Location determination in a wireless network

• US 8,072,381 B1
• Filed: 04/30/2009
• Issued: 12/06/2011
• Est. Priority Date: 04/30/2009
• Status: Active Grant

• Current Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Original Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Inventors: Ziegler, Philip
• Primary Examiner(s): LIU, HARRY K
• Application Number:
  US12/432,983
• Time in Patent Office: 950 Days
• Field of Search: 342/369, 342/386
• US Class Current: 342/386
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/0242 Determining the position of transmitters to be subsequently used in positioning G01S5/0289 takes precedence

Abstract

A method for improving location determination for a mobile device location of which precludes it from sufficiently accurate determination by a standard position determination mechanism is disclosed. The method includes a step of receiving, at a server and from a mobile device, an indication that the mobile device detects a supplemental position determination signal not associated with an overhead channel set that is transmitted in support of traffic channels required to support voice or data communications. The method also includes steps of referencing a database to identify one or more criteria associated with the supplemental position determination signal; determining that the one or more criteria associated with the supplemental position determination signal indicates that a source generating the supplemental position determination signal is within a close proximity of the mobile device; and identifying the location of the source generating the supplemental position determination signal. The method also includes a step of using the location of the source generating the supplemental position determination signal as the location of the mobile device.

Claims

1. A method for improving location determination in a wireless network, the method comprising:

receiving, at a server and from a mobile device, an indication that the mobile device detects a first supplemental position determination signal not associated with an overhead channel set that is transmitted in support of traffic channels required to support voice or data communications;

receiving, at the server and from the mobile device, an indication that the mobile device detects a second supplemental position determination signal not associated with the overhead channel set that is transmitted in support of the traffic channels required to support the voice or data communications;

referencing a database to identify one or more criteria associated with the first and second supplemental position determination signals;

determining from the one or more criteria associated with the first and second supplemental position determination signals that the first and second supplemental position determination signals should be used for determining the location of the mobile device;

based on determining that the first supplemental position determination signal should be used for position determination, determining a location associated with a source of the first supplemental position determination signal;

based on determining that the second supplemental position determination signal should be used for position determination, determining a location associated with a source of the second supplemental position determination signal; and

using the locations associated with the sources of the first and second supplemental position determination signals to determine the location of the mobile device.

2. The method of claim 1, further comprising:

receiving an indication that the mobile device detects one or more pilot signals associated with the overhead channel set that is transmitted with the traffic channels required to support the voice or data communications; and

deciding not to use the one or more pilot signals for determining the position of the mobile device upon determining that the first and second supplemental position determination signals should be used for determining the position of the mobile device.

3. The method of claim 1, wherein:

the source of the first supplemental position determination signal includes a first pilot beacon transmitter deployed within a campus or municipality to improve the location determination capability therein;

the location associated with the source of the first supplemental position determination signal includes the location of the first pilot beacon transmitter;

the source of the second supplemental position determination signal includes a second pilot beacon transmitter deployed within the campus or municipality to improve the location determination capability therein; and

the location associated with the source of the second supplemental position determination signal includes the location of the second pilot beacon transmitter.

4. The method of claim 3, wherein the first and second pilot beacon transmitters are capable of adjusting their respective time base to compensate for time delays through signal distribution mechanism in another part of the network.

5. The method of claim 3, wherein using the locations associated with the sources of the first and second supplemental position signals to determine the location of the mobile device further includes:

determining the time the first supplemental position determination signal was transmitted from the first pilot beacon transmitter and the time the first supplemental position determination signal was received by the mobile device;

determining the difference between the time the first supplemental position determination signal was transmitted from the first pilot beacon transmitter and the time the first supplemental position determination signal was received by the mobile device;

determining the time the second supplemental position determination signal was transmitted from the second pilot beacon transmitter and the time the second supplemental position determination signal was received by the mobile device;

determining the difference between the time the second supplemental position determination signal was transmitted from the second pilot beacon transmitter and the time the second supplemental position determination signal was received by the mobile device; and

calculating the location of the mobile device based on the difference between the time the first supplemental position determination signal was transmitted from the first pilot beacon transmitter and the time the first supplemental position determination signal was received by the mobile device and the difference between the time the second supplemental position determination signal was transmitted from the second pilot beacon transmitter and the time the second supplemental position determination signal was received by the mobile device.

