Channel Estimation with Tightly-Coupled Antenna Arrays

This paper develops a linear minimum mean-square error (LMMSE) channel estimator that takes advantage of the mutual coupling in antenna arrays. We model the mutual coupling through multiport networks and express the singleuser multiple-input multiple-output (MIMO) communication channel in terms of the impedance and scattering parameters of the antenna arrays. It is shown that appropriately accounting for mutual coupling through the developed physically consistent model leads to remarkable improvements in terms of channel estimation performance. We demonstrate the gains in our algorithm in a rich-scattering environment using a connected array of slot antennas both at the transmitter and receiver sides.