An Efficient MAC Protocol for Cognitive Radio Networks

Energy efficiency Abstract: At present cognitive radio networks allow moderate sharing of the radio spectrum without causing any harmful interference to licensed users. In this paper, we propose a new efficient medium access control (MAC) protocol that aims at improving the coexistence of licensed primary users (PU’s) & unlicensed secondary users (SU’s) in cognitive radio networks. However, there are many new challenges associated with cognitive radio networks such as multichannel hidden terminal problem (MHTP), channel availability problem, sensing error, flooding control messages on the common control channel, energy wastage problem. This might cause the MAC to suffer from serious performance degradation. Our MAC protocol minimizes the number of the channels to be sensed & time consumptions in sensing phase. Our mechanism also addresses the energy efficiency issue. Sensing is done at the beginning of each time frame to avoid the out of date spectrum sensing. Our proposed MAC protocol considers collision avoidance among SU’s and between SU’s and PU’s. We analyze the saturation throughput performance of the proposed MAC protocol. Computer simulations show that significant improvement in the throughput of the secondary users is achieved with energy saving mechanism.