Iterative decoding of GMSK modulated convolutional code with multiple differential detection

A novel receiver architecture for the serial concatenation system of a convolutional code and a Gaussian minimum shift keying (GMSK) modulator is proposed. A maximum a posteriori probability algorithm for the multiple differential detection (MDD) of GMSK signals, which accepts a priori information and provides a soft-output for the subsequent convolutional decoder, is derived. The soft-output of the decoder is fed back to the MDD receiver for further improvement, thus resulting in an iterative decoding structure.