Path loss, beamforming gain and time dynamics measurements at 28 GHz for 90
Achieving adequate coverage with high gain antennas is key to realizing the full promise of the wide bandwidth available at mm/cm bands. We report extensive indoor measurements at 28 GHz, with over 1000 links with and without Line-of-Sight (LOS) using a specialized narrowband channel sounder, capable of reliable measurements up to 171 dB path loss to characterize 90 Azimuthal power spectra were captured with 1-deg granularity using a 10-deg receive horn spun at speeds up to 300 rpm. Measured path gain-distance dependence in LOS and NLOS are well represented by power-law models, with 3.1 dB standard deviation in NLOS, and by a mode-diffusion model with 3.5 dB RMS error. Excess loss at 28 GHz suffered in turning a corner or into a room was found to be 30 and 32 dB respectively, in contrast to 20 dB found previously at 2 GHz. Degradation of azimuthal gain by scattering was within 4 dB in the hallway and 7 dB inside a room with 90 canonical building indicate that every hallway needs an access point to provide 1 Gbps rate in 90 terminals, with temporal fading caused by pedestrians, long term average-power-based aiming was within 3.7 dB of rapid beam switching in 90 high traffic locations.
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