Stelios J. Patsiokas

Propagation of radio signals inside buildings at 150, 450 and 850 MHz

A comprehensive study designed to characterize the propagation of radio frequency signals inside buildings is presented. Propagation curves at 150, 450 and 850 MHz are generated for a large office building in Ft. Lauderdale, Florida. The measurement apparatus is computer driven, to enable rapid integration of a large number of samples from a test location. The representation of the signals in the time domain provides for a good characterization of multipath fading for the different frequency bands. The number of samples needed for repeatable and accurate power averaging, are determined empirically. The vast amount of data is used to document the attenuation due to office walls and building floors. Probability distributions and standard deviations for the three frequency bands are also presented.

Traffic aspects in future low power, multi-channel trunked systems

A traffic analysis is presented for a low-power, multichannel, trunked system. A comparison between exponentially distributed and constant holding times is generated by incorporating two delay theory traffic modules, Erlang C and Grommelin-Pollaczek. The effects of queuing and time-out-timing on the system capacity and grade of service are also discussed. Four types of communication systems are investigated: (a) fixed telephone; (b) cellular telephone; (c) dispatch and (d) two-way selective calling. Bar charts of the number of channels in a two-cell system are also presented.<<ETX>>