Progressive Frequency-Offset Compensation in Turbo Receivers

Based on the recently-proposed iterative receiver by Colavolpe et al., we extend it to further incorporate the mechanism of frequency-offset compensation. As a progressive approach, the factor graph of a long frame is first divided into numerous subgraphs of short block, iterative decoding can successfully start its work as the effect of frequency-offset can be well mitigated due to the small size of subgraph. As the iteration goes on, the extrinsic information from decoder can be employed to get finer estimate of the frequency-offset. The system performance can be steadily improved as the block size is progressively expanded to the final frame size.