Characterization of UHF multipath radio channels in factory buildings

Abstract

Wideband multipath measurements at 1300 MHz were made in five factory buildings in Indiana. Root-mean-square delay spread ( sigma ) values were found to range between 30 and 300 ns. Median sigma values were 96 ns for line-of-sight paths along aisleways and 105 ns for obstructed paths across aisles. Worst-case sigma or 300 ns was measured in a modern open-plan metal-working factory. Delay spreads were not correlated with transmitter-receiver separation or factory topography but were affected by factory inventory, building construction materials, and wall locations. Wideband path loss measurements consistently agreed with continuous-wave measurements made at identical locations. It is shown that such empirical data suggest independent and identical uniform distributions on the phases of resolvable multipath signal components. Average factory path loss was found to be a function of distance to the 2.2 power.