Point-to-point MAC protocol for high speed wireless bridging

• US 7,567,537 B1
• Filed: 07/29/2002
• Issued: 07/28/2009
• Est. Priority Date: 07/29/2002
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Gurbuz, Ozgur, Meier, Robert, Ayanoglu, Ender
• Primary Examiner(s): Rao; Seema S
• Assistant Examiner(s): Juntima; Nittaya
• Application Number:
  US10/207,694
• Time in Patent Office: 2,556 Days
• Field of Search: 370/310, 370/328, 370/338, 370/443, 370/445, 370/447, 370/449, 370/461, 370/462
• US Class Current: 370/338
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Abstract

Systems and methods for improving throughput in point-to-point wireless communication links are provided. In one particular implementation, a media access control (MAC) layer of the IEEE 802.11 standard is enhanced for use in point-to-point links to take advantage of the limited number of nodes participating in the link. In one embodiment, a master/slave type protocol provides contention free operation between two wireless nodes. Multiple priority levels and voice traffic may be accommodated with guaranteed Quality of Service.

Claims

1. A method for operating an IEEE 802.11 node to participate in a point-to-point wireless communication link, said method comprising:

sensing a medium shared with a node constituting an opposite side of said point-to-point wireless communication link to determine if a transmission is detected, one of said nodes configured as a master bridge and the other of said nodes configured as a slave bridge;

if a transmission is detected on said shared medium, deferring transmission by a period of time, wherein said period of time for said master bridge is shorter than said period of time for said slave bridge;

exchanging control of said shared medium with said node constituting an opposite side of said point-to-point link without contention and without polling; and

transmitting data when in control of said shared medium;

wherein transmitting said data comprises selecting one of modes of operation, said modes of operation comprising an alternating mode wherein the IEEE 802.11 node transmits a first packet and then transmits a second packet after receiving an acknowledgement for said first packet, and a burst mode wherein the IEEE 802.11 node transmits a plurality of packets consecutively in a burst and requests acknowledgement at the end of said burst.

2. The method of claim 1 wherein transmitting comprises:

transmitting a packet that includes a source address and a destination address but not a transmitting station address and a receiving station address.

3. The method of claim 2 further comprising presenting said source address and said destination address in compressed form within said packet.

4. The method of claim 1 wherein transmitting comprises:

concatenating a series of MAC layer packets to form a concatenated packet; and

transmitting said concatenated packet.

5. The method of claim 1 wherein transmitting comprises:

transmitting a series of consecutive packets before giving up control of said shared medium.

6. The method of claim 1 wherein transmitting comprises:

transmitting an acknowledgement packet including piggybacked data.

7. The method of claim 1 wherein transmitting comprises:

selecting a packet to transmit based on strict priority from a series of priority queues.

8. The method of claim 7 wherein voice packets are assigned a highest priority to implement Guaranteed Quality of Service.

9. The method of claim 1 wherein transmitting comprises:

transmitting a packet that does not include a duration field.

11. The method of claim 1 wherein transmitting said data comprises transmitting a packet comprising an acknowledgement number indicating a next packet sequence number expected.

12. The method of claim 11 further comprising retransmitting said packet if a packet containing said next packet sequence number expected is not received and said packet is not a voice packet.

23. The apparatus of claim 1 wherein all of said plurality of packets transmitted in said burst mode except a final packet in said burst, comprise a bit set to instruct the node at the opposite side of said point-to-point link to delay transmittal of an acknowledgement packet.

10. The method of 1 wherein said period of time transmission is deferred by said IEEE 802 node operating as said master bridge comprises Point Coordination Function Interframe Space and wherein said period of time transmission is deferred by said IEEE 802 node operating as said slave bridge comprises Distributed Coordination Function Interframe Space.

13. Apparatus for operating an IEEE 802.11 node to participate in a point-to-point wireless communication link, said apparatus comprising:

a MAC layer block configured to;

sense a medium shared with a node constituting an opposite side of said point-to-point wireless communication line to determine if a transmission is detected, one of said nodes configured as a master bridge and the other of said nodes configured as a slave bridge,

if a transmission is detected on said shared medium, defer transmission by a period of time, wherein said period of time for said master bridge is shorter than said period of time for said slave bridge, and

exchange control of said shared medium with said node constituting an opposite side of said point-to-point link without contention and without polling; and

a physical layer block through which said MAC layer transmits data when in control of said shared medium;

wherein the MAC layer block is configured to select one of modes of operation, said modes of operation comprising an alternating mode wherein the physical layer block transmits a first packet and then transmits a second packet after receiving an acknowledgement for said first packet, and a burst mode wherein the physical layer block transmits a plurality of packets consecutively in a burst and requests acknowledgement at the end of said burst.

14. The apparatus of claim 13 wherein said MAC layer block transmits a packet that includes a source address and a destination address but not a transmitting station address and a receiving station address.

15. The apparatus of claim 14 wherein said MAC layer block compresses at least one of said source address and said destination address prior to insertion within said packet.

16. The apparatus of claim 13 wherein said MAC layer block concatenates a series of MAC layer packets to form a concatenated packet and transmits said concatenated packet.

17. The apparatus of claim 13 wherein said MAC layer block transmits a series of consecutive packets before giving up control of said shared medium.

18. The apparatus of claim 13 wherein said MAC layer block transmits an acknowledgement packet including piggybacked data.

19. The apparatus of claim 13 wherein said MAC layer block selects a packet to transmit based on priority.

20. The apparatus of claim 13 wherein said MAC layer block suppresses transmissions when there is no data to send.

21. The apparatus of claim 13 further comprising a MAC layer processor that receives said data from a higher layer protocol and inserts said data into said packets, wherein said packets do not include a duration field.

22. The apparatus of claim 13 further comprising a retransmission buffer to allow for retransmission if an acknowledgement packet containing an expected next packet sequence number is not received within a specified time.

24. Apparatus for operating an IEEE 802.11 node to participate in a point-to-point wireless communication link, said apparatus comprising:

means for sensing a medium shared with a node constituting an opposite side of said point-to-point wireless communication link to determine if a transmission is detected, one of said nodes configured as a master bridge and the other of said nodes configured as a slave bridge;

if a transmission is detected on said shared medium, means for deferring transmission by a period of time, wherein said period of time for said master bridge is shorter than said period of time for said slave bridge;

means for exchanging control of said shared medium with said node constituting an opposite side of said point-to-point link without contention and without polling; and

means for transmitting data when in control of said shared medium;

wherein means for transmitting said data comprises means for selecting one of modes of operation, said modes of operation comprising an alternating mode wherein the IEEE 802.11 node transmits a first packet and then transmits a second packet after receiving an acknowledgement for said first packet, and a burst mode wherein the IEEE 802.11 node transmits a plurality of packets consecutively in a burst and requests acknowledgement at the end of said burst.