Point-controlled contention arbitration

• US 7,869,412 B2
• Filed: 05/16/2007
• Issued: 01/11/2011
• Est. Priority Date: 11/22/2000
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Meier, Robert C.
• Primary Examiner(s): Ahmed; Salman
• Assistant Examiner(s): LEE, ANDREW CHUNG CHEUNG
• Application Number:
  US11/749,408
• Publication Number:
  US 20070217385A1
• Time in Patent Office: 1,336 Days
• Field of Search: 370/338, 370/352, 370/331, 370/337, 370/348, 370/465, 370/468, 370/355
• US Class Current: 370/338
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames

Abstract

In an example embodiment, there is described herein a method for providing quality of service during a contention period. A tiered access protocol enables an Access Point to act as a channel arbitrator and gain control a channel during a contention period. The Access Point waits a specified amount of time before taking control of a channel for either transmitting an outbound frame or initiating Polled-Contention Free Bursts. In addition, a method for increasing the time span between Delivery Traffic Indication Message beacons by tracking when Wireless Stations are able to receive messages and instantly delivering messages to those Wireless Stations.

Claims

1. A method, comprising:

determining a predetermined interval corresponding to a service rate for providing quality of service;

waiting for the predetermined interval to expire;

reserving a channel for a predetermined time period during a contention period using high priority access; and

polling to initiate a point controlled contention free burst during the contention period while the channel is reserved, wherein the polling comprises sending an outbound unicast data frame with a priority token, the priority token instructing a receiving station to send an inbound frame with an equal priority or a greater priority than the priority token.

2. The method according to claim 1, the reserving a channel further comprising sensing the channel for a sensing time period by an arbitrator before reserving the channel, wherein the arbitrator senses the channel for a sensing time period before reserving the channel that is shorter than that required for all other stations.

3. The method according to claim 2, wherein the sensing time period is a point coordination interframe space.

4. The method according to claim 3, wherein the sensing time period is a short interframe space after receiving an inbound transmission.

5. The method according to claim 4, wherein the sensing time period is a short interframe space after a station to station transmission that originates within a basic service set.

6. The method according to claim 1, further comprising determining a channel load, wherein the polling to initiate a point controlled contention free burst is responsive to determining the channel load exceeds a predetermined threshold.

7. The method according to claim 1, further comprising:

receiving an inbound frame; and

re-starting the waiting for the predetermined interval to expire responsive to receiving the inbound frame.

8. The method according to claim 1, further comprising the steps of:

determining whether a channel load exceeds a predetermined level;

reserving the channel using high priority access responsive to determining the channel exceeds the predetermined level; and

,

polling to initiate a point controlled contention free burst responsive to determining the channel exceeds the predetermined level during the contention period.

9. The method according to claim 8, wherein the reserving a channel further comprising sensing that the channel is idle for one of the group consisting of a point coordination interframe space and a short interframe space.

10. The method according to claim 1, wherein an arbitrator gains control of the channel by sensing the channel is clear for a shorter time frame than all other stations within a basic service set.

11. The method according to claim 1, further comprising receiving at least one data frame in the point controlled contention free burst during the contention period while the channel is reserved responsive to the polling.

12. The method according to claim 1, wherein the predetermined time period is longer than a worst-case maximum fragment transmission time.

13. An apparatus, comprising:

an access point configured to wirelessly communicate with at least one station over a channel within a basic service set;

wherein the access point is configured to determine a predetermined interval corresponding to a service rate for providing quality of service to a wireless station;

wherein the access point is configured to wait for the predetermined interval to expire;

wherein the access point is responsive to the predetermined interval expiring to reserve the channel for a predetermined time period during a contention period using high priority access; and

wherein the access point is configure to poll the station to initiate a point controlled contention free burst during the contention period while the channel is reserved, where the access point is configured to send an outbound unicast data frame with a priority token, the priority token instructing a receiving station to send an inbound frame with an equal priority or a greater priority than the priority token.

14. The apparatus according to claim 13, further comprising:

the access point is configured to determine a channel load;

wherein the access point is configured to employ polling to initiate a point controlled contention free burst responsive to determining the channel load exceeds a predetermined threshold.

15. The apparatus according to claim 13 further comprising the access point is configured to receive at least one data frame in the point controlled contention free burst during the contention period while the channel is reserved responsive to the polling.

16. The apparatus according to claim 13, wherein the access point is configured to gain control of the channel by sensing the channel is clear for a shorter time frame than all other stations within the basic service set.

17. The apparatus according to claim 13, further comprising:

the access point is configured to wait for the channel to be clear a sensing time period before initiating polling;

wherein the sensing time period is a short interframe space after receiving an inbound transmission, the sensing time period is a short interframe space after a station to station transmission that originates within the basic service set, otherwise the sensing time period is a point coordination interframe space.

18. The apparatus according to claim 13, further comprising:

a poll timer coupled to the access point, the poll timer is set to the predetermined interval for the station;

wherein the access point is responsive to receiving an inbound frame from the station to reset the poll timer to the predetermined interval.