| The radio over fiber (ROF) system, which can achieve a flexible wireless and high-speed broadband transmission, also reduce the cost of base stations, is becoming one of hot spots of the next generation communications technology research. In wireless communications, ultra-wideband (UWB) technology is favored for its Carrier-free, high-speed, low cost and miniaturization, but low power consumption and ultra-broadband make it can not realize long-distance, large-scale communications, and restricted the range of its applications. In view of the characteristics of ROF technology and UWB technology, the UWB over fiber systems which has complementary advantages get more and more attention.Fist of all, the UWB technology and ROF technology are specifically described in this dissertation, including domestic and international progress, the basic concepts, key technologies, and applications. Then, UWB over fiber system is introduced, this part focuse on its background and research. In the full theory based on research, UWB signal generation is completed, UWB signal transmission in the fiber and its topological structure is studied, and a UWB over fiber system based multi-mode fiber is designed in this dissertation. Based on cost considerations, while meeting the performance requirements of the system, a low-cost 850nm vertical cavity surface emitting laser (VCSEL) and a direct modulation is used. In addition, for user terminals can communicate with each other, both transmitter and receiver of the design system have mobility, and amplification module is designed to compensate for the UWB signal transmitter fading.Dsign system simulation completed by OptiSystem and ADS, simulation results show that this UWB over fiber system can extend UWB signal transmission distance from less than 10 meters to 100 meters, greatly expanded the coverage of UWB signals; a reference for the practical has been provided. |
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