Channel characteristics for elevator shafts at 5 GHz

We provide some measured channel characterization results for two elevator shaft channels in the 5-GHz band, for two distinct elevator shaft types in two buildings. The elevator shaft channel is of interest for several applications, including public safety. Even though other authors have reported elevator shaft channel characteristics for lower-frequency bands (255-MHz, 900-MHz, 1.9-GHz), to our knowledge ours is the first work for the 5-GHz band. Prior work has also not thoroughly addressed channel characteristics when the elevator car is in motion, whereas here we provide some initial measurement results for this dynamic condition. We measured power delay profiles and from these estimated propagation path loss and root-mean square delay spread (RMS-DS). Path loss exponents were approximately 2 in one building and 6 in the other. Mean RMS-DS values range from 14-60 ns when the elevator car is motionless, with RMS-DS generally increasing with link distance. Maximum RMS-DS values increase to 58 ns and 70 ns in the two buildings when the elevator car is moving and the receiver is inside the car.