Performance of Reduced State S–T Trellis Coded MC-CDMA Systems

In this paper, performance of reduced state space-time trellis coded multi carrier code division multiple access (STTC-MC-CDMA) system is evaluated and compared with the performance of original state STTC-MC-CDMA system. The optimum decoding scheme, i.e., maximum likelihood sequence estimation is employed which uses Viterbi algorithm for decoding STTC code. To simplify the implementation of the STTC decoder, the number of states is reduced by reducing the constraint length of the STTC encoder using generating function technique. In this technique, the generator matrix of STTC code is minimized to reduce the number of states of S–T trellis decoder. It is observed that the performance loss in terms of frame error rate of the reduced state STTC-MC-CDMA system is negligible compared to the original state STTC-MC-CDMA system. It is also noted that by using the reduced state technique the STTC decoder can be made faster since it is having lower computational complexity.