In　this　paper,　a　social-aware　virtual　medium　access　control　(SV-MAC)　is　devised　to　integrate　virtualization　and　social　awareness　to　D2D　communications　underlying　heterogeneous　cellular　networks.　SV-MAC　is　a　converged　network　layer.　Through　SV-MAC,　heterogeneous　networks　can　be　unified　in　a　single　protocol　stack,　providing　a　common　abstraction　for　users　and　mobile　network　operators　(MNOs)　to　share　their　network　resources.　Leveraging　users＇　social　information,　SV-MAC　can　realize　social-aware　D2D　discovery,　association,　and　resource　allocation　for　improved　D2D　communication　efficiency.　In　order　to　validate　the　advantages　of　the　proposed　SV-MAC　protocol,　we　study　the　cellular　and　D2D　resource　allocation　problems　under　the　SV-MAC　protocol.　The　problems　are　formulated　as　maximizing　the　cellular　and　D2D　energy　efficiency　(EE).　The　cellular　resource　allocation　problem　is　first　solved　considering　its　priority　to　D2D　users.　The　resource　allocation　problem　for　D2D　users　is　solved　after　cellular　users　to　control　the　D2D-to-cellular　interference　within　a　tolerable　threshold.　In　the　simulation,　we　introduce　real　mobile　user　traces　to　simulate　the　user　social　information.　Simulation　results　show　that　the　proposed　SV-MAC　resource　allocation　schemes　obtain　a　beneficial　EE　improvement　comparing　with　conventional　schemes.