Combined Higher Order Spectral Nulls Codes and OFDM Modulation for Power Line Communications

We present different techniques for designing codes with higher order spectral nulls, based on the power spectral density function; the binary representation of permutation codes and the finite state machine representation. Distance increasing mappings (a technique for mapping convolutional code outputs onto constrained symbols) is applied to generate codes with a certain power spectral density function and enhanced error correction capabilities. Combining this class of new codes with an OFDM modulation scheme is a very strong candidate-coding scheme for non-AWGN channels such as the power line communications channel