Joint multi-user space time block coding and beamforming via convolutional weighting

A convolutional weighting (CW) scheme applied to a half-wavelength spacing array was proposed for multi-user system to joint STBC (space time block coding) and beam forming (BF). The transmitting beam is equivalent to the product of two sub-beams. One is used to realize interference suppression,while the other is employed to form a couple of uncorrelated channels from base station (BS) to the desired user (to meet the requirement of STBC) and to maximize SINR (signal-to-interference-plus noise ratio) at the desired receiver. As an optimtum combination of STBC and beam forming, the proposed scheme can achieve both full diversity order of STBC and array gain of BF. Meanwhile, it can also effectively restrain multi-user interference by nulling. Simulation results show that the proposed scheme can significantly improve the BER (Bit Error Rate) performance and enhance system capacity as compared with the conventional eigen-beamforming (EBF) technique applied to a half-wavelength spacing array.