MIMO 4 X 4 vs. MIMO 2 X 2 performance assessment of a real life LTE base station in a reverberation chamber

The performance of a MIMO 4×4 transmission solution applied to 4th generation LTE FDD technology are evaluated inside a reverberation chamber (RC) to quantify its benefit against the LTE typical MIMO 2×2 transmission scheme, in different environment conditions. The implementation of MIMO 4×4 in live networks requires the connection of two additional cables between base station transmitters and antennas, and operators face additional costs. Throughput and modulation code scheme allocation are analyzed as a function of the signal to interference-plus-noise ratio (SINR), for both indoor and outdoor environments. Experimental results in a live network are compared to those obtained in the RC of our laboratory. Results highlight that MIMO 4×4 is convenient for SINR greater than 10–15 dB. These results can help mobile network operators to evaluate if the expected benefit justifies the additional costs in an operating actual network.