Communication system and encoding method having low overhead

• US 7,809,021 B2
• Filed: 05/09/2006
• Issued: 10/05/2010
• Est. Priority Date: 07/10/2002
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: SolarFlare Communications Incorporated (Advanced Micro Devices, Inc.)
• Inventors: McClellan, Brett A.
• Primary Examiner(s): Moe; Aung S
• Assistant Examiner(s): RIYAMI, ABDULLA A
• Application Number:
  US11/431,929
• Publication Number:
  US 20060256875A1
• Time in Patent Office: 1,610 Days
• Field of Search: 370/310, 370/315, 370/316, 370/319, 370/321, 370/328, 370/329, 370/335, 370/336, 370/337, 370/347, 370/389, 370/470, 370/474, 370/475, 370/477, 370/479, 370/498, 370/395.2, 370/392, 370/465, 370/466, 370/467, 370/468, 370/471, 370/472, 370/473, 370/476, 714/701, 714/751, 714/755, 714/759, 714/777, 712/200, 712/201, 712/208, 712/225, 712/220, 712/300, 375/E7.138, 375/E7.124, 375/E7.206
• US Class Current: 370/476
• CPC Class Codes: H04J 3/06 Synchronising arrangements for television systems H04N5/04; bit-synchronisation H04L7/00
• CPC Class Codes: H04J 3/0602 Systems characterised by the synchronising information used
• CPC Class Codes: H04J 3/1617 carrying packets or ATM cells
• CPC Class Codes: H04J 3/1658 carrying packets or ATM cells; H04J3/1664 takes precedence for payloads with different packet types
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers

Abstract

A communication system processes blocks of input data that include control words and a packet of information words are received. The packet has a start preceded by ones of the control words and an end followed by others of the control words. When the block consists exclusively of information words, a one bit block header having a first sense is appended to the block to form a frame. When the block does not consist exclusively of information words, the block is condensed to accommodate a TYPE word, the TYPE word is generated and inserted into the block and a one bit block header is appended to the block to form the frame. When the block does not consist exclusively of information words the one bit block header has a second sense, opposite to the first sense. Use of a one bit block header reduces overhead. Forward error correction is also utilized.

Claims

1. A 64B/65B coding method for coding a packet of information words into frames for transmission over 4 twisted pair conductor in connection with an Ethernet based communication device, the method comprising:

receiving blocks of input data at an Ethernet communication device, the input data including control words and the packet of information words, the packet having a start preceded by ones of the control words and an ending followed by others of the control words, the blocks being smaller than the packet;

within the Ethernet communication device, determining when a block consists exclusively of information words and;

when the block consists exclusively of information words;

appending to the block a one bit block header having a first sense to form one of the frames;

when the block does not consist exclusively of information words;

condensing the block to accommodate a TYPE word; and

generating the TYPE word having a value that indicates one of the following structural properties of the block;

(a) a position of the start of the packer in the block,

(b) a position of the end of the packet in the block, and

(c) the block being composed exclusively of control words, and inserting a TYPE word into the block, and appending to the block a one bit block header having a second sense, opposite to the first sense, to form the one of the frames, wherein the method reduces overhead to less than 3%;

performing a CRC operation on frames to create CRC data;

appending the CRC data to frames to form a frame group having CRC data; and

performing low density parity check coding on the frame group having CRC data.

2. The method of claim 1, in which compressing the block includes re-coding ones of the control words using fewer bits.

3. The method of claim 1, in which the type word is selected from a set of type words having a specified mutual Hamming distance.

4. The method of claim 3, in which:

the type words each consist of T bits; and

the method additionally comprises generating the set of possible bit patterns by a process including;

adopting a (T/2)-bit binary pattern as a first half of a bit pattern in the set of possible bit patterns, and generating a second half of the bit pattern by duplicating or complementing the first half of the bit pattern depending on a bit parity value of the first half of the bit pattern.

5. The method of claim 1, wherein a one bit block header in the first sense comprises a 1 and a one bit block header in the second sense comprises a 0 value.

6. The method of claim 5, wherein the method is performed in a conjunction with forward error correction.

7. The method of claim 1, in which condensing the block includes removing from the block a control word that indicates one of (a) the start of the packet and (b) the end of packet.

8. The method of claim 7, in which condensing the block includes re-coding remaining ones of the control words using fewer bits.

9. The method of claim 1, wherein the method is utilized in a 10 gigabit/second communication system.

10. A communication coder for 64B/65B type coding of blocks of input data into respective frames for transmission over twisted pair conductor, the input data including control words and a packet of information words, the packet having a start preceded by ones of the control words and an ending followed by others of the control words, the blocks being smaller than the packet, the frames including a frame corresponding to the block, the coder comprising:

a type word generator that receives the block and generates a TYPE word for a block, the TYPE word having a value that indicates one of the following structural properties of the block;

(a) whether the block is composed exclusively of control words,

(b) a position of the start of the packet in the block,

(c) a position of the end of the packet in the block, and

(d) whether the block is composed exclusively of control words;

a one bit block header generator that operates in response to the TYPE word and generates a one bit block header in a first sense when the TYPE word indicates that the block is composed exclusively of information words, and otherwise generates the one bit block header in a second sense, opposite to the first sense, wherein use of a one bit block header reduces overhead to less than 3%;

a payload field generator that operates in response to the TYPE word and that adopts the block to form a payload field of the frame when the TYPE word indicates that the block is composed exclusively of information words, and that otherwise condenses the block and inserts the TYPE word into the block to form the payload field;

a frame assembler that appends the block header to the payload field to form the frame;

a CRC encoder configured to calculate a CRC value and append the CRC value to a group of two or more frames; and

a forward error correction coder configured to perform forward error correction coding on the group of two or more frames having the CRC value appended thereto.

11. The coder of claim 10, in which the payload field generator includes a re-coder that condenses the block by re-coding remaining ones of the control words using fewer bits.

12. The coder of claim 10, in which the type word is selected from a set of type words having a specified mutual Hamming distance.

13. The coder of claim 12, in which:

the type words each consist of T bits; and

the coder additionally comprises a type word generator that generates the set of possible bit patterns, the type word generator including;

a first-half generator that adopts a (T/2)-bit binary pattern as a first half of a bit pattern in the set of possible bit patterns, and a second-half generator that generates a second half of the bit pattern by duplicating or complementing the first half of the bit pattern depending on a bit parity value of the first half of the bit pattern.

14. The coder of claim 10, wherein the communication coder operation in conjunction with forward error correction.

15. The coder of claim 10, wherein the twisted pair conductors comprise 4 twisted pair conductors and the communication coder'"'"'s use of a one bit block header establish a overhead of 1.5625%.

16. The coder of claim 10, in which the payload field generator includes a control word removal module that condenses the block by removing from the block a control word that indicates one of (a) the start of the packet and (b) the end of the packet.

17. The coder of claim 16, in which the payload field generator additionally includes a re-coder that condenses the block by re-coding remaining ones of the control words using fewer bits.

18. The coder of claim 17, in which the re-coder re-codes the control words using codes having a specified mutual Hamming distance.