station in a communication network; a memory comprising program code for integer ambiguity resolution corresponding to one or more target devices within the communication network; and a controller communicatively coupled to the at least one network interface and the memory and which: identifies an approximate location of an apparatus that is a target device within the communication network, the target device requiring location assistance to identify an exact location of the target device within the network; receives, via the at least one network interface from each of a plurality of positioning reference units, data derived from reference carrier phase measurements performed by a corresponding one of the plurality of positioning reference units; generates assistance information from data received from at least two selected positioning reference units that are located proximate to the target device and which receives a similar positioning reference signal from a base station as received by the target device, for at least one positioning reference signal carrier frequency; and forwards a message comprising the assistance information to the base station for transmission to the target device to enable the target device to more efficiently and accurately compute the location of the target device, using the data provided by the at least two positioning reference units.

14. The network device of claim 13, wherein: the assistance information comprises at least a first value of N1 cycles for a first positioning reference unit that is closer to the base station than the target device and a second value of N2 cycles for a second positioning reference unit that is further away from the base station than the target device, computed by respective positioning reference units, for a similar reference signal for at least one positioning reference signal carrier frequency, based on a known distance of the first and second positioning reference units, respectively; and the N1 cycles and N2 cycles are used as a lower bound and an upper bound, respectively, the lower and upper bounds enabling the controller to reduce an integer ambiguity search space when performing carrier phase reference measurement to determine a precise location of the target device.

15. The network device of claim 14, wherein the controller: provides network-assisted positioning of the target device by locally performing a carrier phase measurement calculation using an approximate location of the target device and the upper bound and lower bound of cycles from associated positioning reference units; and forwards a calculated location to the target device.

16. The network device of claim 13, wherein the controller: identifies a plurality of user equipments with known locations within proximity of an approximate location of the target device; forwards a configuration request to selected ones of the plurality of user equipments, the configuration request triggering a controller of each selected user equipment to configure the selected user equipment to operate as a positioning reference unit and perform carrier phase measurements using a similar reference signal as the reference signal presented to the apparatus, for each of at least one positioning reference signal carrier frequency, in order to provide a respective integer value of a number of cycles for the selected user equipment; and forwards a deactivation request to each selected user equipment in response to receiving, from the selected user equipment, carrier phase measurement data for inclusion within assistance data transmitted to the target device.

17. A method for wireless communication performed by a user equipment, the method comprising: receiving, from a first base station via a transceiver of the user equipment, a reference signal transmitted over a known carrier frequency with an unknown integer number, N, of cycles between the first base station and the user equipment; receiving, from at least one network device, a message comprising assistance information corresponding to a plurality of neighboring network apparatuses having known locations in proximity to the user equipment; and calculating and reporting a substantially precise location of the user equipment by performing carrier phase measurement that integrates received assistance information to resolve a value of N, wherein integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the user equipment.

18. The method of claim 17, wherein: the assistance information comprises exact coordinates of each of the plurality of neighboring network apparatuses and associated reference carrier phase measurements comprising a calculated value of integer cycles for that neighboring network entity using a similar reference signal for each of at least one positioning reference signal carrier frequency; and the method further comprises: identifying an approximate location of the user equipment relative to the first base station; selecting, as a lower bound for calculating an accurate value of N, a first value, N 1 , corresponding to received data from a first neighboring network entity that is a smaller distance away from the first base station than the user equipment; selecting, as an upper bound for calculating an accurate value of N, a second value, N2, corresponding to received data from a second neighboring network entity that is a greater distance away from the first base station than the user equipment; and performing the carrier phase measurement using the upper bound and lower bound to more efficiently compute a precise value of N and compute the more precise location and distance of the user equipment from the first base station.

19. The method of claim 17, further comprising: receiving, within the assistance information, at least a first value of N1 cycles for a first neighboring network apparatus that is closer to the first base station than the user equipment and a second value of N2 cycles for a second neighboring network apparatus that is further away from the first base station than the user equipment, the N1 cycles and N2 cycles computed for a similar reference signal, for each of at least one positioning reference signal carrier frequency, based on a known distance of the first and second neighboring network apparatuses, respectively; and calculating an actual value of N cycles using the N 1 cycles as a lower bound and the N2 cycles as an upper bound within the carrier phase measurement for the user equipment.

20. The method of claim 17, wherein: the first base station is one of at least three base stations, each having a known physical location and each transmitting a respective reference signal to the user equipment over different frequencies; and the method further comprises: receiving, from each of the at least three base stations, the respective reference signal of each base station; and performing carrier phase measurements via a calculation that comprises triangulation over different frequencies to generate a final value of N and an absolute position of the user equipment, the performing of the carrier phase measurements comprising: estimating a distance of the user equipment to each of the at least three base stations; computing at least three integer ambiguities respectively associated with each of the at least three base stations, in part based on the assistance information received from the neighboring network apparatuses; resolving the value of N for the user equipment using an upper bound and a lower bound of integer ambiguity from the at least three integer ambiguities computed; and computing location coordinates of the user equipment based on the value of N.

Description:
INTEGER AMBIGUITY RESOLUTION FOR CARRIER PHASE-BASED POSITIONING

PRIORITY APPLICATION

[0001] This application claims priority to U.S. Provisional Application No. 63/371,072 filed August 10, 2022, the content of which is fully incorporated herein.

TECHNICAL FIELD

[0002] The present disclosure relates to wireless communications, and more specifically to carrier phase-based positioning of user equipment in wireless communication.

BACKGROUND

[0003] A wireless communications system may include one or multiple network communication devices, such as base stations, which may be otherwise known as an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. Each network communication devices, such as a base station 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). 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)).

[0004] During wireless communication between a base station and a UE, the UE and/or other network entity typically determines the UE’s coarse location relative to the base station using timing-based and angle -based radio access technology (RAT)-dependent positioning methods. Current timing-based and angle-based RAT-dependent positioning methods benefit from the current new radio (NR) positioning reference signal, which includes positioning refence signal (PRS) design of the base station. Additionally, the resource element pattern design follows a comb structure that supports different densities, which allows for improved estimation properties for the reference signal for timing measurements, such as reference signal time difference (RSTD). Integer ambiguity exists whenever a reference signal is being used for such measurements.

SUMMARY

[0005] The present disclosure relates to methods, apparatuses, and systems that support or provides resolution of integer ambiguity in carrier-phase based positioning of a target device, such as a target user equipment (UE), using a plurality of positioning reference units (PRUs) that are in the location of the target UE. According to one aspect, the PRUs are network apparatuses with known locations that can perform reference measurements over a plurality of reference frequencies in order to help with reducing integer ambiguity (IA) for carrier phase measurements performed by the target UE. Unlike integer ambiguity resolution that uses virtual wavelengths, which requires the positioning reference signal (PRS) be transmitted over different high and low frequencies, the present disclosure allows for quicker and more accurate/previse resolution of integer ambiguity, with respect to the number of cycles, using one carrier frequency (i.e., the PRS carrier frequency). Accurate location of the target UE can thus be determined. The processes of the disclosure are also applicable for standalone carrier phase positioning.

[0006] According to a first aspect, some implementations of the method and apparatuses described herein may further include receiving, from a first base station via a transceiver of the apparatus (target UE), a reference signal transmitted over a known carrier frequency with an unknown integer number, N, of cycles between the first base station and the apparatus. The method includes receiving, from at least one network device, a message comprising assistance information corresponding to a plurality of neighboring network apparatuses having known locations in proximity to the apparatus. The method further includes calculating and reporting a substantially precise location of the apparatus by performing carrier phase measurement that integrates the received assistance information to resolve a value of N, wherein integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the apparatus.

[0007] In some implementations of the method and apparatuses described herein: the assistance information is received from a location server performing a location management function, the location server receiving the assistance information from at least two of the plurality of neighboring network apparatuses; the apparatus is a target user equipment (UE); and the plurality of neighboring network apparatuses are positioning reference units deployed in a neighborhood of the target UE and selected by the location server based on proximity to the target UE.

