On capacity of BF-MIMO wireless downlink transmission

Aiming at the combination of BF (Beamforming) and MIMO (Multiple Input and Multiple Output), a generalized wireless downlink transmission scheme with the named of BF-MIMO is presented. According to a series of transformations of the signals in the transmit and receive antenna pairs, a combined flat fading channel matrix is analyzed and formulated. And then, based on the steering vector of transmit subarrays, the closed-form expression of the channel capacity is given. Finally, the capacity enhancement of the proposed scheme over traditional MIMO systems is demonstrated and verified by simulation results.