Soft FEC with parity check

Patent metadata

Field	Value
Publication number	US-11265109-B2
Application number	US-202016824261-A
Country	US
Kind code	B2
Filing date	Mar 19, 2020
Priority date	Aug 30, 2017
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

The present invention is directed to data communication systems and techniques thereof. More specifically, embodiments of the present invention provide an FEC encoder that processes an interleaved data stream and generates parity symbols that are embedded into FEC blocks. An FEC decoder determines whether to perform error correction based on the parity symbols. When performing error correction, the decoder selects a worst symbol from a segment of symbols, and the worst symbol is corrected. There are other embodiments as well.

First claim

What is claimed is:

1. A data transmission device comprising:
an interface configured to receive one or more input data streams;
a forward error correction (FEC) lane de-interleaver configured to de-interleave the one or more input data streams into four de-interleaved streams;
an alignment marker framer configured to frame the four de-interleaved data streams to generate four framed data streams;
an interleaver configured to generate an intermediate data stream based on the four framed streams, the intermediate data stream comprising an even data block and an odd data block based on a predetermined block size;
a delay line configured to delay a predetermined number of bits of the intermediate data stream to provide the even data block;
a multiplexer configured to output the even data block and the odd data block;
an encoder module configured to generate a plurality of FEC blocks, each of the FEC blocks comprising an odd section corresponding to the odd data block and an even section corresponding to the even data block and a parity section, the odd section comprising parity information for the odd block data block, the FEC blocks including a first FEC block, the first FEC block including a parity bit based on a parity of the first FEC block; and
a transmission module configured to transmit the FEC blocks.

2. The device of claim 1 further comprising a de-skew module configured to de-skew by aligning the even data blocks and the odd data blocks.

3. The device of claim 1 wherein the encoder module is configured to perform Reed-Solomon (RS) FEC encoding.

4. The device of claim 1 wherein the FEC blocks are transmitted through a pulse-amplitude modulation 4 (PAM4) channel.

5. The device of claim 1 wherein the predetermined number of bits is 5440 bits.

6. The device of claim 1 further comprising an FEC-lane (FECL) deskew module configured to de-skew the four framed streams.

7. The device of claim 1 wherein respective ones of the FEC blocks correspond to a plurality of PAM4 symbols.

8. The device of claim 1 wherein the encoder module is configured to calculate the parity bit.

9. The device of claim 1 wherein the device is compatible with an IEEE 802.3 bs standard and with an IEEE 802.3 cd standard.

10. The device of claim 1 wherein the parity section provides at least 1.2 dB coding gain when interleaving the odd data block and the even data block.

11. A communication system comprising:
an interleaver configured to provide a data stream that includes even data blocks and odd data blocks, both the even data blocks and the odd data blocks having a first block size;
a forward error correction (FEC) encoder configured to generate FEC blocks, each of the FEC blocks including an even portion and an odd portion and a parity bit, the FEC blocks being characterized by a second block size different from the first block size;
a data communication channel configured to transmit the FEC blocks;
an FEC decoder configured to decode the blocks and to generate a decoded data stream;
a first de-interleaver configured to generate a de-interleaved data stream based on the decoded data stream;
a second de-interleaver configured to generate four data streams based on the de-interleaved data stream; and
an FEC-lane (FECL) interleaver configured to generate one or more data streams for a host device based on the four data streams.

12. The system of claim 11 wherein the first block size is 5440 bits.

13. The system of claim 11 wherein the data communication channel comprises a pulse-amplitude modulation (PAM) channel.

14. The system of claim 11 wherein the FEC encoder includes a mapping module configured to perform Gray code mapping.

15. The system of claim 11 wherein the FEC blocks comprise pulse-amplitude modulation 4 (PAM4) symbols.

16. A communication device comprising:
a communication interface configured to transmit forward error correction (FEC) data blocks, each of the FEC data blocks comprising an even section and an odd section and a parity bit;
an FEC decoder configured to provide bit-error correction for the FEC data blocks based on the parity bit and to generate a decoded data stream;
an alignment marker (AM) framer configured to generate a framed data stream by locating boundaries from the decoded data stream and inserting alignment markers;
a first de-interleaver configured to generate an output data stream by de-interleaving the framed data stream defined by odd data blocks and even data blocks; and
a second de-interleaver configured to generate four output data streams by de-interleaving the output data stream.

17. The device of claim 16 wherein each of the FEC blocks includes 21 bits.

18. The device of claim 16 further comprising an FEC-lane (FECL) interleaver configured to interleave the four output data streams into one or two host data streams.

19. The device of claim 16 wherein the first de-interleaver comprises a delay line configured to buffer 5440 bits.

20. The device of claim 16 further comprising an FEC codeword framer configured to frame the FEC data blocks.

Assignees

• Marvell Asia Pte Ltd

Inventors

• Riani Jamal
• Smith Benjamin
• Shvydun Volodymyr
• Swaminathan Srinivas
• Farhoodfar Arash

Classifications

• H04L1/0063

  Single parity check · CPC title

• H04L1/0041 Primary

  Arrangements at the transmitter end · CPC title

• H04L2001/0096

  Channel splitting in point-to-point links · CPC title

• H04L1/0045

  Arrangements at the receiver end · CPC title

• H04L1/0046

  Code rate detection or code type detection (H04L1/0038 takes precedence; detection of the data rate H04L25/0262; for packet format H04L1/0091) · CPC title