Iterative receivers with joint channel and frequency offset estimation in time-variant fading channels

We develop iterative turbo receivers for time-variant fading channels which jointly perform channel and frequency offset estimation together with data detection and decoding. Three versions of the joint estimator, the Bayesian, the maximum likelihood and the regularised-maximum likelihood are presented depending on how much knowledge of channel statistics is available. The estimation and detection are based on the basis expansion model of the fading time variations and use the di-chotomous search frequency estimation technique. Soft information generated in the turbo decoder is used to improve the quality of detection in the subsequent iterations. Simulation results show that the proposed receivers provide as good performance as the corresponding ones operating with perfect knowledge of the frequency offset.