Research into Demodulation of Continuous Phase Modulation Signal
|School||PLA Information Engineering University|
|Course||Electronics and Communication Engineering|
|Keywords||CPM Viterbi decoder Matched filter Laurent decomposition Coherent detection|
The continuous phase modulation (CPM) is a class of memory nonlinear modulation , spectrum utilization and power utilization , and has a good prospect in the radio communication environment . This efficient modulation technique having such excellent characteristics , but , since the CPM itself is a memory of the non - linear modulation scheme , the large-scale application of the CPM in the various types of wireless communication system is still subject to the complexity of the demodulator and synchronization constraints . Typically, the the CPM signal demodulation in AWGN channel with high complexity Maximum Likelihood Sequence Detection (MLSD ) . Therefore , the study of a low- complexity demodulation algorithm is of great significance for the wide application of the CPM signal . This paper first introduces the general expression of the CPM signal , the phase characteristics and power spectral density function , based on a computer simulation of its power spectral density , analyzed the characteristics of the the CPM signal modulation parameter values ??of its power spectrum impact; then depth study of the CPM signal maximum likelihood coherent demodulator and the Viterbi algorithm , using the Laurent decomposition CPM signal optimal coherent demodulator and sub-optimal coherent demodulator , and the different methods of demodulating simulation performance , through comparative analysis based on Laurent algorithm optimal coherent demodulator and sub-optimal coherent demodulator greatly reduces the complexity of the receiver in the case of loss or little loss in BER performance is almost no .