USING A SINGLE FHT TO DECODE ACCESS-BASED HANDOFF PROBES FROM MULTIPLE USERS

• US 20080181096A1
• Filed: 01/29/2008
• Published: 07/31/2008
• Est. Priority Date: 01/30/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gorokhov, Alexei, Bhushan, Naga, Khandekar, Aamod
• Granted Patent: US 8,023,398 B2
• Time in Patent Office: Days
• US Class Current: 370/209
• CPC Class Codes: H04B 2001/70935 using a bank of matched fileters, e.g. Fast Hadamard Transform
• CPC Class Codes: H04B 2201/70707 Efficiency-related aspects
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

Aspects describe a Fast Hadamard Transform that is common to multiple mobile devices. A scrambled sequence produced by the Fast Hadamard Transform can be utilized to decode access-based handoff probes from multiple terminals within a wireless communications system. A Walsh Sequence can be scrambled with a common random sequence to produce a scrambled sequence. At least a portion of the scrambled sequence is included in an access probe.

Claims

1. A method for using a single Fast Hadamard Transform for access-based handoff probes, comprising:

receiving an access probe from a mobile device, the access probe includes a Walsh Sequence; and

demodulating the Walsh Sequence with a Fast Hadamard Transform that comprises a random sequence that is common to at least a subset of a plurality of mobile devices.

2. The method of claim 1, further comprising:

selectively granting the mobile device access to the sector based on the demodulation utilizing the random sequence.

3. The method of claim 1, further comprising:

receiving access probes from two or more of the plurality of mobile devices; and

demodulating the Walsh Sequence included in the access probes with the Fast Hadamard Transform that comprises the random sequence.

4. The method of claim 1, wherein selectively granting the mobile device access to the sector based on the demodulation comprises transmitting an Access Grant over a Shared Signaling MAC Protocol.

5. The method of claim 1, wherein the Walsh Sequence comprises 1,024 modulation symbols.

6. A wireless communications apparatus, comprising:

a processor that receives from a mobile device a Walsh Sequence included in an access probe and demodulates the Walsh Sequence with a Fast Hadamard Transform that comprises a random sequence; and

a memory that stores information related to the analysis performed by the processor, wherein the random sequence is common to at least a subset of a plurality of mobile devices.

7. The apparatus of claim 6, the processor further selectively grants the mobile device access based on the demodulation utilizing the random sequence.

8. The apparatus of claim 6, the processor further receives access probes from two or more of the plurality of mobile devices and demodulates the Walsh Sequence included in the access probes with the Fast Hadamard Transform that comprises the random sequence.

9. The apparatus of claim 6, wherein the processor further transmits an Access Grant over a Shared Signaling MAC Protocol to grant the mobile device access.

10. The apparatus of claim 6, wherein the Walsh Sequence comprises 1,024 modulation symbols.

11. A wireless communications apparatus that utilizes a single Fast Hadamard Transform for access-based handoff probes, comprising:

means for receiving an access probe from a mobile device, the access probe includes a Walsh Sequence; and

means for demodulating the Walsh Sequence with a Fast Hadamard Transform that comprises a random sequence that is common to at least a subset of a plurality of mobile devices.

12. The wireless communications apparatus of claim 11, further comprising:

means for selectively granting the mobile device access to the sector based on the demodulation utilizing the random sequence.

13. The wireless communications apparatus of claim 11, further comprising:

means for receiving access probes from two or more of the plurality of mobile devices within the sector; and

means for demodulating the Walsh Sequence included in the access probes with the Fast Hadamard Transform that comprises the random sequence.

14. The wireless communications apparatus of claim 11, wherein the means for selectively granting the mobile device access to the sector based on the demodulation comprises means for transmitting an Access Grant over a Shared Signaling MAC Protocol.

15. The wireless communications apparatus of claim 11, wherein the Walsh Sequence comprises 1,024 modulation symbols.

16. In a wireless communication system, an apparatus comprising:

a processor configured to;

receive an access probe from a mobile device, the access probe includes a Walsh Sequence; and

demodulate the Walsh Sequence with a Fast Hadamard Transform that comprises a random sequence that is common to at least a subset of a plurality of mobile devices.

17. The wireless communication system of claim 16, the processor further configured to:

receive access probes from two or more of the plurality of mobile devices; and

demodulate the Walsh Sequence included in the access probes with the Fast Hadamard Transform that comprises the random sequence.

18. A machine-readable medium having stored thereon machine-executable instructions for demodulating access probes, comprising:

receiving an access probe from a mobile device, the access probe includes a Walsh Sequence;

demodulating the Walsh Sequence with a Fast Hadamard Transform that comprises a random sequence that is common to at least a subset of a plurality of mobile devices.

19. A method for using a single Fast Hadamard Transform for access-based handoff probes, comprising:

scrambling a Walsh Sequence with a random sequence to produce a scrambled sequence; and

transmitting the scrambled sequence as an access-based handoff probe, wherein the random sequence is common to a first subset of devices.

20. The method of claim 19, further comprising:

receiving an Access Grant over a Shared Signaling MAC Protocol in response to the transmitted access-based handoff probe.

21. The method of claim 19, wherein at least one of the sub-sequence of the scrambled sequence is utilized to transmit the access-based handoff probe.

22. The method of claim 19, wherein the set of Walsh sequences comprises 1,024 modulation symbols.

23. A wireless communications apparatus, comprising:

a processor that scrambles a Walsh Sequence with a random sequence to produce a scrambled sequence and sends the scrambled sequence as an access-based handoff probe; and

a memory that stores information related to the analysis made by the processor.

24. The wireless communications apparatus of claim 23, the processor further receives an Access Grant over a Shared Signaling MAC Protocol in response to the access-based handoff probe.

25. The wireless communications apparatus of claim 23, wherein at least one sub-sequences of the scrambled sequence is included in the access-based handoff probe.

26. The wireless communications apparatus of claim 23, wherein the set of Walsh sequences comprises 1,024 modulation symbols.

27. A wireless communications apparatus that uses a single Fast Hadamard Transform for access-based handoff probes, comprising:

means for scrambling a Walsh Sequence with a random sequence to produce a scrambled sequence; and

means for transmitting the scrambled sequence as an access-based handoff probe, wherein the random sequence is common to a first subset of devices.

28. The wireless communications apparatus of claim 27, further comprising means for receiving an Access Grant over a Shared Signaling MAC Protocol in response to the transmitted access-based handoff probe.

29. The wireless communications apparatus of claim 27, wherein at least one sub-sequence of the scrambled sequence is used to transmit the access-based handoff probe.

30. The wireless communications apparatus of claim 27, wherein the set of Walsh sequences comprises 1,024 modulation symbols.

31. In a wireless communication system, an apparatus comprising:

a processor configured to;

scramble a Walsh Sequence with a random sequence to produce a scrambled sequence; and

transmit the scrambled sequence as an access-based handoff probe;

wherein the random sequence is common to a first subset of devices.

32. A machine-readable medium having stored thereon machine-executable instructions for using a single Fast Hadamard Transform for access-based handoff probes, comprising:

scrambling a Walsh Sequence with a random sequence to produce a scrambled sequence; and

transmitting the scrambled sequence as an access-based handoff probe;

wherein the random sequence is common to a first subset of devices.