Segment bursting with priority pre-emption and reduced latency

• US 6,909,723 B1
• Filed: 08/04/2000
• Issued: 06/21/2005
• Est. Priority Date: 08/04/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Intellon Corporation (Qualcomm, Inc.)
• Inventors: Yonge, Lawrence W. III, Earnshaw, William E., Patella, James Philip, Markwalter, Brian E., Kostoff, Stanley J. II
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Hyun, Soon D.
• Application Number:
  US09/632,597
• Time in Patent Office: 1,782 Days
• Field of Search: 370/444, 370/447, 370/455, 370/462, 370/474, 370/464, 370/465, 370/468, 370/470, 370/471, 370/443, 370/458, 370/322, 370/346, 370/347, 370/348, 370/445, 370/449, 370/461
• US Class Current: 370/447
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/245 using preemption

Abstract

A scheme for bounding latency of transmissions for QoS in network stations operating in shared medium access network. The length of segment burst transmissions are limited by allowing the segment burst transmission of a given priority to be interrupted by higher priority traffic. Restrictions are placed on frame length for transmissions of all priority levels or, alternatively, at all but the highest of the priority levels.

Claims

1. A method of bounding latency of transmissions by stations on a shared access medium comprising:

associating one of multiple priority levels with a transmission; and

controlling the amount of time the transmission occupies the shared access medium based on the associated priority level,

wherein the transmission is a burst transmission of frames and wherein controlling comprises;

providing the burst transmission with control of the medium at the associated priority level, and

wherein providing comprises;

providing in all but the last of the frames in the burst transmission a contention control indicator for indicating contention-free access and providing in all of the frames in the burst transmission the associated priority level so that the burst transmission may be interrupted by another of the stations having a pending frame with a higher priority level than the associated priority level.

2. The method of claim 1, further comprising:

relinquishing control of the shared access medium when such pending frame is detected between transmissions of the frames in the burst transmission.

3. The method of claim 2, further comprising:

resuming the burst transmission after successfully contending for access to the shared access medium.

4. The method of claim 1, wherein the frames of the burst transmission comprise segments of a segmented MAC service data unit.

5. A media access control unit for bounding latency of transmissions by stations on a shared access medium comprising:

a transmit handler to associate one of multiple priority levels with a transmission and to control the amount of time the transmission occupies the shared access medium based on the associated priority level,

wherein the transmission is a burst transmission and the transmit handler comprises;

a segmentation unit for segmenting a MAC service data unit into segments for transmission in frames on the shared access medium in the burst transmission; and

a frame transmit unit for providing segments in frames in the burst transmission at the associated priority level, and

wherein the frame transmit unit provides a set contention control indicator for indicating contention-free access in all but the last of the frames in the burst transmission and provides in all of the frames in the burst transmission the associated priority level so that the burst transmission may be interrupted by another of the stations having a pending frame with a higher priority level than the specified priority level.

6. The media access control apparatus of claim 5, further comprising:

wherein the frame transmit unit relinquishes control of the shared access medium when such pending frame is detected between transmissions of the frames in the burst transmission.

7. The media access control apparatus of claim 6, further comprising:

wherein the frame transmit unit resumes the burst transmission after successfully contending for access to the shared access medium.

8. A method of reducing latency of transmission by stations on a shared access medium, the method comprising:

having a first station begin a burst transmission of frames;

associating one of multiple priority levels with the burst transmission;

providing an inter-frame contention phase between frames;

during the inter-frame contention phase, having the first station signal the priority level of the burst transmission and signal that the first station desires contention-free access to complete the burst transmission;

during the inter-frame contention phase, having at least a second station contend to interrupt the burst transmission with a second transmission by signaling a priority level associated with the second transmission; and

having the first station interrupt the burst transmission in the event that the priority level signaled by the second station is higher than the priority level of the burst transmission.

9. The method of claim 8 wherein having the first station signal that the first station desires contention free access comprises setting a contention control indicator.

10. The method of claim 8 further comprising having the first station resume the burst transmission in the event that no other station contends with a higher priority during the inter-frame contention phase.

11. The method of claim 8 wherein the frames of the burst transmission comprise segments of a segmented MAC service data unit.

12. The method of claim 8 wherein the first and second station signal the priority level of their transmissions by signaling during predetermined priority slots during the inter-frame contention phase.

13. A method of operating a media access control unit for reducing latency of transmission by stations on a shared access medium, wherein one such medium access control unit is associated with each of a plurality of stations, the method comprising:

beginning a burst transmission of frames;

associating one of multiple priority levels with the burst transmission;

providing an inter-frame contention phase between frames;

during the inter-frame contention phase, having the station transmitting the burst transmission signal the priority level of the burst transmission and signal that the station desires contention-free access to complete the burst transmission;

during the inter-frame contention phase, having the station transmitting the burst transmission listen for the priority level of another station contending to interrupt the burst transmission with a second transmission; and

interrupting the burst transmission in the event that the priority level signaled by the other station is higher than the priority level of the burst transmission.

14. The method of claim 13 wherein having the station signal that the station desires contention free access comprises setting a contention control indicator.

15. The method of claim 13 further comprising resuming the burst transmission in the event that no other station contends with a higher priority during the inter-frame contention phase.

16. The method of claim 13 wherein the frames of the burst transmission comprise segments of a segmented MAC service data unit.

17. The method of claim 13 wherein station signal the priority level of a transmissions by signaling during predetermined priority slots during the inter-frame contention phase.