ANALYSIS AND PERFORMANCE COMPARISON OF THE TRELLIS-CODED AND CONVOLUTIONAL CODED DS SSMA SYSTEMS IN IMPULSIVE NOISE ENVIRONMENT/

The authors investigate the performance of two types of direct-sequenc e spread-spectrum multiple-access (DS/SSMA) systems in an impulsive no ise, Rician fading environment. It is observed that it is possible to get some coding gain over uncoded systems except at low SNR and that a dditional coding gain can be obtained by using optimum asymmetric TCM. It is also shown that the performance of the DS/SSMA systems degrades more as the noise becomes more impulsive.