Wireless sensor network

A wireless sensor network (WSN) is a distributed system of small, low-power devices that communicate wirelessly to monitor physical or environmental conditions. Each sensor node combines sensing, computation, and radio communication capabilities, operating on limited battery power and typically deployed in large numbers over a geographic area.

WSNs are used for environmental monitoring, industrial process control, military surveillance, and smart building management. The central challenge is not sensing but coordination: how to aggregate data from thousands of nodes without exhausting their energy reserves. Clustering algorithms and data aggregation protocols are used to reduce communication overhead, but the network's lifetime is fundamentally constrained by the energy cost of radio transmission.