Method and apparatus for providing orthogonal spot beams, sectors, and picocells

• US 6,285,655 B1
• Filed: 09/08/1997
• Issued: 09/04/2001
• Est. Priority Date: 09/08/1997
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tiedemann, Edward G. Jr., Lundby, Stein A., Odenwalder, Joseph P.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US08/925,521
• Time in Patent Office: 1,457 Days
• Field of Search: 375/200, 375/206, 375/207, 375/208, 375/209, 375/210, 375/130, 375/133, 375/134, 375/137, 375/135, 375/136, 375/140, 375/142, 375/144, 375/145, 375/146, 375/147, 375/150, 375/149, 370/335, 370/331, 370/342, 370/206, 370/207, 370/208, 370/209, 455/436
• US Class Current: 370/209
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/107 by concatenation
• CPC Class Codes: H04W 16/00 Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information

Abstract

A method and apparatus for providing orthogonal spot beams, sectors, and picocells. The transmissions can be made orthogonally by using orthogonal auxiliary pilots and different Walsh traffic channels in adjacent areas. In accordance with the IS-95 standard, the pilot signal is covered with the 64-chip Walsh sequence zero. The 64-chip all zeros Walsh sequence can be designated as P and the 64-chip all one sequence can be designated as M. In the present invention, additional pilot signals can be provided by concatenating 64-chip all zeros P and all ones M sequences. Thus, for two pilot signals, pilot Walsh sequences of PP and PM can be used. For four pilot signals, pilot Walsh sequences of PPPP, PMPM, PPMM, and PMMP can be used. The present invention can be extended such that any required number of pilot Walsh sequences can be generated by substituting each bit in an K-bit Walsh sequence with the 64-chip all zeros P or all ones M sequence depending on the value of that bit.

Claims

1. A method for providing an auxiliary pilot comprising the steps of:

receiving pilot data; and

covering said pilot data with a pilot Walsh sequence, said pilot Walsh sequence comprising a concatenated sequence of a basic Walsh sequence and a complementary sequence of said basic Walsh sequence.

2. The method of claim 1 wherein said basic Walsh sequence comprises an all zeros sequence.

3. The method of claim 1 wherein said basic Walsh sequence is 64 chips in length.

4. The method of claim 1 wherein said pilot Walsh sequence is 128 chips in length.

5. The method of claim 1 wherein said pilot Walsh sequence is 256 chips in length.

6. The method of claim 1 wherein said pilot Walsh sequence is 64 times K chips in length, where K is a number of pilot Walsh sequences available.

7. The method of claim 1 wherein said pilot Walsh sequence comprises a K-bit sequence of a Walsh code mapping and wherein each bit of said K-bit sequence is substituted with a basic Walsh sequence or a complementary sequence depending on a value of said bit.

8. The method of claim 7 wherein said complementary sequence is derived by inverting each bit within said basic Walsh sequence.

9. The method of claim 7 wherein said complementary sequence is a second basic Walsh sequence.

10. The method of claim 1 wherein a gain of said auxiliary pilot is adjusted based on a gain of a particularized transmission wherein said auxiliary pilot is transmitted.

11. The method of claim 1 wherein a length of said pilot Walsh sequence is minimal based on a number of required pilot channel.

12. The method of claim 1 wherein one auxiliary pilot is provided for each particularized transmission.

13. The method of claim 1 wherein said pilot data for all auxiliary pilots is identical.

14. The method of claim 1 wherein said pilot data for all auxiliary pilots comprises an all ones sequence.

15. The method of claim 1 wherein said pilot data for all auxiliary pilots comprises an all zeros sequence.

16. A method for receiving an auxiliary pilot comprising the steps of:

receiving a pilot signal and providing pilot data;

accumulating said pilot data over a length of a basic Walsh sequence to provide I and Q pilot values;

accumulating I and Q pilot values for a current interval and previous intervals in accordance with a pilot hypothesis to provide a decovered pilot.

17. The method of claim 16 wherein said length of said basic Walsh sequence is 64 chips.

18. The method of claim 16 wherein said decovered pilot is compared against a set of predetermined threshold.

19. The method of claim 16 wherein a particularized transmission corresponding to said decovered pilot is added to a candidate set if said decovered pilot exceeds an add threshold.

20. The method of claim 16 wherein a particularized transmission corresponding to said decovered pilot is removed from a candidate set if said decovered pilot is below a drop threshold.

21. The method of claim 16 wherein a particularized transmission corresponding to said decovered pilot is added to an active set if said decovered pilot exceeds an add threshold.

22. The method of claim 16 wherein a particularized transmission corresponding to said decovered pilot is removed from an active set if said decovered pilot is below a drop threshold.

23. An apparatus for receiving an auxiliary pilot comprising:

a receiver for receiving a pilot signal and providing pilot data; and

a pilot correlator for receiving said pilot data and providing a decovered pilot, said pilot correlator further comprising;

a first accumulator for accumulating said pilot data over a length of a basic Walsh sequence to provide I and Q pilot values;

second accumulator for accumulating said I and Q pilot values for a current interval and previous intervals in accordance with a pilot hypothesis to provide said decovered pilot.

24. A method for providing orthogonal particularized transmissions comprising the steps of:

covering traffic channels of each particularized transmission with different Walsh sequences; and

covering pilot signals of each particularized transmission with different pilot Walsh sequences.

25. The method of claim 24 wherein said pilot Walsh sequences are derived from a basic Walsh sequence.

26. The method of claim 25 wherein said basic Walsh sequence is Walsh sequence zero.

27. A method for providing improved performance in a particularized transmission comprising the steps of:

covering traffic channels of said particularized transmission with Walsh sequences orthogonal to those of surrounding transmissions; and

covering pilot signal of said particularized transmission with a pilot Walsh sequence orthogonal to those of surrounding transmissions.

28. The method of claim 27 wherein said pilot Walsh sequence is derived from a basic Walsh sequence.

29. The method of claim 28 wherein said basic Walsh sequence is Walsh sequence zero.