The Synchronization And Channel Equalization Algorithm Research And Implementation Of HF Communication System

Shortwave communication plays an important role in the military communications. Increasing communication the data transferring rate, developing more and more related products, enhancing the ability of constructing networking, these becomes the development trends of shortwave communication. Using traditional technology has been difficult to meet these demands. This thesis is based on the technology of digital signal processing and software radio. It improves the performance of the transferring data in the data link layer of the short-wave communication system.In this thesis, the main research is the technology of modulation and demodulation in the short-wave communication system. Shortwave communication channel have the characteristics of multipath debilitating and Doppler frequency shifting. I mainly focus on the synchronization and channel equalization algorithm.This HF communication system uses these main technologies as follows: convolution coding, interleaved, Walsh coding (software spread spectrum technique), the PN code,8PSK modulation and demodulation.The major work done, synchronization and phase synchronization in the receiver by using the sliding FFT related technology to complete the capture of the signal on the receiving end of the frequency difference is estimated, the PN code symbols. Using DDE algorithm estimates channel equalization, significantly improving the reliability of the short-wave communication system.The paper mainly discusses the principles of related technologies and the methods of implementing these technologies in shortwave communication platform. In the end of the thesis, summarize the shortage of the short-wave communication system which needs to be improved.