Calibration of a fully-switched MIMO channel sounder with internal crosstalk

Abstract In this paper, the calibration of a fully-switched MIMO channel sounder with internal crosstalk is considered. A system model is proposed, taking into account the effect of the internal crosstalk in the transmitter and receiver response matrices. A least-square system identification problem is then formulated to find the estimates of the response matrices from a set of back-to-back measurement data. It is shown that the problem can be converted to rank-one approximation problems in the frequency domain. In addition, a channel estimation method is proposed for calibrating over-the-air measurement data by using the identified response matrices of the sounder. Experimental and simulation results show that the proposed system modeling and identification procedure compensate for the internal crosstalk of the sounder much better than the conventional approach that ignores the crosstalk.