Packet sub-frame structure for selective acknowledgment

• US 20050157715A1
• Filed: 12/24/2003
• Published: 07/21/2005
• Est. Priority Date: 12/24/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Wezelenburg, Mark, Hiddink, Gerritt W., van Leeuwen, Richard M.
• Granted Patent: US 7,586,948 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/1621 Group acknowledgement, i.e. the acknowledgement message defining a range of identifiers, e.g. of sequence numbers
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A wireless local area network includes transmission of data packets between endpoints in which packet frames are divided into sub-frames. On reception of a frame, the integrity of each individual sub-frame is checked. Sub-frames that pass the integrity check are acknowledged and retransmission is requested only for sub-frames that failed the integrity check. Consequently, only the affected sub-frames require retransmission instead of the whole frame.

Claims

1. A method of generating a packet frame for a data payload comprising one or more sub-frame payloads, the method comprising the steps of:

(a) appending, to each of the sub-frame payloads, a corresponding sub-frame sequence number and a corresponding sub-frame integrity check value to generate a sub-frame;

(b) arranging the sub-frames into a sub-frame sequence;

(c) generating a header integrity check value for a header; and

(d) appending the header integrity check value to the sub-frame sequence to form a frame.

2. The invention as recited in claim 1, further comprising the step of appending the header and a packet frame integrity value to the frame to generate the packet frame.

3. The invention as recited in claim 2, further comprising the step of transmitting the packet frame.

4. The invention as recited in claim 2, wherein the header and the packet frame integrity value conform to a medium access control (MAC) layer protocol.

5. The invention as recited in claim 1, wherein, for step (c), the sub-frame integrity check value for a sub-frame is either a checksum value or a forward error correction value.

6. The invention as recited in claim 1, further comprising the step of varying either a length or a number of sub-frames in the sub-frame sequence based on a channel condition.

7. The invention as recited in claim 1, wherein the method is employed by a central processor of a wireless network operating in accordance with one or more editions of an 802.11 standard.

8. The invention as recited in claim 1, wherein the method is embodied as processing steps in a processor of an integrated circuit.

9. A method of sending data by a transmitter, the method comprising the steps of:

(a) forming a packet frame from payload data, the packet frame including one or more sub-frames and each sub-frame comprising sub-frame payload data and a sub-frame sequence number;

(b) transmitting the packet frame to a receiver;

(c) receiving an acknowledgment message from the receiver; and

(d) determining each sub-frame of the packet frame not received by the receiver based upon the acknowledgment message; and

(e) re-transmitting each sub-frame not received by the receiver to the receiver.

10. The invention as recited in claim 9, wherein the acknowledgment message identifies each sub-frame of the packet frame received by the receiver.

11. The invention as recited in claim 9, further comprising the step of repeating steps (c), (d), and (e) until the receiver has received the payload data.

12. The invention as recited in claim 11, wherein repeating steps (c), (d), and (e) is in accordance with a block acknowledgment policy.

13. The invention as recited in claim 9, wherein step (a) forms the packet frame by the steps of:

(a1) dividing the data payload into one or more sub-frame payloads;

(a2) appending, to each of the sub-frame payloads, the corresponding sub-frame sequence number and a sub-frame integrity check value to generate a sub-frame;

(a3) arranging the sub-frames into a sub-frame sequence;

(a4) generating a header integrity check value for a header;

(a5) appending the header integrity check value to the sub-frame sequence to form a frame; and

(a6) appending the header and a packet frame integrity value to the frame to generate the packet frame.

14. The invention as recited in claim 9, further comprising the step of varying either a length or a number of sub-frames in the sub-frame sequence based on a channel condition.

15. The invention as recited in claim 9, wherein the method is employed by the transmitter of a wireless network operating in accordance with one or more editions of an 802.11 standard.

16. The invention as recited in claim 15, wherein, for steps (a) through (e), the method transmits the packet frame in accordance with a carrier sense multiple access collision avoidance (CSMA/CA) method in accordance with the 802.11 standard.

17. The invention as recited in claim 15, wherein, for step (a), the method generates the packet frame in accordance with a medium access control (MAC) layer protocol.

18. The invention as recited in claim 9, further comprising the step of recording each un-verified sub-frame as a measure of channel quality.

