Adjacent channel interference between 800 MHz trunked FM and multiple site reuse systems
K.A. Brailean, G.C. Hess · 2002
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.>