Toward the realization of the 5th generation (5G) mobile communication network that offers super high bit rates and capacity, a further enhancement of the mobile optical network to support 5G radio access technologies is indispensable. At first, this paper briefly summarizes the concept of 5G radio accessnetwork based on the Phantom Cell concept in which small cells that offer super high bit rate transmission using higher frequency bands and wider bandwidth are overlapped onto macro cells that support coverage and mobility, and the radio links corresponding to User (U)-plane and (C)-plane are separately supported by small cells and macro cells, respectively.
Next, technical issues and requirements on the mobile optical network for supporting 5G radio access technologies are discussed, focusing on massive MIMO and carrier aggregation.