Design Of Wireless Sensor Networks For Environmental Monitoring Studies

With the development of sensor technology, micro-electronic technology, nested computation technology and wireless communication technology, Wireless sensor network (WSN) developed very rapidly. It is a new research area of computer and has a wide application future. WSN can be defined as an ad hoc system consisting of a collective of networked sensor designed to intercommunicate via wireless radio. These nodes coordinate to apperceive, collect and compute the information of the objects, then transmit the aggregated data to the observer. WSN is popular in environmental monitoring.This paper surveys environmental monitoring-based wireless sensor networks. We found that there two conditions of environmental monitoring, first is continuous monitoring, second is query/respond monitoring. Then we design routing protocol and MAC protocol for these situations differently. Environmental monitoring always in large tracts of land, needs large of nodes, so we use hierarchical clustering approach in routing protocols. For continuous monitoring, based on the survey of LEACH, we found three problems, so we improved LEACH protocol. By simulation, the results show that the improved LEACH is more advantageous in prolong the system lifetime than LEACH protocol. The chain in PEGASIS protocol is best, but it not fit for large-scale application. Then we improved this into more chain. We pour chord of P2P into WSN for query/respond monitoring. That is BQRP protocol. Through analyzing, we prove the bounded times for data lookup is O(MlogN).Media Access Control protocol decides the way what wireless channel used, distributes limited communication resource between sensor nodes, it becomes a focus of studying WSN. Because the constraint of node energy, we design the MAC protocol for two application.