Internal Crosstalk Calibration for a Fully-Switched MIMO Channel Sounder

In this paper, the problem of calibrating a fully switched MIMO channel sounder is considered that has internal crosstalk. A system model is proposed that takes into account the effect of the internal crosstalk in the transmitter and receiver response matrices. Then, a least-square system identification problem is formulated that utilizes to a set of back-to-back measurement data to find the estimates of the response matrices. It is shown that the solution can be found by making rank one approximations in the frequency domain. In addition, a channel estimation method for calibrating field measurement data is proposed by using the identified response matrices of the sounder. Experimental and simulation results show that the proposed approach outperforms the conventional approach that ignores the crosstalk.