Research On UWB Spectrum Coexistence With Other Communication Systems

Since UWB technology has a lot of advantages such as high date rate, low power spectral density, high precision location identification and inherently exceptional multipath immunity, it has become the research focus in the wireless communication field.As the UWB technology is a kind of radio technology sharing frequency band with other kinds of radio technologies, it is crucial to deal with the interference problem between the UWB communication systems and narrow band communication systems for the further development of UWB systemsIn this paper, the basic theory and the characteristics of UWB communication are introduced at first. Then the spectrum coexisting and compatible problems between UWB systems and other radio systems are analyzed. We summarize the three aspects of solving the spectrum coexisting and compatible problems: controlling the power spectral density mask of UWB signals, reducing the UWB interference to existing radio systems, reducing the existing radio systems to UWB systems. We lay emphasis on the study of the influence of pulse waveforms, information modulation mechanisms and time-hopping parameters on the power spectrum mask of UWB signals from the view of power restriction. While the influence of short pulses on the spectrum mask of UWB signals is studied, mathematics relation between Gaussian pulse derivatives and the spectrum mask of UWB signals is derived, which is significant when we choose and design new pulses. By computer simulation, we analyze UWB signals with different modulation mechanisms and time-hopping parameters, and conclude that the polar randomicity and the time shift randomicity of ultra-short pulse can make the power spectrum of UWB signals smoother.Finally, after studying the interference features of UWB signals at the receiver of narrow band communication systems, we conclude two main factors which influence the interference of UWB systems on narrow band systems. They are the average transmission power of UWB signals and the number of UWB pulses to victim receivers in fixed time.All these study will provide some useful ideas and methods to achieve the spectrum coexistence between the radio systems in the band.