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Prolonging Lifespan of Sensor Networks Using Redundant Nodes
Wei Zha and Wee Ng

The latest hardware technology has provided various options in low power consuming and low cost sensors.In fact, the low cost of sensor nodes brings about the feasibility and viability of dense deployment of sensors within a monitored area in order to achieve high accuracy and reliability. However, the high level of redundancy in such dense deployment has its own problems such as message collision and duplication of information. To overcome these problems, we distinguish between physical and logical sensor node redundancy and propose the concept of virtual nodes to leverage on both redundancies. The virtual node approach groups together a set of redundant sensor nodes so that only one node needs to be active while the rest are in sleeping mode. In this way, energy consumption is significantly reduced. However, physical and logical redundancies determine different sizes of such grouping.We empirically tested our virtual node strategy on three sensor network spatial index structures. Experimental results showed that the proposed approach is able to prolong network lifespan especially when virtual node is large or node density is high. The experiments also yielded various interesting information on the performance of the proposed approach under various conditions of the sensor network.

Keywords: Wireless sensor networks, redundant nodes, energy efficient, spatial index, dynamic sensor network, lifespan

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