Interference detection for other systems using MIMO-OFDM signals

This paper proposes an interference detection method in MIMO transmission, which utilizes periodical preamble signals in a frequency domain. In this paper, we assume the collision between the short preamble signal in WLAN system and interfering signal like a microwave oven. In the propose method, second antenna receives the signals while first antenna transmits the preamble signals. Hence, the interference can be detected by observing the subcarriers which are not mapped short preamble signal using the received signal after the FFT processing. Moreover, we utilize the dual polarized antennas to reduce the mutual coupling between the transmitter and receiver. By a computer simulation and measurement with the use of orthogonal polarized antenna, it is shown that the proposed method can successfully detect interference from the other system when the interfering power is greater than the noise power.