[0008] In some implementations of the method and apparatuses described herein, the assistance information comprises exact coordinates of each of the plurality of neighboring network apparatuses and associated reference carrier phase measurements comprising a calculated value of integer cycles for that neighboring network apparatus using a similar reference signal for each of at least one positioning reference signal carrier frequency. The method further includes identifying an approximate location of the apparatus relative to the base station. The method includes selecting, as a lower bound for calculating an accurate value of N, a first integer value, LI, corresponding to received data from a first neighboring network apparatus that is a smaller distance away from the base station than the apparatus. The method includes selecting, as an upper bound for calculating an accurate value of N, a second integer value, L2, corresponding to received data from a second neighboring network apparatus that is a greater distance away from the base station than the apparatus. The method further includes performing the carrier phase measurement using the upper bound and lower bound in order to more efficiently compute a precise value of N and compute the precise location and distance of the apparatus from the base station.

[0009] According to a second aspect, some implementations of the method and apparatuses described herein may further include performing, by a controller of a network apparatus, an exploration session to generate a table of data to be used for integer ambiguity computations by an apparatus located within a neighboring area of the network apparatus. The method includes transmitting, to at least one of a network device and a target device, frequency-based integer ambiguity values to enable at least one of the network device and the target device to more precisely calculate a location of the target device relative to a base station form which the network apparatus receives a positioning reference signal that is similar to a reference signal received by the target device from the base station.

[0010] In some implementations of the method and apparatuses described herein, performing the exploration session incudes: communicatively connecting with each surrounding base station via different reference signals transmitted at a plurality of different frequencies. The method further includes evaluating, for each of the plurality of different frequencies, a value of an integer number of cycles in a corresponding reference signal. The method includes generating the table of data comprising the integer number of cycles associated with a specific frequency at a known distance of the network apparatus from a corresponding base station.

[0011] According to a third aspect, some implementations of the method and apparatuses described herein may further include identifying, by a network device in a communication network, an approximate location of an apparatus that is a target device requiring location assistance to identify an exact location of the target device within the communication network. The method includes receiving, from each of a plurality of positioning reference units, data derived from reference carrier phase measurements performed by a corresponding one of the plurality of positioning reference units. The method includes generating assistance information from the data received from at least two selected positioning reference units that are located in an area proximate to the target device and which receives a similar positioning reference signal from a base station as the target device. The method further includes forwarding a message comprising the assistance information to the base station for transmission to the target device to enable the target device to more efficiently and accurately compute the location of the target device, using the data provided by the at least two positioning reference units.

[0012] In some implementations of the method and apparatuses described herein, the assistance information comprises at least a first value of LI cycles for a first positioning reference unit that is closer to the base station than the target device and a second value of L2 cycles for a second positioning reference unit that is further away from the base station than the target device, computed by respective positioning reference units, for a similar reference signal for each of at least one positioning reference signal carrier frequency, based on a known distance of the first and second positioning reference units, respectively. Additionally, the LI cycles and L2 cycles are used as a lower bound and an upper bound, respectively, the lower and upper bounds enabling the controller to reduce the integer ambiguity search space when performing carrier phase reference measurement to determine a precise location of the target device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates an example of a wireless communications system that supports resolution of integer ambiguity using positioning reference units (PRUs) for determining a precise location of a target device, in accordance with aspects of the present disclosure.

[0014] FIG. 2A illustrates a positioning reference signal communicated at a first frequency from a base station to a target UE that performs carrier phase measurement with integer ambiguity resolution to accurately determine a distance between the two network entities/de vices, in accordance with aspects of the present disclosure.

[0015] FIG. 2B illustrates an example carrier phase measurement for a positioning reference signal communicated at a first frequency from a base station to a PRU having a known location, enabling resolution of integer ambiguity based on the set location of the PRU relative to the base station, in accordance with aspects of the present disclosure.

[0016] FIG. 3 illustrates a wireless communications environment with a base station and a plurality of PRUs that generates and transmits integer ambiguity tables to a location server, which integrates appropriate data from the tables into a message to a target UE for use in performing carrier phase measurements by resolving integer ambiguity, in accordance with aspects of the present disclosure.

[0017] FIG. 4 illustrates a wireless communications environment with a base station and a plurality of static UEs configured by a location server to temporarily operate as PRUs and provide upper and lower bound values for use by a target UE to resolve integer ambiguity when performing carrier phase measurements for distance determination, in accordance with aspects of the present disclosure.

[0018] FIG. 5 illustrates a wireless communications environment with at least three base stations and a plurality of PRUs, the base stations providing respective reference signals to enable the target UE to identify the UE’s precise position using a combination of signal triangulation and carrier phase measurements using the integer data from the PRUs to resolving integer ambiguity, in accordance with aspects of the present disclosure.

[0019] FIG. 6 illustrates an example block diagram of a target UE that supports resolution of integer ambiguity using data received from a plurality of PRUs, in accordance with aspects of the present disclosure.

[0020] FIG. 7 illustrates an example block diagram of a network apparatus that supports resolution of integer ambiguity for a target UE during reference carrier phase measurements by providing reference integer data derived by the PRUs, in accordance with aspects of the present disclosure.

[0021] FIG. 8 illustrates an example block diagram of a network device that supports resolution of integer ambiguity for a target UE during reference carrier phase measurements by providing assistance information that reduces the processing time of the target UE in completing the carrier phase measurements to resolve the integer ambiguity, in accordance with aspects of the present disclosure.

[0022] FIGs. 9 through 11 illustrate flowcharts of methods that support resolution of integer ambiguity within a reference carrier phase measurement for a target UE using data from a plurality of PRUs, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

[0023] Current timing-based and angle -based radio access technology (RAT)-dependent positioning methods benefit from the current positioning reference signal (PRS) design in order to enable flexible and high positioning accuracies. Standardized timing-based and angle-based positioning techniques allow for sub-meter level accuracy. For high precision positioning (i.e., centimeter-level accuracies), RAT-dependent carrier phase ranging could be a promising positioning technique due to its high resolution. Carrier phase measurement is a ranging technique that uses the receiver to determine the phase difference between the received signal and the transmitted signal. Carrier phase measurement is used in global navigation satellite systems (GNSS) systems but is not yet commonly used in wireless orthogonal frequency division multiplex (OFDM) systems. Applying carrier phase technology to OFDM systems can significantly improve positioning accuracy.

[0024] Like GNSS carrier phase positioning, using the OFDM carrier phase for positioning has the following two problems. First, multipath and non-line-of-sight (NLOS) propagation have severe effects on carrier phase measurements. Second, integer ambiguity resolution is also a primary issue in the carrier phase positioning. Integer ambiguity represents the unknown integer number of cycles in a reference signal. The present disclosure provides solutions to the known problems of carrier phase positioning measurement from an understanding that, without integer ambiguity, more accurate knowledge of the UE and gNB distance can be ideally computed.

[0025] In 5G NR, carrier phase positioning measurements involve different base stations (serving and neighboring) transmitting the PRS using narrow beams over frequency range 1 (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. As used herein, a base station can be interchangeably referred to as a network node or transmission-reception point (TRP). Similarly, UE positioning measurements such as Reference Signal Time Difference (RSTD) and PRS reference signal received power (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. 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 (e.g., a target UE) positioning. [0026] The present disclosure provides methods for resolving the integer ambiguity of the carrier phase measurement for a reference signal using assistance information provided by positioning reference units (PRUs) to a location management function (LMF) at a location server, in the case of network-assisted positioning, and to the target UE, in the case of UE- based positioning. As presented herein, integer ambiguity is the unknown number, N, of cycles in a reference signal between the base station or network node (e.g., gNB) and target network device (e.g., target UE). Resolving the integer ambiguity allows for an accurate distance estimation and eventually accurate absolute/relative position of the target UE. The method allows for the use of one carrier frequency and standalone carrier phase positioning, unlike other methods that are based on virtual wavelength.

[0027] According to one aspect, the methods of the disclosure solve integer ambiguity using assistance information from positioning reference units (PRUs) located in the neighborhood of a target UE. In one embodiment, the PRUs and target UE can be served by the same Tx beam from the base station. The PRUs each perform an exploration session during which the controller of the PRU calculates integer ambiguities corresponding to different frequencies. The PRU generates and transmits a table of data to a position server hosting the LMF. In one embodiment, this assistance information is transmitted by the LMF to the target UE as an assistance information message, in order to reduce the integer ambiguity search space at the UE side. The upper bound on integer ambiguity can be provided by a PRU whose distance to the base station is higher than the distance between the target UE and the gNB (calculated on the basis of a coarse location). Similarly, the lower bound on integer ambiguity can be provided by a PRU whose distance to the gNB is smaller than the distance between the target UE and the gNB (again calculated on the basis of the coarse location of the target UE).

