Characterization of UHF Multipath Radio Channels in Factory Buildings

Wide-band multipath measurements at 1300 MHz have been made in five factory buildings in Indiana. Root mean square (rms) delay spread (a) values were found to range between 30 and 300 ns. Median a values were 96 ns for line-of-sight (LOS) paths along aisleways and 105 ns for obstructed paths across aisles. Worst case a of 300 ns was measured in a modern open plan metal-working factory. Delay spreads were not correlated with transmitter-receiver (T-R) separation or factory topography, but were affected by factory inventory, building construction materials, and wall locations. Wide band path loss measurements consistently agreed with continuous wave (CW) measurements made at identical locations. It is shown here 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. Wide-band factory propagation measurements have not been previously reported in the literature.