Frequency Domain Channel Characteristics in an Outdoor-to-Indoor Environment at 6 and 37 GHz

Fixed Wireless Access (FWA) aims to provide users with high data rates. The unlicensed 6-GHz band (5.925 - 7.125 GHz) and the shared lower-37-GHz band (37.0 - 37.6 GHz) are considered for FWA due to their low cost and high bandwidth availability. We studied the frequency domain characteristics of multiple outdoor-to-indoor channel realizations at 6.175 and 37.3 GHz, emulating FWA scenarios. Channel transfer functions from a measurement campaign were analyzed to study the impact of frequency-selective fading on OFDM. Power flatness within each subcarrier and power variation across multiple subcarriers were studied. Subcarrier channels were generally flat-fading with a 95% probability of less than 1 dB variation. Channel power gain across subcarriers followed a Log-Normal distribution with an average standard deviation of 3.2 and 5.2 for outdoor and indoor receivers, respectively. The channel was more dispersive at 37 GHz compared to 6 GHz with respect to both intra-subcarrier power flatness and power gain variation across subcarriers.