Full Dimension MIMO (FD-MIMO) - Reduced Complexity System Design and Real-Time Implementation

Full-Dimension MIMO (FD-MIMO) technology has been shown to increase spectral efficiency 2-4X compared to current LTE systems by exploiting a large number of antennas to support high order multiuser MIMO. High order multiuser MIMO with large number of antennas increase design and implementation complexity significantly. Furthermore, practical challenges such as antenna calibration for RF mismatches and failure need to be considered. In this paper, reduced-complexity precoding algorithm is introduced and optimized for real-time FPGA based implementation. Novel antenna calibration architecture is designed for FD-MIMO large 2-dimension array with the consideration of RF failure in practice. Field experimental results are also presented based on a proof of concept (PoC) FD-MIMO base-station (BS) with 32 antennas that supports up to 12 users and achieves spectral efficiency of ~21 bits/sec/Hz.