Two classes of convolutional codes over GF(q) for q-ary orthogonal signaling

Two classes of nonbinary convolutional codes for error control in communication systems employing q-ary orthogonal signaling are discussed. These classes include as special cases, the dual-k codes and the codes treated by B.D. Trumpis (1975). The types of code, extensions of previous bounds on free distance, the noncatastrophic condition for these codes, and conditions for catastrophic error propagation are described. Codes obtained by a computer search, optimal in that the truncated transfer function bound on the probability of symbol error is minimized, are presented. It is shown how good convolutional codes can be constructed from cyclic block codes. The performance of some of these codes over additive white Gaussian noise channels, Rayleigh channels, and partial-band interference channels is also discussed.<
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