Cognitive radio: Making software radios more personal

Software radios are emerging as platforms for multiband multimode personal communications systems. Radio etiquette is the set of RF bands, air interfa ces, protocols, and spatial and temporal patterns that moderate the use of the radio spectrum. Cognitive radio extends the software radio with radio-d omain model-based reasoning about such etiquettes. Cognitive radio enhances the flexibility of personal services through a Radio Knowledge Representat ion Language. This language represents knowledge of radio etiquette, device s, software modules, propagation, networks, user needs, and application sce narios in a way that supports automated reasoning about the needs of the us er. This empowers software radios to conduct expressive negotiations among peers about the use of radio spectrum across fluents of space, time, and us er context. With RKRL, cognitive radio agents may actively manipulate the p rotocol stack to adapt known etiquettes to better satisfy the user's needs. This transforms radio nodes from blind executors of predefined protocols t o radio-domain-aware intelligent agents that search out ways to deliver the services the user wants even if that user does not know how to obtain them . Software radio [1] provides an ideal platform for the realization of cogn itive radio.