Construction of good space-time trellis codes based on cyclic codes over rings

"In this paper, we propose a systematic procedure for constructing good space-time trellis codes derived from cyclic BCH codes over local finite commutative rings. The procedure is based on finding a primitive element in the group of units of the Galois extension ring. For a given design distance, the polynomial generator of a BCH cyclic block code over Q is determined. Such a generator polynomial must contain no binary factor. Hence, the coefficients of the generator polynomial is used as the tap connections for the Q-ary convolutional encoder. Some examples of these codes were tabulated."