Method and Apparatus for Indoor Location Estimation Among Peer-To-Peer Devices

Patent metadata

Field	Value
Publication number	US-2016337808-A1
Application number	US-201615044253-A
Country	US
Kind code	A1
Filing date	Feb 16, 2016
Priority date	May 15, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

Methods and apparatus perform location estimation among peer-to-peer devices. For the various methods, data of several different types, such as received signal strength, timing measurements, time stamps, actual transmit power, etc., is measured, stored, and propagated within a peer-to-peer network to enable each device in the peer-to-peer network to calculate positioning coordinates for one or more devices having unknown positioning coordinates.

First claim

I claim:

1 . A method performed by a first peer-to-peer device, the method comprising:
sending a transmission, and recording a start time of the transmission; receiving a set of signals sent from remaining peer-to-peer devices in a group of devices that also includes the first peer-to-peer device, and recording a time of receipt of each signal in the set of signals; recording a first set of timing measurements each indicating a time difference between the start time of the transmission and the time of receipt of a different signal of the set of signals; sending the first set of timing measurements for propagating to the remaining peer-to-peer devices; receiving from the remaining peer-to-peer devices a second set of timing measurements each indicating a time difference between a start time of a signal transmitted by one of the remaining peer-to-peer devices and a time of receipt of a signal sent from another of the peer-to-peer devices in the group of devices; determining unknown positioning coordinates for at least one peer-to-peer device in the group of devices using the first and second sets of timing measurements.

2 . The method of claim 1 , wherein the unknown positioning coordinates are further determined using known positioning coordinates of multiple devices in the group of devices.

3 . The method of claim 1 , wherein a subset of the second set of timing measurements each indicates a time difference between the start time of a signal transmitted by one of the remaining peer-to-peer devices and a time of receipt of the transmission from the first peer-to-peer device.

4 . The method of claim 1 , wherein a subset of the second set of timing measurements each indicates a time difference between the start time of a signal transmitted by one of the remaining peer-to-peer devices, excluding the first peer-to-peer device, and a time of receipt of a signal in the set of signals.

5 . The method of claim 1 further comprising:
determining a first propagation delay value indicating a propagation delay from a reference device to the first peer-to-peer device;
sending the first propagation delay value for propagating to the remaining peer-to-peer devices;
wherein the unknown positioning coordinates are further determined using the first propagation delay value.

6 . The method of claim 5 further comprising receiving a first set of propagation delay values indicating measured propagation delays from the reference device to each of the remaining peer-to-peer devices, wherein the unknown positioning coordinates are further determined using the first set of received propagation delay values.

7 . The method of claim 6 further comprising determining a set of device pair propagation delay values using the first and second sets of timing measurements, the first propagation delay value, and the first set of propagation delay values, wherein each device pair propagation delay value indicates a propagation delay between different pairs of peer-to-peer devices in the group of devices, wherein the unknown positioning coordinates are further determined using the set of device pair propagation delay values.

8 . The method of claim 7 further comprising determining, using the set of device pair propagation delay values, a set of distance values indicating distances between the different pairs of peer-to-peer devices in the group of devices, wherein the unknown positioning coordinates are determined using the set of distance values.

9 . The method of claim 7 , wherein the propagation delay Tpropji between each of the different pairs (i, j) of peer-to-peer devices is determined using a function Tpropi+T_Rx_ji−Tpropj, where Tpropi is the propagation delay from the reference device to a first device in the pair of peer-to-peer devices, Tpropj is the propagation delay from the reference device to a second device in the pair of peer-to-peer devices, and T_Rx_ji is the timing measurement indicating the time difference between the start time of the signal transmitted by the first device in the pair of peer-to-peer devices and the time of receipt by the first device of the signal sent from the second device in the pair of peer-to-peer devices.

10 . The method of claim 1 further comprising:
receiving an anchor signal from an anchor device in the group of devices, wherein positioning coordinates of the anchor device are known;
recording a first anchor timing measurement indicating a time difference between the start time of the transmission and a time of receipt of the anchor signal;
sending the first anchor timing measurement for propagation to the remaining peer-to-peer devices;
wherein the unknown positioning coordinates are further determined using the first anchor timing measurement.

11 . The method of claim 10 further comprising:
receiving a set of anchor timing measurements from the remaining peer-to-peer devices, each anchor timing measurement in the set indicating a time difference between a start time of a signal sent by a different remaining peer-to-peer device and a time of receipt of the anchor signal;
wherein the unknown positioning coordinates are further determined using the set of received anchor timing measurements.

12 . The method of claim 11 further comprising:
determining, as a function of the first anchor timing measurement and the set of received anchor timing measurements, a set of propagation delay difference values with each propagation delay difference value indicating, for a different peer-to-peer device pair of the group of devices, a difference in first and second propagation delay values, wherein the first propagation delay value indicates a time of travel of the anchor signal from the anchor device to a first device of the pair, and the second propagation delay value indicates a time of travel of the anchor signal from the anchor device to a second device of the pair;
wherein the unknown positioning coordinates are determined using the set of propagation delay difference values.

13 . The method of claim 12 further comprising:
determining, using the set of propagation delay difference values, a set of distance difference values with each distance difference value indicating, for a different peer-to-peer device pair of the group of devices, a difference between first and second distances, wherein the first distance is from the first device of the pair to the anchor device and the second distance is from the second device of the pair to the anchor device;
wherein the unknown positioning coordinates are determined using the set of distance difference values.

14 . The method of claim 12 further comprising:
determining a first propagation delay value indicating a propagation delay from a reference device to the first peer-to-peer device;
sending the first propagation delay value for propagating to the remaining peer-to-peer devices;
receiving a first set of propagation delay values indicating measured propagation delays from the reference device to each of the remaining peer-to-peer devices, wherein the unknown positioning coordinates are further determined using the first set of received propagation delay values;
determining a set of device pair propagation delay values using the first and second sets of timing measurements, the first propagation delay value, and the first set of propagation delay values, wherein each device pair propagation delay value indicates a propagation delay between different peer-to-peer device pairs in the group of devices;
wherein the set of propagation delay difference values is further determined based on the set of device pair propagation delay values.

Assignees

• Motorola Mobility Llc

Inventors

• Narasimha Murali

Classifications

• G01S5/0289

  of multiple transceivers, e.g. in ad hoc networks · CPC title

• H04W4/70

  Services for machine-to-machine communication [M2M] or machine type communication [MTC] · CPC title

• H04W24/10

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title

• H04L67/104

  Peer-to-peer [P2P] networks · CPC title

• H04L43/0852 Primary

  Delays · CPC title