Algorithm Study Of Multi-h CPM Communication System

Continuous Phase Modulation technology,as a constant envelope modulation method,CPM has high bandwidth utilization,channel utilization,a broad application prospect in wireless communication,telemetry and other high-speed data transmission systems.Multi-modulation index CPM（Multi-h CPM）can make full use of spectrum resources and have higher bandwidth utilization due to its hopping modulation index.There are two main limitations in implementing Multi-h CPM communication systems:the high complexity of coherent sequence detection and the difficulty of synchronization.In this thesis,these two problems are studied,and the main work and innovations are as follows:（1）A joint TP-Laurent-SSP sequence detection algorithm is proposed.The algo-rithm utilizes Laurent decomposition to approximately characterize Multi-h CPM signals,reduces the number of matching filters by selecting pulse subsets and averaging pulses,and simplifies the grid states by combining Tilted Phase and State-Space Partitioning,thus reducing the computational complexity in the Viterbi decoding module.Based on reason-able parameter settings,the number of required matching filters is reduced from 128 to 3,and the number of grid states is 1/16 of the Maximum Likelihood Sequence Detection.The algorithm effectively solves the problem of high complexity of MLSD algorithm for Multi-h CPM signals,and the simulation shows that the joint sequence detection algo-rithm at P₄=10^-4,the BER performance decreases only 1.12d B compared with the MLSD algorithm.（2）A Multi-h CPM symbol timing synchronization structure with correction of false locks is designed.The structure is divided into three modules,the main synchronization algorithm is based on Laurent decomposition and decision-directed symbol timing syn-chronization algorithm,the auxiliary synchronization algorithm is composed of auxiliary symbol timing error detector and Markov chain-based design of false lock detector.Be-sides,the auxiliary judgment module is introduced to enhance the reliability of the judg-ment.The structure effectively solves the problem of false locking that easily occurs in the S-curve when the decision-directed symbol timing synchronization algorithm is ap-plied to the high binary partial response Multi-h CPM signal.Computer simulation shows that the structure in this thesis has a shorter false-locking capture time compared to the conventional false-lock detector,and a wider locking range compared to the single use of the main synchronization algorithm.