[0028] In various embodiments, the term ‘PRS’ may refer to any signal such as a reference signal, which may or may not be used primarily for positioning. Within the described embodiments, a positioning-related reference signal may be referred to as a reference signal used for positioning procedures/purposes in order to estimate the location of a target UE. The positioning -related reference signal is generated by the base station and can be a PRS, or can be based on existing reference signals such as channel state information reference signal (CSI-RS) or sounding reference signal (SRS), or can be a new reference signal for carrier phase positioning. Within the description, a target UE may be referred to as the network device or network entity to be localized/positioned.

[0029] The novel aspects of the disclosure provide several different advantages over the existing technology. By implementing the processes of the disclosure, the integer ambiguity search space is reduced and resolved using information from the neighboring PRUs (i.e., PRUs within geographical proximity to the target UE and which may receive the same Tx beam). The PRUs provide the target UE (directly through a sidelink, in some embodiments, or indirectly through the location server) with an upper and lower bound on the integer ambiguity in order to reduce the integer ambiguity search space and to more accurately and efficiently resolve integer ambiguity. Providing accurate integer ambiguity resolution enables an accurate carrier phase estimation and thus a high positioning accuracy for the target UE.

[0030] Aspects of the present disclosure are described in the context of a wireless communications system. Aspects of the present disclosure are further illustrated and described with reference to device diagrams and flowcharts.

[0031] FIG. 1 illustrates an example of a wireless communications system that supports resolution of integer ambiguity using positioning reference units (PRUs) for determining a precise location of a target device, in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more network entities 102, one or more UEs 104, one or more reference positioning units (or network apparatuses) 130, a core network 106, and a packet data network 108. 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 5G network, such as an NR 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 beyond 5G. Additionally, the wireless 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.

[0032] The one or more network entities 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the network entities 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a radio access network (RAN), a base transceiver station, an access point, a NodeB, an eNodeB (eNB), a next-generation NodeB (gNB), or other suitable terminology. A network entity 102 and a UE 104 may communicate via a communication link 110, which may be a wireless or wired connection. For example, a network entity 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface. A network entity can also communicate via a different communication link 110 to a global positioning system (GPS) satellite 120, which can assist with location positioning of UE 104 and other mobile devices within communication network.

[0033] A network entity 102 may provide a geographic coverage area 112 for which the network entity 102 may support services (e.g., voice, video, packet data, messaging, broadcast, etc.) for one or more UEs 104 within the geographic coverage area 112. For example, a network entity 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, a network entity 102 may be moveable, for example, a satellite associated with a non-terrestrial network. In some implementations, different geographic coverage areas 112 associated with the same or different radio access technologies may overlap, but the different geographic coverage areas 112 may be associated with different network entities 102. Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. [0034] 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 mobile device, a wireless device, a remote device, a remote unit, a handheld device, or a subscriber 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 (loT) device, an Internet-of-Everything (loE) device, or machine-type communication (MTC) device, among other examples. In some implementations, a UE 104 may be stationary in the wireless communications system 100. In some other implementations, a UE 104 may be mobile in the wireless communications system 100.

[0035] The one or more UEs 104 may be communication devices or devices in different forms or having different capabilities. Some examples of UEs 104 are illustrated in FIG. 1. A UE 104 may be capable of communicating with various types of devices, such as the network entities 102, other UEs 104, or network equipment (e.g., the core network 106, the packet data network 108, a relay device, an integrated access and backhaul (IAB) node, or another network equipment), as shown in FIG. 1. Additionally, or alternatively, a UE 104 may support communication with other network entities 102 or UEs 104, which may act as relays in the wireless communications system 100.

[0036] A UE 104 may also be able to support wireless communication directly with other UEs 104 over a communication link 114. For example, a UE 104 may support wireless communication directly with another UE 104 over a device -to-de vice (D2D) communication link. In some implementations, such as vehicle -to-vehicle (V2V) deployments, vehicle-to- everything (V2X) deployments, or cellular-V2X deployments, the communication link 114 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.

[0037] A network entity 102 may support communications with the core network 106, or with another network entity 102, or both. For example, a network entity 102 may interface with the core network 106 through one or more backhaul links 116 (e.g., via an SI, N2, N2, or another network interface). The network entities 102 may communicate with each other over the backhaul links 116 (e.g., via an X2, Xn, or another network interface). In some implementations, the network entities 102 may communicate with each other directly (e.g., between the network entities 102). In some other implementations, the network entities 102 may communicate with each other or indirectly (e.g., via the core network 106). In some implementations, one or more network entities 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).

[0038] In some implementations, a network entity 102 may be configured in a disaggregated architecture, which may be configured to utilize a protocol stack physically or logically distributed among two or more network entities 102, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, a network entity 102 may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a RAN Intelligent Controller (RIC) (e.g., a Near-Real Time RIC (Near-RT RIC), a Non-Real Time RIC (Non-RT RIC)), a Service Management and Orchestration (SMO) system, or any combination thereof.

[0039] An RU may also be referred to as a radio head, a smart radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmission reception point (TRP). One or more components of the network entities 102 in a disaggregated RAN architecture may be co-located, or one or more components of the network entities 102 may be located in distributed locations (e.g., separate physical locations). In some implementations, one or more network entities 102 of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU), a virtual DU (VDU), a virtual RU (VRU)).

[0040] Split of functionality between a CU, a DU, and an RU may be flexible and may support different functionalities depending upon which functions (e.g., network layer functions, protocol layer functions, baseband functions, radio frequency functions, and any combinations thereof) are performed at a CU, a DU, or an RU. For example, a functional split of a protocol stack may be employed between a CU and a DU such that the CU may support one or more layers of the protocol stack and the DU may support one or more different layers of the protocol stack. In some implementations, the CU may host upper protocol layer (e.g., a layer 3 (L3), a layer 2 (L2)) functionality and signaling (e.g., Radio Resource Control (RRC), service data adaption protocol (SDAP), Packet Data Convergence Protocol (PDCP)). The CU may be connected to one or more DUs or RUs, and the one or more DUs or RUs may host lower protocol layers, such as a layer 1 (LI) (e.g., physical (PHY) layer) or an L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and the one or more DUs or RUs may each be at least partially controlled by the CU 160.

[0041] Additionally, or alternatively, a functional split of the protocol stack may be employed between a DU and an RU such that the DU may support one or more layers of the protocol stack and the RU may support one or more different layers of the protocol stack. The DU may support one or multiple different cells (e.g., via one or more RUs). In some implementations, a functional split between a CU and a DU, or between a DU and an RU may be within a protocol layer (e.g., some functions for a protocol layer may be performed by one of a CU, a DU, or an RU, while other functions of the protocol layer are performed by a different one of the CU, the DU, or the RU).

[0042] A CU may be functionally split further into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU may be connected to one or more DUs via a midhaul communication link (e.g., Fl, Fl-c, Fl-u), and a DU may be connected to one or more RUs via a fronthaul communication link (e.g., open fronthaul (FH) interface). In some implementations, a midhaul communication link or a fronthaul communication link may be implemented in accordance with an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 102 that are in communication via such communication links.

[0043] The core network 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The core network 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 network entities 102 associated with the core network 106.

[0044] The core network 106 may communicate with the packet data network 108 over one or more backhaul links 116 (e.g., via an SI, N2, N2, or another network interface). The packet data network 108 may include an application server 118. In some implementations, one or more UEs 104 may communicate with the application server 118. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the core network 106 via a network entity 102. The core network 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server 118 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 core network 106 (e.g., one or more network functions of the core network 106).

[0045] In the wireless communications system 100, the network entities 102 and the UEs 104 may use resources of the wireless communication 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 network entities 102 and the UEs 104 may support different resource structures. For example, the network entities 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the network entities 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 network entities 102 and the UEs 104 may support various frame structures (i.e., multiple frame structures). The network entities 102 and the UEs 104 may support various frame structures based on one or more numerologies.

