Rakuten and NEC take on global telecom vendors with 5G core by Jun 3, 2020 12:03pm Two Japanese companies to offer 5G SA core to other carriers. (Rakuten CEO Mickey Mikitani) Rakuten Mobile launched its greenfield 4G network on April 8, but it’s moving fast on its 5G network. And the Japanese operator seems to have even bigger ambitions. Today it said it’s working with NEC to develop a standalone 5G core network based on containers.