Method and apparatus for identifying transmitters in a wireless communication system using power predictions

• US 8,073,464 B2
• Filed: 05/10/2010
• Issued: 12/06/2011
• Est. Priority Date: 10/22/2002
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Lin, Ie-Hong
• Primary Examiner(s): Miller, Brandon
• Application Number:
  US12/776,883
• Publication Number:
  US 20100279727A1
• Time in Patent Office: 575 Days
• Field of Search: 455/404.2, 455/67.11, 455/456.4, 455423-424, 455/561, 455/61.16, 455524-525, 455/464, 455/450, 455/67.16, 4554561-4566, 342/464, 342/450
• US Class Current: 455/456.1
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Identification of transmitters for signals received by a terminal. To determine the transmitter of a given received signal, a list of candidate transmitters that may have transmitted that signal is determined. A coverage zone to use for the received signal is also determined. This coverage zone is the area where the terminal may receive the signal being identified. The predicted power for each candidate transmitter is then determined, e.g., using a path loss prediction model and the coverage zone. The predicted powers for the candidate transmitters are compared (directly or relatively) against the measured power of the received signal. The candidate transmitter with (direct/relative) predicted power closest to the (direct/relative) measured power is deemed as the one that transmitted the signal. Propagation delays may also be predicted and used for transmitter identification. The identified transmitters may be used to determine a position estimate for the terminal.

Claims

1. Processor-executable program code, stored on a memory unit, configured to cause a processor to:

obtain a plurality of received signals for a plurality of transmitters, wherein the plurality of received signals are received by a user terminal; and

determine a transmitter for each received signal, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to;

determine a measured power for the received signal,

determine a list of a plurality of candidate transmitters for the received signal,

obtain predicted power for each candidate transmitter in the list, and

identify the transmitter for the received signal based on the predicted powers for the candidate transmitters and the measured power for the received signal.

2. The program code of claim 1 wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to compare the predicted power for each candidate transmitter against the measured power for the received signal, and wherein the identified transmitter for the received signal is the candidate transmitter with predicted power closest to the measured power.

3. The program code of claim 1, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to determine a coverage zone to use for the received signal, and wherein the predicted power for each candidate transmitter is obtained based on the coverage zone.

4. The program code of claim 3, wherein the program code configured to cause the processor to obtain predicted power for each candidate transmitter in the list is configured to cause the processor to obtain the predicted power for a centroid of the coverage zone.

5. The program code of claim 3, wherein the program code configured to cause the processor to determine the coverage zone is configured to cause the processor to derive the coverage zone based on one or more coverage areas of one or more identified transmitters.

6. The program code of claim 1, wherein the program code configured to cause the processor to obtain the predicted power is configured to cause the processor to determine the predicted power for each candidate transmitter based on a path loss prediction model.

7. The program code of claim 6, wherein the path loss prediction model is based on Okumura-Hata model.

8. The program code of claim 1, wherein the program code configured to cause the processor to obtain the predicted power is configured to cause the processor to determine the predicted power for each candidate transmitter based on field data.

9. The program code of claim 1, wherein the list of candidate transmitters for each received signal comprises a list of base station transceivers (BTSs) with same PN offset.

10. The program code of claim 1, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to obtain a predicted propagation delay for each candidate transmitter in the list, determine a measured propagation delay for the received signal, and wherein the program code configured to cause the processor to identify the transmitter is configured to cause the processor to identify the transmitter based on the predicted propagation delays for the candidate transmitters and the measured propagation delay for the received signal.

11. The program code of claim 10, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to:

determine a power delta for each candidate transmitter as a difference between the predicted power for the candidate transmitter and the measured power of the received signal,

determine a propagation delay delta for each candidate transmitter as a difference between the predicted propagation delay for the candidate transmitter and the measured propagation delay for the received signal, and

obtain a weighted sum of the power delta and the propagation delay delta for each candidate transmitter, and wherein the identified transmitter for the received signal is the candidate transmitter with a smallest weighted sum.

12. The program code of claim 1 wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to:

determine an identified transmitter,

determine measured power of the identified transmitter,

obtain predicted power for the identified transmitter, and

determine the transmitter for the received signal based on the predicted powers for the candidate transmitters, the predicted power for the identified transmitter, the measured power of the received signal, and the measured power for the identified transmitter.

13. The program code of claim 12, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to:

compare a relative predicted power for each candidate transmitter against a relative measured power for the received signal, the relative predicted power being a difference between the predicted power for the candidate transmitter and the predicted power for the identified transmitter, the relative measured power being a difference between the measured power of the received signal and the measured power for the identified transmitter, and

wherein the identified transmitter for each received signal is the candidate transmitter with relative predicted power closest to the relative measured power.

14. The program code of claim 12, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to determine a coverage zone to use for the received signal based on one or more coverage areas of one or more identified transmitters, and wherein the predicted power for each candidate transmitter is obtained based on the coverage zone.

15. The program code of claim 12, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to:

determine measured propagation delay for the received signal,

determine measured propagation delay for the identified transmitter,

obtain predicted propagation delay for each candidate transmitter in the list, and

obtain predicted propagation delay for the identified transmitter, and

wherein the transmitter for the received signal is further identified based on the predicted propagation delays for the candidate transmitters, the predicted propagation delay for the identified transmitter, the measured propagation delay for the received signal, and the measured propagation delay for the identified transmitter.

16. The program code of claim 15, wherein the program code configured to cause the processor to determine the transmitter for each received signal is configured to cause the processor to:

determine a relative power delta for each candidate transmitter,

determine a relative propagation delay delta for each candidate transmitter, and

obtain a weighted sum of the relative power delta and the relative propagation delay delta for each candidate transmitter, and wherein the identified transmitter for the received signal is the candidate transmitter with a smallest weighted sum.

17. An apparatus operable to identify transmitters in a wireless communication system, the apparatus comprising:

a receiver configured to obtain a plurality of received signals for a plurality of transmitters, wherein the plurality of received signals are received by a user terminal; and

a processing unit configured to;

determine a plurality of lists of candidate transmitters for the plurality of received signals, one candidate list for each received signal;

obtain predicted power for each candidate transmitter;

determine a measured power for each of the plurality of received signals; and

identify the transmitter for each received signal based on measured power for the received signal and predicted powers for the candidate transmitters in the list determined for the received signal.

18. The apparatus of claim 17, wherein the processing unit is further configured to determine a coverage zone to use for each received signal, and wherein the predicted power for each candidate transmitter of each received signal is obtained based on the coverage zone for the received signal.

19. The apparatus of claim 17, wherein the processing unit is configured to determine the predicted power for each candidate transmitter based on a path loss prediction model.

20. The apparatus of claim 19, wherein the path loss prediction model is based on Okumura-Hata model.

21. The apparatus of claim 19, wherein the processing unit is further configured to store information used for the path loss prediction model.

22. The apparatus of claim 17, wherein the processing unit is further configured to obtain predicted power for an identified transmitter for each received signal, and wherein the transmitter for each received signal is further identified based on the predicted power for the identified transmitter for the received signal.

23. The apparatus of claim 17, wherein the processing unit is further configured to obtain predicted propagation delay for each candidate transmitter, and wherein the transmitter for each received signal is further identified based on measured propagation delay for the received signal and predicted propagation delays for the candidate transmitters in the list determined for the received signal.

24. The apparatus of claim 17, wherein the wireless communication system is a CDMA system.

25. The apparatus of claim 17, wherein the processing unit comprises at least one of a processor, an application specific integrated circuit, a digital signal processor, a programmable logic device, a field programmable gate array, a controller, a micro-controller, or a microprocessor.