# US 12,216,222 B2 · Reference signal design and device procedures for downlink-based positioning/ranging using multi-frequency phase difference of arrival > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,222 B2 - Document ID: US12216222B2 - Status: Granted - Kind: B2 - Application number: 17/796,187 - Filed: 2021-01-29 - Published: 2023-03-09 - Granted: 2025-02-04 - Earliest claimed: 2020-01-30 - Assignees: InterDigital Patent Holdings, Inc. - Applicants: Interdigital Patent Holdings, Inc. - Inventors: Loran Jatunov; Hussain Elkotby; Tanbir Haque; Patrick Cabrol; Ravikumar Pragada - Web page: https://patentgrep.com/patent/US12216222B2 ## CPC - G01S 5/0244: {Accuracy or reliability of position solution or of measurements contributing thereto} - G01S 11/02: using radio waves (G01S19/00 takes precedence) - G01S 13/84: for distance determination by phase measurement - H04W 64/003: {locating network equipment} - G01S 5/06: Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/12 takes precedence) - G01S 5/10: Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements {, e.g. omega or decca systems}(G01S5/12 takes precedence {; beacons and receivers cooperating therewith G01S1/306, G01S1/308}) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method for use in a wireless transmit/receive unit (WTRU) configured to communicate through a zero energy (ZE) interface in accordance with an embodiment disclosed herein is provided. The method includes the WTRU receiving, a first positioning reference signal (PRS) resource with parameters characterizing the first PRS and determining the suitability of the first PRS resource for use by the WTRU. The method also includes measuring the phase difference of arrival (PDOA) for available frequency pairs and generating a range estimate based on the PDOA measurement. Further, the method includes the WTRU evaluating a reliability of the PDOA measurement and an accuracy of the range estimate and, on a condition that a sufficient accuracy has been achieved, reporting the range estimate. ## Claims ### Claim 1 A method performed by a wireless transmit receive unit (WTRU) that is configured for use in a zero energy (ZE) interface, the method comprising: receiving a message indicating a plurality of positioning reference signal (PRS) configurations, wherein each PRS configuration provides frequency and time resources for reception, by the WTRU, of a plurality of PRSs, and wherein the message indicates a default PRS configuration; upon a condition that the default PRS configuration is not suitable for one or more capabilities or requirements of the WTRU, transmitting a message including a request to use another one of the plurality of PRS configurations, wherein the another one of the plurality of PRS configurations is requested based on the one or more capabilities or requirements of the WTRU; receiving a message indicating ranging assistance information applicable during a time duration; receiving, within the time duration, the plurality of PRSs using the another one of the plurality of PRS configurations and using the indicated ranging assistance information; and transmitting a report indicating a range estimate that meets a required accuracy, wherein the range estimate is based on a phase difference of arrival (PDOA) of the received plurality of PRSs. ### Claim 2 (depends on 1) The method of claim 1, wherein the message indicating ranging assistance information applicable during the time duration includes an indication of the time duration. ### Claim 3 (depends on 1) The method of claim 1, wherein the ranging assistance information includes one or more supported range resolutions and one or more multiplexing parameters. ### Claim 4 (depends on 1) The method of claim 1, further comprising transmitting a message indicating the one or more capabilities or requirements of the WTRU. ### Claim 5 (depends on 1) The method of claim 1, wherein the report indicating the range estimate is transmitted in response to a message requesting the range estimate. ### Claim 6 (depends on 1) The method of claim 1, further comprising on a condition that the PDOA is determined to not be sufficiently reliable or on a condition that the range estimate is determined to not be sufficiently accurate, transmitting another message including a request to use a further one of the plurality of PRS configurations, wherein parameters of the further one of the plurality of PRS configurations differ from parameters of previously used PRS configurations. ### Claim 7 (depends on 1) The method of claim 1, wherein parameters of the another PRS configuration are a subset of or a superset of parameters of a default PRS resource. ### Claim 8 (depends on 1) The method of claim 1, wherein the message including the request to use another one of the plurality of PRS configurations includes an indication of a PRS Set ID or a device ID. ### Claim 9 (depends on 1) The method of claim 1, wherein the suitability of a PRS configuration for use by the WTRU is determined based on a subset of frequency co-prime factors supported by the WTRU. ### Claim 10 (depends on 1) The method of claim 1, wherein the range estimate is based on quantized PDOA values and associated co-prime factors. ### Claim 11 A wireless transmit/receive unit (WTRU) configured to communicate through a zero energy (ZE) interface, the WTRU comprising: a transceiver; and a ZE transceiver; the transceiver configured to receive a message indicating a plurality of positioning reference signal (PRS) configurations, wherein each PRS configuration provides frequency and time resources for reception, by the WTRU, of a plurality of PRSs, and wherein the message indicates a default PRS configuration; upon a condition that the default PRS configuration is not suitable for one or more capabilities or requirements of the WTRU, transmit a message including a request to use another one of the plurality of PRS configurations, wherein the another one of the plurality of PRS configurations is requested based on the one or more capabilities or requirements of the WTRU; and receive a message indicating ranging assistance information applicable during a time duration; the ZE transceiver configured to receive, within the time duration, the plurality of PRSs using the another one of the plurality of PRS configurations and using the indicated ranging assistance information; and the transceiver configured to transmit a report indicating a range estimate that meets a required accuracy, wherein the range estimate is based on a phase difference of arrival (PDOA) of the received plurality of PRSs. ### Claim 12 (depends on 11) The WTRU of claim 11, wherein the message indicating ranging assistance information applicable during the time duration includes an indication of the time duration. ### Claim 13 (depends on 11) The WTRU of claim 11, wherein the ranging assistance information includes one or more supported range resolutions and one or more multiplexing parameters. ### Claim 14 (depends on 11) The WTRU of claim 11, the transceiver configured to transmit a message indicating the one or more capabilities or requirements of the WTRU. ### Claim 15 (depends on 11) The WTRU of claim 11, wherein the report indicating the range estimate is transmitted in response to a message requesting the range estimate. ### Claim 16 (depends on 11) The WTRU of claim 11, the transceiver configured to, on a condition that the PDOA is determined to not be sufficiently reliable or on a condition that the range estimate is determined to not be sufficiently accurate, transmit another message including a request to use a further one of the plurality of PRS configurations, wherein parameters of the further one of the plurality of PRS configurations differ from parameters of previously used PRS configurations. ### Claim 17 (depends on 11) The WTRU of claim 11, wherein parameters of the another PRS configuration are a subset of or a superset of parameters of a default PRS resource. ### Claim 18 (depends on 11) The WTRU of claim 11, wherein the message including the request to use another one of the plurality of PRS configurations includes an indication of a PRS Set ID or a device ID. ### Claim 19 (depends on 11) The WTRU of claim 11, wherein the suitability of a PRS configuration for use by the WTRU is determined based on a subset of frequency co-prime factors supported by the WTRU. ### Claim 20 (depends on 11) The WTRU of claim 11, wherein the range estimate is based on quantized PDOA values and associated co-prime factors.