Research On System Level Simulation And Evaluation Of Broadband Wireless Access System

With the growing demand for the Internet Network, the mobilization and broadband is the inevitable development trends of future communication systems. Broadband Access Technologies has a wide application prospect as the last-mile technologies. WiMAX based on IEEE 802.16e has become a major technology for broadband access. As a broadband access scheme for Wireless Metropolitan Area Networks (WMAN), WiMAX has received much attention for its outstanding performance and wide market prospects, and has been approbated by many network operators.The dynamic relationship among quality, coverage, capacity of WiMAX network is very complicated. In addition, many kinds of services are being introduced into the WiMAX network. As a result, it is difficult to analyze the whole performance of the system accurately in theory. Nowadays, software simulation technique has become a popular basic method for mobile communication protocol research, network planning, performance evaluation and optimization.The work of this dissertation could be divided into two parts, one part is the design and implementation of system level simulation platform, and the other part is system performance evaluation. Through the research of simulation models for wireless communication system, combined with the IEEE 802.16e protocol, we designed and developed system level simulation platform for WiMAX system based on OPNET network simulation software. This paper addressed the implementation of radio resource scheduler and radio channel simulation in detail. Moreover, we made system performance simulation for cell coverage, sector throughput under different subcarrier permutation, and hybrid automatic repeat request(HARQ). At the last section, we analyzed and compared the three real-time scheduling schemes specified in the protocol when they were used for a specific type of real-time service, and proposed an improved scheduling scheme. System level simulations show that the proposed scheme reduced the user's uplink access delay, and consequently improved the communication quality.