Structured distance approach to block coded modulation

Coded modulation schemes that use a block encoder are known as block coded modulation (BCM) schemes. This paper introduces a new approach, called the structured distance approach, for finding codes to be used with BCM schemes over additive white Gaussian noise (AWGN) channels. A set-theoretic representation of the Euclidean distance between signals of a channel signal constellation is used to find the distance distribution of the code. The code words are obtained from the distance distribution by selecting appropriate signals from the constellation to satisfy the distribution. The proposed approach is specifically suitable for obtaining short general (non-linear) codes with higher rates which result in short soft decoding delays. Codes over arbitrary channel signal constellation with redundancy over space and time are reported