Abstract—In this paper, a transmit power-saving scheme incorporated with multiple relay-selection for performance enhancement of underlay relay-assisted cognitive radio networks (RCRNs) is proposed. For this purpose, a secondary source assisted by a set of Amplify-and-Forward (AF) cognitive relays to communicate with its intended destination, is considered. The relays operate in half duplex mode below the interference threshold of a primary user (PU). In contrast to the previous relay selection schemes in this context, our proposed technique is focused on the difference of signal-to-noise ratio (SNR) of source-relay and corresponding relay-destination link for each candidate relay and decisions regarding power-saving and SNR maximization are solely based on this factor. However, for the sake of interference-mitigation, multiple relay selection is performed and assigns a selection priority factor for each relay based on SNR of its corresponding relay-destination link. Finally, ease of implementation and quick convergence along with strong exploration and exploitation techniques of Artificial Bee Colony (ABC) algorithm convinced us to employ this global optimizer to achieve the optimum results of our multi-constrained problem. Performance of the proposed scheme is shown through computer simulations.


Index Terms—Cognitive radio network, underlay spectrum sharing, amplify-and-forward, relay networks, artificial bee colony

Cite: Kiran Sultan, Atta-ur-Rahman, Bassam A. Zafar, Nahier Aldhafferi, and Abdullah Alqahtani  " Intelligent Multiple Relay Selection and Transmit Power-Saving with ABC Optimization for Underlay Relay-assisted CRNs," Journal of Communications, vol. 13, no. 7, pp. 377-384, 2018. Doi: 10.12720/jcm.13.7.377-384.