Method and apparatus for estimating the position of a terminal based on identification codes for transmission sources

• US 7,139,580 B2
• Filed: 04/24/2002
• Issued: 11/21/2006
• Est. Priority Date: 04/24/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Stein, Jeremy M., Weissman, Haim
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Lee, John J.
• Application Number:
  US10/132,908
• Publication Number:
  US 20030008669A1
• Time in Patent Office: 1,672 Days
• Field of Search: 455/456.1, 455/456.3, 455/456.5, 455/456.6, 455/414.2, 455/422.1, 455/435.1, 455/435.2, 455/11.1, 455/9, 455/506, 455/507, 455/517, 455/12.1, 455/13.1, 455/404.2, 455/67.11, 455/115.1, 455/456.2, 342/357.01, 342/357.14, 342/357.12, 342/357.05, 342/357.02, 370/345, 370/337
• 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
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Techniques to determine the position of a terminal under the coverage of a repeater in a wireless communication system. In an aspect, an identification code is transmitted for each repeater and used by the terminal (or a PDE) to unambiguously identify the repeater. The identification codes for the repeaters in the system can be implemented with PN sequences at defined offsets that are specifically reserved for repeater identification. In another aspect, the identification code for each repeater is transmitted using a spread-spectrum signal designed to have minimal impact on the performance of the system and to be recoverable by the terminal in similar manner as for a forward modulated signal. In this way, no additional hardware is required for the terminal to recover the identifier signal. In one specific design, the spread spectrum identifier signal is generated in accordance with and conforms to the IS-95 CDMA standard.

Claims

1. A method for determining the location of a device in a wireless communication system, comprising:

receiving from a transmission source comprising a terrestrial-based wireless repeater at a known location, a first signal having included therein transmitted data and a second signal having included therein an identification code assigned to the transmission source, wherein the identification code comprises a plurality of delayed and attenuated versions of the first signal and representative of a particular multipath profile;

processing the second signal to recover the identification code; and

determining a position estimate of the device based on the recovered identification code.

2. The method of claim 1, wherein the identification code comprises a pseudo-noise (PN) sequence at a particular offset.

3. The method of claim 1, wherein the identification code comprises a plurality of pseudo-noise (PN) sequences.

4. The method of claim 3, wherein the plurality of PN sequences are at particular offsets.

5. The method of claim 1, wherein the identification code comprises a delayed and attenuated version of the first signal.

6. The method of claim 1, wherein the identification code comprises a signal transmitted at a frequency different from the frequency of the first signal.

7. The method of claim 1, wherein the identification code is a pseudo-noise (PN) sequence at a particular offset.

8. The method of claim 1, wherein the position estimate of the device is a particular location within a coverage area of the repeater.

9. A method for determining the location of a device in a wireless communication system, comprising;

receiving from a transmission source comprising a terrestrial-based wireless repeater at a known location, a first signal having included therein transmitted data and a second signal having included therein an identification code assigned to the transmission source;

processing the second signal to recover the identification code; and

determining a position estimate of the device based on the recovered identification code;

wherein the identification code comprises a signal transmitted at a frequency different from the frequency of the first signal and at a particular transmit offset.

10. The method of claim 9, wherein the identification code comprises one or more Gold code sequences.

11. The method of claim 10, wherein each Gold code sequence is at a particular offset.

12. The method of claim 9, further comprising:

adjusting a set of measurements for position determination in accordance with the recovered identification code.

13. The method of claim 9, wherein the position estimate of the device is a particular location within a coverage area of the transmission source.

14. The method of claim 13, wherein the position estimate of the device is approximately the center of the coverage area of the transmission source.

15. A method for generating a signal suitable for use to estimate the location of a device in a wireless communication system, comprising:

receiving at a transmission source a forward link signal having included therein at least a pilot signal;

processing the forward link signal to recover a timing reference, and processing the forward link signal to recover a frequency reference for a carrier signal of the forward link signal,

generating at the transmission source a second signal having included therein an identification code assigned to the transmission source;

combining the forward link signal and the second signal to provide a combined signal, wherein the second signal is further generated in accordance with the recovered frequency reference and the recovered timing reference; and

transmitting the combined signal from the transmission source.

16. The method of claim 15, wherein the identification code is a pseudo-noise (PN) sequence at a particular offset.

17. A method for generating a signal suitable for use to estimate the location of a device in a wireless communication system, comprising:

receiving at a transmission source a forward link signal having included therein at least a pilot signal;

generating at the transmission source a second signal having included therein an identification code assigned to the transmission source;

combining the forward link signal and the second signal to provide a combined signal; and

transmitting the combined signal from the transmission source;

wherein the identification code is a pseudo-noise (PN) sequence at a particular offset, and wherein the offset of the PN sequence used for the identification code is one of a plurality of possible offsets and is reserved for identification of the transmission source.

