Investigation Of Smart Antennas Beamforming Algorithms

Smart antennas technique is a primary development direction of future wireless communication systems. How to cancel co-channel interference, multi-access interference, and combat the multi-paths fading effects, are major factors needed to be considered, when people attempt to enhance the communication system. Smart antennas system, which introduces advanced adaptive array processing, produces space beams whose main beam directs at the direction of desired user, null steering beams directing at the direction of interference, thus suppressing or canceling the interfering signals, therefore, it can improve the signal-to-interference ratio and system capacity. Recently, the smart antennas technique is one of the hot research topics in mobile communication area as a solution to the frequency lack.Based on the other persons' research on smart antennas algorithms, especially on beamforming techniques, two aspects of the smart antennas beamforming algorithms are thoroughly investigated in this paper. Firstly, to combat the array non-ideal geometry error, DOA estimation error, not exact calibration of antennas, multi-beams based robust beamforming algorithms are studied to improve the beamforming performance. Secondly, aiming at the complex electromagnetic environments when existing strong interference, null steering algorithms are exploited to cancel the strong interference. Based on this, a proposal synthesizing null steering technique and dynamic channel allocation is presented to cancel interference resulted from inconsistent timeslot allocation between base stations.