As Chinese President Xi Jinping announced the opening of the HongKong-Zhuhai-Macao Bridge (HZMB) on October 23, 2018, the 55-kilometer bridge crowned one of the “seven wonders of the modern world” was officially put into operation. ZTE teamed with the Guangdong arm of China Mobile to provide a comprehensive solution for customized wireless network coverage for the world's longest sea-crossing bridge.
On the first day of opening, the peak number of 4G network users of the HZMB exceeded 5,000, the wireless connection rate exceeded 99.6%, and the VoLTE connection rate exceeded 99.7%.
The on-site VoLTE user experience was good. Whether in the bridge steel frame structure or the 6.75-kilometer submarine tunnel, the mobile 4G download and upload rate reach up to 50 Mbps and 18 Mbps respectively at a high speed scene, recording the world’s advanced level. As of the bridge's first month of operation on November 23, the cumulative traffic was 67.4T and the cumulative number of users reached 378,000.
The number of single-day traffic and users reached a peak of 2.76T and 16,800 respectively on October 27. All indicators on site were within the design range.
After eight years' consecutive construction and investment of over RMB 100 billion, the 55-kilometer HZMB is the first “Super Project” integrated with bridges, tunnels and artificial islands.
The complex structure poses a big challenge on continuous coverage of bridge network signals.
The bridge belongs to special linear coverage scenarios and is located in the South Coast of China where typhoon, thunderstorm, high temperature and other extreme weather regularly rage in this region. Many wireless signals in Hong Kong and Macao form mutual interference on the bridge.
Faced with this challenge, ZTE and China Mobile have a clear aim, that is, to build a ubiquitous, powerful and easy-to-manage full-coverage wireless network for HZMB to ensure safe and smooth use of the network when crossing the sea. However, deploying a wireless network on the world’s longest sea-crossing bridge is not an easy task. The two sides set up a joint project team of over 100 technical experts to solve the problems one by one.
In respect to the equipment model, the project adopted ZTE's TDD LTE multi-mode RRU and FDD LTE high-power RRU for the purpose of supporting varied modes of network coverage while addressing the storage enhancement resulting from eMBB in future.
As the waters of the Pearl River estuary where HZMB is located are wide, the bridge will be subjected to various harsh environments such as strong winds, huge waves, heavy rains, and lightning that impose stringent requirements on equipment. ZTE customized the fastened component in case of extreme weathers. All the components are specially treated to protect equipment from high humidity and salinity.
On September 15, 2018, the subtropical super typhoon “Hawthorn” was registered in the northeastern part of the South China Sea. HZMB was in the center and withstood the test of the 16-level typhoon. All communication equipment on the bridge was operating normally, providing stable communication guarantee for the real-time update of disaster information and the follow-up disaster relief work. The wireless coverage scheme for HZMB provided by ZTE has been convincingly proven in practice.
To address the linear coverage scenario of HZMB, ZTE located the equipment rooms on the Zhuhai-Macao Artificial Island and West Artificial Island beside the bridge, extending the range of RRU to over 10 kilometers. Considering space, future 5G deployment and fiber core resources, ZTE also adopted “two directional single core” solution, thereby saving 75% of fiber core.
In collaboration with China Mobile, ZTE spent 43 months in formulating a comprehensive solution of customized wireless network coverage for HZMB. In fact, during the 43 months, it only took three months to complete base station construction (from September to December 2017), and the rest time was spent on solution verification including the use of special technologies, the requirements for ultra-long coverage, and the design of special bows. ZTE creatively proposed to employ the crane on the land to carry RRU in order to conduct an efficient field trial on the bridge. This ensured complete compliance and one-time construction completion.
GPS is a clock synchronization signal used by a conventional 4G network, but it may be artificially interfered during special periods such as major festivals. To prevent potential social security problems, GPS signals need to be improved. ZTE used wireless GPS and wired IEEE1588 V2 to provide stable clock synchronization signals to ensure stable operation of wireless equipment on the bridge.
The bridge network signal coverage provided by ZTE can not only meet the existing 4G network coverage requirements but also take into account the smooth evolution of the 5G network coverage in the future. By means of 5G-Ready and Cloud RAN solutions, ZTE's network enables GSM/FDD/NB-IoT/eMTC/TDD multi-mode, multi-band integration and deployment while adopting the architecture of shared MEC and CU server for future 5G.
It is a huge challenge for both telecom operators and equipment vendors to provide wireless coverage for the super HZMB project because of its extremely high requirements for delivery capabilities, network quality and user experience. The success in this super project shows that China's mobile coverage technology has reached the highest level of performance and specifications in the world. ZTE will customize and develop more innovative technologies in the future, providing integrated telecom solutions as well as quality and reliable products for overseas wireless communications.
China Mobile, Hongkong-Zhuhai-Macao Bridge, wireless coverage