[0046] 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., /r=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., /r=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., /r=l) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., /r=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., /r=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., /r=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

[0047] 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.

[0048] 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 numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (i.e., /r=0, jU=l, /r=2, /r=3, /r=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., /r=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

[0049] 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 network entities 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 network entities 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 network entities 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

[0050] 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., /r=0), which includes 15 kHz subcarrier spacing; a second numerology (e.g., /r=l), which includes 30 kHz subcarrier spacing; and a third numerology (e.g., /r=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., /r=2), which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., /r=3), which includes 120 kHz subcarrier spacing.

[0051] According to one aspect of the disclosure, the wireless communications system 100 also includes a plurality of PRUs 130 that are in fixed locations at a known distance away from one or more base stations 102. The PRUs, which are generally referred to as network apparatuses herein, can be in a same cell as a target UE 104 and can receive a same transmission (Tx) beam as the target UE 104, in one embodiment. Aspects of the disclosure refers to neighboring network apparatuses or PRUs to indicate PRUs that are geographically close to the target UE 104 to enable reception of the same Tx beam, in some embodiments. [0052] FIG. 2A illustrates a positioning reference signal 210 communicated at a first frequency (fl) from a network entity 102 (e.g., a base station or eNB) to a UE 104 (also referred to as a target UE and/or apparatus) that performs carrier phase measurement with integer ambiguity resolution, using received assistance information, to accurately determine a distance, d, between the network entity 102 and the UE 104, in accordance with aspects of the present disclosure. The figure further shows the relationship between carrier phase and distance between the network entity 102 and the UE 104. The number of cycles, N, of the reference signal 210 is an unknown that has to be calculated in order to accurately determine the distance, d. The assistance information is provided from a network device (i.e., a positioning server and/or a field replaceable unit (FRU) and/or and FRU-configured device) via assistance information message 215 communicated to the UE 104.

[0053] FIG. 2B illustrates an example carrier phase measurement by a PRU 130 for a positioning reference signal 210B communicated at a first frequency (fl) from the network entity 102 (i.e., base station or eNB) to the PRU 130, both having a known, fixed location, in accordance with aspects of the present disclosure. With the fixed location of network entity 102 and the PRU 130 both known, the distance dl between the two network components can be determined, thus enabling resolution of integer ambiguity, to yield a determinable number of cycles, L, based on the fixed location of the PRU 130 relative to the network entity 012. Notably, both the target UE 104 and the PRU 130 are served by a different PRS having the same frequency. Because the distance to the PRU 130, dl, is less than the distance to the UE 104, d, the resulting value of LI can be used as a lower bound during the calculation of the value of N in FIG. 2A. Thus, when a second PRU in proximity to the UE 104 is at a second distance, d2, from the network entity 102 that is greater than the distance to the UE 104, a resulting value of L2 can be used as an upper bound during the calculation of N in FIG. 2A. LI and L2 are integer values of the number of cycles determined from the integer ambiguity calculations by the respective PRUs.

[0054] For simplicity, the remaining description will refer to the network entity 102 as base station 102 to align with what is presented within the figures. According to one aspect of the disclosure, and as generally presented by FIGs. 3-5 various different methods are performed at one or more of an apparatus (i.e., a target UE) 104, a network device (e.g., a location server) 220 and a network apparatus (e.g., a PRU) 130 that collectively enables the target UE 104 to more efficiently and accurately resolve integer ambiguity and determine the distance of the target UE 104 from the serving base station 102. As indicated generally by FIG. 2, the target UE 104 initiates a process to determine a position of the target UE 104 using carrier phase measurements. The target UE 104 receives assistance information from PRUs 130 in the neighborhood (i.e., the area surrounding and/or proximate to the target UE 104) in order to resolve the integer ambiguity of the estimated phase of the reference signal, PRS(fl) 210. According to one or more embodiments, the assistance information (provided within assistance information message 115) consists of an upper and lower bound on the integer ambiguity of the target UE 104. The incorporation of the upper and lower bounds identified by the assistance information reduces the search space of integer ambiguity at the target UE 104 and therefore provides for straightforward resolution of the value of N.

[0055] A first aspect of the disclosure provides for integer ambiguity resolution using neighboring PRUs in proximity to the target UE to provide integer values of an upper and a lower bound in order to efficiently resole the integer ambiguity for the target UE. When carrier phase measurement positioning is performed by the target UE, centimeter-level accuracies are achievable. However, the carrier phase of the received signal is composed of a fractional part and an unknown integer number of cycles, N, which is called integer ambiguity, as presented in FIG. 2A. Resolution of integer ambiguity is fundamental to improve the accuracy of carrier phase measurements and for achieving the targeted positioning centimeter-level accuracies.

[0056] According to a first embodiment, integer ambiguity is resolved using assistance information from PRUs deployed in the neighborhood of the target UE. FIG. 3 illustrates a wireless communications environment with a base station 102 and a plurality of PRUs 130A- 130C, with two PRUs 103A-130B located within a physical area 305 considered to be neighboring to target UE 104. In one embodiment, the physical area 305 is further defined as one that is covered by and/or receives the same Tx beam generated by the base station 102. A third PRU 103C that is also in range of the base station is, however, not a neighboring PRU (e.g., does not receive the same Tx beam as the target UE) and data originating from that third PRU 103C is thus not provided to (from location server) and not used by the target UE 104 when resolving integer ambiguity. During an exploratory session or phase (e.g., following PRU processor bootup and/or periodically on some preset or externally-triggered schedule), each PRU 103A-103C generates a respective one of integer ambiguity tables 215A-215C that includes integer values calculated for a plurality of different frequencies. The PRUs transmits the data within the generated integer ambiguity tables 215A-215C to a location server 220. The location server 220 can be local to the base station 102, in one embodiment, or communicatively coupled via a wireless connection 116 to the base station 102 through the core network 106, in another embodiment.

[0057] As shown by FIG. 3, according to one aspect of the disclosure, each of the PRUs generates a mapping table during an exploration session, where each PRS carrier frequency is associated with a value of a resolved integer ambiguity, given a fixed distance between the PRU and base station. The location server 220 receives the data from the PRUs 130 and integrates appropriate data from the received tables 215A-215C into an assistance information message 215 (FIG. 2). During location processing/determination by the target UE 104, the LMF process being performed by the location server transmits the message 215 to the target UE 104 for use in performing carrier phase measurements that involve resolving integer ambiguity using the received assistance information.

[0058] In one or more alternate embodiments, the location server processes a location management function (LMF), which chooses/selects candidate PRUs based on the distance between each PRU and the target UE. In one embodiment, the LMF transmits a “Provide_assistance_data” message to each of the selected PRUs in order to get the lower and upper bounds on integer ambiguity of the estimated carrier phase at the target UE.

[0059] Generally, according to a first aspect, the disclosure provides an apparatus, such as the target UE, for wireless communication. The apparatus includes a controller that executes code to cause the apparatus to perform a series of processes within the communication network environment provided by FIGs. 1, 2A-2B, and 3-5. The controller receives, from the first base station, a reference signal transmitted over a known carrier frequency with an unknown integer number, N, of cycles between the first base station and the apparatus. The controller receives, from the at least one network device, a message comprising assistance information corresponding to a plurality of neighboring network apparatuses having known locations in proximity to the apparatus. The controller then calculates and reports a substantially precise location of the apparatus by performing carrier phase measurement that integrates the received assistance information to resolve a value of N, wherein integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the apparatus.

[0060] In one embodiment, the assistance information is received from a location server performing a location management function, the location server receiving the assistance information from at least two of the plurality of neighboring network apparatuses. Also, the plurality of neighboring network apparatuses includes/are positioning reference units deployed in a neighborhood of the target UE and selected by the location server based on proximity to the target UE.

