# US 11,445,470 B2 · Position measurement in presence of MBSFN signals

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- Number: US 11,445,470 B2
- Document ID: US11445470B2
- Status: Granted
- Kind: B2
- Application number: 17/165,540
- Filed: 2021-02-02
- Published: 2022-08-04
- Granted: 2022-09-13
- Earliest claimed: 2021-02-02
- Assignees: QUALCOMM Incorporated
- Applicants: QUALCOMM Incorporated
- Inventors: Mukesh Kumar; Guttorm Ringstad Opshaug; Siddhant
- Web page: https://patentgrep.com/patent/US11445470B2

## CPC

- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04W 64/006: {with additional information processing, e.g. for direction or speed determination}
- G01S 5/0236: {Assistance data, e.g. base station almanac}
- H04B 17/27: for locating or positioning the transmitter
- H04B 17/327: Received signal code power [RSCP]
- H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT}
- H04L 5/001: {the frequencies being arranged in component carriers}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04L 5/0094: {Indication of how sub-channels of the path are allocated}
- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04W 72/56: based on priority criteria
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- 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
- H04B: TRANSMISSION

## Abstract

In one example, a method comprises: receiving assistance data from a location server; classifying a plurality of candidate cells in the assistance data into a first group of candidate cells and a second group of candidate cells, wherein the classification is based on whether a candidate cell transmits position reference signal (PRS) symbols in one or more multimedia broadcast single frequency network (MBSFN) subframes in a positioning occasion, and based on a cyclic prefix (CP) length of the PRS symbols being transmitted by the candidate cell in the positioning occasion; selecting, based on one or more predetermined criteria, one of the first group or the second group of candidate cells to measure the one or more PRS in the positioning occasion; and measuring the one or more PRS from one of the first group or the second group of candidate cells in the positioning occasion to measure PRS measurements.

## Claims

### Claim 1

A method, on a user equipment (UE), for performing position measurement in a wireless communication network, the method comprising:
receiving assistance data from a location server, wherein the assistance data identify a plurality of candidate cells with which the UE can measure one or more position reference signals (PRS) to support a position measurement operation of the UE;
classifying the plurality of candidate cells into a first group of candidate cells and a second group of candidate cells, wherein the classification is based on whether a candidate cell transmits PRS symbols in one or more multimedia broadcast single frequency network (MBSFN) subframes in a positioning occasion, and based on a cyclic prefix (CP) length of the PRS symbols being transmitted by the candidate cell in the positioning occasion;
selecting, based on one or more predetermined criteria, one of the first group or the second group of candidate cells to measure the one or more PRS in the positioning occasion; and
measuring the one or more PRS from the selected one of the first group or the second group of candidate cells in the positioning occasion to measure PRS measurements.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first group of candidate cells includes cells that transmit the PRS symbols having extended cyclic prefix (ECP) only in MBSFN subframes; and
wherein the second group of candidate cells includes cells that transmit the PRS symbols having normal cyclic prefix (NCP) in non-MBSFN frames.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
receiving, from one or more of the candidate cells, Information Block Type 2 (SIB2) messages,
wherein the SIB2 messages include MBSFN configuration information indicating whether a candidate cell transmits MBSFN subframes and their subframe numbers; and
wherein the plurality of candidate cells is classified into the first group and the second group based on the MBSFN configuration information included in the SIB2 messages.

### Claim 4 (depends on 1)

The method of claim 1, wherein the assistance data include MBSFN configuration information of the candidate cells; and
wherein the plurality of candidate cells is classified into the first group and the second group based on the MBSFN configuration information included in the assistance data.

### Claim 5 (depends on 1)

The method of claim 1, wherein the assistance data include identifiers of the plurality of candidate cells arranged in a list following a predetermined order;
wherein the method further comprises:
assigning a priority score to each of the plurality of candidate cells based on the candidate cell's order in the list;
computing a first combined priority score of the first group based on the priority score assigned to each candidate cell classified into the first group; and
computing a second combined priority score of the second group based on the priority score assigned to each candidate cell classified into the first group; and
wherein the one of the first group or the second group of candidate cells is selected based on the first combined priority score and the second combined priority score.

### Claim 6 (depends on 5)

The method of claim 5, wherein the first combined priority score is computed based on averaging the priority score of each candidate cell classified into the first group; and
wherein the second combined priority score is computed based on averaging the priority score of each candidate cell classified in the second group.

### Claim 7 (depends on 5)

The method of claim 5, further comprising:
measuring a signal quality of the one or more PRS with at least some of the plurality of candidate cells,
wherein the one of the first group or the second group of candidate cells is selected based on the signal quality results of the candidate cells.

### Claim 8 (depends on 7)

The method of claim 7, further comprising:
selecting the first group of candidate cells based on the first combined priority score and the second combined priority score; and
responsive to determining the PRS measurements with the first group of candidate cells are potentially less accurate than the PRS measurements with the second group of candidate cells:
measuring a signal quality of the one or more PRS symbols with the at least some of the plurality of candidate cells;
based on the signal quality results, determining a first overall signal quality for the first group and a second overall signal quality for the second group; and
selecting one of the first group or the second group based on the first overall signal quality and the second overall signal quality.

