Adaptive antenna transmission for frequency duplex digital wireless communication

Abstract

Methods are reported for adaptive phased array transmission of digital wireless communication signals for the purpose of improving network call capacity. Frequency division duplex (FDD), time division multiple access (TDMA) communication channels are considered. The proposed techniques are designed for severe multipath environments with large Doppler, angle and delay spreads. No knowledge of array geometry, propagation path angles or portable feedback is required to adapt the transmission weight vectors. The time or frequency averaged spatial covariance of the received reverse link signal vector is decomposed into desired signal and interference subspaces which are used to form quadratic optimization problems involving matched filter bound cost functions. A dynamic channel allocation algorithm searches for frequency channels in which the adjacent cell portables are spatially compatible with the desired portable. Results of cellular network simulations are provided to illustrate the network call capacity improvements that are possible with the proposed FDD transmission approach.