The future noise environment at 800 MHz

Due to the relatively low noise environment which currently prevails in the 800 MHz spectrum recently allocated for land mobile radio systems, it is of considerable interest to determine the extent to which this situation is likely to deteriorate as the usage of the band grows. To this end, an extensive series of measurements of both noise level and received signal levels around 450 MHz has been conducted at a typical base station repeater site in the Chicago area, and the resulting data used to estimate the future noise environment at 800 MHz when this band reaches a similar level of maturity. In order to gather the data, a specialized scanning receiver system was constructed which sequentially samples the signal level on every channel over a 4 MHz band around 456 MHz while simultaneously monitoring the noise level on two unused channels near the middle of the band. During data collection each of the channels is sampled at a 6 Hz rate for a period of approximately 30 minutes during the midday peak of activity. This data, in conjunction with analytical models to convert it to equivalent 800 MHz data, has been used to estimate the probable noise level at 800 MHz in the future.