Permutation modulation

A class of codes and decoders is described for transmitting digital information by means of bandlimited signals in the presence of additive white Gaussiau noise. The system, called permutation modulation, has many desirable features. Each code word requires the same energy for transmission. The receiver, which is maximum likelihood, is algebraic in nature, relatively easy to instrument, and does not require local generation of the possible sent messages. The probability of incorrect decoding is the same for each sent message. Certain of the permutation modulation codes are more efficient (in a sense described precisely) than any other known digital modulation scheme. PCM, ppm, orthogonal and biorthogonal codes are included as special cases of permutation modulation.