Design of RSSI based fingerprinting with reduced quantization measures

This paper investigates the role of quantization in the Received Signal Strength Indicator (RSSI) information used for fingerprinting (FP) applications. One of the common drawbacks of FP is the large data size and consequently the large search space and computational load as a result of either vastness of the positioning area or the finer resolution in the FP grid map: this limits the application of FP to small environments or scenarios with largely spaced grid points leading to poor localization performance. We show that the computational complexity can be limited adapting the RSSI quantization w.r.t. the variance of the measured RSSI error at the target. This approach turns out to be advantageous for the deployment of FP systems based on beacons equipped with inexpensive technologies, in which the measures precision loss could be compensated by larger numbers of beacons. An appropriate quantization and design of RSSI signatures will make possible the deployment of FP in larger areas maintaining the same computational load and/or the desired localization performance.