On the optimal array and signal design for multiple-antenna systems

Most of the literature on MIMO systems which assume Rayleigh flat fading, model the multipath channel propagation taking the channel correlation into account make simplifying assumptions on the statistics (e.g. uniform linear arrays with rich scattering all around the antennas). These assumptions lead to symmetric and separable correlation structure and leads to some insights on the impact of correlation on capacity and on the optimal signalling. In the recent past, several multiple-element antenna geometries, different the linear arrays, which exploit the ability to excite different spatial modes in the radiated E-field vector have been proposed in the cellular radio access link context. The aforementioned channel model is not rich to capture the EM properties of the antenna elements and its relation on the availability of scattering resources. In this paper, we propose a channel model based on EM theory which incorporates the joint impact of the antenna element properties (radiation pattern, mutual coupling between elements, etc.) and the scattering environment. This model provides a good compromise between complexity and tractability. We use this channel model to propose a rank and determinant criterion for array design in a multiple-antenna system for maximizing the ergodic capacity