The capacity of orthogonal and bi-orthogonal codes on the Gaussian channel

This paper analyzes the performance of concatenated coding systems operating on the additive white Gaussian noise (AWGN) channel by examining the loss of capacity resulting from each of the processing steps. The described techniques allow the separate evaluation of codes and decoders and thus the identification of where loss of capacity occurs. Knowledge of this capacity loss is useful in the overall design of a communications system, e.g., for evaluating the benefits of inner decoders that produce information beyond the maximum likelihood (ML) estimate. The development of this paper is restricted to orthogonal and bi-orthogonal codes operating on the AWGN channel; however, the methods have wide application and can be used to assess arbitrary codes on other channels