18. The method of claim 17, wherein the transmission source is a wireless repeater unit in the communication system.

19. The method of claim 18, further comprising:

conditioning the combined signals within the repeater unit, and

wherein the conditioned signal from the repeater unit is transmitted from the repeater.

20. The method of claim 18, further comprising:

conditioning the forward link signal within the repeater unit, and

wherein the second signal is combined with the conditioned forward link signal within the repeater unit.

21. The method of claim 17, wherein a carrier frequency of the second signal approximates a carrier frequency of the forward link signal.

22. A method for generating a signal suitable for use to estimate the location of a device in a wireless communication system, comprising;

receiving at a transmission source a forward link signal having included therein at least a pilot signal;

generating at the transmission source a second signal having included therein an identification code assigned to the transmission source;

combining the forward link signal and the second signal to provide a combined signal; and

transmitting the combined signal from the transmission source;

wherein the identification code is a pseudo-noise (PN) sequence at a particular offset, and wherein the timing of the PN sequence used for the identification code is approximately aligned with the timing of a PN sequence used to spread the pilot signal.

23. A method for generating a signal suitable for use to estimate the location of a device in a wireless communication system, comprising:

receiving at a transmission source a forward link signal having included therein at least a pilot signal;

generating at the transmission source a second signal having included therein an identification code assigned to the transmission source;

combining the forward link signal and the second signal to provide a combined signal wherein an amplitude of the second signal is set to a particular level below the amplitude of the forward link signal; and

transmitting the combined signal from the transmission source.

24. A method for generating a signal suitable for use to estimate the location of a terminal in a wireless communication system, comprising:

receiving and processing at a transmission source a forward link signal having included therein at least a pilot signal;

generating a second signal having included therein an identification code assigned to the transmission source;

wherein the second signal comprises a plurality of signals at different offsets and representative of a particular multipath profile;

transmitting the forward link signal from the transmission source; and

transmitting the second signal to a plurality of terminals within the communication system.

25. A method for generating a signal suitable for use to estimate the location of a terminal in a wireless communication system, comprising:

receiving and processing at a transmission source a forward link signal having included therein at least a pilot signal;

generating a second signal having included therein an identification code assigned to the transmission source wherein the second signal comprises a plurality of pseudo-noise (PN) sequences at a plurality of offsets and representative of a particular multipath profile;

transmitting the forward link signal from the transmission source; and

transmitting the second signal to a plurality of terminals within the communication system.

26. A transmission unit in a wireless communication system, comprising:

a first unit operative to receive, condition, and retransmit signals on both forward and reverse links of the communication system; and

a second unit coupled to the first unit and including

a first module operative to receive and process a forward link signal having included therein at least a pilot signal,

a second module operative to generate a second signal having included therein an identification code assigned to the transmission unit, and

a third module operative to combine the forward link signal and the second signal to provide a combined signal for transmission from the transmission unit;

wherein the first module is further operative to process the forward link signal to recover a frequency reference for a carrier signal of the forward link signal, and wherein the second signal is further generated in accordance with the recovered frequency reference.

27. A method for determining the location of a device in a wireless communication system, comprising:

receiving from a first transmission source a first signal having included therein transmitted data and a second signal having included therein a first identification code assigned to the first transmission source, wherein the first identification code is selected from among a list of identification codes used for nearby transmission sources, wherein the first identification code comprises a plurality of identification codes in the list, and wherein the plurality of identification codes for the first identification code are associated with different offsets;

processing the second signal to recover the first identification code; and

determining a position estimate of the device based on the recovered first identification code.

28. The method of claim 27, wherein a determination of whether the first identification code is received from the first transmission source or another transmission source is made based on geometric constraint.

29. The method of claim 28, wherein the geometric constraint relates to time difference of arrival (TDOA) measurement.

30. The method of claim 27, wherein only identification codes in the list that are not repeated by other transmission sources are available for use as the first identification code for the first transmission source.

31. The method of claim 27, wherein the nearby transmission sources are neighbor base stations, and the identification codes in the list are PN sequences assigned to the neighbor base stations.

32. A method for determining the location of a device in a wireless communication system, comprising:

receiving from a first transmission source a first signal having included therein transmitted data and a second signal having included therein a first identification code assigned to the first transmission source, wherein the first identification code is selected from among a list of identification codes used for nearby transmission sources;

wherein the identification code assigned to the first transmission source is delayed relative to the first signal by a particular amount of delay;

processing the second signal to recover the first identification code; and

determining a position estimate of the device based on the recovered first identification code.

33. The method of claim 32, wherein the amount of delay is selected to allow for determination of whether the first identification code is received from the first transmission source or another transmission source.