Temporary priority promotion for network communications in which access to a shared medium depends on a priority level

• US 20050169296A1
• Filed: 02/03/2004
• Published: 08/04/2005
• Est. Priority Date: 02/03/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Yonge, Lawrence W. III, Katar, Srinivas
• Granted Patent: US 7,660,327 B2
• Time in Patent Office: Days
• US Class Current: 370/445
• CPC Class Codes: H04L 12/40156 by using dedicated slots associated with a priority level
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• CPC Class Codes: H04W 74/0875 with assigned priorities based access

Abstract

A method of operating in a network in which a plurality of stations communicate over a shared medium (e.g., using a carrier sense multiple access (CSMA) service). The stations contend for access to the shared medium using a contention procedure that relies on a priority level, wherein transmissions with a lower priority level have a reduced chance of gaining access to the shared medium during a contention process. Selected stations are given the capability of temporarily promoting the priority level of transmissions they are attempting to make. The priority level is increased during an interval to reduce the chance that other stations gain access to the shared medium during that interval, and the priority level is restored to its normal level following the interval.

Claims

1. A method of operating in a network in which a plurality of stations communicate over a shared medium, the method comprising

having the stations contend for access to the shared medium using a contention procedure that relies on a priority level, wherein transmissions with a lower priority level have a reduced chance of gaining access to the shared medium during a contention process;

giving selected stations the capability of temporarily promoting the priority level of transmissions they are attempting to make, wherein the priority level is increased during an interval to reduce the chance that other stations gain access to the shared medium during that interval, and the priority level is restored to its normal level following the interval.

2. The method of claim 1 wherein the promoted priority level is used to interrupt burst traffic.

3. The method of claim 2 wherein the priority level is restored to the normal level for contention following the interrupted burst.

4. The method of claim 1 wherein the promoted priority level is used not to interrupt burst traffic but to reduce the chance that some stations gain access to the shared medium.

5. The method of claim 1 wherein priority may be promoted by a station under predefined circumstances.

6. The method of claim 5 wherein the predefined circumstances include detection that another station is using a robust transmission protocol of a type indicative of a low transmission rate.

7. The method of claim 5 wherein the predefined circumstance include that another station is sending a burst transmission.

8. The method of claim 7 wherein the predefined circumstances include that the burst transmission has continued uninterrupted for more than a defined number of frames.

9. The method of claim 1 wherein the selected stations use the same communication protocol as the other stations.

10. The method of claim 1 wherein the selected stations employ a QoS guarantee protocol and the other stations are legacy stations lacking a QoS guarantee protocol.

11. The method of claim 2 wherein the station transmitting the burst follows a protocol that requires the station to interrupt a burst transmission if a higher priority level is asserted in priority resolution slots between frames, and the selected stations are capable of increasing the priority that they assert in the priority resolution slots to interrupt the burst transmission.

12. The method of claim 1 wherein the selected station asserting a temporarily promoted priority has data to transmit.

13. The method of claim 1 wherein the selected station asserting a temporarily promoted priority does not have data to transmit.

14. The method of claim 4 or 13 wherein the selected station asserts the promoted priority in order to assist other stations by increasing the likelihood that stations will see the promoted priority and refrain from transmission.

15. The method of claim 14 wherein the selected station employs a QoS guarantee protocol that transmits QoS traffic during regularly repeated contention free intervals, and by asserting the promoted priority the station increases the likelihood that other stations do not attempt to transmit during the regularly repeated contention free intervals.

19. The method of claim 1 or 16 wherein the shared medium over which the stations communicate uses a carrier sense multiple access (CSMA) service.

20. The method of claim 1 or 16 wherein the shared medium is a power line within a building.

16. A method of operating in a network in which a plurality of stations communicate over a shared medium, the plurality of stations comprising

at least one legacy station that uses a legacy contention protocol not suited for quality of service guarantees, and

a second plurality of stations that use a second contention protocol different from the legacy contention protocol and suited for providing a quality of service guarantee,

the method comprising

having the legacy station transmit a burst of frames without halting for contention between frames, by asserting a contention-free signal in a frame delimiter and by asserting a priority level in priority resolution slots between frames, wherein the burst is only halted if another legacy station asserts a higher priority level in the priority resolution slots;

having at least one of the second plurality of stations asserts a promoted priority level during the priority resolution slots to interrupt the burst transmission of the legacy station and a normal priority during contention following interruption of the burst transmission.

17. The method of claim 16 wherein there are two priority resolution slots, and a total of four priority levels can be asserted using the two slots.

18. The method of claim 16 wherein the use of a promoted priority level occurs after the burst transmission has spanned more than a defined number of frames.