A joint multi-channel assignment and power control scheme for energy efficiency in cognitive radio networks

In this paper, we focus on energy efficiency in cognitive radio networks (CRNs). This is formally stated as the problem of maximizing the energy efficiency (defined as the ratio of the total rate of secondary users (SUs) to total energy consumption), which is a nonlinear integer programming, and then a polynomial time heuristic algorithm is presented to address it. In contrast to existing schemes, in our proposed scheme, each SU is allowed to transmit on multiple channels. After the channel assignment, according to the number of channels assigned to each SU and their conditions, the transmission power of SUs on each assigned channel is adjusted. Moreover, the SUs, who do not have any data to transmit or no channel is assigned to them, transit into the sleep-mode, which would significantly reduce the energy consumption. Our simulation results indicate that our proposed algorithm (MCAS) outperforms existing algorithms for CRNs in terms of energy efficiency, throughput and energy consumption.