Performance Study Of WiMAX-Based RF (Radio Frequency) Over Fiber Systems

Nowadays, science and technologies are developing rapidly. Communications technologies, especially the wireless communications, are now playing more and more important roles in people's everyday life. As the latest wireless Metropolitan Area Network standard, WiMAX/IEEE 802.16 standard is designed to fulfill the requirements of "the last one kilometer" in networks. It features high quality, broad bandwidth, high performance and low price. In Oct. 2007, WiMAX was ratified as the fourth 3G standard. It's no doubt that this is a milestone for its further application. Several experiment networks based on IEEE 802.16e WiMAX have been constructed in China and it is believed that WiMAX technologies will be widely applied with more available products.The carrier frequencies of WiMAX/IEEE 802.16 standard lie among 2-66 GHz. In such circumstances, the reflection and absorbability of atmosphere cannot be ignored. Hence a large quantity of base stations are needed to fulfill the requirement of coverage, and finally the cost of facilities of the whole network increases. In order to address this issue, this paper propose a solution which combines WiMAX technology with one of Radio over Fiber technology--RF(Radio Frequency) over Fiber to provide high quality transmission of broadband wireless signals.The integration of WiMAX and RFOF (WiMAX-RFOF system for simplicity) is studied in this paper.(1) WiMAX and RFoF technology, including operation principles, technical features, and current status are extensively and systematically investigated. A RFoF system based on WiMAX is designed. The structure of point-to-point downlink between center station and base station are mainly discussed. (2) Theoretical models of power budget and carrier bandwidth selection are established. The feasibility of the system is analyzed based on existing apparatus. Several instructions on system construction are given.(3) A simulation platform is presented. The performance of RFoF system based on different kinds of WiMAX mainstream modulation methods are firstly analyzed by BER and signal constellation and then evaluated by simulation. Several comments on optimizing of practical systems are given.