MAC header compression for use with frame aggregation

• US 7,633,970 B2
• Filed: 12/22/2004
• Issued: 12/15/2009
• Est. Priority Date: 05/07/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: van Leeuwen, Richard, van Kampen, Harald
• Primary Examiner(s): Cho; Hong
• Assistant Examiner(s): Choi; Eunsook
• Application Number:
  US11/019,581
• Publication Number:
  US 20050249222A1
• Time in Patent Office: 1,819 Days
• Field of Search: None
• US Class Current: 370/473
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

A method of generating an aggregate frame having a header unit, which carries MAC-header information applicable to one or more data units of said aggregate frame. Since each data unit of the aggregate frame no longer needs to carry the full MAC-header information, the overhead associated with the MAC header can be significantly reduced. At the receiver, the full MAC header corresponding to the data unit is reconstructed by (i) matching the appropriate header and data units to one another and (ii) combining the information present in the header unit and the compressed header portion of the data unit. Embodiments of the present invention are capable of improving the data throughput, for example, in an entertainment network having paired source and destination devices (e.g., a DVD player and an LCD screen) with a relatively large amount of data streamed from the former to the latter.

Claims

1. A method of generating an aggregate PHY frame for one or more MAC sub-frames, the method comprising:

(a) generating a MAC header unit from headers of a first set from said one or more MAC sub-frames, the MAC header unit having header information applicable to each MAC sub-frame in the first set;

(b) for each MAC sub-frame in the first set, generating a compressed-header data unit having a compressed header portion and a payload data portion; and

(c) forming the aggregate PHY frame containing the generated MAC header unit and the generated one or more compressed-header data units, wherein;

the MAC header unit has (i) a frame control field and (ii) a frame check sequence (FCS) having error detection/correction information for the MAC header unit; and

each of the one or more compressed-header data units has (i) a respective frame control field and (ii) a respective frame check sequence (FCS) having error detection/correction information for the compressed-header data unit;

wherein the MAC header unit has no user data.

2. The invention of claim 1, wherein for each MAC sub-frame in step (b):

the compressed header portion has header information applicable to the MAC sub-frame; and

the payload data portion has the user data of the MAC sub-frame.

3. The invention of claim 1, wherein all MAC sub-frames in the first set are intended for a single destination.

4. The invention of claim 1, wherein, for each MAC sub-frame in the first set:

the compressed header portion of the corresponding compressed-header data unit has less than all of the header information of the corresponding MAC sub-frame; and

said compressed header portion and the MAC header unit together have all of the header information of said corresponding MAC sub-frame.

5. The invention of claim 1, wherein each of the MAC header unit and the compressed header portion has a header identity (HID) field, which enables matching of the MAC header unit to one or more of the corresponding compressed-header data units in the aggregate PHY frame.

6. The invention of claim 1, further comprising duplicating the MAC header unit at least one time.

7. The invention of claim 6, wherein step (c) comprises ordering the positions of the MAC header units and the one or more compressed-header data units such that at least one copy of the MAC header unit precedes all corresponding compressed-header data units.

8. The invention of claim 1, wherein step (c) comprises:

generating a sequence from the MAC header unit and the one or more compressed-header data units; and

inserting a delimiter between each two adjacent units.

9. The invention of claim 1, wherein the compressed header portion further comprises a sequence control field indicating the position of the corresponding MAC sub-frame relative to other MAC sub-frames of the first set.

10. The invention of claim 1, further comprising forming a physical layer packet using the aggregate PHY frame.

11. The invention of claim 10, further comprising transmitting the physical layer packet through a medium.

12. The invention of claim 10, wherein forming the physical layer packet comprises appending a packet preamble and a packet header to the aggregate PHY frame.

13. The invention of claim 1, wherein the method is implemented as steps in a processor of an integrated circuit (IC).

14. The invention of claim 13, wherein the IC is embodied in a device operating in accordance with an IEEE 802.11 standard.

15. The invention of claim 1, wherein:

said one or more MAC sub-frames comprise two or more MAC sub-frames; and

the method further comprises;

repeating steps (a) and (b) for each of one or more additional sets from said one or more MAC sub-frames; and

for each of said one or more additional sets, generating a sequence from the corresponding MAC header unit and compressed-header data units.

