Link maintenance scheme for OFDM-based cognitive radio Ad Hoc networks

Transmission among the cognitive users (CUs)´ is always interrupted by the primary users (PUs)´ reclaim of the spectrum and the fading effect of wireless channels. To maintain reliable continuous communication among CUs, an efficient scheme for link maintenance in OFDM-based cognitive radio Ad Hoc networks is proposed in this paper. In the scheme, redundant sub-channels (RSC) are employed by CUs to tackle the outage problem caused by the PUs´ reclaim of the spectrum and wireless fading effect in the transmission. Meanwhile, backup sub-channels (BSC) are arranged to help select sub-channels with better channel quality. Additionally, to lower the overhead and improve the accuracy of the spectrum sensing, a partial sensing module is designed to enable the CUs to inherit and update the original idle spectrum list until it expires. Simulation results show that the proposed scheme can realize higher throughput and lower sensing overhead with slight reduction of the forced termination probability (FTP) performance compared to the existing approaches.