Wireless Mesh Networks Protocol Research And Realization

As the modern technology of networks developes rapidly, the WMN (Wireless Mesh-Networks) come to the spring. WMN is one kind of networks with high speed and large capacity. Also it is a distributed network which is a new solution to the"Last Mile"issue. It can be viewed as a static wireless multi-hop network which contains routers and terminal equipments connected by the wireless link. Any node with wireless facilities in the network can be used as an AP (Access Point) as well as a router. Every node can send and receive signals to communicate directly with the equivalent nodes. The biggest advantage of this structure is that if the closest AP is blocked because of the over-flow, the packets can be routed to another node near by with smaller flow. And so on, packets can be passed to the next node which is closest to itself till the destination is reached. Just the same as the other networks, routing protocol is a key point of WMN. And this essay focus on the research of routing protocol based on the WMN.This essay firstly introduces the features and the structure of WMN and presents the similarities and differences of Ad hoc network. Afterwards, WMN is introduced for its existing routing protocol following by the analysis of characteristics and disadvantages. Then, the essay puts the most attention on the realization of the KTRP (Kernal Tree Routing Protocol). In the end, a new routing protocol AGRP (Access Gateway Protocol) is given out, which is based on the KTRP and its idea. AGRP has three different versions. The first one is AGRP-OD(AGRP On-Demand), which is a reactive routing protocol. The nodes about to join the network must start the routing searching process. After the routing seeking and registering, it becomes a full-connected node. The second one is AGRP-B(AGRP Beacon). In this condition, a beacon message is used to broadcast the path information. Every full-connected node, including the gate way, must send beacon message periodically to show the active path. The nodes which want to join in only need to listen to the neighbor nodes for this kind of messages. And the following steps are the same to AGRP-OD(AGRP On-Demand). The last version is AGRP-H(Hybrid AGRP), which combines the former two versions, requiring the joining nodes to send requests and listening for the beacon message at the same time. Through tradeoff, this version can be fit for more situations with higher efficiency. In the end of the essay, a simulation work is carried out with the results showing the differences between the AGRP and former routing protocols, followed by a conclusion: without the concerning of single-way link, AGRP does better than the others in the simulation in the aspects of delaying, routing overhead and so on.