Transmit Design for Short-Range MIMO Channels With the Spherical-Wave Model

In this letter, we investigate the transmit design for short-range multiple-input multiple-output (MIMO) channels with the spherical-wave model (SWM) in three-dimensional (3D) space. We first establish the antenna array with arbitrary orientations in 3D space. On this basis, we propose a practical and low-complexity transmit scheme with the SWM in short-range MIMO channels. The analytical expressions for the transmit directions and the power allocation of the proposed transmit scheme is also derived. Both the analytical and simulation results show that the proposed scheme can obtain performance improvement compared with the equal power transmission.