Design and analysis of trellis codes for orthogonal signal sets
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This paper studies trellis codes to be used with orthogonal signal constellations. The intended application is in direct-sequence code-division multiple-access communication systems. The problem of designing good codes is addressed showing how to construct trellis codes from block codes with good burst-error detecting capabilities. Several examples are given resulting in codes equivalent to those found previously by computer search in [8]. The procedure presented can be done by hand and is applicable for designing codes with long constraint lengths and large signal sets where a computer search becomes prohibitive. Performance of such coded systems can be determined through transfer functions of the specific codes used. A general transfer function is given which provides a reasonable approximation to the actual transfer function of good codes. Thus, a first-order approximation to the performance of a given system can be determined without actually going through the process of designing and analyzing a specific code. 1995 IEEE