Synchronized Multi-Channel Cognitive MAC Protocol with Efficient Solutions for Second Spectrum Access

The MAC protocols for cognitive radio network should permit access to unused white spectrum without (or with minimal) interference to incumbent devices. With in mind the fact that channel availability can rapidly change over space and time, the coordination between the users is important. In this paper a synchronized cognitive MAC protocol for decentralized network is proposed, the protocol works in multiple channels so it can deal with resource availability and with the aide of time slots the scarcity of the dedicated common control channel had been resolved. With the enhancement of GPS receiver capabilities, a prominent neighboring discovery, transmission power estimation and synchronization have been achieved. Efficient sensing and updating information exchange mechanism enhance the primary detection and resolve the hidden terminal problem. The protocol enables the secondary users to identify and utilize the leftover frequency spectrum in a way that constrains the level of interference to the primary users, preserve the transmission energy, and improves the network performance as demonstrated by the analysis and simulation.