AIR-TIME FAIR TRANSMISSION REGULATION WITHOUT EXPLICIT TRAFFIC SPECIFICATIONS FOR WIRELESS NETWORKS

• US 20090147765A1
• Filed: 11/16/2005
• Published: 06/11/2009
• Est. Priority Date: 11/22/2004
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Chen, Richard, Chen, Yingwei, Nandagopalan, Saishankar, Schmitt, Ruediger
• Granted Patent: US 9,215,621 B2
• Time in Patent Office: Days
• US Class Current: 370/345
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04W 28/14 using intermediate storage

Abstract

A system and method are provided for non-transmission specification fair air-time, NT-AirFair, allocation control by tracking the transmission time (308) consumed by each link to detect any increase and enforcing air -time allocation (309) based on the pattern of usage derived therefrom.

Claims

1. An apparatus (100) for non-TSPEC (traffic specification) air-time fair transmission control regulation, comprising:

a memory (102) comprising n queues (101.i) having corresponding pre-determined scheduling weights q_i,old=q_i,new,i=1,2, . . . , n;

a queue-level scheduler (103) to enqueue (304) a received packet and dequeue (305) for transmission an enqueued packet of at least one flow in a queue of said n queues (101.i) respectively according to a pre-determined queue allocation scheme (302) (303) and a weighted transmission scheduling scheme (305) using said weights q_i,new,i=1,2, . . . , n;

a time monitor module (104) to determine if there is an increase in a transmission time per byte T_i,tj (308) for each queue of said at least one flow enqueued therein and adjust the corresponding scheduling weights q_i,new,i=1,2, . . . , n according to a pre-determined weight adjustment scheme.

2. The apparatus (100) of claim 1, further comprising:

a priority-based MAC;

said queue-level scheduler (103) is contained in one of the components selected from the group consisting of a queuing module of an operating system kernel, a device driver, and a MAC; and

wherein, delay-sensitive traffic flows per flow category are enqueued (302) (304) in a separate queue (101.i) per flow by the queue-level scheduler (103).

3. The apparatus of claim 1, wherein the time monitor (104) computes T_ij (308) as a window-averaged transmission time per byte for a pre-determined window size t.

4. The apparatus of claim 1, wherein said allocation scheme comprises enqueuing each delay-sensitive flow in a separate queue (302) of said n queues (101.i).

5. The apparatus of claim 4, wherein the time monitor (104) computes T_ij (308) as a window-averaged transmission time per byte for a pre-determined window size t.

6. The apparatus of claim 1, wherein said allocation scheme comprises enqueuing all non-delay-sensitive flows in a single separate queue (303) of said n queues (101.i).

7. The apparatus of claim 6, wherein the time monitor computes T_ij (308) as a window-averaged transmission time per byte for a pre-determined window size t.

8. The apparatus of claim 1, wherein said allocation scheme comprises enqueuing each delay-sensitive flow and all non-delay-sensitive flows in a separate queue (302) of said n queues (101.i).

9. The apparatus of claim 8, wherein the time monitor computes T_ij (308) as a window-averaged transmission time per byte for a pre -determined window size t.

10. The apparatus of claim 9, wherein the weighted transmission scheduling scheme is selected from the group consisting of weighted round-robin and weighted fair queuing.

11. The apparatus of claim 10, wherein

T_ij (308)=transmission_time_consumed/packet_size, for j=1,2, . . . , and i=1, . . . , n;

and

the pre-determined weight adjustment scheme (310) is to obtain a sequence T_ij (308) For j=1, . . . k over the window t and, if this sequence increases, on a window-averaged basis by more than a pre-determined threshold to adjust the queue weight inversely proportionally to the increase.

12. The apparatus of claim 11, wherein the queue weight is adjusted (309) according to the formula:

q_i,new=q_i,old*(T_i,old/T_i,new).

13. The apparatus of claim 11, wherein the pre-determined weight adjustment scheme further comprises an adjustment to the retry limit for the flow I and determination of a minimum PHY rate under the adjusted retry limit (309).

14. The apparatus of claim 13, wherein the pre-determined weight adjustment scheme further comprises setting TXOP (309) to a pre -determined allowed airtime.

15. The apparatus of claim 13, wherein the adjustment is selected from the group consisting of lowering the retry limit (309) by a pre-determined lowering amount and setting the retry limit to 0.

