Energy-Efficient MAC Protocol for IEEE 802.11-Based Cognitive Radio Networks

In a cognitive radio (CR) network, it is extremely important to implement periodic spectrum sensing in order to prevent secondary users (SUs) from interfering with primary users (PUs). Contention from SU transmitters may increase the back-off interval to the point that the time remaining to the beginning of next sensing interval is too short to transmit a frame. In this paper, we propose an energy-efficient medium access control (MAC) protocol that allows a single SU sender to transmit a sequence of packets to its intended receivers until the next spectrum sensing interval begins. The sender, which is allowed to monopolize the channel for a certain length of time, sends to a restricted number of intended receivers in the wake state while all other nodes switch to sleep mode to reduce overall power consumption. We provide an analytical model for throughput and power consumption performance of cognitive networks under our proposed MAC protocol. Through performance analysis and extensive simulation, we show that our proposed energy saving protocol efficiently reduces power consumption while retaining high throughput performance.