Method and system for selecting a best serving sector in a CDMA data communication system

• US 6,680,925 B2
• Filed: 10/16/2001
• Issued: 01/20/2004
• Est. Priority Date: 10/16/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sindhushayana, Nagabhushana, Attar, Rashid, Black, Peter J., Vijayan, Rajiv, Wu, Qiang
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): JAIN, RAJ K
• Application Number:
  US09/982,239
• Publication Number:
  US 20030072278A1
• Time in Patent Office: 826 Days
• Field of Search: 370/331, 370/332, 370/329, 370/333, 370/328, 370/431, 375/136, 375/147, 375/150, 375/349, 375/347
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point

Abstract

In a disclosed embodiment, signal levels of the active sectors of an access terminal are compared with the signal level of the current serving sector of the access terminal. Next, a delta credit is accumulated. If a DRC lock bit is available, then an accumulated total credit is authorized to produce an authorized accumulated total credit. Afterwards, a new serving sector is identified from a pool of candidate sectors based on the signal levels of the active sectors and the authorized accumulated total credits.

Claims

1. A method for selecting a best serving sector in a CDMA communication system, said method comprising steps of:

comparing a plurality of signal levels received from a plurality of active sectors with a signal level of a current serving sector to produce a difference;

generating a delta credit for each of said plurality of active sectors based on said difference;

accumulating a plurality of delta credits to produce an accumulated total credit;

identifying said best serving sector from said accumulated total credit.

2. The method of claim 1 wherein said plurality of signal levels received from said plurality of active sectors comprises a fixed rate signal level and a variable rate signal level.

3. The method of claim 2 further comprising a step of adjusting said fixed rate signal level to produce an adjusted fixed rate signal level prior to said comparing step.

4. The method of claim 3 further comprising a step of authorizing said plurality of delta credits prior to said identifying step.

5. The method of claim 4 further comprising steps of:

receiving a plurality of DRC lock bits;

adjusting said variable rate signal to produce an adjusted variable rate signal level.

6. The method of claim 5 further comprising steps of:

determining a sector having a highest variable rate mode from said plurality of active sectors;

determining a sector having a highest fixed rate mode from said plurality of active sectors.

7. The method of claim 6 further comprising a step of determining a preferred mode.

8. An apparatus for selecting a best serving sector in a CDMA communication system, said apparatus comprising:

means for comparing a plurality of signal levels received from a plurality of active sectors with a signal level of a current serving sector to produce a difference;

means for generating a delta credit for each of said plurality of active sectors based on said difference;

means for accumulating a plurality of delta credits to produce an accumulated total credit;

means for identifying said best serving sector from said accumulated total credit.

9. The apparatus of claim 8 wherein said plurality of signal levels received from said plurality of active sectors comprises a fixed rate signal level and a variable rate signal level.

10. The apparatus of claim 9 further comprising a means for of adjusting said fixed rate signal level to produce an adjusted fixed rate signal level.

11. The apparatus of claim 10 further comprising a means for authorizing said plurality of delta credits.

12. The apparatus of claim 11 further comprising:

means for receiving a plurality of DRC lock bits;

means for adjusting said variable rate signal to produce an adjusted variable rate signal level.

13. The apparatus of claim 12 further comprising:

means for determining a sector having a highest variable rate mode from said plurality of active sectors;

means for determining a sector having a highest fixed rate mode from said plurality of active sectors.

14. The apparatus of claim 13 further comprising a means for determining a preferred mode.

15. A method for selecting a best serving sector in a CDMA communication system, said method comprising steps of:

comparing a plurality of signal levels received from a plurality of active sectors with a signal level of a current serving sector to produce a difference, said plurality of signal levels comprising a fixed rate signal level and a variable rate signal level;

generating a delta credit for each of said plurality of active sectors based on said difference;

accumulating a plurality of said delta credits to produce an accumulated total credit;

authorizing said accumulated total credit to produce a final credit total;

identifying said best serving sector from said final credit total.

16. The method of claim 15 further comprising a step of adjusting said fixed rate signal level to produce an adjusted fixed rate signal level prior to said comparing step.

17. The method of claim 16 further comprising steps of:

receiving a plurality of DRC lock bits;

adjusting said variable rate signal to produce an adjusted variable rate signal level.

18. The method of claim 17 further comprising steps of:

determining a sector having a highest variable rate mode from said plurality of active sectors;

determining a sector having a highest fixed rate mode from said plurality of active sectors.

19. The method of claim 16 further comprising a step of determining a preferred mode.

20. A method for selecting a best serving sector in a CDMA communication system, said method comprising steps of:

determining a plurality of signal levels received from a plurality of active sectors, said plurality of signal levels comprising a fixed rate signal level and a variable rate signal level;

adjusting said fixed rate signal level to produce an adjusted fixed rate signal level;

comparing said plurality of signal levels received from said plurality of active sectors with a signal level of a current serving sector to produce a difference;

generating a delta credit for each of said plurality of active sectors based on said difference;

accumulating a plurality of said delta credits to produce an accumulated total credit;

receiving a plurality of DRC lock bits for said plurality of active sectors;

authorizing said accumulated total credit to produce a final credit total based on said plurality of DRC lock bits;

identifying said best serving sector from said final credit total.

21. The method of claim 20 further comprising steps of:

determining a sector having a highest variable rate mode from said plurality of active sectors;

determining a sector having a highest fixed rate mode from said plurality of active sectors.

22. The method of claim 21 further comprising a step of determining a preferred mode.

23. A computer readable medium including a computer program, said computer program for implementing a method for selecting a best serving sector in a CDMA communication system, said computer program comprising:

a first code segment for comparing a plurality of signal levels received from a plurality of active sectors with a signal level of a current serving sector to produce a difference;

a second code segment for generating a delta credit for each of said plurality of active sectors based on said difference;

a third code segment for accumulating a plurality of delta credits to produce an accumulated total credit;

a fourth code segment for identifying said best serving sector from said accumulated total credit.

24. The computer readable medium of claim 23 wherein said plurality of signal levels received from said plurality of active sectors comprises a fixed rate signal level and a variable rate signal level.

25. The computer readable medium of claim 24 further comprising a fifth code segment for adjusting said fixed rate signal level to produce an adjusted fixed rate signal level prior to said comparing said plurality of signal levels received from said plurality of active sectors with said signal level of said current serving sector to produce said difference.

26. The computer readable medium of claim 25 further comprising a sixth code segment for authorizing said plurality of delta credits prior to said identifying said best serving sector from said accumulated total credit.