Ultra-densification of radio access network (RAN) is a key to efficiently support the exponentially growing mobile data traffic in 5G era. Furthermore, extremely high frequency band like mmWave band was utilized to solve the bandwidth shortage problem. However, untra-dense reusing the same radio resource produced severe interference. And the mmWave link was very harsh due to frequent blockage by obstacles. Therefore a new RAN architecture needed to be introduced to realize ultra-reliable communications in such a severe radio propagation environment. An architecture of distributed MIMO based RAN was presented. Then, enhanced interference coordination (eIC) was described. Finally, the effectiveness of distributed MIMO based RAN with eIC by computer simulation was showed.