Parallel interference cancellation with inner and outer iterations for detection of orthogonal space-time block coding over time-selective fading channels

In order to simplify the decoding algorithm of the orthogonal space-time block codes (O-STBC), it is usually assumed that the channel remains static over the length of the code block. While this assumption is reasonable in most cases, it is not accurate when the channel is time-selective, which varies during the length of the code block. In such case, the conventional O-STBC decoders proposed in [1] will produce interference caused by time variations of the channel, resulting an irreducible error floor in the high signal-to-noise ratio (SNR) region depending on the normalized Doppler frequency of the time-varying channel. In this paper, we address this issue by proposing an iterative parallel interference cancellation (PIC) detection approach with inner and outer iterations based on the conventional O-STBC decoder for G(i) [1] (i=4) codes over time-selective fading channels. Simulation results will show that the proposed PIC detector can offer better performance than the conventional decoder by reducing the interference to a negligible level.