QoS scheduling methods for WLANs with heterogenous applications

• US 8,169,941 B2
• Filed: 12/04/2007
• Issued: 05/01/2012
• Est. Priority Date: 12/18/2006
• 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: Cavalcanti, Dave, Schmitt, Ruediger
• Primary Examiner(s): Lai, Andrew
• Assistant Examiner(s): NGO, NGUYEN HOANG
• Application Number:
  US12/519,767
• Publication Number:
  US 20100039973A1
• Time in Patent Office: 1,610 Days
• Field of Search: 370/310, 370/310.2, 370/311, 370/328, 370/230, 370/318
• US Class Current: 370/311
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A wireless system (100) includes at least one power-save wireless station (PS STA)(102). A method of wireless includes allocating deterministic time intervals (206,207) to the PS-STAs.

Claims

1. A wireless system, comprising:

a plurality of wireless stations (STA), wherein at least one of the STAs is a power save (PS) STA; and

another wireless STA adapted to control access to a medium of a wireless network, wherein the at least one PS STA is provided deterministic access to the medium before other STAs of the plurality of STAs;

wherein the another wireless STA is an access point (AP) and the wireless network is a centralized wireless network;

wherein the AP transmits a beacon to the STAs at the beginning of a superframe or a beacon interval;

wherein a power-save (PS) communication period succeeds a beacon transmission period (BT) and precedes other communication periods;

wherein a power save transmission opportunity (PS-TXOP) is granted to each of the at least one PS STAs at a respective deterministic start time and consecutive PS-TXOPs are granted to the same PS STA at deterministic start times in consecutive PS periods.

2. The wireless system as claimed in claim 1, wherein the deterministic access is provided by assigning a PS-TXOP to each of the at least one PS STA in the PS communication period.

3. The wireless system as claimed in claim 1, wherein the at least one PS STA is at least one of a medical telemetry device and a medical monitoring device.

4. The wireless system as claimed in claim 1, wherein each of the at least one PS STAs enters a sleep mode after it completes its access to the medium.

5. The wireless system as claimed in claim 1, wherein in response to a PS STA completing its access to the medium prior to termination of the PS-TXOP, the AP allocates a remaining portion of the PS-TXOP to a non-PS STA.

6. The wireless system as claimed in claim 1, wherein the PS communication period includes consecutive PS-TXOPs.

7. The wireless system as claimed in claim 6, wherein the consecutive PS-TXOPs satisfy

x_n+1start time>

x_nstart time+x_nTXOP duration

wherein x_n and x_n+1 are the consecutive PS-TXOPs.

8. The wireless system as claimed in claim 1, wherein the AP assigns service intervals for all of the PS STAs as a multiple of the beacon interval.

9. The wireless system as claimed in claim 1, wherein the AP generates a PS STA fixed scheduling list and a non-PS STAs list.

10. The wireless system as claimed in claim 9, wherein the PS STA fixed scheduling list includes at least the deterministic start time and PS-TXOP duration for each PS STA and the non-PS STA list includes at least the TXOP duration for each non-PS STA.

11. A method of wireless communication, the method comprising:

classifying at least one power save (PS) wireless station (STA) and at least one non-PS STA from a plurality of STAs;

transmitting a beacon to the plurality of STAs at the beginning of a superframe or a beacon interval from an access point (AP), wherein the AP is one of the plurality of STAs;

providing deterministic access to a medium of a wireless network in a PS communication period for the at least one PS STA before the at least one non-PS STA, wherein the PS communication period succeeds a beacon transmission (BT) period and precedes all other communication periods;

scheduling a power save transmission opportunity (PS-TXOP) to each of the at least one PS-STAs at a respective deterministic start time in the PS communication period after a termination of the BT period and before other transmission opportunities (TXOPs), wherein the consecutive PS-TXOPs are scheduled for the same PS STA at deterministic starts in the consecutive PS periods.

12. The method as claimed in claim 11, further including:

accessing the medium during an assigned PS-TXOP, wherein, after completing access to the medium, the PS STA enters a sleep mode.

13. The method as claimed in claim 11, further including:

accessing the medium during an assigned PS-TXOP, wherein, after completing access to the medium, but before an end of the PS-TXOP, allocating a remaining portion of the PS-TXOP to another STA.

14. The method as claimed in claim 13, wherein one STA is an access point (AP) and the another STA is a non-PS STA.

15. The method as claimed in claim 11, further including:

scheduling consecutive PS-TXOPs for a PS STA at deterministic start times.

16. The method as claimed in claim 15, wherein the consecutive PS-TXOPs are granted to the same PS STA at deterministic start times in consecutive PS communication periods.

17. The method as claimed in claim 11, further including:

accessing the medium from an access point (AP) or other STA within the PS-TXOP, and after completing access to the medium, receiving an acknowledgement (ACK) from the PS STA, the AP or other STA allocates a remaining portion of the PS-TXOP to another STA.

18. The method as claimed in claim 11, wherein the consecutive PS-TXOPs satisfy

x_n+1start time>

x_nstart time+x_nTXOP duration

wherein x_n and x_n+1 are the consecutive PS-TXOPs.

19. The method as claimed in claim 11, further including:

generating a PS STA fixed scheduling list and a non-PS STAs list.

20. The method as claimed in claim 19, wherein the PS STA fixed scheduling list includes at least the deterministic start time and PS-TXOP duration for each PS STA and the non-PS STA list includes at least the TXOP duration for each non-PS STA.