Theoretical analysis of antenna cancellation technique in full-duplex communication system

In Band Full Duplex communication systems have received much research attention over the past few years. Such systems are characterized by simultaneous transmission and reception of information using the same range of frequencies. The central focus of research in this scenario has been to reduce Self-Interference, i.e., the interference from the transmitter to the receiver in the same transceiver. Antenna Cancellation is a prominent Self Interference Cancellation technique in the propagation domain that helps reduce interference to manageable levels before reception. In this paper, an improved model for the Antenna Cancellation scheme has been proposed that is derived from antenna theory. The optimum allocation of transmit power for the transmitting antennae is determined. Analytical expression has been derived for residual self-interference which takes into account the distribution of transmit power across various frequencies. The effect of errors on antenna placement and power allocation to the transmitting antennae on the amount of cancellation achieved has been studied with reference to the new model and compared with the results for the existing model. Finally, the results obtained were cross-verified using industry standard simulation tools.