China Unicom Jilin, the local affiliate of China Unicom in the Jilin province, has completed the deployment of a 2.1 GHz 8T8R 5G network for a segment of the national Harbin-Dalian high-speed railway with 5G network equipment from Huawei.
Tests show that 8T8R AAUs increase the coverage area by 44% compared with 4T4R, and 5G user experience improves by 5.2 times compared with 4G. The train passengers can heartily access the network for entertainment such as HD video, live streaming, and New Calling as well as for work on-the-move such as remote video conferencing.
In 2023, China Unicom embarked on a 5G coverage project along China’s sixteen trunk high-speed railways. Its affiliate in Jilin province contributed to its share of constructing the province’s premium 5G network for high-speed railways within the provincial borders. At first, this network construction project was daunted by four serious challenges. To begin with, the distance between sites is large. What’s worse, the penetration loss was greater with high-speed railways than common railways. Additionally, high-speed mobility increased the Doppler shift, a direct cause of performance deterioration. Lastly, user experience was poor due to short camping time caused by frequent handovers (every 3–4 seconds) on trains running at a high speed of 300 km/hr.
To address these challenges, in this project, China Unicom Jilin deployed the 2.1 GHz 8T8R AAU, and activated the High-speed Railway Excellent Experience feature and Cell Combination feature.
The 2.1 GHz 8T8R AAU solution integrates with technologies like multi-antenna, integrated high-gain array, intelligent beamforming, and precise and fast beam sweeping. Compared with 4T4R, it improves coverage by 7.5 dB, user experience by an impressive 55%, and capacity by 85%. This solution solves the problem of poor coverage caused by large distances and large insertion loss on high-speed railways. It also uses the same antenna as the legacy 4G 1.8 GHz network, simplifying site deployment and reducing tower rental by 10%. This series of solutions with Huawei FDD beamforming technology took home the GSMA GLOMO award for “Best Mobile Technology Breakthrough” and was listed in the “Guangdong Province Energy Saving Technology and Equipment (Product) Recommendation Catalogue”, issued by the Guangdong Energy Bureau in July 2023, for its excellent performance in energy saving.
After the High-Speed Railway Excellent Experience feature is enabled, the 5G base station proactively adjusts the signal frequency to offset the negative impact caused by frequency offset. This solves the Doppler shift problem in high-speed railway continuous coverage scenarios. After Cell Combination feature is enabled, the number of inter-cell handovers can be reduced in a cell combination network, which solves the problems of fast handovers and short camping time on high-speed railways. Test results show that after this feature is enabled, the access success rate increases to 99.4% and the call drop rate decreases by 57%. This overcomes the difficulties of difficult network access in ultra-high-speed scenarios.
This commercial deployment of the 2.1 GHz 8T8R AAU solution will greatly facilitate the operator’s future plans for similar 5G rollouts. China Unicom Jilin will continue to explore 5G network deployments in different scenarios as well as innovative applications of 2.1 GHz 8T8R in order to build differentiated 5G advantages based on service requirements in various 5G scenarios.
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