Smart Antenna Beamforming Algorithm

The technology of the smart antenna is accepted as an advanced technology which introduces the pattern of Space Division Multiple Access to differentiate the signals with the same frequency,the same time slot and the same code but with the different transmission paths.The smart antenna can be used with other multiple access technologies,so the range of communication resource extends from time region,frequency region and code region to space region.As the result of the technoloty of smart antenna utilized,the capacity of communication system increase remarkably,and limited frequency spectrum resource will be utilized sufficiently.The core technology of the smart antenna is beamforming technology,this paper focused on the adaptive beamforming algorithm.It contains:First of all,the paper introduces the basic operation principle of the smart antenna,the basic structure and signal model, and expatiates some adaptive beamforming criterion,and analyzes and contrasts the several common non-blind adaptive beamforming algorithms;For traditional LMS algorithm,affected by the step size in convergence speed, tracking abilities of time-varying system and imbalance between contradictions,the paper gives a new variable step size LMS algorithm and a transform domaing variable step size LMS algorithm, and expatiates the theoretical model and the derivation of the theoretical process, and points out the advantages and disadvantages of each algorithm.And the convergence speed and perfomance are simulated and compared.Finally, the paper introduces the blind adaptive algorithms, which have the problems of convergence rate, computation amount and capturing the interference signals,and gives a new algorithm which can solve these problems.