Out of Many, Many: The Path towards Scalable, Integrated, mm-Wave MIMO Arrays

Wireless data usage is doubling every year and network providers are projecting demand approaching 1Gb/user/day, necessitating a 1000x increase in network capacity and 100x increase in worst-case data rates with perhaps only 2x increase in available spectrum at frequencies below 3GHz. Future cellular wireless networks will evolve to higher center frequencies that provide larger available spectrum and to ultra-dense multi-user MIMO (MU-MIMO) with heterogenous cell size (macro, pico, femto) for increased spatial spectrum reuse. Therefore, scalable RF and mm-wave transceivers with 10 (user terminal) to 1000 (base station) elements operating in ad-hoc frequency-reuse scenarios are the future paradigm for wireless transceivers.  Over the last 15 years, the feasibility of integrating multiple transceivers in silicon to achieve multiple-input single-output phased-array operation has been extensively demonstrated.