Adjacent channel interference between 800 MHz trunked FM and multiple site reuse systems

The interference implications of introducing multisite mobile communication systems into the 800-MHz FM trunked spectrum are examined. Emphasis is on talk-in interference into an FM system caused by multisite systems, as this is the worst of four possible interference scenarios. A Monte Carlo simulation which determines the range reduction when the adjacent channel has multiple interferers is described. The method for calculating each interferer´s power at the FM base is explained and includes a means of accounting for log-normal fades and frequency drifts. Results are presented for a modulation just fitting the US FCC data mask, Part 90.209(g), and an actual modulation which fits the passband of the US FCC data mask but has 15-dB more protection in the stopband. Two different FM receivers are modeled to show the importance of receiver selectivity. Power control is evaluated for its ability to reduce interference