19. The invention as recited in claim 18, further comprising the step of adjusting either a rate or an antenna diversity based on the measure of channel quality.

20. A method of processing a packet frame into payload data at a receiver, the method comprising the steps of:

(a) receiving the packet frame, wherein

     1) the packet frame comprises a header, a header integrity check value, a packet frame integrity check value, and one or more sub-frames, and

     2) at least one sub-frame comprises a sub-frame integrity check value;

(b) verifying the integrity of the received packet frame based on the packet frame integrity check value;

(c) verifying, if the integrity of the received packet frame is verified, the integrity of the header based on the header integrity check value;

(d) verifying, if the integrity of the header of the received packet frame is verified, the integrity of a sub-frame based on the corresponding sub-frame integrity check value.

21. The invention as recited in claim 20, wherein, for step (a), each sub-frame comprises a sub-frame sequence number.

22. The invention as recited in claim 20, further comprising the step of (e) acknowledging, to a transmitter, each verified sub-frame received by the receiver based on the corresponding sub-frame sequence number.

23. The invention as recited in claim 22, further comprising the step of (f) receiving a subsequent packet containing sub-frames of the packet frame not verified by the receiver.

24. The invention as recited in claim 23, further comprising the step of (g) repeating steps (e) and (f) to generate the payload data.

25. The invention as recited in claim 22, wherein step (e) is in accordance with a block acknowledgment policy.

26. The invention as recited in claim 22, further comprising the step of recording each un-verified sub-frame as a measure of channel quality.

27. The invention as recited in claim 26, further comprising the step of adjusting either a rate or an antenna diversity based on the measure of channel quality.

28. The invention as recited in claim 20, wherein, for step (d), the sub-frame integrity check value for a sub-frame is either a checksum value or a forward error correction value.

29. The invention as recited in claim 20, further comprising the step of dropping, if the integrity of the header of the received packet frame is not verified, the received packet frame.

30. The invention as recited in claim 20, wherein the method is employed by the transmitter of a wireless network operating in accordance with one or more editions of an 802.11 standard.

31. The invention as recited in claim 30, wherein, for steps (a) through (e), the method transmits the packet frame in accordance with a carrier sense multiple access collision avoidance (CSMA/CA) method in accordance with the 802.11 standard.

32. The invention as recited in claim 30, wherein, for step (a), the method generates the packet frame in accordance with a medium access control (MAC) layer protocol.

33. A computer-readable medium having stored thereon a plurality of instructions, the plurality of instructions including instructions which, when executed by a processor, cause the processor to implement a method for processing a packet frame into payload data at a receiver, the method comprising the steps of:

(a) receiving the packet frame, wherein

     1) the packet frame comprises a header, a header integrity check value, a packet frame integrity check value, and one or more sub-frames, and

     2) at least one sub-frame comprises a sub-frame integrity check value;

(b) verifying the integrity of the received packet frame based on the packet frame integrity check value;

(c) verifying, if the integrity of the received packet frame is verified, the integrity of the header based on the header integrity check value;

(d) verifying, if the integrity of the header of the received packet frame is verified, the integrity of a sub-frame based on the corresponding sub-frame integrity check value.

34. A wireless local area network device, comprising:

a media access controller adapted to transmit a packet frame including a header, a plurality of sub-frames, and a plurality of sub-frame integrity check values, and

a physical layer device adapted to receive the packet frame from the media access controller.

35. The device of claim 34, wherein the packet frame includes a sub-frame integrity check value associated with each of the sub-frames in the packet frame.

36. The device of claim 34, wherein each of the sub-frames includes a sub-frame payload.

37. The device of claim 34, wherein each of the sub-frames includes a sub-frame sequence number.

38. The device of claim 34, wherein the packet frame includes a header integrity check value.

39. The device of claim 34, wherein the physical layer device includes a radio for transmitting the packet frame over free space.

40. A method of generating a packet frame for a data comprising one or more sub-frames, each of the sub-frames having a corresponding sub-frame sequence number, a sub-frame integrity check value, and sub-frame payload, the method comprising the steps of:

(a) arranging the sub-frames into a sub-frame sequence;

(b) generating a header integrity check value for a header; and

(c) appending the header integrity check value to the sub-frame sequence to form a frame.