Interference Mitigation Study For UWB And TD-SCDMA Based On Pulse Shaping

Because of the obvious advantage in short-range wireless communication, ultra wide-band (UWB) systems have drawn great attention. Since UWB signals use extremely broad bandwidth for transmission by sharing the same frequency spectrum with other existing systems, interference with other systems is caused, which become the bottleneck of the UWB technique development. In this paper, based on compressed Chirp pulses and Hermite orthogonalization process, a novel method to generate UWB pulses is proposed. Selecting significant TD-SCDMA as the co-existing system, the principle, application and effect of the new pulse shaping method in the interference mitigation between UWB with TD-SCDMA system are discussed in detail.This paper is made up of the following parts:First, the definition, character and application of UWB technique are overviewed. A variety of interference mitigation solutions for UWB and other systems are introduced. The advantages and shortcomings of the traditional pulses in UWB systems application are pointed out. The effect of time-hopping code on pulses power spectral density (PSD) is studied as the reference of UWB pulses PSD control.Secondly, based on advanced Physical Layer, Smart Antennas, Joint Detection and Radio Resource Management, TD-SCDMA link-level and system-level simulation platforms are set up. With this system selected as the co-existing system, the application and effect of pulse shaping technology in mitigating UWB interference to the TD-SCDMA are studied.Last, the development status of UWB pulse shaping technology is summarized. Four-point principle of the pulse design is proposed. Calculation method of matching degree between pulse power spectral densities with FCC radiation mask is presented. New UWB pulses are generated based on multiple time-domain overlapping Chirp pulse in order to mitigate the interference between UWB and TD-SCDMA. Chirp pulses are orthogonalized by Hermite matrix eigenvector decomposition to avoid UWB system multi-user interference effectively. Finally, various pulses in the mitigating interference are evaluated through TD-SCDMA link-level and system-level simulation platforms, and compressed Chirp pulses and Hermite orthogonalization process have been proved great advanced.