Uwb Devices With Narrow-band System Between The New Emc Methods And Technology Research

Ultra-wideband (UWB) is been thought as one of the most promising technology for high-speed and short-range wireless communication applications. Due to its spreading energy over very large frequency band, UWB devices usually bring about severe interference on the narrow band communication devices. The issue of electromagnetic compatibility (EMC) between the narrow band communication devices and UWB devices has become a significant research.Time reversal (TR) technique can make use of multipath effects to achieve temporal and spatial focusing simultaneously at the target point, consequently. TR-UWB communication technology can suppress the communication interference which is encountered by traditional UWB devices, and then have the great potential to improve the performance of communication devices.This thesis firstly presents the review of UWB interference and anti-interference research, and simply presents the developments of TR technique.Secondly, the basic research, including UWB interference research and UWB anti-interference research, is introduced. Also, the analysis methods of UWB interference and the technique of interference eliminated is shown.The parameters represented as UWB interference and anti-interference level are defined and explained. The temporal and spatial focusing properties is analyzed by the equivalent channel impluse response(CIR), which is applied to UWB EMC to reduce the interference and improve the performance of communication systems.Thirdly, we investigate the interference caused by TR-UWB to narrowband system and compare the interference in traditional UWB with TR-UWB based on Finite Difference Time Domian(FDTD) simulation. The anaylsis show that the transmitted power in TR-UWB is smaller than traditional UWB device when separation distance between the co-existing communication devices and UWB transmitters are the same, especially in rich multipath environment.Therefore, the EMC area in TR-UWB is larger than traditional UWB, which is benefit for co-existence. Finally, we investigate the performance of PPM-TH-UWB device with TR method. We also analyze the SINR and BER of PPM-TH-UWB device with TR method. The results show that the anti-interference ability of TR-UWB device become satisfactory, especially in rich multipath. The carrier frequence, bandwidth, and interference power of narrowband will influent performance of anti-interference.