NTT Corporation, NTT DOCOMO and NEC Corporation have announced their successful demonstration of a distributed MIMO technology system that suppresses the degradation of communication quality in the 40 GHz band when a large number of antennas are distributed among multiple locations. The technology selects the most appropriate antennas and beams at high speed and uses frequency- and timing-compensation technology to prevent significant changes in reception frequency and timing on the mobile-terminal side, even if the terminals are moving at high speed or are shielded by other vehicles moving at high speed.
The demonstration verified the potential of millimeter-wave distributed MIMO to achieve stable, high-capacity wireless communications in high-speed moving environments, such as automobiles and trains, for purposes such as providing large-volume content to many passengers and collecting massive sensing data for automated driving. In the future, the three companies will proceed with verifications of actual services on roads and railways, aiming to eventually implement high-frequency distributed MIMO in high-speed mobile environments, and will also consider the application of distributed MIMO to a wider range of frequency bands, such as the mid-band spectrum, to expand distributed MIMO use.
NTT, DOCOMO, and NEC have developed a beam-search technology to rapidly detect the optimum combination of distributed antennas and beams using the same beam identification signal at the same time and frequency for multiple distributed antennas. The results showed improved communication quality, even when a moving vehicle blocked a stationary mobile terminal.