Error Rates in Coherent Communication Systems

In coherent PCM communication systems where the noise is additive and Gaussian (such as in space communication systems) two classes of nonredundant coding are of special interest. One is Regular Simplex Coding which yields the lowest possible error rate for fixed SNR. The other is Bi-orthogonal Coding because of its many desirable features from the practical point of view. In this paper the error rates per word and per bit are computed for both of these classes. The communication efficiency-a quantity of major importance in space communications-is also calculated for fixed error rate as a function of code size.