Demonstrating seamless communication for multiple vehicles -High-capacity communication technology for high-speed vehicles using millimeter waves- [2:02]

NEC is working with NTT and NTT DOCOMO to advance high-speed mobile communications for Beyond 5G. In this experiment, a 40GHz band millimeter-wave equipment developed by NEC was used to evaluate the stability of high-capacity communication for multiple vehicles.

The experiment was conducted in a tunnel environment. Under base station antennas installed at approximately 150-meter intervals, two vehicles passed each other, while evaluating the performance of multi-user multiplex transmission. In tunnel environments, frequent antenna switching occured, while rapid changes in Doppler frequency and propagation delay led to degradation in communication quality.

To address this challenge, NEC has developed a technology to improve the stability of communications for a single vehicle by pre-compensating the transmission frequency and timing at the base station. Building on this approach, NEC has developed a new technology that extends this capability to multiple vehicles. Frequency-multiplexed signals are generated for each vehicle, pre-compensated, and then combined. This enables compensation for multiple terminals.

With the application of the new technology, frequency and timing deviations after antenna switching are suppressed for both vehicles, significantly reducing throughput degradation. The averaged sum throughput of the two vehicles improved by 1.3 times, resulting in stable millimeter-wave communications for each vehicle.

NEC will continue to drive the future of mobility through advancements in next-generation communication technologies.

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