What will 6G be? My current research goal is to seek a set of possible answers for this challenging question. Although it is unclear whether 6G will continue to enhance (peak) data rates further, or focus to newer metrics such as ultra-low latency, energy efficiency, and massive connectivity, I believe that multiple-input multiple-output (MIMO) communication technologies using a massive number of antennas still stand out as a key ingredient for 6G, as it has been adopted to the salient feature for both 4G and 5G in 3GPP and next generation WiFi systems (e.g., IEEE 802.11ax, ay). By harnessing a massive number of antennas (> 100), 6G is expected to not only increase network capacity, but also enable low-latency mobile applications, and provide wireless connectivity for massive mobile devices. This mega trend will be continued for 6G, but will face different levels of challenges that have not been seen before. Our research group’s research goals are intended to explore novel solutions to meet these technological challenges for the design of 6G by capitalizing on physical- layer and some cross-layer communication technologies. Specifically our research team has taken three different research directions: 1) ultra-low power massive MIMO, 2) super-dense MIMO networks, and 3) innovative multiplexing techniques for future MIMO.