Impact of heterogeneous deployment on lifetime sensing coverage in sensor networks

While most research on wireless sensor networks have focused on the deployment of large numbers of cheap homogeneous sensor devices, in practical settings, it is often feasible to consider heterogeneous deployments of devices with different capabilities. Under the prescribed cost constraints, we analyze such heterogeneous deployments both mathematically and through simulations, and show how they impact the coverage aging process of a sensor network, i.e., how it degrades over time as some nodes become energy-depleted. We derive expressions for the heterogeneous mixture of devices that optimizes the lifetime sensing coverage in a single-hop direct communication model. We then investigate a multi-hop communication model through simulations, and examine the impact of heterogeneity on lifetime sensing coverage and coverage aging both with and without data aggregation. Our results show that using an optimal mixture of many inexpensive low-capability devices and some expensive high-capability devices can significantly extend the duration of a network's sensing performance.