Study Of UWB Interference To 3G Systems

Ultra-wideband (UWB) is a promising short-range wireless communication technology. With the extensive application of the 3rd-generation (3G) terminals, it is necessary to consider the coexistence issue between the UWB devices and the 3G terminal. Therefore, the study has important theoretical and practical significance in this paper.As to the height of 3G base stations and the environment of UWB devices applications, the performance of only the TD-SCDMA, WCDMA, CDMA2000 terminals is analyzed and compared in presence of UWB interference under UWB emission power limit regulations of FCC, ETSI and China respectively. A parameter which characterizes the performance degradation at the 3G terminal is defined to measure the UWB interference to the 3G terminals firstly, and then two three-dimensional models are constructed. The first model is a hollow sphere. The 3G terminal is located at the center of the hollow sphere, and the UWB devices are uniformly distributed throughout the three-dimensional space. By using the model, the maximum acceptable density of UWB devices for the 3G terminal is simulated. The second model is a rectangular grid where a discrete spatial distribution of UWB devices is considered and UWB devices are separated by the same distance. The 3G terminal is also located at the center of the model. The maximum acceptable density of UWB devices for the 3G terminals and the minimum acceptable distance between UWB devices and the 3G terminal are analyzed under different performance degradations respectively. In addition, by using the second model, the maximum acceptable density of UWB automotive radars for the 3G terminal and the minimum acceptable distance between UWB automotive radars and the 3G terminal are simulated in the military vehicles.A series of theoretical analysis and simulation results reveal that the anti-UWB-interference capability of TD-SCDMA is the strongest, and the one of CDMA2000 is the weakest. The UWB interference immunity of WCDMA lies between them. In addition, the UWB emission power limit regulation of China is stricter than FCC and ETSI under which the UWB devices make the least effect on the 3G terminal.