Beam Synthesis Method for Beamforming Adaptation in Cognitive Radio Based Wireless Communications Systems

In this paper, we propose an algorithm, namely, beam synthesis (BES) method for updating the beamforming weights from one TV channel to another TV band in cognitive radio based wireless regional area network (WRAN) communications systems. The proposed BES method tries to constrain not only the same null positions, but also the same main beam positions for different TV channels. The proposed method takes care of some problems associated with previously developed beamforming adaptation schemes for frequency division duplex (FDD) based wireless communications systems