MEDIUM ACCESS CONTROL LAYER THAT ENCAPSULATES DATA FROM A PLURALITY OF RECEIVED DATA UNITS INTO A PLURALITY OF INDEPENDENTLY TRANSMITTABLE BLOCKS

• US 20110128973A1
• Filed: 02/11/2011
• Published: 06/02/2011
• Est. Priority Date: 11/24/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Blanchard, Bart W., Gargrave, Timothy R., Yonge, Lawrence W. III, Earnshaw, William E., Kostoff, Stanley J. II, Katar, Srinivas
• Granted Patent: US 8,654,635 B2
• Time in Patent Office: Days
• US Class Current: 370/469
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1867 Arrangements specially adapted for the transmitter end
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/24 Traffic characterised by specific attributes, e.g. priority or QoS
• CPC Class Codes: H04L 47/36 by determining packet size, e.g. maximum transfer unit [MTU]
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]

Abstract

A method of operating in a network in which a plurality of stations communicate over a shared medium, comprising providing a physical layer (e.g., PHY) for handling physical communication over the shared medium; providing a high level layer (e.g., PAL) that receives data from the station and supplies high level data units (e.g., MSDUs) for transmission over the medium; providing a MAC layer that receives the high level data units from the high level layer and supplies low level data units (e.g., MPDUs) to the physical layer; at the MAC layer, encapsulating content from a plurality of the high level data units; dividing the encapsulated content into a plurality of pieces (e.g., segments) with each piece capable of being independently retransmitted; and supplying low level data units containing one or more of the plurality of pieces.

Claims

1. A method of operating in a network in which a plurality of stations communicate over a powerline communications medium, comprising

providing a physical layer for handling physical communication over the powerline communications medium;

providing a high level layer that receives data from the station and supplies high level data units for transmission over the powerline communications medium;

providing a MAC layer that receives the high level data units from the high level layer and supplies low level data units to the physical layer;

at the MAC layer, encapsulating content from a plurality of the high level data units into a stream of sub-frames;

dividing the encapsulated content into a plurality of pieces with each piece capable of being independently retransmitted; and

supplying low level data units containing a plurality of the pieces.

2. The method of claim 1 wherein at least some information common to the encapsulated high level data units is not repeated for each high level data unit encapsulated in a low level data unit.

3. The method of claim 2 wherein the information common to the encapsulated high level data units comprises destination and source addresses.

4. The method of claim 2 wherein the high level data units each comprise a payload, and encapsulating comprises forming a queue comprising the stream of sub-frames, each sub-frame comprising a header and a plurality of payloads.

9. The method of claim 1 further comprising generating parity pieces derived from other pieces and capable of being used at a destination to recover one or more lost pieces at the destination without having to retransmit the lost pieces.

15. The method of claim 4 wherein clock information characterizing the time setting of a clock in a transmitting station is transmitted to a receiving station within a header of the low level data units, and the clock information is used by the receiving station along with the delivery time stamps to establish the time at which payloads are delivered.

21. The method of claim 4 wherein the MAC layer has the capability of transmitting data in a plurality of sessions within a regularly-repeated contention free interval, wherein a station to which data is transmitted is identified by a destination address and a station from which data is transmitted is identified by a source address, and wherein the queue contains sub-frames for the same session, same source address, and same destination address.

24. The method of claim 21 wherein a stream identifier is used to associate content of a queue with a particular session, and there are a plurality of queues, each containing payloads having a unique combination of stream identifier, source address, and destination address.

28. The method of claim 4 wherein the queue is divided into a plurality of sub-blocks, wherein a plurality of sub-blocks are grouped to form a segment, with a segment crossing sub-frame boundaries in the queue, wherein a segment constitutes one of the pieces.

32. The method of claim 28 wherein the sub-blocks have an associated sequential numbering adapted for use at the receiving station for re-establishing the correct sequential order of the sub-blocks, and the sub-blocks have a predetermined size, which combined with the associated sequential numbering, eliminates the need for buffer reordering when out of order segments are received.

37. The method of claim 1 wherein individual segments are individually encrypted and encryption information common to a plurality of segments is carried in a header.

41. The method of claim 1 wherein each piece constitutes a segment that is transmitted as a physical layer block, each block separately undergoes forward error correction, and the level of forward error correction used provides greater error correction capability for selected blocks that are being retransmitted after failing to be correctly transmitted in an earlier attempt.

5-8. -8. (canceled)

10-14. -14. (canceled)

16-20. -20. (canceled)

22-23. -23. (canceled)

25-27. -27. (canceled)

29-31. -31. (canceled)

33-36. -36. (canceled)

38-40. -40. (canceled)

42-48. -48. (canceled)

49. A method of operating in a network in which a plurality of stations communicate over a powerline communications medium, comprising

providing a physical layer for handling physical communication over the powerline communications medium;

providing a high level layer that receives data from the station and supplies high level data units for transmission over the powerline communications medium;

providing a MAC layer that receives the high level data units from the high level layer and supplies low level data units to the physical layer;

at the MAC layer, forming low level data units by encapsulating content from a plurality of the high level data units; and

adaptively escalating the robustness of transmission of the low level data units depending on the frequency of transmission errors.

50. The method of claim 49 wherein

the method further comprises incorporating forward-error correction information into the transmitted stream of low level data units, and

wherein the step of adaptively escalating comprises adaptively varying the forward-error correction information depending on the frequency of transmission errors.

51. The method of claim 50 wherein varying the forward-error correction information comprises varying one or both of the amount and type of forward-error correction information.

52. The method of claim 49 wherein decisions on adaptively escalating are made at a transmitting station.

53. The method of claim 50 wherein the low level data units comprise a plurality of pieces.

54. The method of claim 52 wherein the forward error correction information comprises information provided with the pieces for use at a destination for recovering a piece that is received with errors.

55. The method of claim 52 wherein the forward error correction information comprises parity pieces derived from other pieces and capable of being used at a destination to recover one or more lost pieces at the destination without having to retransmit the lost pieces.

56. The method of claim 55 wherein each piece is transmitted as a physical layer block, and the parity pieces are also transmitted as parity physical layer blocks.