Soft Detection of CPM in Multipath Fading

We consider single-h continuous phase modulation (CPM) systems that use linear prediction receivers with coefficient look up table (LUT) for mitigating the effect of multipath fading. This type of receiver shows superior performance over conventional ones; however, high channel delay spread and fast fading can still lead to a high error floor in its performance. A sub-optimal soft/iterative detection based on the soft output Viterbi algorithm (SOVA) is presented for reducing such error floors while maintaining low complexity. The design is extended with a simple spatial diversity combining scheme and the utilization of multiple coefficient LUTs. The proposed approach allows a significant performance gain to be achieved.