Heterogeneous wireless sensors are widely used to perform a cooperative monitoring task for critical applications. For reducing cost, powerful sensors are activated only when an interesting event is detected, while the other low-cost and error-prone sensors contrarily play an important role in detection. A significant issue arises: How do we provide fault tolerance in such a heterogeneous wireless sensor network (HWSN) while maximizing the system lifetime? In this paper, we propose an energy-efficient K-coverage configuration (KCH) to guarantee detection quality in HWSNs with very low cost. Despite the deployed sensors having heterogeneous capacities, KCH accurately determines whether a sensor should sleep or stay active by tracing only a few essential regions within the sensing range of each sensor. Experimental results show that KCH (1) minimizes the computation cost as low as 0.7% of that of a well-known deterministic algorithm, and (2) maximizes the system lifetime of the K-covered HWSN.
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