16. The invention of claim 15, further comprising:

concatenating the generated sequences to form the aggregate PHY frame; and

forming a physical layer packet using the aggregate PHY frame, wherein forming the physical layer packet comprises appending a packet preamble and a packet header to the aggregate PHY frame.

17. The invention of claim 15, further comprising:

for each sequence, forming a physical layer sub-packet using the sequence; and

forming a physical layer packet using the sub-packets.

18. The invention of claim 1, wherein:

the frame control field of the MAC header unit complies with an IEEE 802.11 standard and has a type value and a subtype value that identify said MAC header unit as a MAC header unit; and

for each of the one or more compressed-header data units, the respective frame control field of the compressed-header data unit complies with the IEEE 802.11 standard and has a type value and a subtype value that identify said compressed-header data unit as a compressed-header data unit.

19. Apparatus for generating an aggregate PHY frame for one or more MAC sub-frames, the apparatus comprising:

a first circuit adapted to generate a MAC header unit from headers of a first set from said one or more MAC sub-frames, the MAC header unit having header information applicable to each MAC sub-frame in the first set; and

a second circuit adapted to, for each MAC sub-frame in the first set, generate a compressed-header data unit having a compressed header portion and a payload data portion, wherein;

the aggregate PHY frame contains the generated MAC header unit and the generated one or more compressed-header data units;

the MAC header unit has (i) a frame control field and (ii) a frame check sequence (FCS) having error detection/correction information for the MAC header unit; and

each of the one or more compressed-header data units has (i) a respective frame control field and (ii) a respective frame check sequence (FCS) having error detection/correction information for the compressed-header data unit;

wherein the MAC header unit has no user data.

20. The invention of claim 19, wherein:

the frame control field of the MAC header unit complies with an IEEE 802.11 standard and has a type value and a subtype value that identify said MAC header unit as a MAC header unit; and

for each of the one or more compressed-header data units, the respective frame control field of the compressed-header data unit complies with the IEEE 802.11 standard and has a type value and a subtype value that identify said compressed-header data unit as a compressed-header data unit.

21. A method of processing a packet by a receiving device, the method comprising:

receiving a physical layer packet having an aggregate PHY frame corresponding to one or more MAC sub-frames, wherein;

the aggregate PHY frame comprises a MAC header unit and, for each of the one or more MAC sub-frames, a corresponding compressed-header data unit;

the MAC header unit has header information applicable to each of the one or more MAC sub-frames; and

each compressed-header data unit has a compressed header portion and a payload data portion; and

based on the MAC header unit and a compressed-header data unit of the aggregate PHY frame, reconstructing the corresponding MAC sub-frame of the one or more MAC sub-frames, wherein;

the MAC header unit has (i) a frame control field and (ii) a frame check sequence (FCS) having error detection/correction information for the MAC header unit; and

each of the one or more compressed-header data units has (i) a respective frame control field and (ii) a respective frame check sequence (FCS) having error detection/correction information for the compressed-header data unit;

wherein the MAC header unit has no user data.

22. The invention of claim 21, wherein:

the compressed header portion of a compressed-header data unit has header information specific to the corresponding MAC sub-frame; and

the payload data portion of said compressed-header data unit has the user data of said corresponding MAC sub-frame.

23. The invention of claim 21, wherein the header information in the MAC header unit is information common to headers of the one or more MAC sub-frames.

24. The invention of claim 21, wherein:

each of the MAC header unit and the compressed header portion has a header identity (HID) field; and

the method comprises matching the MAC header unit to the corresponding compressed-header data unit using a value in the HID field.

25. The invention of claim 21, further comprising for each of the MAC header unit and the compressed-header data units, correcting one or more errors based on the error detection/correction information.

26. The invention of claim 21, wherein the compressed header portion comprises a sequence control field indicating the position of the corresponding MAC sub-frame with respect to other MAC sub-frames of the one or more MAC sub-frames.

27. The invention of claim 21, wherein the method is implemented as steps in a processor of an integrated circuit (IC).

28. The invention of claim 27, wherein the IC is embodied in a device operating in accordance with an IEEE 802.11 standard.

