Mitigating query hotspots for wireless sensor networks

A query-based wireless sensor network may generate frequent queries to a specific node, and then a hotspot problem emerges and fast consumes the energy of the specific node. A hotspot also influences the traffic flow near its neighboring area. To solve the hotspot problem, this paper presents two agents setting algorithms, distance-based agent selection (DAS) and greedy-based agent selection (GAS) to mitigate the traffic flow near hotspot. A sensor node, called limb node, is attached an agent that is responsible for aggregating query packets to hotspot and replying the interested data to the corresponding requestors. By assigning agents, DAS and GAS both mitigate the hotspot phenomenon. This paper investigates and simulates the proposed algorithms in different environment conditions. From simulation results, both DAS and GAS can mitigate the traffic rates of hotspot up to 60%.