We present the Cognitive Radio (Policy) Language (CoRaL), a new language for expressing policies that govern the behavior of cognitive radios that opportunistically share spectrum. A Policy Reasoner validates radio transmissions to ensure that they are compliant with the spectrum policies. The Policy Reasoner also discovers spectrum sharing opportunities by deriving what requirements must be fulfilled for transmissions to be valid, i.e., in compliance with policies. A novel mix of reasoning techniques is required to implement such a reasoner.
Keywords: spectrum sharing, policy language, policy reasoner