A solution for BER performance and energy efficiency improvements of OFDM-CDMA system with pilot tone

In this paper, incorporation of MIMO concept is proposed as a solution for improving BER performance and energy efficiency of OFDM-CDMA downlink system with pilot tone and threshold detection combining (optimum TDC). The new presented system with MIMO included uses space-time block coding applied to two, three and four transmit antennas and it has an arbitrary number of receive antennas. BER (Bit Error Rate) performance in the case of Ricean frequency selective fading is evaluated for the original system as well as for the one with MIMO included. For that reason an adequate simulation model is developed. The results show that the proposed system significantly outperforms the OFDM-CDMA downlink system with pilot tone and optimum TDC. The proposed system provides greater energy efficiency and lower BER in comparison with the original system.