WLAN admission control for multimedia service

• US 20040240463A1
• Filed: 05/30/2003
• Published: 12/02/2004
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Ho, Jin-Meng, Shaver, Donald P.
• Granted Patent: US 7,403,531 B2
• Time in Patent Office: Days
• US Class Current: 370/437
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]

Abstract

The present invention provides a system for controlling isochronous data admission, within a WLAN system (102) that transports both isochronous and asynchronous data. The system includes an apparatus (300), functioning as an access point within a WLAN system. The apparatus comprises a memory (306) and a transceiver (312) communicatively coupled to the memory. The apparatus further comprises an access coordinator (302), communicatively coupled to the memory, and adapted to: evaluate actual access times of previous isochronous data streams, to determine projected access times needed by a new isochronous data stream, and to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times.

Claims

1. A method for controlling admission of a new isochronous data stream, within a WLAN system that transports both isochronous and asynchronous data, the method comprising the steps of:

evaluating actual access times of previously admitted isochronous data streams;

determining projected access times needed by the new isochronous data stream; and

deciding to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times.

2. The method of claim 1, wherein the WLAN system schedules successive isochronous data streams for transport during successive service periods.

3. The method of claim 2, wherein a service period comprises a primary access portion and an extended access portion.

4. The method of claim 3, wherein the step of evaluating actual access times of previously admitted isochronous data streams further comprises the steps of:

providing a first threshold number;

determining a first value equal to the length of an individual previous service period; and

calculating a second value equal to an average of actual total access times used for isochronous streams during each of the first threshold number of previous service periods.

5. The method of claim 4, wherein the step of determining projected access times needed by the new isochronous data stream further comprises the steps of:

calculating a third value equal to, if and when the new isochronous data stream is admitted, the length of a new service period; and

calculating a fourth value equal to, if and when the new isochronous data stream is admitted, a total primary access portion of the new service period.

6. The method of claim 5, wherein the step of deciding to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprises the steps of:

calculating a fifth value equal to the second value divided by the first value;

determining a sixth value equal to a total primary access portion of an individual previous service period;

calculating a seventh value equal to the sixth value divided by the first value; and

calculating an eighth value equal to the fourth value divided by the third value.

7. The method of claim 6, wherein the step of deciding to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprises the steps of:

providing a second threshold value; and

comparing the eighth value with the second threshold value.

8. The method of claim 7, wherein the step of deciding to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprises rejecting the new isochronous data stream upon determining that the eighth value is greater than the second threshold value.

9. The method of claim 7, wherein, upon determining that the eighth value is less than or equal to the second threshold value, the step of deciding to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprises the steps of:

providing a third threshold value;

calculating a ninth value equal to the sum of the fifth and eighth values, less the seventh value; and

comparing the ninth value with the third threshold value.

10. The method of claim 9, further comprising rejecting the new isochronous data stream upon determining that the ninth value is greater than the third threshold value.

11. The method of claim 9, further comprising admitting the new isochronous data stream for scheduling access upon determining that the ninth value is less than or equal to the third threshold value.

12. The method of claim 7, wherein the second threshold value is 0.75.

13. The method of claim 9, wherein the third threshold value is 0.9.

14. A system for controlling isochronous data admission, within a WLAN system that transports both isochronous and asynchronous data, the system comprising:

a processor; and

a computer readable medium communicatively coupled to the processor, comprising processor instructions adapted to cause the processor to;

evaluate actual access times of previously admitted isochronous data streams;

determine projected access times needed by a new isochronous data stream; and

decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times.

15. The system of claim 14, wherein the WLAN system schedules successive isochronous data streams for transport during successive service periods.

16. The system of claim 15, wherein a service period comprises a primary access portion and an extended access portion.

17. The system of claim 16, wherein the processor instructions adapted to cause the processor to evaluate actual access times of previously admitted isochronous data streams further comprise instructions adapted to cause the processor to:

provide a first threshold number;

determine a first value equal to the length of an individual previous service period; and

calculate a second value equal to an average of actual total access times used for isochronous streams during each of the first threshold number of previous service periods.

18. The system of claim 17, wherein the processor instructions adapted to cause the processor to determine projected access times needed by the new isochronous data stream further comprise instructions adapted to cause the processor to:

calculate a third value equal to, if and when the new isochronous data stream is admitted, the length of a new service period; and

calculate a fourth value equal to, if and when the new isochronous data stream is admitted, a total primary access portion of the new service period.

19. The system of claim 18, wherein the processor instructions adapted to cause the processor to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprise instructions adapted to cause the processor to:

calculate a fifth value equal to the second value divided by the first value;

determine a sixth value equal to a total primary access portion of an individual previous service period;

calculate a seventh value equal to the sixth value divided by the first value; and

calculate an eighth value equal to the fourth value divided by the third value.

20. The system of claim 19, wherein the processor instructions adapted to cause the processor to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprise instructions adapted to cause the processor to:

provide a second threshold value; and

compare the eighth value with the second threshold value.

21. The system of claim 20, wherein the processor instructions adapted to cause the processor to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprise instructions adapted to cause the processor to reject the new isochronous data stream upon determining that the eighth value is greater than the second threshold value.

22. The system of claim 20, wherein, upon determining that the eighth value is less than or equal to the second threshold value, the processor instructions adapted to cause the processor to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times further comprise instructions adapted to cause the processor to:

provide a third threshold value;

calculate a ninth value equal to the sum of the fifth and eighth values, less the seventh value; and

compare the ninth value with the third threshold value.

23. The system of claim 22, further comprising instructions adapted to cause the processor to reject the new isochronous data stream upon determining that the ninth value is greater than the third threshold value.

24. The system of claim 22, further comprising instructions adapted to cause the processor to admit the new isochronous data stream for scheduling access upon determining that the ninth value is less than or equal to the third threshold value.

25. The system of claim 20, wherein the second threshold value is 0.75.

26. The system of claim 22, wherein the third threshold value is 0.9.

27. The system of claim 20, wherein one or more steps are managed by an upper MAC layer associated with the processor.

28. The system of claim 22, wherein one or more steps are managed by an upper MAC layer associated with the processor.

29. The system of claim 27, wherein the processor is adapted to operate on time quantities with latencies on the order of milliseconds.

30. The system of claim 28, wherein the processor is adapted to operate on time quantities with latencies on the order of milliseconds.

31. An apparatus, functioning as an access point within a WLAN system that transports both isochronous and asynchronous data, the apparatus comprising:

a first memory;

a transceiver communicatively coupled to the first memory; and

an access coordinator communicatively coupled to the first memory and adapted to evaluate actual access times of previous isochronous data streams, to determine projected access times needed by a new isochronous data stream, and to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times.

32. The apparatus of claim 31, wherein the access coordinator further comprises a first processor coupled to the first memory and adapted to evaluate actual access times of previous isochronous data streams, to determine projected access times needed by a new isochronous data stream, and to decide to admit or reject the new isochronous data stream based on an evaluation of the actual and projected access times.

33. The apparatus of claim 32, wherein the access coordinator further comprises a second processor, coupled to the first memory and to a second memory, and adapted to schedule access time for a new isochronous data stream once the first processor decides to admit the new isochronous data stream.

34. The apparatus of claim 32, wherein the first processor is adapted to operate on time quantities with latencies on the order of milliseconds.

35. The apparatus of claim 33, wherein the second processor is adapted to operate on time quantities with latencies on the order of milliseconds.