Estimation of Isotropic Pathloss From Directional Channel Measurements in Azimuth and Elevation

Pathloss is one of the essential characteristics of wireless propagation channels. It is usually captured from channel measurements with (quasi)isotropic antennas. To characterize the wireless channels at high frequencies, beamforming or directional antennas are commonly used, in which case a method for estimating the isotropic pathloss is needed. The method should account for the possible spatial overlap of the different directional measurements while including the received signal from all the multipath components in the channel. In this letter, we propose an efficient method that uses a weighted sum of the powers received from the directional measurements. The weights can be calculated using matrix inversion. We verify the solution using synthetic data and demonstrate the usage with measurements at sub-THz frequencies.