Design And Implementation Of Wireless Mesh System Based On Wi-Fi

Wireless mesh network(WMN),also known as "multi hop" network,is a kind of distributed wireless self-organized multi hop network suitable for large area or complex.It has the characteristics of ad hoc network,self-healing,network dynamic change,high bandwidth and so on.It can easily expand the coverage of WLAN network at low cost.However,the wireless mesh network is different from the general network,its network topology changes at any time,and its nodes are flexible,which makes it very inconvenient to obtain its information.Moreover,wireless mesh network construction needs a large number of nodes to maintain,the cost of short-distance networking is too high,and the networking time is too long.Therefore,based on wireless mesh network,this paper focuses on mesh network technology,openwrt system and SNMP protocol.On this basis,combined with OLSR routing protocol,a wireless mesh system based on Wi Fi is designed and developed,which solves the problems of short-distance network selection and difficult access to mesh network information.The main contents of this paper are as follows:First of all,according to the characteristics of wireless mesh network,based on the analysis of existing wireless routing protocols,the OLSR routing protocol is selected as the core routing protocol of the system.But there are also some problems in OLSR,such as high overhead and redundancy.Therefore,on this basis,this paper optimizes the selection of the core MPR set of OLSR protocol,reduces the redundancy of MPR nodes and the delay caused by packet messages.The simulation results show that the optimized OLSR protocol improves the end-to-end delay and throughput performance significantly.Secondly,in the design of wireless mesh system based on Wi Fi,this paper gives the whole design process from three aspects: network structure design,overall schemedesign and function design.Finally,in the implementation of wireless mesh system based on Wi Fi,this paper selects the raspberry pie 3B + in hardware,and completes the compilation of openwrt system and the implementation of olsrd in software.Then,based on the openwrt system,the mesh network nodes are configured and the wireless mesh network is built.The system node discovery module is realized by extending MIB library and sub agent,and the system management module is realized by the interaction between database and Java Web.Finally,a real test environment is built to test the performance of wireless mesh network and the function of related modules.