Study On Detection Algorithm For Serially Concatenated Continuous Phase Modulation

Continuous phase modulation (CPM) is a kind of constant-envelope digital modulation schemes with continuous phase which provides good bandwidth-efficiency and power-efficiency, so it is suitable to the communications where the transmission power and channel bandwidth are both limited severely.Firstly, this paper introduced CPM's presentation methods, and the fairly good power efficiency of CPM as well as various realization methods of the modulator are explained. Subsequently, the demodulation algorithms of CPM are studied as a key point, and some merits such as the Bit Error Rate (BER) performance and the complexity are analyzed synthetically. Then introduced the Laurent Decomposition method, which means CPM signal can be presented by the linear combination of a set of Pulse Amplitude Modulation (PAM) signals. This scheme can reduced the complexity of the receiver by detect the"main pulse". Finally A new non-coherent sequence detection (NSD) is proposed in this paper, the results of simulation show that the algorithm can achieve a high performance based a low complexity.Since CPM can be decomposed into a continuous-phase encoder (CPE) and a memoryless modulator (MM), and the CPE is equivalent to a convolutional encoder, there is no need of inner code in Serially Concatenated Continuous Phase Modulation (SCCPM). SCCPM with iterative decoding based on soft-input soft-output shows a large coding gain. So it is robust under highly dynamic and fading environment.