Adaptive Distance Estimation Based on RSSI in 802.15.4 Network

This paper deals with the distance estimation issue in 802.15.4 wireless sensor networks. On a basis of signal strength of received frames a distance between two sensor nodes is estimated. Estimation is done by using the log-normal shadowing radio propagation model (LNSM). Basic problems of signal strength based systems are variation of RSSI parameter and correct calibration of coefficients for the LNSM model. For distance estimation in wireless networks, static and dynamic methods of calibration have been already introduced. Static calibration has significant drawback in adaptation to the dynamical environment changes. The proposed work deals with an experimental validation of dynamic calibration method for distance estimation in wireless sensor networks. This method for dynamic estimation of radio environment parameters for LNSM results in the significant improvements in the distance estimation accuracy in comparison with the known static methods.