Research And Implementation Of Routing Algorithms Of Wireless Mesh Networks

Wireless mesh network is a multi-hop network.Unlike traditional wireless networks,it combines the advantages of WLAN and Ad-hoc networks.It has the advantages of cost-effective,fast deployment and strong scalability.In the wireless campus network,wireless city,tourism and leisure places,video surveillance and so on,it has a broad application prospects.But the traditional wireless mesh network often has network congestion,instability and low QoS and other issues.Aiming at these problems,this thesis presents a new wireless mesh network system structure.Then based on Open Wrt system and improved AODV routing protocol,the hardware and software development and function testing of the system are designed and implemented.The detailed works in this thesis are as follows:(1)A new wireless mesh network system structure is proposed.In this thesis,a network controller is added to the traditional wireless mesh networks for the collection of network resource information and the unified allocation of routes.Each node periodically reports its own information.When the node initiates a route request,the network controller chooses a different route decision based on the different service request type and allocates an appropriated path with QoS guarantee according to the current network conditions.Therefore,in this system the network resources can be effectively used and avoid network congestion can be avoided and meanwhile QoS is guaranteed.(2)The AODV routing protocol is revised and improved.The AODV original hop count routing policy is changed to a unified allocation route by the controller.According to the design requirements of the system,HELLO mechanism,RREQ mechanism,RREP mechanism and Netfilter hook function mechanism are improved to make it suitable for Mesh network system with centralized controller designed in this thesis.The improved HELLO mechanism is added the function of obtaining the delay and packet loss rate between nodes.RREQ mechanism is changed from the original broadcast route request to a unified route request to the network controller.RREP mechanism is used to achieve the construction of the route instead of the original routing response function.Netfilter hook function mechanism is added the function of obtaining and analyzing packet information,and the corresponding routing request or packet forwarding and other operations according to the source of the packet.(3)Hardware and software of wireless mesh network system are developed C/C++ is used as the main development language.Using Visual Studio and GCC and other development environment to develop nodes and controller program.As well as modifying the AODV-UU to achieve system networking,resource storage,routing decision-making and other functions.(4)The building,test and analysis of the wireless mesh network system is finished.The test results show that the wireless mesh network system designed in this thesis can make more efficient use of network resources and provide QoS-guaranteed routes as well as achieving the expected design goals.