Adaptive turbo decoding technique for two transmit antennas space time block code

A novel adaptation technique is used in the receiver (decoder) side to improve performance of turbo coded space time block code. The main idea of adaptive turbo decoding is simply achieved by multiplying the extrinsic information passed between decoders (component decoders) by weight factor depending on number of iteration and signal to noise ratio of the system. The performance of the turbo coded system with AWGN channel and STBC scheme of two transmit antennas and one receive antenna over block fading channel is evaluated. The performance of the turbo coded space time block code systems is simulated using MATLAB, and the results show that this system provides about 0.5 dB gain at a BER of 10^-5 compared to non-adaptive system.