Research And Simulation Of An Energy-Efficient Scheme In Wireless Sensor Network

Recently, wireless sensor network is developing rapidly, which depends on advances in sensors, embedded microprocessors, wireless communication and network. There are a large number of sensors which can communicate with each other in a self-organizing wireless mode to implement appointed assignments. Because of these sensors, wireless sensor network becomes a special intelligent network and can be used for sensing, collecting and processing information of monitored objects. Wireless sensor network is greatly valuable in national defense, environment science, traffic control, medical treatment, space exploration and disaster monitoring, so more and more offices, educational organizations and enterprises have paid attention to it and consider it as one of the important technologies in the 21st century.Generally, sensor nodes are very small and use battery supply for power, but their batteries are hard to charge and replace, so the energy is limited. Due to the energy limitation of sensor nodes in wireless sensor network, how to reduce energy consumption and prolong lifetime of the network is a principal problem in this research domain. The energy consumption expended on wireless communication accounts for the majority of the entire consumption. There are a lot of energy-efficient protocols which can reduce energy consumption on wireless communication for each divided node in physical layer, MAC layer and network layer. However, a problem exists in wireless sensor network that nodes around base stations expend energy much faster than remote nodes. It is an energy consumption problem related to the topology and can not be solved by many protocols. In this thesis, an energy-efficient scheme with multiple base stations is introduced to solve this problem. In this scheme, the lifetime of the network is divided into rounds and base stations are moved to new locations at the beginning of each round. It can balance the energy expenditure and prolong the lifetime of the network with an optimal placement of base stations. Further more, improved strategies of rounds time are presented for different applications. The scheme and improved strategies of rounds time are proved observably effective and useable in the simulations.