16. The apparatus of claim 15, wherein the pre-determined weight adjustment scheme further comprises setting TXOP (309) to a pre-determined allowed airtime.

17. The apparatus of claim 16, wherein the apparatus (100) is selected from the group consisting of an IEEE 802.11 wireless local area network (LAN) integrated circuit (IC), a wireless personal area network (PAN) IC, a wireless video server, a wireless video receiver, a wireless media adapter, a media personal computer (PC), and a wireless video transmission module.

18. A communications network (200) for non-TSPEC (traffic specification) air-time fair transmission control regulation comprising a plurality of devices (201.i) each including an apparatus (100) according to claim 17.

19. A communications network (200) for non-TSPEC (traffic specification) air-time fair transmission control regulation comprising a plurality of devices (201.i) each including an apparatus (100) according to claim 16.

20. A method for non-TSPEC (traffic specification) air-time fair transmission control regulation, comprising the steps of:

providing n queues (101.i) each having a corresponding pre-determined scheduling weight q_i,old=q_i,new, i=1,2, . . . , n;

enqueuing (302) (303) (304) a received packet of at least one flow in a separate queue of said n queues according to a pre-determined queue allocation scheme;

dequeuing (304) for transmission an enqueued packet in accordance with a weighted transmission scheduling scheme using said weights q_i,new,i=1,2, . . . , n;

determining (310) if there is an increase in a transmission time per byte T_ij (308) for each queue; and

adjusting (309) the corresponding scheduling weights q_i,new,i=1,2, . . . , n according to a predetermined weight adjustment scheme.

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

providing a priority-based MAC; and

the enqueuing step further comprises enqueuing delay-sensitive traffic flows per flow category in a separate queue per flow (302) in one of the components selected from the group consisting of a queuing module of an operating system kernel, a device driver, and a MAC.

22. The method of claim 20, wherein the determining step further comprises the step of computing T_ij (308) as a window-averaged transmission time per byte for a pre-determined window size t.

23. The method of claim 20, wherein said queue allocation scheme comprises the step of allocating (302) each delay-sensitive flow to a separate queue of said n queues (101.i).

24. The method of claim 23, wherein the determining step further comprises the step of computing T_ij (308) as a window-averaged transmission time per byte for a pre-determined window size t.

25. The method of claim 20, wherein said queue allocation scheme comprises the step of allocating (303) all non-delay-sensitive flows to a single separate queue of said n queues (101.i).

26. The method of claim 25, wherein the determining step further comprises the step of computing T_ij (3-08) as a window-averaged transmission time per byte for a pre-determined window size t.

27. The method of claim 20, wherein said allocation scheme comprises the steps of:

allocating (302) each delay-sensitive flow to a separate queue of said n queues (101.i); and

allocating (303) all non-delay-sensitive flows to a separate queue of said n queues (101.i).

28. The method of claim 27, wherein the determining step further comprises the step of computing T_ij (308) as a window-averaged transmission time per byte for a pre-determined window size t.

29. The method of claim 28, wherein the weighted transmission scheduling scheme is selected from the group consisting of weighted round-robin and weighted fair queuing.

30. The method of claim 29, wherein

T_i,tj (308)=transmission_time_consumed/packet_size, for j=1,2, . . . , and i=1, . . . , n;

and

the pre-determined weight adjustment scheme comprises the steps of;

i. obtaining a sequence T_ij (308) for j=1, . . . , k over the window t; and

ii. determining (310) if the obtained sequence increases, on a window-averaged basis by more than a pre-determined threshold; and

iii. when the increase exceeds the threshold, adjusting (309) the queue weight inversely proportionally to the increase.

31. The apparatus of claim 30, wherein the step of adjusting (309) the queue weight uses the formula:

q_i,new=q_i,old*(T_i,old/T_i,new).

32. The method of claim 30, wherein the pre-determined weight adjustment scheme further comprises the steps of:

adjusting (309) the retry limit; and

determining (309) a minimum PHY rate under the adjusted retry limit.

33. The method of claim 32, wherein the pre-determined weight adjustment scheme further comprises the step of setting TXOP (309) to a pre-determined allowed airtime.

34. The method of claim 32, wherein the step of adjusting the retry limit (309) comprises selecting an adjustment from the group consisting of lowering the retry limit by a pre-determined lowering amount and setting the retry limit to 0.

35. The method of claim 34, wherein the pre-determined weight adjustment scheme further comprises the step of setting TXOP (309) to a pre -determined allowed airtime.