Soft FEC with parity check
The present invention is directed to data communication systems and techniques thereof. More specifically, embodiments of the present invention provide an FEC encoder that 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.
1. A data transmission device comprising:
a first Reed-Solomon (RS) encoder which generates a first data stream, the first data stream being characterized by a first block size;
a second RS encoder which generates a second data stream, the second data stream being characterized by the first block size;
a first multiplexer which distributes the first data stream and the second data stream into a first plurality of data streams, the first plurality of data streams including a third data stream and a fourth data stream, the third data stream comprising data blocks from the first data stream and the second data stream;
a first plurality of communication lanes which transmits the first plurality of data streams;
a second multiplexer which transmits the first plurality of data streams into a second plurality of data streams, the second plurality of data streams including a fifth data stream, the fifth data stream comprising data blocks from the third data stream and fourth data stream;
a second plurality of communication lanes which transmits the second plurality of data streams, the second plurality of communication lanes comprising a first communication lane;
a third multiplexer which splits the fifth data stream into a first odd data stream and a first even data stream;
a first amplitude modulation (AM) lock module which locks a plurality of odd RS symbols based on the first odd data stream;
a second AM lock module which locks a plurality of even RS symbols based on the first even data stream; and
an encoder module for generating a plurality of forward-error correction (FEC) blocks, each of the FEC blocks comprising an odd section and an even section and a parity section, the parity section comprising an odd parity bit corresponding to the odd section and an even parity bit corresponding to the even section, wherein the parity section provides at least 1.5 dB coding gain.
2. The device of claim 1 further comprising a mapping module for mapping the FEC blocks to a sixth data stream.
3. The device of claim 1 wherein the first block size is 10 bits.
4. The device of claim 1 wherein the first plurality of communication lanes consists of eight physical coding sublayer (PCS) lanes.
5. The device of claim 1 wherein the second plurality of communication lanes consists of four CDAUI lanes.
6. The device of claim 1 wherein the first AM lock module is configured to determine boundaries for RS symbols.
7. The device of claim 1 wherein each of the FEC blocks corresponds to a plurality PAM4 symbols.
8. The device of claim 1 wherein the encoder module is configured to calculate the odd parity bit based on the odd section.
9. The device of claim 1 wherein the device is compatible with the 802.3bs standard.