Spread spectrum transmission in the 902-928 MHz band

The 902-928 MHz band has been assigned, on a nonprotected basis, to unlicensed spread spectrum devices subject to the constraints outlined in DOC TR76 and FCC Part 15.247. The rules allow for direct sequence, frequency hopping and combinations of both. The specified operating parameters, interference environment and typical propagation conditions suggest certain limitations which may not be consistent with general expectations. The authors discuss the rules and the potential licensed and unlicensed interference sources and propagation conditions faced by these spread spectrum devices. The attributes of direct sequence and frequency hopping systems are presented and compared in various interference scenarios. The diversity properties of spread spectrum in multipath fading environments are analyzed