Calibration of the attenuation-rain rate power-law parameters using measurements from commercial microwave networks

A common way to describe the relation between rain-rate R [mm/h] and attenuation A [dB] in radio signal is the Power-Law A = aRb, where a and b are the Power-Law parameters, which depend on the radio signal (frequency, polarization) and on some properties of the specific environmental conditions. These parameters are usually set off-line using special purpose equipment and are used from existing tables. However, such tables provide averaged, approximated values to the Power-Law parameters. Using these values for local network design and/or for rainfall estimation can cause inaccuracies. In this paper we propose a new method for calibrating the power law parameters locally, in almost real time, using standard equipment - that is, measurements from rain-gauges and from existing commercial microwave networks deployed in cellular backhauling systems. We suggest an estimation procedure and demonstrate its operation using real scenario in the south of Israel.