System and method for channel assignment with adaptive modulation in wireless communications

• US 7,145,880 B2
• Filed: 04/24/2002
• Issued: 12/05/2006
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: AT&T Mobility II LLC (AT&T, Inc.)
• Original Assignee: Cingular Wireless II LLC (AT&T, Inc.)
• Inventors: Saxena, Alok, Wahlstrom, Don, Russo, David
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Chou, Albert T.
• Application Number:
  US10/131,947
• Publication Number:
  US 20030202478A1
• Time in Patent Office: 1,686 Days
• Field of Search: 370/252, 370/465, 455/69, 455/452.1, 455/452.2, 375/261, 375/272, 725/111
• US Class Current: 370/252
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0017 where the mode-switching is based on Quality of Service requirement
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

Embodiments include a system and method for solving a wireless communications channel packing problem by using a cost-like accounting metric that includes channel packing efficiency as well as modulation efficiency, channel conditions and or noise thresholds. The cost-like accounting metric is used to adjust the rated effectiveness of using each available modulation scheme where modulation schemes in adjacent spectrum will produce differing degrees of packing efficiency. By selecting those available carrier wave modulation schemes based on channel conditions versus noise threshold and accounting for packing factor as well as modulation efficiency, some embodiments the invention achieve higher quality within the framework of creating the greatest overall channel efficiency by selecting the best modulation scheme for each part of the spectrum being used.

Claims

1. A method for allocating communications channels selected from a plurality of available communications channels and for selecting an associated modulation method from a plurality of candidate modulation methods for establishing wireless communications with a receiver, comprising:

selecting a plurality of candidate communications channels from the available communications channels;

measuring noise on each candidate communications channel in the plurality of candidate communications channels to provide a channel noise level for each candidate communications channel;

comparing the channel noise level associated with of each candidate communications channel with a noise threshold associated with each candidate signal modulation method of the plurality of available signal modulation methods to eliminate any unacceptable candidate signal modulation methods;

assigning a packing factor associated with each combination of each candidate channel with a candidate signal modulation method, the packing factor having a value influenced by conditions in at least one other channel;

assigning a modulation efficiency factor based at least in part on the amount of information that can be transmitted by a candidate modulation method;

deriving a cost factor at least in part by combining the packing factor and the modulation efficiency factor; and

selecting a least-cost channel from the plurality of candidate communications channels and selecting an associated least-cost modulation method from the plurality of candidate modulation methods based on the best cost factor from the plurality of candidate communications channels and the plurality of candidate signal modulation methods.

2. The method of claim 1, wherein the step of selecting a least-cost channel is performed in a radio base station.

3. The method of claim 1, wherein the step of measuring noise on each candidate communications channel is performed by the transmission of a pilot signal between a base station and a wireless telephone.

4. The method of claim 1, wherein the channel noise level is a Candidacy Factor.

5. The method of claim 1, wherein the step of deriving a cost factor is performed by multiplying the packing factor and the modulation efficiency factor.

6. The method of claim 1, wherein the available communications channels is comprised of at least four available communications channels.

7. The method of claim 1, wherein the plurality of available signal modulation methods includes three different signal modulation methods each having a different associated modulation efficiency factor.

8. The method of claim 1, wherein the step of assigning a packing factor, further comprises the packing factor having a value influenced by conditions in a cluster of channels.

9. The method of claim 1, wherein the step of selecting a least-cost channel from the plurality of candidate communications channels and selecting an associated least-cost modulation method from the plurality of candidate modulation methods further comprises deriving a cost factor by multiplying the packing factor and the modulation efficiency factor and selecting the candidate communications channel and associated modulation method with the numerically smallest cost factor of those considered.

10. A method for allocating communications channels selected from a plurality of available communications channels in combination with an associated signal modulation method for establishing wireless communications, comprising:

selecting a plurality of candidate communications channels from the available communications channels;

assigning a packing factor associated with each combination of each candidate channel in the plurality of candidate communications channels with the associated signal modulation method, the packing factor having a value influenced by one or more conditions in at least one other channel;

deriving a cost factor based at least in part on the packing factor; and

selecting a least-cost channel from the plurality of candidate communications channels, based on the cost factor from the plurality of candidate communications channels.

11. The method of claim 10, wherein the step of selecting a least-cost channel is performed in a radio base station.

12. The method of claim 10, wherein the step of deriving a cost factor is performed by multiplying the packing factor by a modulation type factor.

13. The method of claim 10, wherein the available communications channels is comprised of at least four available communications channels.

14. The method of claim 10, wherein the step of assigning a packing factor, further comprises the packing factor having a value influenced by conditions in a cluster of channels.

15. The method of claim 10, wherein the step of selecting a least-cost channel from the plurality of candidate communications channels and selecting an associated least-cost modulation method from the plurality of candidate modulation methods further comprises deriving a cost factor by multiplying the packing factor and by a modulation type factor and selecting the candidate communications channel and associated modulation method with the numerically smallest cost factor of those considered.

