Research On MPSK Signal Demodulation Method For Non-Cooperative Communication

Practically, signal receivers always fail to get whole signal parameters. To solve this problem, blind signal processing method and signal demodulation are employed. However, since there exist numerous kinds of signals, the working process is time-consuming and arduous. Thus, exploring a general algorithm to complete the blind demodulation of various signals in a general hardware platform is of great practical value. Not only is it an effective way to simplify the hardware design, this approach is also an opportunity to improve the efficiency of engineering development.This paper is dedicated to realize the generalization of the algorithm and the hardware by putting forward a general demodulation architecture, including the general algorithm architecture and general hardware architecture, for MPSK and MQAM signals. Based on thorough research of blind demodulation algorithm, the paper will complete simulation and hardware implementation of the algorithm. Paper content is a part of the international cooperation key engineering projects undertaken by the author’s teaching and research section.In this paper, the main work and achievements are as follows:1、On the basis of the universal recognition of the signal processing hardware platform, researching the modulation and demodulation method for MPSK and MQAM signal. Studies have found that the demodulation algorithm is so multifarious for different signals that it causes a lot of inconvenience for project implementation. Aiming at this problem, this paper puts forward a general demodulation architecture suitable for MPSK and MQAM signals, so that it generalizes the algorithm and simplifies the engineering development.2、Studying the key technologies and the corresponding design method involved in the blind demodulation algorithm: carrier traction technology, carrier synchronization technology, symbol synchronization technology and differential decoding technology, respectively. On the basis of the theoretical deduction, this paper shows that the corresponding algorithm and the overall demodulation performance have been increased greatly.3、To verify the practicability of the proposed general demodulation algorithm, the paper tests the performance of frequency traction, carrier synchronization and symbol synchronization module, while running the bit error performance test on the whole blind demodulation system. Frequency traction algorithm achieves high precision frequency estimation under the condition of small data quantity. Carrier synchronization algorithm solves the contradiction between large dynamic capture and high precision tracking. The excessive timing jitter of multi-band signal is reduced by Symbol synchronization algorithm. The bit error performance reaches the best level and is much better than the project requirements.4、Under the hardware architecture of DSP+FPGA, implementing a general blind demodulation algorithm for a variety of signals, and the performance reaches a advanced level. The bit error rate of BPSK, QPSK, and 16 QAM signals can approach the theoretical bit error rate. At the bit error rate of 0.001, the performance degradation is less than 0.5 dB. For 8PSK signal, the performance degradation is at about 1 dB.