Research On Low Complexity Detection Technology Of Multi-h CPM Signal

Continuous Phase Modulation(CPM)signal,as a continuous constant envelope signal,has the characteristics of high spectral efficiency and power efficiency.However,the structure of CPM signal receiver is very complicated because that CPM signal has many modulation parameters.Based on the concept of the Single-h CPM signal,the Multi-h CPM signal is proposed.Compared to the Single-h CPM signal,constant modulation index in the Multi-h CPM signal is cycled periodically,which enabled the Multi-h CPM signal have better bit error performance and better confidentiality.But the Multi-h CPM signal also has more complicated detection process relatively.Therefore,to better put the Multi-h CPM signal into practical application,the key problem we need to solve is to reduce the detection complexity of the receiver of the Multi-h CPM signal.First of all,some basic concepts of the Multi-h CPM signal are introduced.Then,the influence of the different modulation parameters on the Multi-h CPM signal is analyzed from the perspective of power spectrum.Besides,the optimal receiver of the Multi-h CPM signal,i.e.,the maximum likelihood sequence detection,is explained.The simulation results show that the spectrum efficiency and bit error rate performance of the Multi-h CPM signal is better than that of the Single-h CPM signal.However,the computational complexity of the Multi-h CPM signal is higher.Next,the existing low-complexity demodulation algorithms of the Single-h CPM signals are reviewed,such as the tilted phase algorithm,the Laurent decomposition algorithm,and the per survivor processing algorithm.The Laurent decomposition algorithm can reduce the number of the matched filters at the receiver,the tilted phase algorithm and the per survivor processing algorithm can reduce the number of trellis states.These algorithms' applicability to the Multi-h CPM signal is analyzed.The conclusion shows that after an effective improvement,these algorithms can be well applied to detect the Multih CPM signal.Moreover,an improvement is made based on the optimal receiver and a low-complexity detection algorithm is proposed using the maximum cumulative metric.This proposed algorithm can be well applied to detect the Multi-h CPM signal.When the parameters are set reasonably,the computational complexity can be greatly reduced with extremely low error performance loss.Then,a reasonable improvement is made based on the existing algorithms,and propose two low-complexity detection schemes based on the Virtual indexes(h)detectiontileted phase(Vh D-TP)pulse amplitude modulated(PAM)decomposition and the cumulative measure-tilted phase(CM-TP)PAM decomposition.The Vh D-TP PAM decomposition based scheme applies the idea of Per survivor processing(PSP)to the PAM decomposition and the tilted phase algorithm,and the CM-TP PAM decomposition based scheme applies the idea of the maximum cumulative measure to the PAM decomposition and the tilted phase algorithm.Therefore,the two schemes reduce the number of the matched filters and the trellis states at the receiver at the same time.These proposed schemes are analyzed and the simulation results show the proposed these schemes can reduce the computational complexity greatly with only little error performance loss.Finally,the conclusion part summarizes the research content of the low-complexity demodulation of the Multi-h CPM signal,explains the shortcomings of this paper,and points out the further research directions in the future.