Empirically Based Study of Channel Characteristics with Near-Ground Base-Stations

Based on outdoor-indoor measurements we study the channel characteristics of wideband multiple-input-multiple-output (MIMO) wireless access with near-ground base-stations (BS). These provide broadband service to indoor nomadic users in suburban residential environments. We compare near-ground channel characteristics with those of a lamp-post BS for line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. Essentially path-loss models, spectral efficiencies for 2 x 2 and 4 x 4 MIMO systems, delay spreads and coherence bandwidth are evaluated. We found that in general lowering the BS array has a detrimental effect on path-loss and efficiencies. Up to 50% less efficiency was observed in the NLOS channel, and path-losses are moderately greater for both LOS and NLOS conditions. Our investigation also shows differences in the power delays profiles when varying the array height.