Iterative non-coherent detection of serially-concatenated codes with differential modulation

In this contribution, we investigate the properties of serially-concatenated coding (SCC) schemes with differential PSK modulation. The differential encoder (DE), which can be interpreted as a recursive non-systematic convolutional code, serves as a component encoder of the SCC system. A novel non-coherent reception algorithm is proposed, which is capable of bridging the performance gap between coherent and noncoherent receivers by iteratively exchanging extrinsic information. Since no prior channel state information (CSI) is available for the proposed non-coherent decoding approach, a low-complexity APP channel estimator is devised and incorporated to provide estimated channel coefficients using the a posteriori probability (APP) generated by the inner decoder. Results of SCC schemes with absolutely-encoded coherently-detected PSK are also presented to demonstrate that differential systems do not necessarily cause performance degradation.