Experimental Validation of Crosstalk Reduction for Wideband MIMO Transceiver Systems

A method for reducing crosstalk interference (or coupling) between multichannel radio frequency (RF) components in a wideband multiple input multiple output (MIMO) RF transceiver was developed. We devised feasible crosstalk parameter estimation, compensation, and calibration methods for joint transmitter (TX) and receiver (RX) coupling. Training signals are used to estimate the crosstalk parameters through the least-squares method. Crosstalk calibration, involving crosstalk estimation and compensation, is then performed sequentially for the RX followed by the TX. A crosstalk circuit board produced by the Industrial Technology Research Institute (ITRI) of Taiwan was used as a testbed for compensation for crosstalk interference for both single-carrier and multicarrier orthogonal frequency division multiplexing (OFDM) test signals. The method was tested on a system comprising a commercial AD9371 wideband RF module and the ITRI RF crosstalk circuit board. Our proposed techniques suppressed crosstalk by approximately 30 dB for single-carrier signals and reduced the error vector magnitude by approximately 20 dB for OFDM signals, effectively proving that this is a practical and effective method for improving wideband MIMO communications.