Research And Improvement Of LEACH Protocol For Wireless Sensor Network

A wireless sensor network which consists of a group of sensor nodes enables themonitoring of a variety of environments for applications that include home security, machinefailure diagnosis and biological detection. Sensor nodes router the collected data to the basestation via multi-hop wireless links. Sensor nodes are severely constrained by the amount ofbattery power available, limiting the lifetime and quality of the network. Therefore, how toimprove the energy efficiency of the sensor nodes to prolong the system lifetime of a sensornetwork is of great significance in practical applications.In wireless sensor networks, data fusion helps to reduce the amount of data transmittedbetween sensor nodes and the base station. Data fusion combines one or more data packetsform different sensor measurements to produce a single packet. The LEACH (Low-EnergyAdaptive Clustering Hierarchy) protocol is an elegant solution to this data collection problem,where a small number of clusters are formed in a self-organized manner. A designated node ineach cluster collects and fuses data form nodes in its cluster and transmits the result to thebase station directly. Based on the research of LEACH protocol, a low energy-consumptionchain-based routing protocol LEACH-CC is proposed in this thesis. The new protocol ischaracterized by each node will send information about its current location and energy levelto the base station. The base station runs the simulated annealing algorithm to determine theclusters for that round. Then a chain routing between clusters is established to reduce theamount of nodes which communicate with the base station. The key idea in the chain routingis to form a chain among the clusters so that each cluster will receive and transmit to a closeneighbor cluster. Gathered data moves from cluster to cluster, get fused, and eventually adesignated cluster transmits to the base station. Clusters take turns transmitting to the basestation so that the average energy spent by each frame is reduced. Finally, this thesis simulated the new protocol using NS2. The simulation resultsindicate that, the clusters formed by the base station will in general be better than thoseformed using the distributed algorithm. The experimental results also show that LEACH-CCperforms better than LEACH protocol. It not only extends the lifetime of the network, butalso improves the energy efficiency.