Digital Active Antenna Systems for 5G and Beyond mm-Wave Massive-MIMO Systems
The 5G specifications demand for enhanced mobile broadband (eMBB), ultra reliable low latency communications (URLLC), and massive machine type communications (mMTC). Using the limited bandwidth in bands below 6GHz, this requires enhanced spectral efficiency modulation formats. In the mm-wave domain, wide-bandwidth, analogue beamforming based active antenna systems (AAS) are approaching the commercial launch. But there is a possibility for enhanced mm-wave digital AAS considering their benefits of multi-user connection (MU-MIMO) for further cell capacity enhancement, and simultaneous channel hardening for mobility. This talk covers the prototyping and performances of analogue AAS and digital AAS, indoor and outdoor verification testing using 28GHz digital AAS including hardware efficiency and spectrum efficiency discussion, their challenges in DAC/ADC implementation using bit streamer techniques, and future perspectives.