Next generation cognitive cellular networks: spectrum sharing and trading [Message from the editor-in-chief]

Dear readers, The April issue of this magazine offers you a Feature Topic (FT) on "Next Generation Cognitive Cellular Networks: Spectrum Sharing and Trading" with 12 articles authored/coauthored by experts from both industry and academia. The call for papers for this FT attracted a fairly large number of submissions. Therefore, it was indeed a great challenge for the Guest Editors to handle their reviews in a very timely manner, and to select the best papers to be included in this FT out of so many submissions.