Space-time coding/decoding with adaptive transmit beamforming in semi-correlated MIMO wireless communication systems

Transmit diversity and space-time coding (STC) technology can achieve an optimal transmission and capacity increment in multi-input multi-output (MIMO) wireless communication systems. However, recent contributions have demonstrated that fading correlations destroy most of their advantages. How to combat the fading correlation is an interesting problem for multiple antenna systems. Extending the concept of transmit beamforming, our research uses multibeam forming correlation characteristics to overcome fading correlation in transmit diversity. Considering the case of having knowledge about the channel at the transmitter side, subspace based decoding is achieved at the receiver. The proposed scheme benefits from adaptive beamforming in achieving STC and obtains diversity gain on the forward link. It also offers an optimum transmission of power, a reduction in interference and an incensement of system capacity. Numerical simulations are presented to illustrate the effectiveness of this structure.