Research On The Adaptive Beam-forming Algorithms Of Smart Antenna

Smart antenna has been used in the field of mobile communication widely. It isformed by some antenna arrays. Smart antenna uses modern digital processingtechniques and select appropriate adaptive algorithms to form space direction beamdynamically. In order to make the main beam of antenna toward the DOA of the desiredsignals and make the null point toward the interfering signals. In this way,we can makefull use of the desired signals Smart antenna is divided into two categories: Switchedbeam smart antenna and adaptive smart antenna. The first uses switching wave to trackmobile users, the latter uses adaptive technology to track the desired signal. Smartantenna has been confirmed as one of the key technologies of the next generationmobile communication system, it will play an important role in the future.An effective beam-forming algorithm is the key of the application of smart antennaan effective beam-forming algorithm. In order to balance the real-time and thecomplexity, this paper is based on digital beam-forming algorithm, researchessemi-blind beam-forming technology, through analysis the feature of algorithm underdifferent norm. The main work is:1) We analyses the structure of smart antenna system and signal model. It will be thebase of all the paper.2) We analyses the principle, characteristics and performance of different typicaladaptive beam-forming norm.3) We analyses the principle, characteristics and performance of some typicaladaptive beam-forming algorithms.4) We give a improved semi-blind least a square constant modulus algorithm.This algorithm is based on constant modulus algorithm (CMA). It uses the subspaceapproach to obtain the initial weights, and then uses the dynamic least squares constantmodulus algorithm to track. The simulation results show that the algorithm has a highconvergence speed, stable performance, and can suppress interference effectively.