Research On Combination Modulation And Demodulation Technology In Deep Space Communication

The basic idea of Combination modulation and demodulation in Deep Space Communication is that in terms of the characteristics of Deep Space channel, some highly efficient modulation and demodulation technology combined together with signal processing methods are applied to achieve a better receiving performance. The main purpose is to study further in the constant envelope and Quasi-constant envelope modulations with high modulation efficiency.Constant envelope modulation such as QPSK and continuous phase-frequency shift keying such as GMSK are set as basic examples of modulation and demodulation scheme in Deep Space Communication in this thesis, as well as quasi-constant envelope modulation such as IJF-OQPSK and FQPSK are discussed as the suitable modulation scheme, combined with Direct Sequence Spectrum Spread (DSSS) technology and other signal processing methods. Each technology is focused on certain characteristic of deep space communication, on combining these methods and modifying some parameters, a better system performance can be got. On the foundation of the holistic modulation and demodulation frame architecture, the system is optimizing further. The feasibility of the scheme can be demonstrated through academic analysis and software simulation, so that technical support can be offered to deep space communication in future.After careful study of the coding scheme in MER system, some coding modulations that may be applied in future deep space communication are also discussed.