MAC header compression for use with frame aggregation

• US 20050249222A1
• Filed: 12/22/2004
• Published: 11/10/2005
• 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
• Granted Patent: US 7,633,970 B2
• Time in Patent Office: Days
• US Class Current: 370/395.500
• 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 frame for one or more sub-frames, the method comprising:

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

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

(c) forming the aggregate frame containing the generated header and data units.

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

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

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

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

4. The invention of claim 1, wherein, for each sub-frame in the first set, the compressed header portion and the header unit together have all of the header information of the sub-frame.

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

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

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

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

generating a sequence from the header and data units; and

inserting a delimiter between each two adjacent units.

9. The invention of claim 1, wherein the header unit comprises a frame control field indicating the type of unit as a header-type unit.

10. The invention of claim 9, wherein the header unit has no user data.

11. The invention of claim 1, wherein the compressed header portion comprises a frame control field indicating the type of unit as a data-type unit.

12. The invention of claim 11, wherein the compressed header portion further comprises a sequence control field indicating the position of the sub-frame relative to other sub-frames of the first set.

13. The invention of claim 1, wherein each of the header and data units has a frame check sequence (FCS) having error detection/correction information for the unit.

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

15. The invention of claim 14, further comprising transmitting the physical layer packet through a medium.

16. The invention of claim 14, wherein forming the physical layer packet comprises appending a packet preamble and a packet header to the aggregate frame.

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

18. The invention of claim 17, wherein the IC is embodied in a device operating in accordance with an IEEE 802.11 standard.

19. The invention of claim 1, wherein:

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

the method further comprises;

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

for each subset, generating a sequence from the header and data units.

20. The invention of claim 19, further comprising:

concatenating the generated sequences to form the aggregate frame; and

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

21. The invention of claim 19, further comprising:

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

forming a physical layer packet using the sub-packets.

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

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

a second circuit adapted to, for each sub-frame in the first set, generate a data unit having a compressed header portion and a payload data portion, wherein the aggregate frame contains the generated header and data units.

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

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

the aggregate frame comprises a header unit and, for each sub-frame, a data unit;

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

the data unit has a compressed header portion and a payload data portion; and

based on the header unit and the data unit, reconstructing the corresponding sub-frame of the one or more sub-frames.

24. The invention of claim 23, wherein:

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

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

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

26. The invention of claim 23, wherein:

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

the method comprises matching the header unit to the corresponding data unit using the value in the HID field.

27. The invention of claim 23, wherein:

each of header and data units comprises a frame control field indicating a type of the unit; and

the method comprises identifying the type of each unit based on the value in the frame control field.

28. The invention of claim 23, wherein;

each of the header and data units comprises a frame check sequence (FCS) having error detection/correction information for the unit; and

the method comprises, for each of the header and data units, correcting one or more errors based on the error detection/correction information.

29. The invention of claim 23, wherein the compressed header portion comprises a sequence control field indicating the position of the corresponding sub-frame with respect to other sub-frames of the one or more sub-frames.

30. The invention of claim 23, wherein the method is implemented as steps in a processor of an integrated circuit (IC).

31. The invention of claim 30, wherein the IC is embodied in a device operating in accordance with an IEEE 802.11 standard.

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

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

the aggregate frame comprises a header unit and, for each sub-frame, a data unit;

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

the data unit has a compressed header portion and a payload data portion; and

a second circuit adapted to, based on the header unit and the data unit, reconstruct the corresponding sub-frame of the one or more sub-frames.

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 of generating an aggregate frame for one or more sub-frames, the method comprising:

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

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

(c) forming the aggregate frame containing the generated header and data units.

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

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

the aggregate frame comprises a header unit and, for each sub-frame, a data unit;

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

the data unit has a compressed header portion and a payload data portion; and

based on the header unit and the data unit, reconstructing the corresponding sub-frame of the one or more sub-frames.