Sensor-assisted localization in cellular systems

We investigate the use of an auxiliary network of sensors to locate mobiles in a cellular system, based on the received signal strength at the sensor receivers from a mobile´s transmission. The investigation uses a generic path loss model incorporating distance effects and spatially correlated shadow fading. We describe four simple localization schemes and show that they all meet E-911 requirements in most environments. Performance can be further improved by implementing the MMSE algorithm, which ideally reaches the Cramer-Rao bound. We compare the MMSE algorithm and the four simple schemes when the model parameters are estimated via inter-sensor measurements.