### Claim 9 (depends on 8)

The method of claim 8, wherein the determination that the PRS measurements with the first group of candidate cells are potentially less accurate than the PRS measurements with the second group of candidate cells is based on the first group including fewer candidate cells than the second group.

### Claim 10 (depends on 8)

The method of claim 8, wherein the at least some of the plurality of candidate cells comprise intra-frequency cells.

### Claim 11 (depends on 8)

The method of claim 8, wherein the signal quality results comprise at least one of: reference signal receive power (RSRP) measurements, or received signal strength indication (RSSI).

### Claim 12 (depends on 1)

The method of claim 1, further comprising:
measuring the one or more PRS from the first group of candidate cells in a first PRS occasion to measure first PRS measurements; and
measuring the one or more PRS from the second group of candidate cells in a second PRS occasion to obtain measure second PRS measurements,
wherein the position of the UE is determined based on the first PRS measurements and the second PRS measurements.

### Claim 13 (depends on 1)

The method of claim 1, wherein measuring the one or more PRS from the selected one of the first group or the second group of candidate cells in the positioning occasion comprises, in each symbol period:
based on the CP length of the selected one of the first group or the second group of candidate cells, skipping a number of samples of radio signals received in the symbol period; performing processing on the remaining samples of radio signals received in the symbol period to recover a PRS symbol; and
determining a time of arrival (TOA) of the recovered PRS symbol.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
measuring the one or more PRS from the non-selected one of the first group or the second group of candidate cells in the positioning occasion based on the CP length of the selected one of the first group or the second group of candidate cells; and
determining a position of the UE based on a weighted combination of the PRS measurements with the selected one of the first group or the second group of candidate cells and the PRS measurements with the non-selected one of the first group or the second group of candidate cells.

### Claim 15 (depends on 13)

The method of claim 13, further comprising:
determining a reference signal time difference (RSTD) based on the TOA of a PRS symbol from a reference cell and the TOAs of the PRS symbols from the selected one of the first group or the second group of candidate cells; and
determining a position of the UE based on the RSTD, a known position of the reference cell, and known position of the selected one of the first group or the second group of candidate cells.

### Claim 16

A user equipment (UE), for performing position measurement in a wireless communication network, the UE comprising:
memory;
a wireless communication interface; and
a processing unit, communicatively coupled to the memory and the wireless communication interface, the processing unit configured to:
receive assistance data from a location server, wherein the assistance data identify a plurality of candidate cells with which the UE can measure one or more position reference signals (PRS) to support a position measurement operation of the UE;
classify the plurality of candidate cells into a first group of candidate cells and a second group of candidate cells, wherein the classification is based on whether a candidate cell transmits PRS symbols in one or more multimedia broadcast single frequency network (MBSFN) subframes in a positioning occasion, and based on a cyclic prefix (CP) length of the PRS symbols being transmitted by the candidate cell in the positioning occasion;
select, based on one or more predetermined criteria, one of the first group or the second group of candidate cells to measure the one or more PRS in the positioning occasion; and
measure the one or more PRS from the selected one of the first group or the second group of candidate cells in the positioning occasion to measure PRS measurements.

### Claim 17 (depends on 16)

The UE of claim 16, wherein the first group of candidate cells includes cells that transmit the PRS symbols having extended cyclic prefix (ECP) only in MBSFN subframes; and
wherein the second group of candidate cells includes cells that transmit the PRS symbols having normal cyclic prefix (NCP) in non-MBSFN frames.

### Claim 18 (depends on 16)

The UE of claim 16, wherein the processing unit is further configured to receive, from one or more of the candidate cells, Information Block Type 2 (SIB2) messages;
wherein the SIB2 messages include MBSFN configuration information indicating whether a candidate cell transmits MBSFN subframes and their subframe numbers; and
wherein the plurality of candidate cells is classified into the first group and the second group based on the MBSFN configuration information included in the SIB2 messages.

### Claim 19 (depends on 16)

The UE of claim 16, wherein the assistance data include MBSFN configuration information of the candidate cells; and
wherein the plurality of candidate cells is classified into the first group and the second group based on the MBSFN configuration information included in the assistance data.

### Claim 20 (depends on 16)

The UE of claim 16, wherein the assistance data include identifiers of the plurality of candidate cells arranged in a list following a predetermined order;
wherein the processing unit is further configured to:
assign a priority score to each of the plurality of candidate cells based on the candidate cell's order in the list;
compute a first combined priority score of the first group based on the priority score assigned to each candidate cell classified into the first group; and
compute a second combined priority score of the second group based on the priority score assigned to each candidate cell classified into the first group; and
wherein the one of the first group or the second group of candidate cells is selected based on the first combined priority score and the second combined priority score.

### Claim 21 (depends on 20)

The UE of claim 20, wherein the first combined priority score is computed based on averaging the priority score of each candidate cell classified into the first group; and
wherein the second combined priority score is computed based on averaging the priority score of each candidate cell classified in the second group.

