The Variable Step-Size Algorithm for Decision Feedback Equalizer Turbo Code DS/CDMA System Using SOVA Algorithm

In this paper a variable step-size algorithm for adaptive decision feedback equalizer (DFE) for turbo coded direct-sequence code division multiple access (DS/CDMA) communication systems is presented. The proposed adaptive equalizer is using a performance of the system or bit error rate to control the adaptation process of the DFE. By this technique, the performances of the proposed adaptive equalizer cooperate with the attractive soft output Viterbi algorithm (SOVA) of turbo decoder for the DS/CDMA system provides a good statistical in non-stationary channel condition scenario. The simulation results confirm that the performance of the proposed system in terms of bit error rate has been improved over the finite impulse response (FIR) equalizer.