With　the　rapid　development　of　smart　terminals　and　infrastructures,　as　well　as　diversified　applications　(e.g.,　autonomous　driving,　virtual　and　augmented　reality,　space-air-ground　integrated　networks)　with　colorful　demands,　current　networks　(e.g.,　4G　and　5G　networks)　may　not　be　well　suited　to　the　requirements　of　novel　applications　and　services.　Recently,　efforts　from　both　the　industry　and　academia　have　been　made　on　the　research　into　6G　networks,　artificial　intelligence　(AI)　will　play　a　pivotal　role　in　the　design　and　optimization　of　6G　networks.