Data encoder for power line communications

Abstract

In a disclosed embodiment, a power line communication (PLC) transmitter includes a forward error correction (FEC) encoder that receives payload data and adds parity information to the data to create an encoded output, a fragmenter that receives the encoded output from the FEC encoder and segments the encoded output into a plurality of fragments, a fragment repetition encoder that receives the plurality of fragments from the fragmenter and copies each of the fragments a selected number of times, and an interleaver that receives the copies of the plurality of fragments from the fragment repetition encoder and interleaves the copies of the plurality of fragments for transmission on a power line.

What is claimed is: 
     
         1 . A method comprising:
 generating a header comprising a first portion and a second portion; and   transmitting a frame that comprises the header, wherein transmitting the frame comprises:
 transmitting the first portion of the header with a first modulation and coding scheme; and 
 transmitting the second portion of the header with a second modulation and coding scheme that is different form the first modulation and coding scheme, wherein the first portion of the header comprises a modulation and coding scheme indication field indicative of the second modulation and coding scheme. 
   
     
     
         2 . The method of  claim 1 , wherein the frame comprises a payload, and wherein transmitting the frame comprises transmitting the payload with the second modulation and coding scheme. 
     
     
         3 . The method of  claim 2 , wherein the payload comprises a cyclic redundancy check (CRC) for the second portion of the header. 
     
     
         4 . The method of  claim 2 , further comprising:
 generating the first portion of the header using a first forward error correction (FEC) encoder;   generating the second portion of the header using a second FEC encoder; and   generating the payload by using the second FEC encoder.   
     
     
         5 . The method of  claim 4 , wherein generating the first portion of the header further comprises using a repetition encoder and channel interleaver. 
     
     
         6 . The method of  claim 4 , wherein the FEC encoder performs Reed-Solomon encoding. 
     
     
         7 . The method of  claim 2 , wherein the first portion of the header comprises a first length field indicative of a length of the second portion of the header, and a second length field indicative of a length of the payload. 
     
     
         8 . The method of  claim 2 , wherein the second portion of the header comprises a length field indicative of a length of the payload. 
     
     
         9 . The method of  claim 8 , wherein the payload includes padding, and wherein the length field is indicative of the length of the payload, excluding padding. 
     
     
         10 . The method of  claim 2 , further comprising generating the payload, wherein generating the payload comprises:
 receiving a set of blocks;   performing a first encoding technique on the set of blocks to add a first set of error correction code to the set of blocks to produce a set of encoded blocks;   performing a second encoding technique on the set of encoded blocks to add a second set of error correction code to the set of encoded blocks to produce a set of forward error correction (FEC) blocks;   dividing the set of FEC blocks into a set of fragments;   copying each fragment of the set of fragments a number of times to produce a set of repeated fragments;   interleaving the set of repeated fragments to produce a set of interleaved fragments; and   concatenating the set of interleaved fragments to produce an encoded payload block, wherein the payload is based on the encoded payload block.   
     
     
         11 . The method of  claim 1 , wherein the frame comprises a preamble, and wherein transmitting the frame comprises transmitting the preamble before transmitting the first portion of the header. 
     
     
         12 . The method of  claim 1 , wherein the modulation and coding scheme indication field comprises a plurality of bits. 
     
     
         13 . The method of  claim 1 , wherein the first portion of the header comprises a length field indicative of a length of the second portion of the header. 
     
     
         14 . The method of  claim 13 , wherein the length field comprises 3 bits or less. 
     
     
         15 . The method of  claim 1 , wherein the frame comprises orthogonal frequency division multiplexing (OFDM) symbols. 
     
     
         16 . The method of  claim 1 , wherein the second portion of the header comprises a medium access control (MAC) header. 
     
     
         17 . The method of  claim 1 , wherein the second portion of the header comprises a source identifier and a destination identifier. 
     
     
         18 . The method of  claim 1 , further comprising generating the second portion of the header, wherein generating the second portion of the header comprises:
 receiving a set of header blocks;   performing Reed-Solomon encoding on the set of header blocks to produce a set of Reed-Solomon encoded header blocks;   performing convolutional encoding of the set of Reed-Solomon encoded header blocks to produce a set of forward error correction (FEC) header blocks;   making a number of copies of each block of the set of FEC header blocks to produce a set of repeated header blocks;   interleaving the set of repeated header blocks to produce a set of interleaved header blocks; and   concatenating the set of interleaved header blocks to produce an encoded header block, wherein the second portion of the header is based on the encoded header block.   
     
     
         19 . The method of  claim 1 , wherein transmitting the frame comprises transmitting the frame over an AC power line. 
     
     
         20 . The method of  claim 1 , wherein transmitting the second portion of the header comprises transmitting the second portion of the header after the first portion of the header.