 This paper proposes a NOMA-based spectrum-sharing scheme for dual-hop CRNs. It mathematically formulates a constrained optimization problem to maximize the sum rate of all SUs while maintaining the total transmit power of the system. Three computational intelligence, CI, based solutions are proposed to solve the problem, including artificial B-colony, ABC, particle swarm optimization, PSO, and genetic algorithm, GA. The comparison of different CI approaches shows that the minimum power required by the secondary NOMA relay to satisfy the primary rate threshold of 5-bit-slash-s-slash-hertz is 20 milliwatts for EABC, while ABC, PSO, and GA achieve the same target at 23 milliwatts, 27 milliwatts and 32 milliwatts, respectively. This indicates that EABC reduces power consumption by 13.95%, while 29.78% and 46.15% power saving is achieved compared to PSO and GA, respectively. This article was authored by Kieran Sultan. We are article.tv, links in the description below.