Viterbi Detection Method of /4-QPSK Signal in VDE

Aiming at the complexity of communication environment, the bad signal quality and influence of different parameters in the study of VHF data exchange (VDE) satellite, a detection method of viterbi is proposed in this paper. According to the characteristic of /4-QPSK signal, this method constructs signal phase states, and gives a cost function of decoding based on the maximum likelihood criterion, and then by using the thoughts of viterbi to decode. The complexity of this method is relatively low, and it is easy to implement for baseband signal detection. The simulation results show that this method has good detection performance, which is about 9dB better than traditional methods under the same Eb/No. It can be applied to the conditions with interference, time delay, frequency offset and phase shift which has good robustness and anti-interference performance, and the detection performance is not affected by constant frequency offset and phase shift.