A new Criterion for Transmit Diversity and Beamforming in Mobile Communications

We consider a wireless communication system in which the base station is equipped with an antenna array and the mobile user has a single antenna. Classically, in this configuration, the antenna array at the base station is used to perform either beamforming or transmit diversity. We propose a scheme that exploits the antenna array to perform beamforming in order to maximize the diversity of the channel seen at the receive end, i.e., the mobile user. This scheme is based on the criterion of minimizing the variation of the power received by the mobile user due to fading. Moreover, we propose an adaptive method to optimize this criterion, which is a type of CM (Constant Modulus) criterion.