Modified finger assignment algorithm for high data rate calls

• US 6,711,420 B1
• Filed: 09/15/1999
• Issued: 03/23/2004
• Est. Priority Date: 09/15/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Glazko, Serguei A., Achour, Baaziz, Amerga, Messay
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Nguyen, Thuan T.
• Application Number:
  US09/398,905
• Time in Patent Office: 1,651 Days
• Field of Search: 455/562, 455/442, 455/450, 455/452, 455/513, 455/522, 455/550, 370/342, 370/351, 370/431, 370/437, 370/441
• US Class Current: 455/562.1
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity

Abstract

A method of creating a path list for use in finger assignments comprising clearing a list of paths (12), choosing a sector for consideration from an active set of sectors (14), establishing a searcher window around the sector for cosideration (16), and determining up to “n” local maxima stronger than a threshold value (18). If a sector under consideration is transmitting on supplemental channels(19), the method involves artificially biasing the findings of the searcher window by a predetermined value (20). The biasing value may be constant, variable or proportional to the number of supplemental channels on the base station. After the local maxima corresponding to base stations transmitting on supplemental channels have been biased (20), the path lists are created (21).

Claims

1. In a wireless communication system, a method of creating a path list for finger assignment comprising:

choosing a base station sector for consideration;

receiving a signal from said sector;

estimating a (Ec/Io) of the received signal;

if said sector is transmitting a supplemental channel, biasing the (Ec/Io) of the received signal by a predetermined value; and

adding said biased Ec/Io of the received signal to said path list.

2. The method of claim 1, further comprising clearing the list of paths before choosing a base station sector for consideration.

3. The method of claim 2, further comprising commanding a searcher window to search around said sector for consideration.

4. The method of claim 3, further comprising finding a predetermined number of local maxima from said sector stronger than a threshold value.

5. The method of claim 1, further comprising adding said Ec/Io of the received signal to said path list without bias if said sector is not transmitting on supplemental channels.

6. The method of claim 5, further comprising choosing the next sector in the active set after adding said biased or said unbiased Ec/Io of the received signal to the path list and if there are more sectors in the active set to be considered.

7. The method of claim 1, wherein biasing the received signal further comprises biasing with a constant.

8. The method of claim 1, wherein biasing the Ec/Io of the received signal comprises biasing with a variable.

9. The method of claim 1, wherein biasing the Ec/Io of the received signal comprises biasing using a value proportional to the number of supplemental channels transmitted by said sector.

10. In a wireless communication system, a method of creating a path list for finger assignment comprising:

choosing a base station sector for consideration;

receiving a signal from said sector;

estimating a Ec/Io of the received signal;

if said sector is transmitting a supplemental channel, biasing the Ec/Io of the received signal by a predetermined value and adding said biased Ec/Io of the received signal to said path list;

choosing a finger for consideration;

if the path list does not contain a path corresponding to said chosen finger, creating a path corresponding to said chosen finger and determining whether said chosen finger is demodulating a supplemental channel; and

if said chosen finger is demodulating a supplemental channel, biasing the Ec/Io of said equivalent path and adding the Ec/Io of said biased equivalent path to said path list.

11. The method of claim 10, further comprising if said chosen finger is not demodulating a supplemental channel, adding the Ec/Io of the equivalent path to the path list without bias;

and

if there are more fingers for consideration after adding said equivalent path to the path list with or without bias, choosing a next finger for consideration.

12. The method of claim 10, wherein said biasing the received signal and biasing said equivalent path are accomplished by using a constant value.

13. The method of claim 10, wherein said biasing the received signal and biasing said equivalent path are accomplished by using a variable value.

14. The method of claim 10, wherein said biasing the received signal and biasing said equivalent path are accomplished by using a value proportional to the number of supplemental channels being transmitted by said base station sector.

15. The method of claim 10, further comprising clearing a list of paths before choosing a base station sector for consideration;

establishing a searcher window around said base station sector for consideration; and

determining up to a predetermined number of local maxima stronger than a threshold value.

16. The method of claim 15, further comprising:

after biasing the Ec/Io of the received signal for sectors transmitting on supplemental channels, adding the predetermined number of local maxima to the path list and if there are more sectors in the active set to be considered, choosing a next sector for consideration from the active set.

17. The method of claim 16, further comprising:

if said chosen finger is not presently in lock, de-assigning said chosen finger from its associated path;

if said chosen finger is presently in lock, determining whether the path list contains a path corresponding to said chosen finger;

if the finger under consideration is not demodulating supplemental channels, adding the Ec/Io of the equivalent path to the path list without bias; and

if there are more fingers for consideration after adding the Ec/Io of said equivalent path or said biased equivalent path to said path list, choosing a next finger for consideration.

