The iterative demodulation and decoding algorithm for convolutional coded GMSK signals over mobile satellite channel

A new simple iterative demodulation and decoding algorithm for convolutional coded GMSK signals, which is suitable for mobile satellite channel is presented. Demodulation is simplified through the approximation of GMSK as pulse amplitude modulated (PAM) signal, leading to a representation as the inner convolutional code of a serially concatenated convolutional code (SCCC). In addition, based on quasi-coherent demodulation of GMSK signals, an iterative channel estimation method, which can improve bit error rate (BER) performance of proposed coded GMSK signal transmission scheme dramatically, was expressed. Numerous simulation results show that the proposed algorithm can largely reduce the implementation complexity and have significant performance.