Development of adaptive beamforming algorithms for wireless communication networks

It is required to provide enough capacity in the wireless communication system due to increased number of users as well as new high bit rate services being introduced. One of the most promising techniques for increasing the capacity is smart antenna based space division multiplexing. One approach to implement smart antennas is based on array beamforming, where a narrow main beam is directed towards the desired user direction, while the nulls or the sidelobes with very low levels are adjusted towards other users. Recently, smart antennas have been proposed as a promising solution that can significantly increase the data rate and improve the quality of wireless transmission, which is limited by interference, local scattering, and multipath propagation. The antenna array is combined with digital signal processing to give a narrow beam pattern in response to the received signal by the smart antenna. The weights of the beamformer is calculated by using the adaptive approach which uses reference signal and the direction of the user based on the received signal. The main beam is then directed toward the specific user, while the nulls are adjusted toward the interferers.