Systems and methods for interleaved hamming encoding and decoding
A communication device includes a first alignment circuit configured to receive, from a host device, a first encoded data stream including a plurality of symbols encoded with a first type of error correction code. The first alignment circuit is configured to output an aligned first encoded data stream that is aligned to boundaries between the plurality of symbols encoded with the first type of error correction code. An interleaver is configured to interleave the plurality of symbols of the aligned first encoded data stream into symbol sections each including a predetermined number of symbols encoded with the first type of error correction code. An encoder is configured to generate, for each of the symbol sections, a parity block corresponding to the symbols in the symbol section and to output a second encoded data stream including the aligned first encoded data stream and the parity block.
1. A communication device for interleaving a first encoded data stream received from a host device, the communication device comprising:
a first alignment circuit configured to (i) receive the first encoded data stream from the host device, wherein the first encoded data stream includes a plurality of symbols encoded with a first type of error correction code, and (ii) output an aligned first encoded data stream that is aligned to boundaries between the plurality of symbols encoded with the first type of error correction code;
an interleaver configured to interleave the plurality of symbols of the aligned first encoded data stream into symbol sections each including a predetermined number of symbols encoded with the first type of error correction code;
an encoder configured to generate, for each of the symbol sections, a parity block corresponding to the symbols in the symbol section and to output a second encoded data stream including the aligned first encoded data stream and the parity block; and
a distribution block configured to distribute a plurality of the second encoded data streams to respective pulse amplitude modulation (PAM) physical channels.
2. The device of claim 1 wherein the first encoded data stream comprises alignment markers between blocks of the plurality of symbols.
3. The device of claim 1 further comprising a mapper for mapping the second encoded data streams to PAM4 format, wherein each of the second encoded data streams corresponds to a distinct 25G FEC data stream.
4. The device of claim 1 wherein respective symbols among the plurality of symbols has 10 bits.
5. The device of claim 4 wherein respective symbol sections includes 12 Reed Solomon (RS) symbols.
6. The device of claim 5 wherein the RS symbols of the first encoded data stream are two-way interleaved, the interleaver is configured to perform six-way interleaving, the 12 RS symbols are from 12 distinct RS codewords, and the second encoded data stream includes the 12 RS symbols and a Hamming parity block.
7. The device of claim 1 wherein the plurality of second encoded data streams are associated with independent alignments.
8. The device of claim 1 wherein encoded data streams defining the plurality of second encoded data streams are distributed to the PAM physical channels according to a round-robin scheme.
9. The device of claim 1 wherein the interleaver comprises n or n/2 delay lines, wherein n is an integer.
10. The device of claim 1 further comprising m alignment circuits, the m alignment circuits including the first alignment circuit, wherein m is an integer.
11. The device of claim 1 wherein the interleaves is configured to perform 12-way interleaving to interleave 12 of the symbols into a block.
12. A method for encoding a data stream, the method comprising:
receiving a first encoded data stream, the first encoded data stream comprising a plurality of encoded symbols each having boundaries with respect to others of the encoded symbols, the encoded symbols being encoded with an error correction code;
aligning the first encoded data stream to the boundaries of the encoded symbols to generate a first aligned symbol stream;
interleaving the first aligned symbol stream into symbol sections, each of the symbol sections including n of the encoded symbols encoded with the error correction code;
performing a first type of FEC encoding on the first aligned symbol stream to generate a first FEC encoded stream, the first FEC encoded stream including first FEC blocks corresponding to each of the symbol sections; and
distributing m FEC encoded streams to k physical channels, the m FEC encoded streams including the first FEC encoded stream,
wherein n, m, and k are integers.
13. The method of claim 12 wherein the first type of FEC encoding comprises Hamming encoding of the first aligned symbol stream.
14. The method of claim 12 wherein the first type of FEC encoding comprises BCH encoding of the first aligned symbol stream.
15. The method of claim 14 , wherein the BCH encoding is characterized by a payload of n*10 bits.
16. The method of claim 12 further comprising mapping the m inner FEC encoded streams to PAM4 format.
17. The method of claim 12 wherein the interleaving comprises convolutional interleaving configured interleave the first aligned symbol stream into Reed Solomon (RS) symbol sections.