Space time block coding with transmitter interference reduction

In this paper, we propose a transmitter based scheme to simultaneously mitigate fading to a desired receiver and cochannel interference to an interference. We focus on downlink transmission at the base station with multiple antennas at transmit and a single receive at the intended and interference receivers. We show how appropriate precoding and space-time coding can be combined to maximize link performance subject to a specified degree of cochannel interference suppression and assuming a limited amount of information at the transmitter. The solution is a multimode beamformer with mode directions and power allocation dependent on the level of the interference mitigation desired. The resulting solution is compared to transmit beamforming and demonstrates performance improvements due to the additional transmit diversity extracted.