[0061] Given the coarse position of target UE and assistance data from PRUs, including the exact coordinates and reference carrier phase measurements of each PRU, the search space for the integer number of cycles could be widely reduced and the integer ambiguity could be resolved in few steps. According to one embodiment, the carrier phase of the received signal (e.g., PRS) could be written as:

(p = 2nN + ^ d (Eq.l)

[0062] Where N is the integer ambiguity, f is the carrier frequency of the received signal, d is the distance between the transmitter and receiver and c is the speed of light. In order to estimate the distance d, it is necessary to estimate the integer ambiguity N correctly. Only when the integer ambiguity is estimated correctly can the positioning accuracy of carrier phase reach the Cramer Rao Lower bound (CRLB).

[0063] According to one or more embodiment, the integer ambiguity can be resolved using multiple PRUs, a single carrier frequency for PRS transmission, and the integer property of the integer ambiguity. The integer ambiguity resolution includes the following features or process steps: (i) During an exploration session, each PRU constructs a table of calculated integer ambiguities corresponding to different carrier frequencies. The exact position of the PRU (without any uncertainty) is known at the network.

(ii) A target UE aiming to determine the target UE’s range to a base station (or gNB) or the absolute or relative position of the target UE using a standalone RAT-dependent carrier phase-based positioning, receives downlink (DL) PRS from the base station over a carrier frequency The network device (i.e., the LMF) has a coarse or approximate location of the target UE. In one or more embodiments, the coarse location could have been calculated using another RAT-dependent positioning technique during a previous positioning session (e.g., using enhanced cell ID (E-CID), NR E-CID, beam ID, etc.). The coarse/approximate location could be also determined using the timing advance of the target UE.

(iii) Given the information about UE coarse location, the LMF identifies/determines PRUs in the neighborhood of the target UE, preferably PRUs served by same Tx beam, i.e., a quasi co-location Type D (QCL-D) relationship. In one alternate embodiment, described in greater detail below with the description of FIG. 4, the LMF activates neighboring (static) UEs with known PRU capabilities. The definition of what constitutes a neighborhood or neighboring apparatus or device may be based on the particular LMF implementation or based on criteria involving a group of PRUs or UEs in the proximity of the target-UE, such as sharing the same Tx Beam, or same PCI, or same zone-ID, or being within a distance threshold, or the like.

[0064] According to one aspect, the integer ambiguity of the carrier phase estimated by target UE could be lower bounded by and upper bounded by N 2 using integer ambiguities solved and saved from different PRUs, as presented within FIGs. 2B and 3. In this scenario, the search space of integer ambiguity can be widely reduced and the determination of the value of N for the target UE can become straightforward. As one consideration, at least a PRU pair that is in the neighborhood of the target UE (i.e., in close proximity to the target UE) is chosen to determine the lower and upper bounds Ni and N2. In one or more embodiments, additional combinations of (i.e., more than two) PRUs may even further reduce the search space to determine the correct number of Integer cycles. The relationship of the integer ambiguity N with the resolved lower and upper bounds can be presented as the following inequality:

Ni < N < N 2 (Eq. 2) where N and N 2 could be chosen to be very close to each other, which significantly reduces the search space and thus enables relatively fast/quicker resolution of the integer N.

[0065] The integer ambiguity resolution includes the following additional features or process steps:

(iv) Information from PRUs can be transmitted to LMF and the distance between the target UE and the base station can be calculated by the LMF in a UE-assisted positioning implementation; and/or

(v) Alternatively, in the UE-based positioning implementation, integer ambiguity information can be provided from the LMF to the target UE as assistance data and the distance calculation can then be performed in/by the target UE.

[0066] In one or more embodiments, the reference signal is transmitted via a transmission beam from the base station, the reference signal used for determining a location of the apparatus relative to the base station. Also, each of the plurality of neighboring network apparatuses is co-located within a propagation area of the transmission beam and receives a similar reference signal for each of at least one positioning reference signal carrier frequency. Additionally, each neighboring network entity computes a respective value of number of cycles for the similar reference signal for each of at least one positioning reference signal carrier frequency, based on a known distance of the neighboring network entity to the base station. At least two of the plurality of neighboring network apparatuses are selected by the network device for respective integer reference data included within the assistance information, based on the at least two neighboring network apparatuses being in a physical location that is proximate to the apparatus and within the propagation area of the transmission beam.

[0067] In one or more embodiments where no pre-processing of the PRU received data is provided by the LMF, the assistance information can include exact coordinates of each of the plurality of neighboring network apparatuses and associated reference carrier phase measurements comprising a calculated value of integer cycles for that neighboring network entity using a similar reference signal for at least one positioning reference signal carrier frequency. The controller of the target UE identifies an approximate location of the apparatus relative to the base station. The controller selects, as a lower bound for calculating an accurate value of N, a first value, Nl, corresponding to received data from a first neighboring network entity that is a smaller distance away from the base station than the apparatus. The controller selects, as an upper bound for calculating an accurate value of N, a second value, N2, corresponding to received data from a second neighboring network entity that is a greater distance away from the base station than the apparatus. The controller then performs the carrier phase measurement using the upper bound and lower bound to more efficiently compute a precise value of N and compute the precise location of the apparatus in terms of distance from the base station.

[0068] In one or more alternate embodiments in which pre-processing is provided by the LMF, the controller of the target UE receives, within the assistance information, at least a first value of N 1 cycles for a first neighboring network apparatus that is closer to the base station than the apparatus and a second value of N2 cycles for a second neighboring network apparatus that is further away from the base station than the apparatus. The N 1 cycles and N2 cycles were computed using a similar reference signal for each of at least one positioning reference signal carrier frequency, based on a known distance of the first and second neighboring network apparatuses, respectively. The controller calculates the actual value of N cycles using the LI cycles as a lower bound and the L2 cycles as an upper bound within the carrier phase measurement for the apparatus.

[0069] In an alternate embodiment, according to another aspect of the disclosure, the PRUs could be replaced by static UEs with perfectly known coordinates. Assistance data for integer ambiguity resolution can then be transmitted over LTE positioning protocol (LPP) using, for example, a ProvideAssistanceData message, sent from LMF to the target UE. According to one related aspect, the LMF may configure regular/normal UEs with capabilities for PRU and carrier phase reference measurement. The LMF configures these second UEs to act as PRUs by switching their positioning processing from the normal/standard positioning to perform PRU carrier phase measurements. The LMF maintains or has access to the PRU and/or static UE locations in relation to the target-UE in order to activate/deactivate a defined number of UEs to operate as PRUs, based on the approximate location of the target UE.

[0070] FIG. 4 illustrates a wireless communications environment with a base station and a plurality of static UEs configured by a location server to temporarily operate as PRUs and provide upper and lower bound values for use by a target UE to resolve integer ambiguity when performing carrier phase measurements for distance determination, in accordance with aspects of the present disclosure. As shown in FIG. 4, wireless communication environment 400 includes a plurality of static UEs 104B-104D, two of which are located within a local area 405 of target UE 104A. In the illustrated embodiment, the static UEs 104B-104C are considered neighboring network apparatuses to target UE 104A, while static UE 104D is not considered among the neighboring network apparatuses. Each neighboring apparatus (i.e., static UE 104B-104C) is triggered by LMF at location server 220 to perform a carrier phase measurement process, similar to a PRU, using a similar reference signal for at least one positioning reference signal carrier frequency, PRS(fl) as the target UE 104A. The neighboring static UEs 104B-104C generate respective result data 410A, 410B that includes the corresponding value of the resolved integer ambiguity, N1 or N2, and the distance information for the respective neighboring static UEs 104B-104C. Notably, the local area 405 also includes a PRU 205C, which has generated data table 215C; However, the LMF may choose to not use data obtained from this PRU in the calculations based on the two neighboring static UEs 104B-104C being closer to target UE 104, or due to one or more other factors. For example, neighboring static UEs 104B-104C may be able to directly connect with target UE 104 via a sidelink and share the required integer ambiguity data for the upper and lower bounds directly with target UE 104. Other factors may be used to determine whether to use one or more of the neighboring static UEs 104B-104C, and a combination of one of the neighboring static UEs 104B-104C and the PRU 205C can be used in some implementations.

[0071] Accordingly, with this configuration, and in one embodiment, the plurality of neighboring network apparatuses are/includes second user equipments that are configured by a downlink message from the location server to generate and communicate respective carrier phase measurement data as the assistance information via a sidelink channel established with the target user equipment.

