China Mobile Deploys World’s First 4.9G Tunnel Resonant Unit to Upgrade Tunnel Network Coverage

China Mobile has completed the world’s first commercial deployment and verification of the innovative 4.9G Tunnel Resonant Unit technology. The breakthrough solution addresses long-standing network coverage challenges in tunnel scenarios, delivering stable high-speed connectivity while greatly simplifying on-site construction procedures and lowering operational safety risks.

Traditional tunnel communication solutions rely on leaky cables and wall-mounted antennas, which suffer severe signal attenuation and uneven coverage, resulting in unstable network quality along tunnel corridors. Different from conventional installation methods, the new technical approach adopts a terrain-adaptive design that integrates tunnel structures into the communication system. It treats the tunnel’s metal or shield structure as part of the antenna system and uses the Tunnel Resonant Unit as a high-gain excitation component to generate a waveguide-like effect.

The tunnel structure functions similarly to a hollow metal pipe, concentrating scattered radio signals and guiding them along the tunnel axis. This innovative mechanism transforms the entire tunnel space into a continuous signal transmission channel and effectively eliminates the inconsistent signal strength caused by linear signal loss in traditional tunnel networking.

Field verification data demonstrates remarkable performance improvements in actual operating scenarios. During high-speed train transit, network signal fluctuations inside carriages are significantly reduced. The user downlink peak rate increases from 700Mbps to 2.2Gbps, with overall network capacity rising by 125%. The upgraded network can steadily support bandwidth-intensive 5G-A applications including ultra-high-definition video streaming, cloud meetings and cloud gaming, achieving consistent and stable speed coverage throughout entire tunnel sections.

The new technology also brings substantial improvements in engineering efficiency and construction safety. The Tunnel Resonant Unit only requires two sets of unit installations inside each tunnel section. The overall construction cycle is shortened by approximately 80%, with fewer deployment points and reduced laying length. It effectively simplifies complex operations in narrow and confined tunnel environments and lowers potential safety hazards during construction.

This pioneering deployment provides a replicable and efficient technical paradigm for future tunnel network construction. It balances user experience improvement, engineering cost control and construction safety management. The mature and verified solution will support large-scale intelligent transportation digital upgrading and further optimise 5G-A full-scenario coverage capabilities.