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

• US 20030008663A1
• Filed: 07/12/2001
• Published: 01/09/2003
• Est. Priority Date: 04/24/2001
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Stein, Jeremy M., Weissman, Haim
• Application Number:
  US09/904,330
• Publication Number:
  US 20030008663A1
• Time in Patent Office: Days
• 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 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.

2. The method of claim 1, wherein the transmission source is a repeater in the wireless communication system.

3. The method of claim 1, wherein the second signal is a spread spectrum signal.

4. The method of claim 3, wherein the spread spectrum signal conforms to a CDMA standard.

5. The method of claim 4, wherein the spread spectrum signal conforms to IS-95 CDMA standard.

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

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

8. The method of claim 7, wherein the plurality of PN sequences are at particular offsets.

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

10. The method of claim 1, wherein the identification code comprises a plurality of delayed and attenuated versions of the first signal and representative of a particular multipath profile.

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

12. The method of claim 1, 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.

13. The method of claim 1, wherein the identification code comprises one or more Gold code sequences.

14. The method of claim 13, wherein each Gold code sequence is at a particular offset.

15. The method of claim 1, further comprising:

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

16. The method of claim 1, wherein the position estimate of the device is a particular location within a coverage area of the transmission source.

17. The method of claim 16, wherein the position estimate of the device is approximately the center of the coverage area of the transmission source.

18. The method of claim 1, wherein the wireless communication system is a CDMA system.

19. The method of claim 1, wherein the wireless communication system is a TDMA system.

20. The method of claim 2, wherein the second signal is a spread spectrum signal.

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

22. The method of claim 2, wherein the position estimate of the device is a particular location within a coverage area of the repeater.

24. The method of claim 23, further comprising:

processing the first signal to recover a timing reference, and

wherein the second signal is generated in accordance with the recovered timing reference.

25. The method of claim 24, further comprising:

processing the first signal to recover a frequency reference for a carrier signal of the first signal, and

wherein the second signal is further generated in accordance with the recovered frequency reference.

26. The method of claim 23, wherein the transmission source is a repeater in the communication system.

27. The method of claim 26, further comprising:

conditioning the combined signals within a repeater unit, and

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

28. The method of claim 26, further comprising:

conditioning the first signal within a repeater unit, and

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

29. The method of claim 23, wherein the identification code is a pseudo-noise (PN) sequence at a particular offset.

30. The method of claim 29, 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.

31. The method of claim 29, 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 transmitted data in the first signal.

32. The method of claim 23, wherein a carrier frequency of the second signal approximates a carrier frequency of the first signal.

33. The method of claim 23, wherein the second signal is a spread spectrum signal.

34. The method of claim 23, wherein an amplitude of the second signal is set to a particular level below the amplitude of the first signal.

35. The method of claim 23, wherein the wireless communication system is a CDMA system.

37. The method of claim 36, wherein the second signal comprises a plurality of signals at different offsets and representative of a particular multipath profile.

38. The method of claim 36, wherein the second signal comprises a plurality of pseudo-noise (PN) sequences at a plurality of offsets and representative of a particular multipath profile.

40. The method of claim 39, wherein a list of identification codes is included in a neighbor list of codes to be searched.

41. The method of claim 39, wherein a list of identification codes is sent to the terminal in response to a call related to position location.

42. The method of claim 39, wherein a list of identification codes is broadcast to the terminal via a broadcast channel.

43. The method of claim 39, wherein a list of identification codes is sent to the terminal upon request by the terminal.

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 first signal having included therein transmitted data;

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

combining the first and second signals to provide a combined signal; and

transmitting the combined signal from the transmission source.

36. 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 first signal having included therein transmitted data;

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

transmitting the first signal from the transmission source; and

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

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

receiving at the terminal an indication for a particular identification code assigned to a transmission source;

receiving from the transmission source a first signal having included therein transmitted data and a second signal having included therein the identification code; and

processing the second signal to recover the identification code, and

wherein the recovered identification code is used to identify the transmission source, and wherein the location of the terminal is estimated based on a position estimate associated with the identification code.

44. 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 first signal on the forward link having included therein transmitted data,

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 first and second signals to provide a combined signal for transmission from the transmission unit.

45. The transmission unit of claim 44, wherein the first module is further operative to process the first signal to recover a timing reference, and wherein the second signal is generated in accordance with the recovered timing reference.

46. The transmission unit of claim 45, wherein the first module is further operative to process the first signal to recover a frequency reference for a carrier signal of the first signal, and wherein the second signal is further generated in accordance with the recovered frequency reference.