Extremely Low Power Indoor Localisation System

In this paper, design, implementation and testing of an extremely low-power and low-cost wireless sensor network for monitoring person or object position in an indoor environment are discussed. Mobile and fixed nodes are used as key elements to detect the position of the object within a building. The localisation is based on the well known received signal strength intensity (RSSI) method. The extremely low-power feature is achieved by using a new Duty-Cycle Controlling (DCC) technique. The DCC technique is based on the Radio Frequency Identification (RFID) principle to wake-up the mobile unit at the right time and save energy when it is not used. The current consumption of the mobile unit is reduced by increasing its power-down period. The proposed DCC technique was experimentally verified and low power was achieved which allows extending the battery lifetime from few months to 5 years.