Spectrum opportunity in UHF - ISM band of 902-928 MHz for cognitive radio

The cognitive radio is an intelligent wireless communication system dynamically adapting itself to the operating environment by changing its parameters, towards reliable communication and efficient spectrum utilization. Radio scene analysis is the first and foremost task based on which the spectrum is sensed towards its efficient utilization. A real-time observation is needed to model the statistical data of spectrum utilization with reference to specific geographic location and time, which can be utilized in resource allocation of cognitive radio system. This paper presents typical spectrum occupancy of the 902-928 MHz ISM band obtained through signal strength measurements and its statistical study. The usage of such channel occupancy statistical data in the spectrum sensing formulation is also elaborated in a typical scenario for a frequency hopping system working in this band. The simulation result of energy based detection of the above system is presented to realize a cognitive environment.