System and method for identification of transmitters with limited information

• US 20050124374A1
• Filed: 08/18/2004
• Published: 06/09/2005
• Est. Priority Date: 09/10/2001
• Status: Active Grant

• Current Assignee: Grant Marshall, Wyatt Riley
• Original Assignee: Grant Marshall, Wyatt Riley
• Inventors: Riley, Wyatt, Marshall, Grant
• Granted Patent: US 7,136,652 B2
• Time in Patent Office: Days
• US Class Current: 455/525
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A system and method are disclosed by which a base transceiver station (BTS) may be uniquely identified. When attempting to determine the location of a mobile unit using signal from multiple BTSs, it is critical that the BTSs be uniquely identified and their position accurately determined. In many cases, the signals received from the BTSs provide limited identification information and cannot be used to uniquely to identify the BTS from which a signal has been received. The present invention uses available information to generate a candidate list and to determine therefrom the most likely candidates for the Measurement BTSs. Based on this information, the system analyzes cell coverage overlap and relative phase delay to determine the likelihood of a candidate BTS being the actual BTS from which a signal is received. As candidate BTSs are uniquely identified, it is possible to use this additional identification information in an iterative process to further identify additional candidate BTSs.

Claims

1. In operating a mobile communications unit in a wireless communication system, a method for distinguishing a base station having partial identification data from another base station having the same partial identification data, comprising:

uniquely identifying a first base station;

receiving transmissions from at least one additional base station, the transmissions containing only the partial identification data;

generating a candidate list providing identification of candidate base stations having the same partial identification data;

analyzing the candidate base stations on the candidate list with respect to identification data of the first base station; and

uniquely identifying a candidate base station based on the analysis of the candidate base stations.

2. The method of claim 1 wherein the first base station is a serving base station with which the wireless device has initially established a communications link.

3. The method of claim 1 wherein said generating a candidate list providing identification of candidate base stations includes including at least one candidate base station that is out of communication range of said first base station.

4. The method of claim 1 wherein said analyzing the candidate base stations is iteratively performed with respect to other ones of the candidate base stations that have been previously uniquely identified.

5. The method of claim 1 wherein said analyzing the candidate base stations comprises analytically determining an area of coverage overlap between a known coverage area of the first base station and a coverage area of a selected one of the candidate base stations.

6. The method of claim 5 wherein said determining the area of coverage overlap includes generating a probabilistic result and wherein said uniquely identifying the candidate base station is based on the probabilistic result.

7. The method of claim 5 wherein said determining the area of coverage overlap further comprises altering a coverage area model for a selected candidate base station based on a received signal strength of a signal received from the selected candidate base station.

8. The method of claim 1 wherein said analyzing the candidate base stations comprises determining a probability that an area of coverage of each of the candidate base stations overlaps an area of coverage for the first base station.

9. The method of claim 8 further comprising deleting a selected candidate base station from the candidate list if the selected candidate base station has a probability of coverage overlap that is less than a probability of coverage overlap of another candidate base station by a predetermined amount.

10. The method of claim 9 wherein said predetermined amount is greater than 10 times.

11. The method of claim 1 wherein said analyzing the candidate base stations comprises analytically determining a relative phase delay between the first base station and a selected candidate base station.

12. The method of claim 11 wherein said determining the relative phase delay comprises generating a probabilistic result and said uniquely identifying the base station comprises basing the identity on the probabilistic result.

13. The method of claim 11 further comprising adjusting the relative phase delay to account for any repeater in the system.

14. The method of claim 11 wherein at least one of the candidate base stations includes a repeater having a known location and signal processing delay, the method further comprising adding the repeater to the candidate list as a candidate base station.

15. The method of claim 11 wherein said analyzing the candidate base stations comprises determining a probability that a phase delay of each of the candidate base stations relative to a phase delay for the first base station corresponds to a distance from each of the candidate base stations to a predetermined location relative to a distance from the first base station to the predetermined location.

16. The method of claim 14 wherein the predetermined location for each of the candidate base stations is an approximate center of an area of combined coverage of each of the respective candidate base stations and the first base station.

17. The method of claim 16 wherein determining the relative phase delay further comprises altering the combined coverage area for a selected base station based on a received signal strength of a signal received from the selected base station.

18. The method of claim 15 further comprising deleting a selected candidate base station from the candidate list if the probability of the relative phase delay corresponding to the relative distance for the selected candidate base station is less than the probability of the relative phase delay corresponding to the relative distance for other candidate base stations by a predetermined amount.

19. The method of claim 18 wherein said predetermined amount is greater than 10 times.