This study proposes a routing algorithm to enhance throughput and spectrum utilisation efficiency for underwater cognitive acoustic sensor networks (UCASNs). In a UCASN, each cognitive acoustic (CA) user would sense the medium to detect available spectrum resources. However, CA users have no exact knowledge about the communication mechanism of the primary users (PUs) such as sonar users or sonar interference sources. In addition, because of the frequency-dependent attenuation, the available frequencies in water are severely limited and are still underutilised. Therefore, by analysing the behaviour of the CA users based on the ON–OFF process in the primary channel, an optimisation problem is derived to maximising the spectrum utilisation taking into account the bandwidth requirement of CA users. In this way, an efficient routing algorithm for UCASNs is proposed to enable throughput improvement of the network while reducing interference to PUs. Finally, simulation results are shown to verify the effectiveness of the authors proposed scheme.
Available online: https://digital-library.theiet.org/content/journals/10.1049/iet-wss.2018.5080