Turbo (iterative) decoding of a unitary space-time code with a convolutional code

A turbo decoding scheme for a noncoherent, unitary space-time modulated [3] communication system employing an FEC convolutional code is proposed. The channel is assumed to be Rayleigh fading with neither the transmitter nor the receiver knowing the channel coefficients. The convolutional encoder is applied to the information symbols before performing unitary spacetime coding. Treating the combination of convolutional code and the unitary space-time code as a serially concatenated turbo code, it is shown that the performance can be improved by iterative decoding. Simulation results suggest that the iterative decoder can offer significant performance gain over conventional, non-iterative method and also can help close the performance gap between coherent (e.g. Alamouti type) and non-coherent techniques by a significant margin. Keywords—Unitary space-time modulation, Turbo decoding.