Pattern Design for Linear Precoded Reconfigurable MU-MISO Communication System

Pattern reconfigurable multi-antenna array can reshape the wireless channel with different radiation patterns to achieve performance gains. In this paper, we exploit the benefits of reconfigurable antennas to maximize the signal-to-noise-ratio (SNR) of users in the downlink of a multi-user multi-input single-output system, when zero-forcing (ZF) precoder is employed. We use the sampling vectors to reveal the physical mechanism of reconfigurable patterns on the wireless channel and further formulate the SNR maximization pattern design problem. For the single-pattern case where all the antenna elements adopt the same radiation pattern, reconfigurable patterns can realize the modification of correlation among each subchannel and redistribute channel gains of all scattering paths, where a Majorization-Minimization (MM) scheme with low complexity is proposed to obtain the optimal solution. For the multi-pattern case where different antenna elements can employ different radiation patterns, a ℓ₂-norm approximation problem is formulated to achieve the solution where the target channel is determined by a Randomization-Orthogonalization (RO) scheme. Numerical results demonstrate that reconfigurable patterns can further improve the bit error rate and throughput performance over the legacy MU-MISO system.