Attenuation of 900 MHz radio waves propagating into a metal building

The attenuation of radio waves propagating into buildings is a crucial factor in the feasibility and design of portable radio telephone systems. In order to characterize signal statistics of an approximate worst-case building, signal levels were measured inside a steel shell building at 900 MHz. Cumulative signal level distributions determined for 4-ft square areas at 3, 5, and 7 ft heights within the building are good approximations to the Rayleigh distribution. Attenuation medians for the 4-ft square areas range from 26 dB to 32 dB.