Noncoherent iterative demodulation and decoding of serially concatenated coded MSK

In this paper, we propose a detection technique for a serially concatenated coded MSK (SC-MSK) modulated signal, based on the noncoherent BCJR (N-BCJR) algorithm, where an exponentially decaying observation window (EDW) in the N-BCJR algorithm is used to get better use of the channel phase memory and reduce the state as well as metric computational complexity. We also derive the decoding metrics of N-BCJR for the Rayleigh fading channel without channel state information (CSI) and incorporate the EDW in the metrics. The BER performance of the proposed noncoherent SC-MSK, using EDW and a rectangular window (RW), are compared via Monte Carlo simulation in both AWGN and slow, flat Rayleigh fading channels.