Performance Analysis of Least Square-Based Decision Feedback Equalization Technique for Mobile Satellite Communications

Satellite signal transmission is not only affected by weather condition at a particular time or region but may also be perturbed by multipath effects and shadowing. To be able to mitigate the effects of the aforementioned phenomena on the transmitted satellite signals, the communication channel condition needs to be estimated so as to take appropriate corrective measures. The study focuses on taking the advantage of the low complexity Least Square (LS) method and combining it with decision feedback to develop an improved equalization technique, Least Square Decision Feedback Equalization (LS-DFE), suitable for mobile satellite communication system. The LS-DFE algorithm involves first estimating the channel response; then the estimated channel statistics is used by the decision feedback equalization to obtain the channel response for the next frame. From the simulation results obtained, it was observed that the transmitter sequence is not well detected by both the conventional LS and Linear Minimum Mean Square Error (LMMSE) methods unlike the LS-DFE method. The ability of the LS-DFE method to detect the signal much better is due to the presence of decision feedback; which contributes significantly to the reduction of the fading effects on the received signals. Further results also reveal that the LS-DFE technique outperforms both the conventional LS and LMMSE in terms of BER performance and time of convergence.