Abstract
We are delighted to introduce the readers to this special section of the IEEE TRANSACTIONS ON COGNITIVE COMMUNICATIONS AND NETWORKING (TCCN), which has the purpose of addressing the current state-of-the-art for research and new efficient schemes, techniques, and protocols to address fundamental and practical challenges in cognitive radio-optical networks and Coexisting Radio and Optical Wireless Deployments (CROWD) networks. We received a total of 13 submissions, and after a rigorous review process, 6 articles have been selected for publication, which are briefly discussed next.