Study Of The Key Technologies In Distributed Radio-Over-Fiber Network Based On Opnet

Distributed Radio-over-Fiber (RoF) network transparently transfers analog RF signals to antennas densely distributed in remote through fibers and realizes the seamless coverage of the service area. Central Office (CO) learns the knowledge of wireless environment in each area by listening to the distributed remote antennas and gains the centralized control of radio resources. In this network, traditional wireless protocols may lose its proper performance, so we should discover some cognitive functions. In this thesis, the key technologies in distributed RoF network have been involved. Then an OPNET-based simulation platform has been used to analysize the peformance of IEEE802.11g DCF in low-load distributed RoF network. Further, OPNET has been used to realize the cognitive funtions of distributed RoF network. The main works of this thesis are summarized as follows:1. Building OPNET-based simulation platformOPNET has been used to build distributed RoF network. Based on the existing Wireless LAN modules and wireless pipeline models of OPNET, Access Point (AP) node model, Remote Antenna Unit (RAU) node model and Fiber Link (FL) model have been created. Finally, an OPNET-based distributed RoF network simulation platform has been completed.2. The impact of distributed RoF network on IEEE802.11We study the impact of distributed RoF network on IEEE802.11protocol. We focus on using OPNET to analyze the performance of IEEE802.llg DCF in low-load distributed RoF network and quantify the network configuration.3. Distributed RoF network with cognitionThe network architecture and functions of distributed RoF network with cognition have been described, including cognitive radio capabilities, load balance, multi-user MAC mechanism and TCP performance improvement. OPNET has been used to realize the cognition of distributed RoF network and four scenarios have been set up to study the functions of distributed RoF network with cognition, including frequency resources schedule, load balance, automatic power deployment and handoff.