| Summary: | 碩士 === 國立交通大學 === 資訊科學與工程研究所 === 96 === In this thesis, we propose a routing mechanism that can mitigate the hot-spot problem of wireless sensor networks (WSNs) so as to extend the network lifetime.
A WSN consists of a coordinator and many sensor nodes that periodically collect and report to the coordinator the sensed information. With such periodical transmission, a sensor node may exhaust its energy sometime if it has limited energy resources. Moreover, the energy consumption may further be aggravated by the hot-spot problem that commonly exists in most WSNs; that is, sensor nodes closer to the coordinator tend to relay more traffic, and will exhaust their power sooner than others. However, in most deployments of sensor networks, there exist some nodes, henceforth referred to as power-nodes, with fixed power supplies or easy to replace if malfunction.
In this thesis, we propose a Backbone-Aware Network Formation (BANF) scheme to mitigate the influence of hot-spot problem. We use power-nodes to construct the backbone of a network and route information toward a backbone power-node first, or the coordinator if it is closer than other power-nodes. The power-nodes then route the traffic toward the coordinator through other power-nodes in the backbone. Therefore, BANF can distribute traffic loads to more spots (nodes near backbone power-nodes) and alleviate the hot-spot problem of WSNs.
BANF has two features: (1) power-node based subtrees and routing, and (2) fault tolerance mechanism for power-node failures. Results from NS2 simulations show that BANF can prolong network lifetime about 193~310%, compared with ZigBee under various network topologies.
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