Packet sub-frame structure for selective acknowledgment

• US 7,586,948 B2
• Filed: 12/24/2003
• Issued: 09/08/2009
• 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.
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): Phung; Luat
• Application Number:
  US10/746,153
• Publication Number:
  US 20050157715A1
• Time in Patent Office: 2,085 Days
• Field of Search: 370/474, 370/465, 370/338, 370/389, 370/394, 370/473, 709/236
• US Class Current: 370/473
• 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 sending data by a transmitter, the method comprising the steps of:

(a) forming a packet frame from payload data, the packet frame including two 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, based upon the acknowledgment message, each sub-frame of the packet frame not properly received by the receiver

(e) re-transmitting, to the receiver, each sub-frame not properly received by the receiver;

(f) determining the number of erroneous sub-frames in the packet frame; and

(g) adjusting antenna diversity based on the number of erroneous sub-frames in the packet frame.

2. The invention as recited in claim 1, wherein the acknowledgment message identifies each sub-frame of the packet frame properly received by the receiver.

3. The invention as recited in claim 1, further comprising the step of repeating steps (c), (d), and (e) until the receiver has properly received all of the payload data.

4. The invention as recited in claim 3, wherein repeating steps (c), (d), and (e) is in accordance with a block acknowledgment policy.

5. The invention as recited in claim 1, 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, a 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.

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

7. The invention as recited in claim 1, wherein the method is employed by the transmitter of a wireless network operating in accordance with an 802.11 standard.

8. The invention as recited in claim 7, 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.

9. The invention as recited in claim 7, wherein, for step (a), the method generates the packet frame in accordance with a medium access control (MAC) layer protocol.

10. The invention as recited in claim 1, wherein step (g) further comprises the steps of:

(h) determining a measure of channel quality using the number of erroneous sub-frames in the packet frame; and

(i) adjusting the antenna diversity based on the measure of channel quality.

11. The invention as recited in claim 1, further comprising the step of:

(g) adjusting a data transmission rate based on the number of erroneous sub-frames in the packet frame.

12. A method of processing a packet frame 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 two 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;

(e) determining a number of erroneous sub-frames in the packet frame; and

(f) adjusting antenna diversity based on the number of erroneous sub-frames in the packet frame.

13. The invention as recited in claim 12, wherein, for step (a), each sub-frame comprises a sub-frame sequence number.

14. The invention as recited in claim 12, further comprising the step of generating payload data from the received packet frame.

15. The invention as recited in claim 12, wherein step (e) is in accordance with a block acknowledgment policy.

16. The invention as recited in claim 12, 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.

17. The invention as recited in claim 12, further comprising the step of dropping, if the integrity of the header of the received packet frame is not verified, the received packet frame.

18. The invention as recited in claim 12, wherein the method is employed by the transmitter of a wireless network operating in accordance with an 802.11 standard.

19. The invention as recited in claim 18, 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.

20. The invention as recited in claim 18, wherein, for step (a), the method receives the packet frame in accordance with a medium access control (MAC) layer protocol.

21. The invention as recited in claim 12, wherein step (f) further comprises the steps of:

(g) determining a measure of channel quality using the number of erroneous sub-frames in the packet frame; and

(h) adjusting the antenna diversity based on the measure of channel quality.

22. The invention as recited in claim 12, further comprising the step of:

(g) adjusting a data transmission rate based on the number of erroneous sub-frames in the packet frame.