Research On Multi - H CPM Synchronization And Sequence Detection Technology

Multi-h CPM will be a key technology in the next generation wireless communication, and will have the dominantly potential advantages in the future of telemetry field, because of high bandwidth efficiency and good BER performance. However, difficulties on synchronization and high complexity of sequence detection have limited the wide application of Multi-h CPM. In this dissertation, in-depth researches on synchronization and sequence detection for Multi-h CPM in telemetry have been conducted. The main contributions are as follows.Firstly, a non data-aided (NDA) carrier frequency synchronization algorithm for Multi-h CPM is proposed. It starts from maximum likelihood estimation theory, and then the concept of modulation index synchronization error is introduced. According to the character of introduced modulation index synchronization error, such as discrete and equiprobable, carrier frequency offset error estimation is obtained by simplifying the joint marginal likelihood function. The proposed algorithm is suitable for full response and partial response formats, and has good performance in the low and median SNR range. A reduced-complexity scheme is introduced through quantification the filter impulse response into rectangle, whose performance loss is small and computational complexity is dramaticlly reduced. Furthermore, MCRB of carrier frequency offset estimation for Multi-h CPM is deduced in order to evaluate the algorithm performance.A decision-directed carrier phase synchronization algorithm based on PAM decomposition for Multi-h CPM is researched, and MCRB of carrier phase estimation is deduced.The carrier phase error estimation is obtained by ultilizing pulses whose energy is dominant, and it makes the researched algorithm have small performance loss and low-complexity.Secondly, a NDA symbol timing synchronization algorithm for Multi-h CPM is proposed. Timing error estimation is obtained by simplifying the joint marginal likelihood function. The proposed algorithm is not only immune to false lock, but also its timing recovery performance is close to ideal synchronization for signal formats with M-ary and L<3. Because of serious inter-symbol interference for signal formats with M-ary and L=3, a solution scheme with rough timing synchronization assisting fine timing synchronization is proposed. By combining their respective advantages of both algorithms, rigorous timing synchronization is achieved at the cost of the small increased-complexity. A NDA modulation index synchronization algorithm is researched, and it don’t need to estimate vector parametres to make its realization simplified. In order to improve performance, a two-step modulation index synchronization algorithm based on post-processing fine estimation is researched. The performance deterioration of rough estimation algorithm with noise aware likelihood function is reduced greatly by setting reasonable post-processing threshold to protect rough estimation.Thirdly, a differential noncoherent sequence detection algorithm for Multi-h CPM is proposed. The carrier frequency offset is eliminated and corrected by introducing symbol difference and reference phase signal, and the BER performance is improved by utilization multiple symbol difference to increase Euclidean distance of differential signals. The reduced-state scheme is researched by introducing Per-survivor processing, which can greatly reduce the implementation complexity with negligible performance loss. Furthermore, modulation index self-synchronization algorithm is researched by using branch metrics information of sequence detection itself to estimate modulation index sequence, which simplifies the receiver structure.Finally, a Multi-h CPM system, including IF receiver and IF transmitter, is built. Some of proposed algorithms are validated.This system provides a preliminary solution for the practicability and engineering realization of Multi-h CPM in telemetry field.