Research On The Coverage Prediction In WLAN System

802.11WLAN (Wireless Local Access Network) have been widely used for its flexibility, mobility, fast access and many other advantages. In recent years, domestic and foreign network operators are increasing their WLAN network coverage. The network convergence of WLAN and mobile network makes the whole network more robust, and provides users with interactive entertainment experience by a high data rate. Before deploying a WLAN network, operators need to make reasonable wireless network planning, in order to make the network have the best coverage and performance. Reasonable and effective wireless network planning can reduce the cost and save the time of network construction. Therefore, a wireless network planning simulation tool is very necessary which can accurately and reasonably simulate the realistic WLAN performance’. This paper studies the design and implementation of WLAN coverage prediction for a WLAN network planning simulation tool.The paper includes three parts:The first part forces on the key technologies of IEEE802.11WLAN standard, and includes detailed summary of the development of the IEEE802.11standard, CSMA/CA mechanism in WLAN, hidden terminal problem, basic knowledge of WLAN channel division and wireless network planning.The second part mainly describes the algorithm design of a WLAN coverage model based on grid traversing method. It describes the principle of grid traversing method, and the process of coverage prediction. Then it mainly describes the four main parts of the coverage model, including WLAN frequency planning and link loss budget which are first two necessary parts of WLAN coverage prediction, and interference analysis and performance indicator calculation, which are the core parts of coverage prediction. Firstly, it describes the coverage prediction progress. Secondly, it describes the principles and progress of WLAN frequency planning. Thirdly, it gives the calculation method of WLAN uplink and downlink.Then, it analyzes inference in WLAN and gives an inference model. Finally, it details definition and calculation of WLAN preference indicators.The Third part shows the software implementation of the WLAN prediction model coding with C#in Visual Studio2008. Firstly, it describes the software framework design and interface, class design and implement. Then, by analyzing the coverage prediction results of simulation using the simulation tool, it shows that the coverage prediction function of this simulation tool is available.