Modulation Recognition Of MPSK And MQAM Signals In Multipath Channel

This thesis discusses the algorithm for modulation recognition of MPSK and MQAM modulation signals in multipath environments. The blind equalization is applied to mitigate effects of multipath and system synchronization errors. Then the signals are processed by subtraction-clustering, normalizing the constellation diagram. Consequently, constellation diagram is rebuilt. A new blind equalization algorithm is used in this thesis. It can be rebuilt the constellation diagram of MPSK and MQAM signals for the order of not more than 64. Based on this thesis, maximum likelihood method based on constellation diagram shape classification is used for modulation recognition of MPSK and MQAM signals with the order of not more than 64.Because of good performance of this blind equalization algorithm, it is shown by computer simulations that the constellation diagram of MPSK and MQAM with the order of not more than 64 can be rebuilt by the proposed method at SNR≥12dB.