6. The method of claim 1, the database includes a Base Station Almanac Database supplemented to include a record for each of the first and second supplemental position determination signals, the record including a sector identification label, a coordinate pair associated with the sources of the first and second supplemental position determination signals, and/or a Maximum Antenna Range value field which defines a reasonable boundary for coverage footprint of the sources of the first and second supplemental position determination signals.

7. The method of claim 1, wherein:

determining the location associated with the source of the first supplemental position determination signal includes determining a coverage area associated with the source of the first supplemental position determination;

determining the location associated with the source of the second supplemental position determination signal includes determining a coverage area associated with the source of the second supplemental position determination signal; and

using the locations associated with the sources of the first and second supplemental position determination signals to determine the location of the mobile device includes using an overlap of the coverage area associated with the source of the first supplemental position determination signal and the coverage area associated with the source of the second supplemental position determination signal to determine the location of the mobile device.

8. The method of claim 6, wherein the Base Station Almanac Database further includes records for one or more pilot signals transmitted from one or more base stations.

9. The method of claim 8, wherein the first and second supplemental position determination signals have a format similar to that of the one or more pilot signals transmitted from the one or more base stations.

10. A Distributed Antenna System (“

DAS”

) configured to improve location determination for a mobile device located within its coverage footprint, location of which precludes it from sufficiently accurate position determination by a standard position determination mechanism, the DAS comprising;

a plurality of first antennas and a first pilot beacon transmitter, the plurality first antennas providing voice or data coverage for a mobile device located within a first coverage footprint of the DAS and the first pilot beacon transmitter providing a first supplemental position determination signal in a first coverage area of the DAS, the first supplemental position determination signal not associated with an overhead channel set that is transmitted in support of traffic channels required to support voice or data communications;

a plurality of second antennas and a second pilot beacon transmitter, the plurality second antennas providing voice or data coverage for the mobile device located within a second coverage footprint of the DAS and the second pilot beacon transmitter providing a second supplemental position determination signal in a second coverage area of the DAS, the second supplemental position determination signal not associated with an overhead channel set that is transmitted in support of traffic channels required to support voice or data communications;

a base station transmitter in communication with the plurality of first and second antennas to provide voice and data coverage within the first and second coverage footprints of the DAS; and

a server in communications with the base station transmitter, wherein the server is configured to perform functions including functions to;

receive from the mobile device an indication that the mobile device detects the first supplemental position determination signal;

receive from the mobile device an indication that the mobile device detects the second supplemental position determination signal;

reference a database to identify one or more criteria associated with the first and second supplemental position determination signals;

determine from the one or more criteria associated with the first and second supplemental position determination signals that the first and second supplemental position determination signals should be used for determining the location of the mobile device;

based on determining that the first and second supplemental position determination signals should be used for position determination, determine the first coverage area associated with the first pilot beacon transmitter and the second coverage area associated with the second pilot beacon transmitter; and

identify the location of the mobile device based on the overlap of the first and second coverage areas.

11. The system of claim 10, wherein the server further includes functions to:

receive an indication that the mobile device detects one or more pilot signals associated with the overhead channel set that is transmitted with the traffic channels required to support the voice or data communications; and

decide not to use the one or more pilot signals for determining the position of the mobile device.

12. The system of claim 10, wherein the DAS includes an indoor DAS associated with a building.

13. The system of claims 10, wherein the DAS includes an outdoor DAS associated with a campus or municipality.

14. The system of claim 10, wherein the energy of the base station transmitter is simulcast to the first and second antennas.

15. The system of claim 10, wherein error is introduced in a time base of a pilot signal from the base station transmitter.

16. The system of claim 10, wherein a range of each of the first and second pilot beacon transmitters is within 150 meters.

17. The system of claim 10, wherein the first and second supplemental position determination signals are only used for position determination.

18. The system of claim 10, wherein the database includes a Base Station Almanac Database supplemented to include for each of the first and second supplemental position determination signals a sector identification label, a coordinate pair associated with the sources of the first and second supplemental position determination signals, and/or a Maximum Antenna Range value field which defines a reasonable boundary for coverage footprint of the sources of the first and second supplemental position determination signals.

19. The system of claim 10, wherein the first and second pilot beacon transmitters are capable of adjusting their respective time base to compensate for time delays through signal distribution mechanism in another part of the network.