Reflected Self-Interference Channel Measurement for mmWave Beamformed Full-Duplex System

In this paper, we present the results and analyses of the reflected self-interference channel measurement in the beamformed full-duplex system. To measure the reflected self-interference channel in mmWave band, we transmit 18-bit PN sequence signal with more than 100 dB SNR using a transceiver with 27.925GHz center frequency. In the measurement results, we found the self-interference channel with long propagation delay caused by the reflection due to various nearby objects. This self-interference channel cannot be removed using conventional analog cancellation circuit which has limited analog delay. To overcome this limitation, it seems to be a good solution to apply opportunistic full-duplex scheme and a beam selection approach taking into account the residual self-interference.