[0072] From the perspective of the PRUs 130 (and/or configured static UEs), the disclosure provides a network apparatus supporting wireless communication. The network apparatus includes at least one transceiver that enables the network apparatus to communicate with at least one base station and to provide data to at least one network device that provides a location management function. The network apparatus also includes a memory having program code for generating and providing data used for integer ambiguity resolution. The network apparatus also includes a controller communicatively coupled to the at least one transceiver and the memory. The controller performs an exploration session to generate a table of data to be used for integer ambiguity computations by an apparatus located within a neighboring area of the network apparatus, and the controller transmits, to at least one of the at least one network device and the apparatus, frequency-based integer ambiguity values to enable the apparatus to accurately calculate a location of the apparatus relative to the base station.

[0073] According to one embodiment, in performing the exploration session, the controller of the network apparatus communicatively connects with each surrounding base station via different reference signals transmitted at a plurality of different frequencies and evaluates, for each of the plurality of different frequencies, a value of an integer number of cycles in a corresponding reference signal. The controller then generates the table of data comprising the integer number of cycles associated with a specific frequency at a known distance of the network entity from a corresponding base station.

[0074] According to one aspect of the disclosure, the controller of the network apparatus receives, from the at least one network device via the transceiver, a request for transmission of frequency-based integer ambiguity values corresponding to a location of the network apparatus relative to a specific base station. In response, the controller transmits, to the network device, the table of data for that specific base station.

[0075] In the embodiments where the network apparatus is a static user equipment with a known location coordinate, the controller receives from the at least one network device, a message comprising an indication for the static user equipment to be configured to operate as a temporary positioning reference unit. The controller configures the static user equipment with capabilities enabling the static user equipment to switch from device positioning operations to perform carrier phase measurements and other functions of an actual positioning reference unit. The controller forwards data, including the distance, frequency, and integer value of cycles derived from the carrier phase measurements to one of (i) the network device via a connection through the base station and (ii) the apparatus via a direct sidelink to the apparatus.

[0076] Various aspects of the described processes occur as LMF operations at the location server 220, which is a network device supporting wireless communication. As a network device, the location server includes at least one network interface that enables the network device to communicate with at least one base station in a communication network. The location server includes a memory having program code for integer ambiguity resolution corresponding to one or more target devices within the communication network and program code for the LMF. The location server also includes a controller communicatively coupled to the at least one network interface and the memory. The controller processes the code of the LMF, which identifies an approximate location of an apparatus that is a target device within the communication network, the target device requiring location assistance to identify an exact location of the target device within the network. The controller receives, via the network interface from each of a plurality of positioning reference units, data derived from reference carrier phase measurements performed by a corresponding one of the plurality of positioning reference units. The controller generates/compiles assistance information from data received from at least two selected positioning reference units that are located proximate to the target device and which receives a similar positioning reference signal from a base station as received by the target device, for at least one positioning reference signal carrier frequency. The controller generates and forwards a message containing the assistance information to the base station for transmission to the target device to enable the target device to more efficiently and accurately compute the location of the target device, using the data provided by the at least two positioning reference units. [0077] In one or more embodiments, the assistance information includes at least a first value of N 1 cycles for a first positioning reference unit that is closer to the base station than the target device and a second value of N2 cycles for a second positioning reference unit that is further away from the base station than the target device, computed by respective positioning reference units, for a similar reference signal for at least one positioning reference signal carrier frequency, based on a known distance of the first and second positioning reference units, respectively. The N 1 cycles and N2 cycles are used as a lower bound and an upper bound, respectively, for computing the integer ambiguity of the reference signal transmitted to the target UE. The lower and upper bounds enable the controller to reduce the integer ambiguity search space when performing carrier phase reference measurement to determine a precise location of the target device.

[0078] In one or more embodiments, the controller of the network device provides network-assisted positioning of the target device by locally performing a carrier phase measurement calculation using an approximate location of the target device and the upper bound and lower bound of cycles from the associated positioning reference units. The controller then forwards a calculated location to the target device.

[0079] In one or more alternate embodiments, in selecting the at least two positioning reference units, the controller selects neighboring positioning reference units that are at least one of (i) served by the same transmission beam as the target device, (ii) sharing a same PCI, (iii) located within a same zone -ID, and (iv) located within a distance threshold of the base station.

[0080] According to one or more embodiments, the controller of the network device identifies a plurality of user equipments with known locations within proximity of an approximate location of the target device and forwards a configuration request to selected ones of the plurality of user equipments, to trigger a controller of each selected user equipment to configure the selected user equipment to operate as a positioning reference unit and perform carrier phase measurements using a similar reference signal as the reference signal presented to the apparatus. The carrier phase measurements are performed for each of at least one positioning reference signal carrier frequency, in order to provide a respective integer value of a number of cycles for the selected user equipment. The determination to select one or more of these a pre-configured user equipments to operate as temporary PRUs can be based on detection that the neighboring user equipment is physically closer to the target UE and thus likely to provide a better value of N 1 or N2 for the lower or upper bound. The determination can also be based on the ability of the neighboring UE to communicate directly to the target UE via a sidelink or other near field communication method. The determination can also be due to the absence of any PRUs in the neighboring space or the absence within the date received from neighboring PRUs of any N1 or N2 values derived from use of the same reference signal within the same reference signal carrier frequency.

[0081] In one embodiment, the controller forwards a deactivation request to each selected user equipment in response to receiving, from the selected user equipment, carrier phase measurement data for inclusion within the assistance data to be transmitted to the target device.

[0082] Another aspect of the disclosure combines triangulation principles in the calculations performed by the target UE to determine the position and distance measurements of the target UE. With reference to FIG. 5, there is illustrated a wireless communications environment 500 with at least three base stations 102A-102C and a plurality of PRUs 205 A- 205D. The base stations 102A-102C provide respective reference signals in different frequencies, PRS(fl), PRS(f2), PRS(f3) to enable the target UE 104 to identify the precise position of the target UE 104 using a combination of signal triangulation and carrier phase measurements performed using the integer data from neighboring PRUs 205A-205C to resolving integer ambiguity, in accordance with aspects of the present disclosure.

[0083] Accordingly, with the embodiments illustrated by FIGs. 3 and 4, the base station 102 presented is a first base station 102 A of at least three base stations 102A-102C. Each of the at least three base stations 102A-102C has a known physical location and each transmits a respective reference signal to the target UE 104 over different frequencies (fl, f2, f3). The controller of the target UE 104 receives, from each of the at least three base stations 102A- 102C, the respective reference signal of each base station and performs carrier phase measurements via a calculation that comprises triangulation over different frequencies to generate a final value of N and an absolute position of the target UE. [0084] According to one embodiment, in performing the carrier phase measurements, the controller estimates a distance of the apparatus to each of the at least three base stations and computes at least three integer ambiguities respectively associated with each of the at least three base stations, in part based on the assistance information from the neighboring network apparatuses (PRUs 130A-130C). The controller resolves the integer value of N for the target UE using an upper bound and a lower bound of integer ambiguity from the at least three integer ambiguities computed. The controller subsequently computes the coordinates of the apparatus based on the value of N.

[0085] Accordingly, the use of triangulation enables the calculation of the absolute positioning of the target UE using the carrier phase measurements. With this embodiment, several base stations can transmit a PRS to the target UE in order to determine the absolute position of the target UE using carrier phase measurements, based on triangulation over different frequencies. The inter-frequency measurements can be performed using measurement gap configuration requested by the UE and activated/deactivated by the base station, in situations having pre-configured measurement gaps.

[0086] With this embodiment, in order to determine the absolute position, the target UE has to estimate the distance of the target UE to at least three base stations (gNB 1 , gNB2 and gNB3) 102A-102C. This further means that three integer ambiguities N 1 , N 2 , and N 3 would need to be resolved. Absolute position of the target UE could be determined by solving the below system of equations:

Where (x gNB i, y g N B i^, i 6 {1,2,3} are the exact coordinates of gNBl, gNB2, and gNB3. Each gNB transmits DL PRS to the target UE over different frequencies. In this situation, the same or different PRUs can be used to determine the upper bounds and lower bounds of the integer ambiguities at the target UE. In both embodiments, the bounds are different, depending on the frequency used for transmitting DL PRS.

