Research And Implementation Of Location-Aided Routing Protocol In Wireless Mesh Network

Wireless mesh network (WMN) is a kind of multi-hop and self-organization network developed from ad hoc networks. Due to its advantages of rapid deployment, low cost, wide coverage, self-healing, strong extensibility, WMN has been a subject of investigation in recent years, and an efficiency and flexibility routing protocol is one of the key of WMN. At the same time, the research of wireless locating is developing constantly on the basis of GPS technology, which makes it possible to obtain nodes' position universally. This thesis combines the location information into routing process and puts forward location aided routing protocol with dynamic searching domain named LAWMP in WMN.Firstly, we introduce the architecture characteristics and application environment of WMN, presenting requirements of the routing algorithm, namely, the concentrated trend of data flow, node mobility and stochastic dynamic inclusion or departure, multi-hop transmission etc. The thesis summarizes the development and the classification methods of wireless routing technology, one is distance vector routing and link state routing according to the method of selecting priority routing, the other is proactive routing and on-demand routing according to the approach that network nodes obtain routing information.Then the foundation of wireless routing protocols AODV and HWMP are investigated respectively in aspect of algorithm procedure and data structure control packet's structure, and routing table entries, process of storing and forwarding packets are analyzed. Simulation for comparison shows that HWMP is more suitable for WMN, but the stability of delay is not sufficient.To improve the stability of wireless routing protocol of HWMP, location information can be put into routing algorithm. Therefore, we study the wireless location algorithm. We select the location algorithm on the basis of the Doppler frequency shift determining whether the mobile node is moving. And if so, Taylor series location algorithm is selected, otherwise classic Chan algorithm is used. Following that this thesis proposes a location aided routing protocol with dynamic searching domain named LAWMP in WMN. After obtaining the position information of nodes in the network through Beacon frame transmitted periodically, the source node should set a circle domain before initiating a routing request. Further more, according to the node's mobility, the moving direction and velocity as well as the neighbor node's density, the searching domain will change dynamically. Fill the domain parameters into request frame and send them with directed flooding, which is simple and easy for implement. Simulation based on NS2 software between LAWMP and HWMP proves that LAWMP has a better performance in packet receiving rate, throughput, and the stability of delay and jitter are also improved.Finally, according to WMN project, we complete the implementation of LAWMP based on VxWorks platform, including the interaction betweeb routing module and MAC layer through a message queue, task creation, getting information of position and setting a searching domain, transmitting or receiving process of routing control message like PREQ, PREP etc. Test results show that the proposed scheme can reduce path detour and hop count, thus to reduce time delay and improve the routing stability.