16. A system for allocating communications channels selected from a plurality of available communications channels and for selecting an associated modulation method from a plurality of candidate modulation methods for establishing wireless communications with a receiver, comprising:

means for selecting a plurality of candidate communications channels from the available communications channels;

means for measuring noise on each candidate communications channel in the plurality of candidate communications channels to provide a channel noise level for each candidate communications channel;

means for comparing the channel noise level associated with of each candidate communications channel with a noise threshold associated with each candidate signal modulation method of the plurality of available signal modulation methods to eliminate any unacceptable candidate signal modulation methods;

means for assigning a packing factor associated with each combination of each candidate channel with a candidate signal modulation method, the packing factor having a value influenced by conditions in at least one other channel;

means for assigning a modulation efficiency factor based at least in part on the amount of information that can be transmitted by a candidate modulation method;

means for deriving a cost factor at least in part by combining the packing factor and the modulation efficiency factor; and

means for selecting a least-cost channel from the plurality of candidate communications channels and selecting an associated least-cost modulation method from the plurality of candidate modulation methods, based on the best cost factor from the plurality of candidate communications channels and the plurality of candidate signal modulation methods.

17. The system of claim 16, wherein the means for selecting a least-cost channel is performed in a radio base station.

18. The system of claim 16, wherein the means for measuring noise on each candidate communications channel is performed by the transmission of a pilot signal between a base station and a wireless telephone.

19. The system of claim 16, wherein the channel noise level is a Candidacy Factor.

20. The system of claim 16, wherein the means for deriving a cost factor is performed by multiplying the packing factor and the modulation efficiency factor.

21. The system of claim 16, wherein the available communications channels is comprised of at least four available communications channels.

22. The system of claim 16, wherein the plurality of available signal modulation methods includes three different signal modulation methods each having a different associated modulation efficiency factor.

23. The system of claim 16, wherein the means for assigning a packing factor, further comprises the packing factor having a value influenced by conditions in a cluster of channels.

24. The system of claim 16, wherein the means for selecting a least-cost channel from the plurality of candidate communications channels and selecting an associated least-cost modulation method from the plurality of candidate modulation methods further comprises deriving a cost factor by multiplying the packing factor and the modulation efficiency factor and selecting the candidate communications channel and associated modulation method with the numerically smallest cost factor of those considered.

25. A system for allocating communications channels selected from a plurality of available communications channels and for selecting an associated modulation method from a plurality of candidate modulation methods for establishing wireless communications with a receiver, comprising:

a base station, further comprising;

base station selection circuitry which selects a plurality of candidate communications channels from the available communications channels;

base station noise measurement circuitry which provides a channel noise level for each candidate communications channel based on measured noise on each candidate communications channel in the plurality of candidate communications channels;

base station comparison circuitry which compares the channel noise level associated with of each candidate communications channel with a noise threshold associated with each candidate signal modulation method of the plurality of available signal modulation methods;

base station packing factor circuitry which assigns a packing factor associated with each combination of each candidate channel with a candidate signal modulation method, the packing factor having a value influenced by conditions in at least one other channel;

base station modulation efficiency circuitry which assigns a modulation efficiency factor based at least in part on an amount of information that can be transmitted by a candidate modulation method;

base station mathematical circuitry which derives a cost factor at least in part from the packing factor and the modulation efficiency factor; and

base station comparison circuitry which selects a least-cost channel from the plurality of candidate communications channels and selects an associated least-cost modulation method from the plurality of candidate modulation methods, based on the cost factor from the plurality of candidate communications channels and the plurality of candidate signal modulation methods.

26. The system of claim 25, wherein the channel noise level is a Candidacy Factor.

27. The system of claim 25, wherein the base station mathematical circuitry which derives a cost factor multiplies the packing factor by the modulation efficiency factor.

28. The system of claim 25, wherein the available communications channels is comprised of at least four available communications channels.

29. The system of claim 25, wherein the plurality of available signal modulation methods includes three different signal modulation methods each having a different associated modulation efficiency factor.

30. The system of claim 25, wherein the base station packing factor circuitry, further comprises the packing factor having a value influenced by conditions in a cluster of channels.

31. The system of claim 25, wherein the base station comparison circuitry derives a cost factor by multiplying the packing factor and the modulation efficiency factor and selected the candidate communications channel and associated modulation method with the numerically smallest cost factor of those considered.

32. A computer-readable medium whose contents cause a base station to allocate communications channels selected from a plurality of available communications channels in combination with an associated signal modulation method for establishing wireless communications, comprising:

selecting a plurality of candidate communications channels from the available communications channels;

assigning a first value associated with each combination of each candidate channel in the plurality of candidate communications channels with the associated signal modulation method, the first value having a magnitude influenced by one or more conditions in at least one other channel;

deriving a cost factor based at least in part on the packing factor; and

selecting a least-cost channel from the plurality of candidate communications channels, based on the cost factor from the plurality of candidate communications channels.