CPM optimization for low-complexity serial concatenated CPM

Serial concatenated continuous phase modulation (SCCPM) combines the constant envelope and bandwidth efficiency of continuous phase modulation (CPM) with the performance of serially concatenated codes making it attractive for satellite communication links with saturated transmitter amplifiers. Iterative demodulation and decoding of SCCPM provides excellent performance with simple outer codes by combining the structures of the modulation and the code. Because of the large space of CPM parameters, finding good SCCPM schemes with desired bandwidth efficiency and reasonable complexity is challenging. We present a systematic, simulation-based approach to this optimization problem with special attention to the interesting trade-off between the CPM bandwidth efficiency and the outer code rate.