Maximizing LoS MIMO capacity using reconfigurable antenna arrays

The presence of line-of-sight (LoS) components is usually regarded as a limiting factor for multiple-input multiple-output (MIMO) systems due to the lower multiplexing gains compared to the prevalent independent and identically (i.i.d.) Rayleigh fading model. In this paper, we present a versatile methodology for maximizing LoS-MIMO capacity at any operating signal-to-noise ratio (SNR) by capitalizing on some recent results in two areas: i) design of optimized LoS MIMO configurations and ii) MIMO capacity maximization with reconfigurable antenna arrays. Our theoretical and numerical results demonstrate that by simply adjusting the antenna spacing as a function of SNR, significant capacity gains are achievable. In the following, the implications of the model parameters on the system performance are also assessed.