Energy Efficient Extreme MIMO: Design Goals and Directions.

Ever since the invention of Bell Laboratories Layer Space-Time (BLAST) in mid 1990s, the focus of MIMO research and development has been largely on pushing the limit of spectral efficiency. While massive MIMO technologies laid the foundation of high spectrum efficiency in 5G and beyond, the challenge remains in improving energy efficiency given the increasing complexity of the associated radio systems. With the substantial negative implications of climate change looming ever closer, minimizing energy use is a key dimension of achieving sustainability and is of paramount importance for any future technology. Thus, every aspect of future extreme MIMO system design, implementation, and operation will be scrutinized to maximize energy efficiency. An analysis of the massive MIMO 5G radio energy consumption at different loads leads to qualitative energy efficiency design goals for emerging extreme MIMO systems. Following this, we focus on novel operational and component technology innovations to minimize energy consumption.