Research On The Application Of Complex Networks Theory In WSNs

Wireless sensor networks (WSNs) combine the technologies of sensor, wireless communication, micro-electro-mechanism systems (MEMS) and distributed computing. The routing technology is one of the key technologies to design WSNs. But many traditional routing protocols are not suitable for WSNs due to the characteristics of WSNs such as hardware resource limitation, power capacity limitation, data-central, self-organization, multi-hop routing, dynamic topology, dense distribution with numerous nodes etc, and requiring lower delay of packet transmission in special applications.In order to meet these requirements, a small world model of the complex network is introduced to the routing protocol design for the WSNs in the thesis. A modified small-world-based adaptable routing protocol MSWR（Modified Small World Routing Protocol）is proposed. We generate routing base on the ideas of week and strong connections, at the Sink Node we add longer week link with N (N>2) hops as shortcut to the WSNs topology structure；moreover we optimize the routing algorithm by taking advantage of the Small World feature in setting up the searching tree; we control the hops to generate searching tree, which reduce the energy consumption for MSWR routing protocol; we optimize MSWR routing protocol by adapting routing policy in route discovery stage to reduce the average delay of the packet; we establish the routing policy for nodes failure to optimize MSWR routing protocol, and make the protocol more robust. This not only reduces the average path length and the transmission delay of the network, it also reduces the energy consumption of the nodes, makes the energy consume more evenly distribute among all the nodes in the network, which greatly extend the life cycle of the network. In addition, the data transmission is not base on fixed routing, hence MSWR can perfectly adapt to the dynamically changing of the network structure.The simulation results indicate that MSWR effectively reduces the energy consumption, reduces the average delay of the data transmission, which prolongs the lifecycle of both the nodes and the network, and enhances the robustness of the networks. The protocol has advantages of superior performance and algorithm simplicity, strong adaptability and it is easy to implement, which make it has strong practicality and high application value.