Design Of IEEE 802.15.4 Wireless Sensor Network

A wireless sensor network(WSN) typically consists of a number of sensor nodes which can sense,measure,and gather information from the environment. With the development in Micro-Electro-Mechanical Systems(MEMS) and Very Large Scale Integrated circuits(VLSI) technology,ubiquitous wireless sensor networks have gained worldwide attention in recent years,and are expected to play an important role in the future society,such as for military applications,health care,traffic control,home automation,industrial process and environmental monitoring,etc.Most of the sensor network devices are designed to be small and low-power for low data-rate transmissions,and therefore energy and power saving is important for extending lifetime of the network devices as well as the network.Besides,the scalability to hundreds or thousands of nodes is another essential issue in designing wireless sensor networks.This thesis studies the design of the wireless sensor network with a cluster topology based on the IEEE Std.802.15.4.By making use of the Slotted CSMA/CA model given in Sofie Pollin's paper,many relationships among the network and sensor parameters are derived in order to further solve the optimization problem.Given the throughput requirement or the sensor nodes distribution,the design finds the amounts of time allocated for contention-based and contention free transmissions at each cluster head as well as the associated status of the sensors in the overlapping area of clusters. The optimization results show that the design can achieve the objective to balance the energy consumptions of all cluster heads and utilize the limited resources effectively to extend lifetime of the network.