Frame aggregation

• US 7,489,688 B2
• Filed: 09/30/2004
• Issued: 02/10/2009
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Giesberts, Pieter-Paul S., van Leeuwen, Richard M.
• Primary Examiner(s): Orgad; Edan
• Assistant Examiner(s): PARK, JUNG H
• Application Number:
  US10/955,943
• Publication Number:
  US 20050152358A1
• Time in Patent Office: 1,594 Days
• Field of Search: None
• US Class Current: 370/392
• CPC Class Codes: H04L 69/26 Special purpose or proprietary protocols or architectures network applications for proprietary or special purpose networking environments H04L67/12
• CPC Class Codes: H04L 69/323 in the physical layer [OSI layer 1]
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols
• 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
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A packet network employs frame aggregation to reduce the number of physical-layer frames employed to transfer a given amount of user data. A packet network might employ physical (PHY) and medium access control (MAC) layers of a wireless local area network (WLAN) operating in accordance with one or more IEEE 802.11 standards. Frame aggregation combines several separate, higher-layer frames with user data into one PHY-layer frame, thus increasing the amount of user data per PHY-layer frame transmitted. Frame aggregation improves the efficiency by reducing both PHY-layer overhead and MAC-layer overhead.

Claims

1. A method of generating a frame of aggregated data, the method comprising the steps of:

(a) associating one or more user data frames into aggregated user data in accordance with a first layer;

(b) generating, at an aggregation layer, one or more sub-frames from the aggregated user data by adding at least one header to the aggregated data, each sub-frame having a format in accordance with a second layer, wherein step (b) comprises the steps of;

(b1) forming one or more sub-frames from the one or more user data frames by adding a sub-frame header in accordance with the second layer to each corresponding user data frame,

(b2) grouping the one or more sub-frames with a predefined order based on a transmission characteristic, and

(b3) adding a descriptor to the grouped sub-frames, wherein the descriptor is an aggregate frame descriptor comprising an aggregate frame header indicating a type of frame, a number of sub-frames, and at least one sub-frame descriptor for the sub-frames; and

(c) forming an aggregated frame from the one or more sub-frames in accordance with a third layer.

2. The invention as recited in claim 1, wherein, step (a) includes the steps of grouping the one or more user data frames into a dummy frame as the aggregated data, and step (b) comprises the step of adding the header to the dummy frame in accordance with the second layer to generate a sub-frame.

3. The invention as recited in claim 2, wherein step (b) further comprises the step of adding error detection/correction information to the dummy frame.

4. The invention as recited in claim 1, wherein step (b) includes the steps of (b1) forming two or more sub-frames from the one or more user data frames by appending a sub-frame header in accordance with the second layer to each corresponding user data frame, (b2) grouping the two or more sub-frames into a dummy frame, and (b3) adding a dummy header to the dummy frame in accordance with the second layer.

5. The invention as recited in claim 4, wherein step (b1) further comprises the step of adding error detection/correction information to each sub-frame.

6. The invention as recited in claim 4, wherein step (b) further comprises the step of adding error detection/correction information to the dummy frame.

7. The invention as recited in claim 1, wherein step (b) includes the step of forming two or more sub-frames from the one or more user data frames by adding a sub-frame header in accordance with the second layer to each corresponding user data frame, and wherein step (c) includes the steps of (c1) grouping the two or more sub-frames with a predefined order, and (c2) adding a header to each sub-frame in accordance with the third layer.

8. The invention as recited in claim 7, wherein step (b) further comprises the step of adding error detection/correction information to each sub-frame.

9. The invention as recited in claim 1, wherein, for step (b3), the aggregate frame header comprises a frame control field indicating the type of frame is an aggregate frame.

10. The invention as recited in claim 1, wherein, for step (b3), the aggregate frame descriptor further comprises an error control field having error detection/correction information for the aggregate frame descriptor.

11. The invention as recited in claim 1, wherein, for step (b3), each sub-frame descriptor comprises an address corresponding to a receiving device for the associated sub-frame, and position information identifying a position of the associated sub-frame.

12. The invention as recited in claim 1, wherein, for step (b3), each sub-frame descriptor comprises an error control field having error detection/correction information for the corresponding sub-frame.

13. The invention as recited in claim 1, wherein step (b1) further comprises the step of adding error detection/correction information to each sub-frame.

14. The invention as recited in claim 1, wherein step (b2) groups the two or more sub-frames into sub-groups, each sub-group corresponding to a user data rate.

15. The invention as recited in claim 1, wherein, for step (b2), the transmission characteristic is at least one of a user data rate and a destination address.

16. The invention as recited in claim 1, wherein step (c) includes the step of adding at least one of a preamble and a third layer header to the sub-frame.

17. The invention as recited in claim 1, wherein, for steps (a), (b), and (c), the first and second layers are included in a data link layer, and the third layer is a physical layer.

18. The invention as recited in claim 17, wherein, for steps (a), (b), and (c), the second layer is a medium access control (MAC) layer.

19. The invention as recited in claim 18, wherein the physical layer and the MAC layer are in accordance with an Institute of Electronic and Electrical Engineers (IEEE)802.11 standard.

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

21. The invention as recited in claim 20, wherein the IC is embodied in either an access point or a station operating in accordance with an IEEE 802.11 standard for wireless local area networks.

22. The invention as recited in claim 1, wherein step (a) comprises associating two or more user frames into aggregated user data in accordance with a first layer.

23. The invention as recited in claim 1, wherein, for step (b3), the aggregate frame header comprises a frame control field indicating the type of frame is an aggregate frame.

24. The invention as recited in claim 1, wherein, for step (b3), the aggregate frame descriptor further comprises an error control field having error detection/correction information for the aggregate frame descriptor.

25. The invention as recited in claim 1, wherein, for step (b3), each sub-frame descriptor comprises an address corresponding to a receiving device for the associated sub-frame, and position information identifying a position of the associated sub-frame.

26. The invention as recited in claim 1, wherein, for step (b3), each sub-frame descriptor comprises an error control field having error detection/correction information for the corresponding sub-frame.