29. The invention of claim 21, wherein:

the frame control field of the MAC header unit complies with an IEEE 802.11 standard and has a type value and a subtype value that identify said MAC header unit as a MAC header unit; and

for each of the one or more compressed-header data units, the respective frame control field of the compressed-header data unit complies with the IEEE 802.11 standard and has a type value and a subtype value that identify said compressed-header data unit as a compressed-header data unit.

30. A receiving device for processing a packet, the device comprising:

a first circuit adapted to receive a physical layer packet having an aggregate PHY frame corresponding to one or more MAC sub-frames, wherein;

the aggregate PHY frame comprises a MAC header unit and, for each of the one or more MAC sub-frames, a corresponding compressed-header data unit;

the MAC header unit has header information applicable to each of the one or more MAC sub-frames; and

each compressed-header data unit has a compressed header portion and a payload data portion; and

a second circuit adapted to, based on the MAC header unit and a compressed-header data unit of the aggregate PHY frame, reconstruct the corresponding MAC sub-frame of the one or more MAC sub-frames, wherein;

the MAC header unit has (i) a frame control field and (ii) a frame check sequence (FCS) having error detection/correction information for the MAC header unit; and

each of the one or more compressed-header data units has (i) a respective frame control field and (ii) a respective frame check sequence (FCS) having error detection/correction information for the compressed-header data unit;

wherein the MAC header unit has no user data.

31. The invention of claim 30, wherein:

the frame control field of the MAC header unit complies with an IEEE 802.11 standard and has a type value and a subtype value that identify said MAC header unit as a MAC header unit; and

for each of the one or more compressed-header data units, the respective frame control field of the compressed-header data unit complies with the IEEE 802.11 standard and has a type value and a subtype value that identify said compressed-header data unit as a compressed-header data unit.

32. A tangible 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 of generating an aggregate PHY frame for one or more MAC sub-frames, the method comprising:

(a) generating a MAC header unit from headers of a first set from said one or more MAC sub-frames, the MAC header unit having header information applicable to each MAC sub-frame in the first set;

(b) for each MAC sub-frame in the first set, generating a compressed-header data unit having a compressed header portion and a payload data portion; and

(c) forming the aggregate PHY frame containing the generated MAC header unit and the generated one or more compressed-header data units, wherein;

the MAC header unit has (i) a frame control field and (ii) a frame check sequence (FCS) having error detection/correction information for the MAC header unit; and

each of the one or more compressed-header data units has (i) a respective frame control field and (ii) a respective frame check sequence (FCS) having error detection/correction information for the compressed-header data unit;

wherein the MAC header unit has no user data.

33. The invention of claim 32, wherein:

the frame control field of the MAC header unit complies with an IEEE 802.11 standard and has a type value and a subtype value that identify said MAC header unit as a MAC header unit; and

for each of the one or more compressed-header data units, the respective frame control field of the compressed-header data unit complies with the IEEE 802.11 standard and has a type value and a subtype value that identify said compressed-header data unit as a compressed-header data unit.

34. A tangible 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 of processing a packet by a receiving device, the method comprising:

receiving a physical layer packet having an aggregate PHY frame corresponding to one or more MAC sub-frames, wherein;

the aggregate PHY frame comprises a MAC header unit and, for each of the one or more MAC sub-frames, a corresponding compressed-header data unit;

the MAC header unit has header information applicable to each of the one or more MAC sub-frames; and

each compressed-header data unit has a compressed header portion and a payload data portion; and

based on the PHY header unit and a compressed-header data unit of the aggregate PHY frame, reconstructing the corresponding MAC sub-frame of the one or more MAC sub-frames, wherein;

the MAC header unit has (i) a frame control field and (ii) a frame check sequence (FCS) having error detection/correction information for the MAC header unit; and

each of the one or more compressed-header data units has (i) a respective frame control field and (ii) a respective frame check sequence (FCS) having error detection/correction information for the compressed-header data unit;

wherein the MAC header unit has no user data.

35. The invention of claim 34, wherein:

the frame control field of the MAC header unit complies with an IEEE 802.11 standard and has a type value and a subtype value that identify said MAC header unit as a MAC header unit; and

for each of the one or more compressed-header data units, the respective frame control field of the compressed-header data unit complies with the IEEE 802.11 standard and has a type value and a subtype value that identify said compressed-header data unit as a compressed-header data unit.