Research On Beamforming Algorithm Of Smart Antenna

Smart antennas system, by introducing advanced digital signal processing and adaptive array processing, produces space beams, whose main beam directs at the direction of the desired user and null steering beams point at the directions of interferences, thus suppressing or canceling the interfering signals. Therefore, smart antennas system can improve the quality of communication.Beamforming algorithm is one of the core technologies of smart antennas. In the paper, two improved beamforming algorithms are proposed. First, basing on the MNLMS algorithm using instantaneous power of input data to control the step factor and NVSS algorithm using the instantaneous power of error to control the step factor, a new algorithm is proposed, which uses the instantaneous power of input data and error to control the factor of step. The simulation results show that the new algorithm can obtain low mean square error and fast convergence. Second, the accuracy of estimating the number of the sources affects the performance of the MUSIC algorithm. The MDL algorithm is complex and difficult to realize. This paper firstly analyzes the factors which affect the accuracy, such as input signal range, the number of snapshots and the ratio of signal to noise, and then proposes a new algorithm, which can reduce the effects of input signal range and the number of snapshots. It can estimate the number of the sources easily and accurately.