Backoff Algorithm in Cognitive Radio MAC Protocol for Throughput Enhancement In this paper, we have explored a novel concept of the medium access control (MAC) protocol for the distributed cognitive radio network. We have implemented the backoff algorithm in the self-scheduled multichannel cognitive radio MAC (SMC-MAC) protocol for the contention solving among the cognitive users and, hence, reserve the licensed channels for data transmission. In this control channel protocol, the cognitive users share the sensing results with each other, and each channel is divided into four intervals such as idle, sensing-sharing, contention, and data transmission. However, the backoff algorithm has been implemented during the contention interval to enhance the number of successful users and, hence, has increased the throughput of cognitive radio network. The backoff algorithm has significantly minimized the competition and, hence, collision among the cognitive users while reserving the unutilized licensed channels.