빔형성기 기반의 TPMS 간섭제거

Abstract

he importance of the auxiliary safety device for vehicles are emerging worldwide in order to prevent traffic accident due to the abnormality of the tires. The TPMS(Tire Pressure Monitoring System) is the auxiliary safety system that transfers the temperature and pressure of the tire, measured at the sensor unit of the tire, indicating them on the display panel and informing the condition of the tire to the driver. TPMS uses the wireless communication technique for transmitting data from the sensor unit to the signal processing unit inside vehicle. Frequencies TMPS are 433.92MHz and 447MHz domestically, and in many other countries including U.S.A and Europe,433.92MHz is used, which should be considered for export reasons. However, about the 433.92MHz, since various devices such as the Amateur wireless station, RKE(Remote Keyless Entry) and RFID(Rdio-Frequency Identification) for container management use high power signals in similar frequency as that of the TPMS, those have a high potentiality of working as a serious interruption in the wireless communication used in the TPMS. Therefore efficient the interference cancellation technique for the TPMS wireless communication is required. In this thesis, we propose Switching Beamformer based on AOA(angle of arrival) of the interesting signal that forms a beam in direction of the desired signal by giving greater weight in order to eliminate the interference and receive accurate data. However, when it forms the beam in receiving direction of desired signal, Switching Beamformer is inferior function for interference rejection for the high-power interference from various electrical and electronic devices received at the receiving antenna. For the suppression of the interference and transmission of exact data, we consider MVDR(Minimum Variance Distortionless Response) beamformer, designed to minimize the power of interference. It generates beam to the desired signal but nulls interference signal. Although the interference rejection performance of MVDR algorithm is excellent, its complexity is extremely high because of the requirement of calculating the auto-correlation matrix. In order to overcome such a high complexity, we suggest the TPMS interference rejection method based on the GSC(Generalized Sidelobe Canceler) with lower complexity than MVDR beamformer and similar performance of the interference rejection. We also propse the hybrid beamformer based on switching beamformer and MVDR beamformer, which choose the most efficient beamformer depending on the situation between the low complexity and excellent performance of the interference suppression. All proposed TPMS beamformers are verified of their performance through computer simulation examples.