[0087] The table below presents the resulting integer values at each PRU for the three different frequencies, when using the triangulation process.

Table: Mapping table at each PRU

[0088] FIG. 6 illustrates an example block diagram 600 of an apparatus 602 for wireless communication, where the apparatus 602 is configured to support resolution of integer ambiguity using data received from a plurality of PRUs, in accordance with aspects of the present disclosure. The apparatus 602 may be an example of a UE 104 as illustrated in the preceding figures and described herein. As a UE 104, performing the functions attributable to a UE, the apparatus 602 is interchangeably referred to as a device 602 or UE 104 that supports wireless communication with one or more network entities 102, other UEs 104, other network devices, such as a location server 220, or any combination thereof. The device 602 may include components for bi-directional communications including components for transmitting and receiving communications, such as a processor (or controller) 604, a memory 606, a transceiver 608, and an I/O controller 610. 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).

[0089] The processor 604, the memory 606, the transceiver 608, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. For example, the processor 604, the memory 606, the transceiver 608, or various combinations or components thereof may support a method for performing one or more of the operations described herein. [0090] In some implementations, the processor 604, the memory 606, the transceiver 608, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field- programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some implementations, the processor 604 and the memory 606 coupled with the processor 604 may be configured as a controller to perform one or more of the functions described herein (e.g., executing, by the processor 604, instructions stored in the memory 606).

[0091] The processor 604 can be interchangeably referred to as a controller. However, it is appreciated that the term controller applies more generally to a combination of one or more components that performs the various functions of the device 602, including processing of program code, digital signal processing, wireless communication, and so on.

[0092] For example, the processor/controller 604 may support wireless communication at the device 602 in accordance with examples as disclosed herein. The processor/controller 604 may be configured as or otherwise support the process steps illustrated within the flow chart of method 900 and as described herein throughout the specification. Accordingly, in one embodiment, the processor 604 receives, from the first base station, a reference signal transmitted over a known carrier frequency with an unknown integer number, N, of cycles between the first base station and the apparatus. The processor 604 receives, from the at least one network device, a message comprising assistance information corresponding to a plurality of neighboring network apparatuses having known locations in proximity to the apparatus. The processor 604 then calculates and reports a substantially precise location of the apparatus by performing carrier phase measurement that integrates the received assistance information to resolve a value of N. The integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the apparatus. [0093] The processor 604 may include an intelligent hardware device (e.g., a general- purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some implementations, the processor 604 may be configured to operate a memory array using a memory controller. In some other implementations, a memory controller may be integrated into the processor 604. The processor 604 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 606) to cause the device 602 to perform various functions of the present disclosure.

[0094] The memory 606 may include random access memory (RAM) and read-only memory (ROM). The memory 606 may store computer-readable, computer-executable code including instructions that, when executed by the processor 604 cause the device 602 to perform various functions described herein. In the illustrative embodiment, the code includes target UE integer ambiguity (IA) resolution code 620 that enables the various functions described herein attributable to the target UE. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 604 but may cause a computer (e.g., when the code is compiled and executed) to perform functions described herein. In some implementations, the memory 606 may include, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

[0095] The I/O controller 610 may manage input and output signals for the device 602. The I/O controller 610 may also manage peripherals not integrated into the device M02. In some implementations, the I/O controller 610 may represent a physical connection or port to an external peripheral. In some implementations, the I/O controller 610 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In some implementations, the I/O controller 610 may be implemented as part of a processor, such as the processor M06. In some implementations, a user may interact with the device 602 via the I/O controller 610 or via hardware components controlled by the I/O controller 610. [0096] In some implementations, the device 602 may include a single antenna 612. However, in some other implementations, the device 602 may have more than one antenna 612 (i.e., multiple antennas), including multiple antenna panels or antenna arrays, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 608 may communicate bi-directionally, via the one or more antennas 612, wired, or wireless links as described herein. For example, the transceiver 608 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 608 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 612 for transmission, and to demodulate packets received from the one or more antennas 612.

[0097] FIGs. 7 and 8 illustrate an example block diagrams 700, 800 of two different network components that each have specific functionality associated with the resolution of integer ambiguity for a target UE 104 using reference data from a plurality of network apparatuses (PRUs 130). Specifically, FIG. 7 represents a network apparatus 702, such as PRU 130, that supports resolution of integer ambiguity for a target UE during reference carrier phase measurements by generating and providing reference integer data derived by the PRUs, in accordance with aspects of the present disclosure. FIG. 8 in contrast represents a network device 802, such as a location server 220 that supports resolution of integer ambiguity for a target UE during reference carrier phase measurements by providing assistance information that reduces the processing time of the target UE in completing the carrier phase measurements to resolve the integer ambiguity.

[0098] The component makeup of FIGs. 7 and 8 can be similar to that of FIG. 6, and FIGs. 7 and 8 are presented with the same primary components of the processor 704, 804 the memory 706, 806, the transceiver 708, 808, the antenna 712, 812, I/O controller 710, 810, the network interface 714, 814, and other components introduced in FIG. 6 and described within the FIG. 6 description. Given the similarity in the component makeup across these figures, no expanded description is provided of FIGs. 7 and 8 for those features of FIG. 6 that are duplicated within FIGs. 7 and 8. The description of these components apply also to the similar components in FIGs. 7 and 8. [0099] FIGs. 7 and 8 respectively provide a network apparatus 702 and a network device 802 that support wireless communication. FIGs. 7 and 8 are illustrated having network interface 714, 814 by which the network apparatus 702 or network device 802 physically connect via a wired connection to another network component, such as a network entity 102. This direct link may be a part of the infrastructure of the communication network.

[0100] In the illustrative embodiment of FIG. 7, the memory 706 includes PRU IA (integer ambiguity) resolution assistance program code 720 that enables the various functions described herein attributable to the PRU 130. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some implementations, the code may not be directly executable by the processor 704, but may cause a computer (e.g., when the code is compiled and executed) to perform the associated functions described herein.

[0101] The processor/controller 704 may be configured to support the process steps illustrated within the flow chart of method 1000 and as described herein throughout the specification. Accordingly, in one embodiment, the processor/controller 704 performs an exploration session to generate a table of data (stored in memory 706) to be used for integer ambiguity computations by an apparatus (i.e., target UE 104) located within a neighboring area of the network apparatus. The processor/controller 704 transmits, to at least one of the at least one network device and the apparatus, frequency-based integer ambiguity values to enable the apparatus to accurately calculate a location of the apparatus relative to the base station. According to one aspect, the network apparatus is a positioning reference unit having a fixed location within a communication network.

[0102] In the illustrative embodiment of FIG. 8, the memory 806 includes both LMF code 820 and IA resolution code 825 that collectively enables the various functions described herein attributable to the location server 220. Both codes 820 and 825 may be stored in a non-transitory computer-readable medium, such as system memory or another type of memory. In some implementations, the codes 820 and 825 may not be directly executable by the processor/controller 804 but may cause a computer (e.g., when compiled and executed) to perform the associated functions described herein. [0103] The processor/controller 804 may be configured to support the process steps illustrated within the flow chart of method 1100 and as described herein throughout the specification. Accordingly, in one embodiment, the processor/controller 804 identifies an approximate location of an apparatus that is a target device within the communication network, the target device requiring location assistance to identify an exact location of the target device within the network. The processor/controller 804 receives, via the at least one network interface from each of a plurality of positioning reference units, data derived from reference carrier phase measurements performed by a corresponding one of the plurality of positioning reference units. The processor/controller 804 generates assistance information from data received from at least two selected positioning reference units that are located proximate to the target device and which receives a similar positioning reference signal from a base station as received by the target device, for at least one positioning reference signal carrier frequency. The processor/controller 804 forwards a message comprising the assistance information to the base station for transmission to the target device to enable the target device to more efficiently and accurately compute the location of the target device, using the data provided by the at least two positioning reference units.

