Blind SISO Detection of M-ary CPM in Fast-Fading Flat Channels

We propose a blind soft-input-soft-output (SISO) detector for continuous phase modulation (CPM) signals in flat fast-fading channels. We follow a Bayesian approach, which leads to a detector, in which a Kalman filter for tracking the varying channel is integrated. We use numerical simulations to evaluate the performance of the derived detector for channels with maximum Doppler frequencies as large as 20% of the baud rate, and compare the results with those of the optimal detector having perfect channel knowledge. The results show that our blind detector is able to track the channel and shows no signs of an error floor, which is common for detectors in fading channels. In addition, we consider serial concatenation with a channel code and iterative decoding to take advantage of the SISO property.