Direction of Arrival Detection System for Radio Surveillance: Frequency Spectrum Analysis of CDMA and Jamming Waves

This paper introduces DOA (direction of arrival) detection system of jamming waves used for radio surveillance of 900 MHz, featuring its function of frequency spectrum analysis to distinguish CDMA (code division multiple access) and jamming waves. There exist many jamming waves arising from illegal (non-licensed) repeating antennas or wireless cameras that seriously interfere to CDMA signals especially in urban districts. It makes lower communication quality such like crossed communication in voice and lower throughputs in data transmission. In order to specify the location of those illegal antennas, we develop a DOA detection system of jamming waves which consists of smart antennas, receivers, A/D converters, spectrum analysis, DOA estimation and location detection. This paper focuses on the analysis of frequency spectrum to detect jamming waves from the observed signals