A simple self-interference cancellation technique for full duplex communication

Recently, a considerable attention has been paid for full duplex communication. Full duplex allows transmitting and receiving at same frequency simultaneously. As a result, the spectral efficiency can be increased two times by utilizing this type of communication. Nevertheless, the substantial issue of applying full duplex communication is the self-interference signal. This paper presents a new method of antenna cancellation with symmetric antenna placements to cancel the self-interference signal. Three monopoles antennas are modelled by using Computer Simulation Technology (CST) program; one as a receive antenna, while others as transmit antennas. The cancellation of the method is calculated by utilizing Matlab code. Moreover, many factors that could degrade the system performance are investigated. Results illustrate that this technique provides higher than 50 dB cancellation in a typical situation. However, results show a decline in the efficiency of the technique when there is an inaccuracy of placing the antennas, or amplitude mismatch between two transmitted signals. The obtained simulation results are verified by testing the technique practically. The results show that the practical prototype can provide more than 40dB cancellation over a wide band frequency.