Method and Apparatus for Measuring Timing of Signals Received from Multiple Base Stations in a CDMA Communication System

• US 20090067477A1
• Filed: 11/11/2008
• Published: 03/12/2009
• Est. Priority Date: 10/11/2000
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Grilli, Francesco, Willenegger, Serge
• Granted Patent: US 7,965,762 B2
• Time in Patent Office: Days
• US Class Current: 375/147
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Unassigned finger processors are used to process and measure the arrival times of transmissions from base stations not in the active set. A first set of one or more base stations in active communication with the remote terminal is identified and each base station in the first set is assigned at least one finger processor. A second set of one or more base stations not in active communication with the remote terminal is also identified and an available finger processor is assigned to each of at least one base station in the second set. A (signal arrival) time measurement is then performed for each base station, and outputs indicative of the measurements are provided for further processing.

Claims

1. A remote terminal comprising:

a first set of finger processors assigned to process signals from a first set of one or more base stations in active communication with the remote terminal and configured to determine a time of arrival of at least one signal from the first set of one or more base stations;

a second set of finger processors assigned to process signals from a second set of one or more base stations not in active communication with the remote terminal and configured to determine a time of arrival of each of the signals from the second set of one or more base stations; and

a combiner selectably configurable to combine processed signals from the first set of finger processors and omit processed signals from the second set of finger processors.

2. The remote terminal of claim 1, further comprising

a searcher finger configured to determine a relative time of arrival of signals from each base station in the second set of one or more base stations, and

wherein each of the second set of finger processors is configured to process an earliest multipath signal from a distinct one of the second set of one or more base stations.

3. The remote terminal of claim 1, further comprising a first receiver operative to receive, process, and digitize a received signal to provide samples to the first and second sets of finger processors.

4. The remote terminal of claim 3, wherein the received signal comprises a composite spread spectrum signal from a plurality of base stations.

5. The remote terminal of claim 4, wherein the plurality of base stations comprises a plurality of asynchronous base stations.

6. The remote terminal of claim 1, further comprising:

a signal quality estimator configured to determine a signal quality estimate from at least one finger processor, and

wherein the second set of finger processors is assigned to process signals from the second set of one or more base stations based in part on the signal quality estimate.

7. The remote terminal of claim 1, wherein the time of arrival of at least one signal from the first set of one or more base stations comprises an earliest time of arrival.

8. The remote terminal of claim 1, wherein the time of arrival of each of the signals from the second set of one or more base stations comprises an earliest time of arrival.

9. The remote terminal of claim 1, wherein the time of arrival for signals from the first and second set of one or more base stations comprises an SFN-SFN measurement.

10. The remote terminal of claim 1, wherein the second set of finger processors comprise a temporarily reassigned subset of the first set of finger processors.

11. The remote terminal of claim 1, wherein the time of arrival of at least one signal from the first set of one or more base stations comprises a time of arrival of a signal from one of a pilot channel or a broadcast channel.

12. A method of determining a position of a remote terminal in a communication system, the method comprising:

assigning each of a first set of finger processors in a rake receiver to a distinct signal from a first plurality of signals from a first set of one or more base stations in active communication with the remote terminal;

assigning each of a second set of finger processors in the rake receiver to a distinct signal from a second plurality of signals from a second set of one or more base stations not in active communication with the remote terminal;

determining at least one time measurement from the first plurality of signals from the first set of one or more base stations;

determining a time measurement for each of the second plurality of signals from the second set of one or more base stations; and

processing the at least one time measurement and the time measurement for each of the second plurality of signals.

13. The method of claim 12, further comprising determining a position of the remote terminal based in part on processing the at least one time measurement and the time measurement for each of the second plurality of signals.

14. The method of claim 12, further comprising transmitting the at least one time measurement and the time measurement for each of the second plurality of signals to a position determination entity.

15. The method of claim 12, wherein assigning each of the second set of finger processors comprises assigning each of the second set of finger processors in the rake receiver to a distinct earliest arriving signal from the second plurality of signals.

16. The method of claim 12, wherein determining at least one time measurement from the first plurality of signals comprises determining an earliest time of arrival from at least one base station in the first set of base stations.

17. The method of claim 12, wherein determining at least one time measurement from the first plurality of signals comprises determining at least one time measurement of a spread spectrum signal to a resolution of less than one spreading chip period.

18. The method of claim 12, wherein determining at least one time measurement from the first plurality of signals comprises determining at least one time measurement from one of a pilot channel signal or a broadcast channel signal.

19. The method of claim 12, wherein assigning each of the second set of finger processors comprises:

determining an earliest arriving multipath signal from a base station from the second set of one or more base stations; and

assigning a finger processor from the second set of finger processors to the earliest arriving multipath signal.

20. The method of claim 12, wherein the first set of one or more base stations comprises a first set of asynchronous base stations.

21. A method of determining a position of a remote terminal in a communication system, the method comprising:

assigning each of a first set of finger processors in a rake receiver to a distinct signal from a first plurality of signals from a first set of one or more base stations in active communication with the remote terminal;

searching for an earliest multipath signal from each base station from a second set of one or more base stations not in active communication with the remote terminal;

assigning each of a second set of finger processors in the rake receiver to a distinct earliest multipath signal from the second plurality of signals from the second set of one or more base stations;

determining at least one time measurement from the first plurality of signals from the first set of one or more base stations;

determining a time measurement for each of the second plurality of signals from the second set of one or more base stations.

22. The method of claim 21, further comprising determining a position of the remote terminal based at least in part on the at least one time measurement and the time measurement for each of the second plurality of signals.

23. The method of claim 21, further comprising transmitting the at least one time measurement and the time measurement for each of the second plurality of signals to a position determination entity.

24. The method of claim 21, wherein searching for the earliest multipath signal comprises searching for an earliest multipath signal exceeding a predetermined signal quality.

25. A remote terminal comprising:

means for assigning each of a first set of finger processors in a rake receiver to a distinct signal from a first plurality of signals from a first set of one or more base stations in active communication with the remote terminal;

means for assigning each of a second set of finger processors in the rake receiver to a distinct signal from a second plurality of signals from a second set of one or more base stations not in active communication with the remote terminal;

means for determining at least one time measurement from the first plurality of signals from the first set of one or more base stations;

means for determining a time measurement for each of the second plurality of signals from the second set of one or more base stations; and

means for processing the at least one time measurement and the time measurement for each of the second plurality of signals.

26. A computer readable medium encoded with executable computer program instructions to enable determining a position of a remote terminal in a communication system, the instructions comprising:

instructions for assigning each of a first set of finger processors in a rake receiver to a distinct signal from a first plurality of signals from a first set of one or more base stations in active communication with the remote terminal;

instructions for assigning each of a second set of finger processors in the rake receiver to a distinct signal from a second plurality of signals from a second set of one or more base stations not in active communication with the remote terminal;

instructions for determining at least one time measurement from the first plurality of signals from the first set of one or more base stations;

instructions for determining a time measurement for each of the second plurality of signals from the second set of one or more base stations; and

instructions for processing the at least one time measurement and the time measurement for each of the second plurality of signals.