18. A method of assigning fingers to paths, comprising:

choosing a base station sector for consideration;

receiving a signal from said sector;

estimating a Ec/Io of the received signal;

if said sector is transmitting supplemental channels, biasing the Ec/Io of the received signal; and

adding said biased Ec/Io of the received signal to said path list;

choosing a finger for consideration;

if the path list does not contain a path corresponding to said chosen finger, creating a path corresponding to said chosen finger and determining whether said chosen finger is demodulating supplemental channels;

if said chosen finger is demodulating a supplemental channel, biasing said Ec/Io of the equivalent path and adding said biased Ec/Io of the equivalent path to said path list; and

executing a finger assignment algorithm to assign fingers to the paths in the path list wherein paths in the path list having supplemental channels are biased.

19. The method of claim 18, wherein said biasing the received signal and biasing said equivalent path are accomplished by using a constant value.

20. The method of claim 18, wherein said biasing the received signal and biasing said equivalent path are accomplished by using a variable value.

21. The method of claim 18, wherein said biasing the received signal and biasing said equivalent path are accomplished by using a value proportional to the number of supplemental channels being transmitted by said base station sector.

22. The method of claim 18 wherein executing said finger assignment algorithm comprises assigning fingers with a cell diversity priority and then assigning fingers with a path diversity priority.

23. The method of claim 18, further comprising:

clearing a list of paths before choosing a sector for consideration;

establishing a searcher window around said sector for consideration;

determining up to predetermined number of local maxima stronger than a threshold value;

adding said maxima to said path list;

if there are more sectors in the active set to be considered after adding said maxima to said path list, choosing a next sector for consideration;

if said chosen finger is not presently in lock, de-assigning said chosen finger from its path;

if said chosen finger is presently in lock, determining whether the path list contains a path associated with said chosen finger;

if said chosen finger is not demodulating supplemental channels, adding said equivalent path to the path list without bias; and

if there are more fingers for consideration, choosing a next finger for consideration.

24. A method of assigning fingers comprising:

determining a forward channel signal strength;

if said forward channel signal strength determination is less than a first threshold value, introducing bias into sectors transmitting supplemental channels and creating a path list using said biased sectors;

assigning fingers to the paths in the path list; and

if the sector forward channel signal strength is less than a second threshold value, then assigning a finger to said sector.

25. The method of claim 24, wherein determining a forward channel signal strength comprises determining the ratio between the pilot energy accumulated over on PN chip period to the total power spectral density in the received bandwidth.

26. A method of assigning fingers in a wireless communication system comprising:

creating a path list by;

choosing a set of forward channel signals that are stronger than a threshold value;

biasing the strength of the forward channel signals from sectors supporting supplemental channels by a predetermined value; and

assigning fingers to the paths in the path list so as to maximize the combined Ec/Io or Eb/Nt of the supplemental channels.

27. The method of claim 26, wherein biasing the strength of the forward channel comprises using a predetermined value based on how many iterations of the finger assignment method.

28. The method of claim 26, wherein biasing the strength of the forward channel comprises using a predetermined value which is proportional to the number of supplemental channels transmitted by that base station.

29. The method of claim 26, wherein biasing the strength of the forward channel comprises using a predetermined value which is a constant value for each iteration of the finger assignment algorithm.

30. The method of claim 26, wherein choosing a set of forward channel signals that are stronger threshold value comprises using a threshold that is the minimum threshold on the fundamental channel to ensure a minimum quality of communication.

31. The method of claim 26, wherein biasing the strength of the forward channel signal comprises biasing the received signal energy estimate of a base station.

32. The method of claim 26, further comprising choosing a finger assignment that will meet a minimum threshold value on the fundamental channel, and

if the minimum threshold value is met, choosing a finger assignment that maximizes a combined Ec/Io or Eb/Nt for the supplemental channels.

33. In a wireless communication system, a method of creating a path list for finger assignment comprising:

choosing a base station sector for consideration;

receiving a signal from said sector;

estimating a strength of the received signal;

if the sector is transmitting a supplemental channel, biasing the estimated strength of the received signal by a predetermined value; and

adding the biased estimated strength of the received signal to the path list.

34. In a wireless communication system, a method for finger assignment comprising:

receiving signals from base station sectors;

estimating a strength of each of the received signals;

if one of the signals is from a base station sector transmitting a supplemental channel, biasing the estimated strength of the received signal by a predetermined value and adding the biased estimated strength of the received signal to a path list;

if one of the signals is from a base station sector not transmitting a supplemental channel, adding the estimated strength of the received signal without bias to the path list;

choosing a finger for consideration; and

assigning the finger to one of signals in the path list based on the estimated strengths of the signals listed in the path list.