Lifetime-aware hierarchical wireless sensor network architecture with mobile overlays

Recent technological advances have led to the emergence of small battery-powered sensors with considerable, albeit limited, processing and communication capabilities. Wireless sensor networks have gained considerable attention in applications where spatially distributed events are to be monitored with minimal delay. We present and analyze a hierarchical wireless sensor network with mobile overlays, along with a mobility-aware multi-hop routing scheme, in order to optimize the network lifetime, delay, and local storage size. Fixed event aggregation relays and mobile relays are used to collect events from the sensors and send them to a central base station. We analyze the effects of various system parameters on the network performance, and formulate a convex optimization problem for maximizing the network lifetime subject to constraints on local storage, delay, and maintenance cost. Network behavior is studied and analytical results are validated through simulations.