A Bit-Mapping Strategy for Joint Iterative Channel Estimation and Turbo-Decoding

In this paper, we investigate turbo-coded transmission over a temporally correlated flat Rayleigh fading channel. Conventionally, channel estimation is performed prior to decoding and is solely based on periodically inserted pilot symbols. We here consider the case that the pilot spacing is not small enough to satisfy the Nyquist criterion for the bandlimited channel process. It is demonstrated that iterative code-aided channel estimation can then significantly improve the bit error rate (BER). Furthermore, we show that the convergence speed of the iterative channel estimation can be significantly accelerated without additional computational power by just carefully choosing the mapping strategy of systematic bits to data symbols.