Research On Blind Equalization Technique Of The Multiplex System

The Spread Spectrum technology has got wide usage upon communication, telemetry, orientation and radar system since it offers many advantages including anti-interference, anti-eavesdropping, strong discrimination, multiple access anti-fading and so on. The complex system has the function of communication and telemetry simultaneously because the DS/SS has the ability of strong discrimination and ranging.In the complex system, the inter-symbol interference is involved because of the multi-path effect. Channel equalization technique is an effective way to combat ISI. In the traditional equalization, training sequence must be sent to track the available of channel. But blind equalization can effectively increase both the communication speed and reliability without the aid of any training sequence.The thesis investigates the application of blind equalization technique in the complex system to improve the capability of the system. Based on the introduction of multiplex system, several typical equalization algorithms are studied in the paper. The properties of these equalizers are compared from these aspects: the convergence of algorithms, MSE, the ability of tracking variation channel and the ability of anti-interference.Furthermore, a dual-mode blind equalizer based on DFE is investigated and applied in the complex system; the proposed algorithm can overcome the signal phase rotation caused by Doppler Shift on the base of quick convergence. Meanwhile, it can keep the error in a robust state and have strong ability of tracking channel. The simulation result proves that the equalization technique can remove the dithering of correlation peak in the system. Multiplex system with the improved algorithm has strong suppression ability of ISI and strong capability of measurement.