Research On Mobile Node In Wireless Sensor Networks

Wireless sensor networks (WSN) are appealing to researchers due to their wide range of application potential in military, industry, home networks and so on. And WSN have been proposed to deliver in situ observation of events and environments over long period of time. A large number of small and simple sensor devices communicate over short range wireless interfaces to deliver observations over multiple hops to central locations called Sink. A significant portion of the energy expenditure is attributed to communications and, in particular, the nodes close to the sensor network gateways used for data collection typically suffer a large overhead as these nodes must relay data from the remaining network. If all the processed data must traverse these nodes to reach the gateway, the network will be invalid for the depletion of these nodes.After systematically reviewing the routing protocols for WSN, this dissertation summarizes the existing problems of routing protocols. And we discuss a network infrastructure based on the use of controllably mobile node to reduce the communication energy consumption at the energy constrained nodes and, thus, increase useful network lifetime. Besides, some attention is paid to security.The main contribution and innovation of this paper are as follows:1. The paper includes the mobile node in WSN and proves the feasibility for using a mobile node to increase the lifetime of the network by reducing the relaying of data.2. Controlled mobile node routing algorithm (CMNRA) is designed, which includes important node and mobile node communication algorithm, motion control algorithm and network security algorithm.3. For the aspect of energy efficient, a hybrid routing model using in important node and mobile node communication algorithm is introduced in the paper, and this model seamlessly combines plane routing and hierarchical routing; Aiming at reliable data delivery of WSN, this article introduces differentiated services (DiffServ).4. An improved secure three-party key exchange protocol is proposed considering security, which can encrypt the transmission data and prevent attack of external nodes.5. In the end of the paper, the analysis is carried on to CMNRA using TOSSIM based on Tiny OS. CMNRA is compared to LEACH protocol and DD protocol which are also the effective algorithm in wireless sensor networks. Simulation results show that as well as saving energy of nodes, CMNRA is able to balance energy dissipation and prolong the lifetime of WSN significantly.