Design and Implementation of Encoder and Decoder for SCCPM System Based on DSP

Serially concatenated continuous phase modulation (SCCPM) combines serially concatenated convolutional coding (SCCC) with continuous phase modulation (CPM). Continuous phase encoder which is decomposed from CPM is used as a convolutional coder, and iterative decoding based on log-MAP (maximum a posteriori probability) algorithm is used in decoding, which bring the system good power efficiency and frequency efficiency, 3.0 dB gain at least. In [1] the effects of different parameters on SCCPM system are presented. In [2] we present a joint parameters query. When a channel quality value is given, optimal joint parameters related will be used in the system to get minimum bit error rate (BER), which can bring system an extra 0.5-1.0 dB gain. The encoder and decoder of SCCPM system is implemented on DSP-TMS320C6416 for its high-speed processing despite the complexity of iterative decoding.