Real-Time Radio Environment Mapping for Cognitive Radio

In this paper it is proposed that cognitive radios consult with a supporting network infrastructure to provide the means by which Quality of Service and coexistence and can be acheived. The network server would either grant or reject transmission requests by estimating, from the cognitive radio´s geo-location, the likely impact its transmission would have on incumbents and other cognitive radio devices. This decision must be based on an accurate real-time Radio Environment Map which is kept up to date by readings from cognitive radios, sensors and dynamic radio propagation prediction. It is concluded that real-time Radio Environment Mapping of signal strength in space, time and frequency will address the most fundamental of cognitive radio´s challanges.