Keynote talk #1: 5G: From MIMO to massive MIMO

Multiple-input multiple-output (MIMO) communications systems have been seriously considered in recent years to achieve substantial gains in spectral, power, and energy efficiency compared to conventional single-input single-output (SISO) systems. Various MIMO configurations based on Single-User (SU)-MIMO, Multi-User (MU)-MIMO, network-MIMO architectures have been proposed for LTE systems. To accommodate the ever-increasing demands of different multimedia services and applications, the evolving next-generation wireless access networks are envisioned to support 1,000-fold gains in capacity, connections for billions of diverse devices, and Gb/s individual user data rates. Massive MIMO has emerged as a promising technology to deal with such challenges. Through the use of an excessively large number of service antennas in a fully coherent and adaptive operation, transmission and reception of signal energy can be focused into small regions to offer large improvements in throughput and energy efficiency, especially when combined with multi-user scheduling and in mmWave bands. Furthermore, massive MIMO can enhance the robustness to interference and intentional jamming. The talk will provide an overview from MIMO, SU-MIMO, MU-MIMO, network-MIMO to massive MIMO developments applicable to next-generation wireless access communications, and highlight various technical issues and solutions.