CRUAM-MAC: A novel cognitive radio MAC protocol for dynamic spectrum access

Current proposals for Cognitive Radio Networks (CRN) are created mainly to solve dynamic spectrum access where several cognitive devices are searching for free frequency bands, i.e. `white spaces´. This is in order to communicate without or with minimum interference to primary users (PU). Cognitive Radio devices must coordinate the communication with peers when they have to change their communication to another frequency band when licensed user communications are established in the same frequency band. Then this coordination comprises sensing, decision making, sharing and mobility as main functionalities. We propose a medium access control (MAC) protocol for CRN which have been tested with a developed discrete event simulator to characterize cognitive radio devices communicating in presence of primary users. We found that our proposed MAC operates with minimum interference to PU transmissions; it also reduces the channel access time and the packet loss when compared with an overlay CSMA/CA implementation for CRN. These advantages are in spite of the increase in the number of PUs communicating. We show a complete solution for dynamic spectrum access which incorporates a control mechanism to coordinate the communication establishment between CR devices. This solution has also the advantage that does not require a control common channel (CCC).