### Claim 22 (depends on 20)

The UE of claim 20, wherein the processing unit is further configured to measure a signal quality of the one or more PRS with at least some of the plurality of candidate cells; and
wherein the one of the first group or the second group of candidate cells is selected based on the signal quality results of the candidate cells.

### Claim 23 (depends on 22)

The UE of claim 22, wherein the processing unit is further configured to:
select the first group of candidate cells based on the first combined priority score and the second combined priority score; and
responsive to determining the PRS measurements with the first group of candidate cells are potentially less accurate than the PRS measurements with the second group of candidate cells:
measure a signal quality of the one or more PRS with the at least some of the plurality of candidate cells;
based on the results of the signal quality results, determine a first overall signal quality for the first group and a second overall signal quality for the second group; and
select one of the first group or the second group based on the first overall signal quality and the second overall signal quality.

### Claim 24 (depends on 23)

The UE of claim 23, wherein the determination that the PRS measurements with the first group of candidate cells are potentially less accurate than the PRS measurements with the second group of candidate cells is based on the first group including fewer candidate cells than the second group.

### Claim 25 (depends on 23)

The UE of claim 23, wherein the at least some of the plurality of candidate cells comprise intra-frequency cells.

### Claim 26 (depends on 23)

The UE of claim 23, wherein the signal quality results comprise at least one of: reference signal receive power (RSRP) measurements, or received signal strength indication (RSSI).

### Claim 27 (depends on 16)

The UE of claim 16, wherein the processing unit is further configured to:
measure the one or more PRS from the first group of candidate cells in a first PRS occasion to measure first PRS measurements; and
measure the one or more PRS from the second group of candidate cells in a second PRS occasion to obtain measure second PRS measurements; and
wherein the position of the UE is determined based on the first PRS measurements and the second PRS measurements.

### Claim 28 (depends on 16)

The UE of claim 16, wherein measuring the one or more PRS from the selected one of the first group or the second group of candidate cells in the positioning occasion comprises the processing unit being further configured to, in each symbol period:
based on the CP length of the selected one of the first group or the second group of candidate cells, skip a number of samples of radio signals received in the symbol period; performing processing on the remaining samples of radio signals received in the symbol period to recover a PRS symbol; and
determine a time of arrival (TOA) of the recovered PRS symbol.

### Claim 29 (depends on 28)

The UE of claim 28, wherein the processing unit is further configured to:
measure the one or more PRS from the non-selected one of the first group or the second group of candidate cells in the positioning occasion based on the CP length of the selected one of the first group or the second group of candidate cells; and
determine a position of the UE based on a weighted combination of the PRS measurements with the selected one of the first group or the second group of candidate cells and the PRS measurements with the non-selected one of the first group or the second group of candidate cells.

### Claim 30 (depends on 28)

The UE of claim 28, wherein the processing unit is further configured to:
determine a reference signal time difference (RSTD) based on the TOA of a PRS symbol from a reference cell and the TOAs of the PRS symbols from the selected one of the first group or the second group of candidate cells; and
determine a position of the UE based on the RSTD, a known position of the reference cell, and known position of the selected one of the first group or the second group of candidate cells.

### Claim 31

An apparatus being part of a user equipment (UE) for performing position measurement in a wireless communication network, comprising:
means for receiving assistance data from a location server, wherein the assistance data identify a plurality of candidate cells with which the UE can measure one or more position reference signals (PRS) to support a position measurement operation of the UE;
means for classifying the plurality of candidate cells into a first group of candidate cells and a second group of candidate cells, wherein the classification is based on whether a candidate cell transmits PRS symbols in one or more multimedia broadcast single frequency network (MBSFN) subframes in a positioning occasion, and based on a cyclic prefix (CP) length of the PRS symbols being transmitted by the candidate cell in the positioning occasion;
means for selecting, based on one or more predetermined criteria, one of the first group or the second group of candidate cells to measure the one or more PRS in the positioning occasion; and
means for measuring the one or more PRS from the selected one of the first group or the second group of candidate cells in the positioning occasion to measure PRS measurements.

### Claim 32

A non-transitory computer readable comprising instructions that, when executed by a processor, cause the processor to:
receive assistance data from a location server, wherein the assistance data identify a plurality of candidate cells with which the UE can measure one or more position reference signals (PRS) to support a position measurement operation of the UE;
classify the plurality of candidate cells into a first group of candidate cells and a second group of candidate cells, wherein the classification is based on whether a candidate cell transmits PRS symbols in one or more multimedia broadcast single frequency network (MBSFN) subframes in a positioning occasion, and based on a cyclic prefix (CP) length of the PRS symbols being transmitted by the candidate cell in the positioning occasion;
select, based on one or more predetermined criteria, one of the first group or the second group of candidate cells to measure the one or more PRS in the positioning occasion; and
measure the one or more PRS from the selected one of the first group or the second group of candidate cells in the positioning occasion to measure PRS measurements.