Wsn Topology Control Information In The Physical System Research, And Mac Protocol

Cyber-physical systems are integrations of computation, networking, and physical worlds. Wireless sensor network is an important part of Cyber-physical systems. The primary challenge at present is how to cut down unnecessary energy consumption, guarantee less time lapse in transmission, and improve the overall performance of the network. The network topology control and the MAC protocol will exert great influence on the energy consumption of the sensors node. Aiming at cutting down energy consumption, lessening time lapse in transmission, and optimizing the network performance, this thesis studies the key technologies on wireless sensor network topology control and the MAC protocol.In order to improve the energy efficiency and the robustness of the topology, a topology control algorithm of energy balance based on geometric structure cutting is brought forward. First of all, the constraint condition that the angle between any two adjacent nodes should be equal or lesser than 2π/ 3 is proposed to ensure network connectivity. On the premise of the connectivity of the whole network, it simplifies network topological connection by sending data through a comparatively low power. Then, since the relationship between the energy consumption of sensor nodes and the square of the transmission distance is in a direct proportion, according to triangular plane geometry characteristics, the node distribution are cut into three sections by drawing auxiliary lines. Different regions establish topology by different methods. In resent regions node connects each other directly. In remote regions node connects each other by multi-hop.Optimizing the formation of topological connection. Finally, according to the neighbor node's residual energy and the power to send data, a fitness function is established. According to this function the topology control algorithm selects different nodes to transmit data.The energy consumption is partaken by each node. Optimizing the energy efficiencyIn order to reduce the information data transmission delay, and enhance the MAC protocol's ability to adapt to dynamic environment in Cyber-physical systems, a multi-hop channel reservation MAC protocol based on a parallel mechanism is brought forward. This protocol proposes the multi-hop channel reservation mechanism on the basis of the cyclical sleeping mechanism. Nodes reserve the channels by transmitting reserved frames.Then data is transmitted according to reserved information. By making use of parallel mechanism, a simultaneously transmitting of the reserved information and data is achieved. On some degree, it reduces energy consumption in Cyber-physical systems, and lessens time lapse in multi-hop transmission.Finally, by using OPNET network simulation tools to create a wireless sensor network model, it emulates on aspects like the energy consumption of nodes, time lapse of data transmission, and the protocol's adjustability to the changing quantity of transferring data, and it validates the suggested topology control arithmetic and the MAC protocol.