Application Of M-ary Hyper Phase Shift Keying In Satellite Communications

In satellite communications, the use of equal energy symbols is preferred so that the non-linear amplifier can operate in its approximately linear range with minimal backoff, because the satellite channel is a typical nonlinear channel. In this thesis, a new modulation technique—M-ary Hyper Shift Keying(MHPSK) is applied to satellite communications system, and a study has been made about anti-noise performance and issues of non-linear distortion in satellite communications.This paper describes the channel code and modulation technique briefly first, introduces LDPC encoding and decoding principle and algorithms in detail, and researches the soft-information extraction method of four kinds of modulations used in DVB-S2 system. Then, this paper focuses on the principle of MHPSK modulation. MHPSK is a spectral efficient modulation technique that uses four orthonormal basis functions to increase the distance between different symbols in the signal space, so it offers an improvement in bit error performance over other modulation techniques for the same average energy per bit-to-noise power spectral density ration. Next, the constellation mapping methods for 16-HPSK,32-HPSK and 64-HPSK are introduced with the computer simulation of their performance and analysis of their spectral efficiency. Furthermore, soft-demapping method of 16-HPSK,32-HPSK and 64-HPSK is proposed with the computer simulation of their performance, which is compared with performance of DVB-S2 system. The results of simulation indicate that a great improvement exists in the performance of noise resistance. Next, the peak-to-average power ratio of 16-HPSK,32-HPSK and 64-HPSK is researched. Finally, the computer simulation of amplifier back-off of MHPSK are done in non-linear channel. The results show that MHPSK is suitable for application to satellite communications whose channel is non-linear, due to the equal energy symbols of MHPSK.