[0104] FIGs. 9 through 11 illustrate flowcharts of methods that support resolution of integer ambiguity within a reference carrier phase measurement for a target UE using data from a plurality of PRUs, in accordance with aspects of the present disclosure. Specifically, FIG. 9 illustrates a flowchart of a method 900 that supports an apparatus that is a target UE accurately predicting its position by resolving the integer value of N cycles using information received from neighboring PRUs, in accordance with aspects of the present disclosure. The operations of the method 900 may be implemented by a device or its components as described herein. For example, the operations of the method 900 may be performed by an apparatus or target UE 104 as described with reference to FIGs. 1-6. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0105] At 905, the method may include receiving, from a first base station via a transceiver of the apparatus, a reference signal transmitted over a known carrier frequency with an unknown integer number, N, of cycles between the first base station and the apparatus. The operations of 905 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 905 may be performed by a device as described with reference to FIGs. 1-6.

[0106] At 910, the method may include receiving, from at least one network device, a message comprising assistance information corresponding to a plurality of neighboring network entities having known locations in proximity to the apparatus. The operations of 910 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 910 may be performed by a device as described with reference to FIGs. 1-6.

[0107] At 915, the method may include calculating and reporting a substantially precise location of the apparatus by performing carrier phase measurement that integrates the received assistance information to resolve a value of N, wherein integration of the assistance information within the carrier phase measurement reduces integer ambiguity and provides a more precise location of the apparatus. The operations of 915 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 915 may be performed by a device as described with reference to FIGs. 1-6.

[0108] In one or more embodiments, the assistance information comprises exact coordinates of each of the plurality of neighboring network entities and associated reference carrier phase measurements comprising a calculated value of integer cycles for that neighboring network entity using a similar reference signal, and additional aspects of the method 900 may include: identifying an approximate location of the apparatus relative to the base station; selecting, as a lower bound for calculating an accurate value of N, a first L value corresponding to received data from a first neighboring network entity that is a smaller distance away from the base station than the apparatus; selecting, as an upper bound for calculating an accurate value of N, a second M value corresponding to received data from a second neighboring network entity that is a greater distance away from the base station than the apparatus; and performing the carrier phase measurement using the upper bound and lower bound to more efficiently compute a precise value of N and compute the precise location of the apparatus in terms of distance from the base station. [0109] In one or more embodiments, the first base station is one of at least three base stations, each having a known physical location and each transmitting a respective reference signal to the apparatus over different frequencies, and the method 900 may further include: receiving, from each of the at least three base stations, the respective reference signal of each base station; and performing carrier phase measurements via a calculation that comprises triangulation over different frequencies to generate a final value of N and an absolute position of the apparatus. Additionally, performing the carrier phase measurements may further include: estimating a distance of the apparatus to each of the at least three base stations; computing at least three integer ambiguities respectively associated with each of the at least three base stations, in part based on the assistance information received from the neighboring network entities; resolving the value of N for the apparatus using an upper bound and a lower bound of integer ambiguity from the at least three integer ambiguities computed; and computing the coordinates of the apparatus based on the value of N.

[0110] FIG. 10 illustrates a flowchart of a method 1000 that supports a network apparatus such as a PRU resolving integer ambiguity and generating resulting data that can facilitate resolution of integer ambiguity by a neighboring target UE, in accordance with aspects of the present disclosure. The operations of the method 1000 may be implemented by a device or its components as described herein. For example, the operations of the method 1000 may be performed by a network apparatus, such as a PRU 130, as described with reference to FIGs. 1 through 7. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using special-purpose hardware.

[0111] At 1005, the method 1000 may include performing, by a controller of a network apparatus, an exploration session to generate a table of data to be used for integer ambiguity computations by an apparatus located within a neighboring area of the network apparatus. The operations of 1005 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1005 may be performed by a device as described with reference to FIGs. 1, 2A-5, and 7. [0112] At 1010, the method 1000 may include transmitting, to at least one of a network device and a target device, frequency-based integer ambiguity values to enable at least one of the network device and the target device to more precisely calculate a location of the target device relative to a base station from which the network apparatus receives a positioning reference signal transmitted over a known carrier frequency that is similar to a reference signal received by the target device from the base station over the known carrier frequency. The operations of 1010 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1010 may be performed by a device as described with reference to FIGs. 1, 2A-5, and 7.

[0113] In one or more embodiments, performing the exploration session may further include: communicatively connecting with each surrounding base station via different reference signals transmitted at a plurality of different frequencies; evaluating, for each of the plurality of different frequencies, a value of an integer number of cycles in a corresponding reference signal; and generating the table of data comprising the integer number of cycles associated with a specific frequency at a known distance of the network apparatus from a corresponding base station.

[0114] In one or more embodiments, the network apparatus is a static user equipment with a known location coordinate, and the method 1000 may further include: receiving from the at least one network device, a message comprising an indication for the static user equipment to be configured to operate as a temporary positioning reference unit; configuring the static user equipment with capabilities enabling the static user equipment to switch from device positioning operations to perform carrier phase measurements and other functions of an actual positioning reference unit; and forwarding data, including the distance, frequency and integer value of cycles derived from the carrier phase measurements to one of (i) the network entity via a connection through the base station and (ii) the apparatus via a direct sidelink to the apparatus.

[0115] FIG. 11 illustrates a flowchart of a method 1100 that supports a location server receiving resolved integer ambiguity data from one or more PRUs and forwarding that data to a target UE to assist the target UE to efficiently and accurately resolve the integer ambiguity of a received reference signal, in accordance with aspects of the present disclosure. The operations of the method 1100 may be implemented by a device or its components as described herein. For example, the operations of the method 1100 may be performed by a network device, such as a location server 220, as described with reference to FIGs. 1-5 and 8. In some implementations, the device may execute a set of instructions to control the function elements of the device to perform the described functions. Additionally, or alternatively, the device may perform aspects of the described functions using specialpurpose hardware.

[0116] At 1105, the method 1100 may include identifying, by a network device in a communication network, an approximate location of an apparatus that is a target device requiring location assistance to identify an exact location of the target device within the communication network. The operations of 1105 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1105 may be performed by a device as described with reference to FIGs. 1-5 and 8.

[0117] At 1110, the method may include receiving, from each of a plurality of positioning reference units, data derived from reference carrier phase measurements performed by a corresponding one of the plurality of positioning reference units. The operations of 1110 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1110 may be performed by a device as described with reference to FIGs. 1-5 and 8.

[0118] At 1115, the method 1100 may include generating assistance information from the data received from at least two selected positioning reference units that are located in an area proximate to the target device and which receives a similar positioning reference signal from a base station as the target device. The operations of 1115 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1115 may be performed by a device as described with reference to FIGs. 1-5 and 8.

[0119] At 1120, the method 1100 may include forwarding a message comprising the assistance information to the base station for transmission to the target device to enable the target device to more efficiently and accurately compute the location of the target device, using the data provided by the at least two positioning reference units. The operations of 1120 may be performed in accordance with examples as described herein. In some implementations, aspects of the operations of 1120 may be performed by a device as described with reference to FIGs. 1-5 and 8.

[0120] In one or more embodiments, the method 1100 may include providing network- assisted positioning of the target device by locally performing a carrier phase measurement calculation using an approximate location of the target device and the upper bound and lower bound of cycles from the associated positioning reference units. The method 1100 may further include forwarding a calculated location to the target device.

[0121] In one or more embodiments, the method 1100 may further include identifying a plurality of user equipments with known locations within proximity of an approximate location of the target device. The method 1100 may further include forwarding a configuration request to selected ones of the plurality of user equipments, the configuration request triggering a controller of each selected user equipment to configure the selected user equipment to operate as a positioning reference unit and perform carrier phase measurements using a similar reference signal as the reference signal presented to the apparatus, for at least one positioning reference signal carrier frequency, in order to provide a respective integer value of a number of cycles for the selected user equipment. The method 1100 may further include forwarding a deactivation request to each selected user equipment in response to receiving, from the selected user equipment, carrier phase measurement data for inclusion within the assistance data transmitted to the target device.

[0122] It should be noted that the methods described herein describes possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

[0123] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0124] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

[0125] 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. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor.

[0126] Any connection may be properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

[0127] 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 “one or more of’ or “one or both of’) indicates an 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.

[0128] The terms “transmitting,” “receiving,” or “communicating,” when referring to a network entity, may refer to any portion of a network entity (e.g., a base station, a CU, a DU, a RU) of a RAN communicating with another device (e.g., directly or via one or more other network entities).

[0129] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described example.

[0130] 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.