ZTE FRMCS: Empowering Railway Digitalization

Being a GSM-R provider, ZTE plays an important role in the future railway mobile communication system (FRMCS). Proactively addressing the supply chain vulnerabilities stemming from the phasing out of 2G technology, ZTE embarked on FRMCS research around 2014 and launched the LTE-R system in 2016. Focused on the enduring evolution potential of railway communication systems and requirements from China Railway and International Union of Railways (UIC), ZTE transitioned towards 5G-R standard research and system development back in 2000.

5G-R, or FRMCS, is not only the successor to GSM-R but also serves as crucial infrastructure and key technological equipment for railway digitalization and intelligence. It plays an essential role in supporting railway operations, ensuring train safety, improving transportation efficiency, and elevating maintenance standards.

ZTE has launched a series of customized 5G-R (hereinafter referred to as FRMCS) products for China Railway. The system supports railway customization solutions such as multi-level reliability solutions, ultracell networks, and intelligent O&M. It can cover all railway services and scenarios, providing secure, efficient, intelligent, and green FRMCS networks. This will improve railway operation safety, production efficiency, and service capabilities, and facilitate railway digitalization. Fig. 1 shows the ZTE FRMCS network architecture.

Customized Railway Products Enables Advanced and Efficient FRMCS Network

ZTE offers a series of railway-dedicated FRMCS products, including the BBU, RRU, and pRRU. These products are developed based on high-performance SOC and ASIC chips. The RRU features a high-efficiency power amplifier with the innovative Super-N architecture, achieving the lowest overall power consumption in the industry. The products meet the requirements for multi-layer redundancy, hot standby, and RRU ring networking. They are capable of operating stably in harsh environments such as low temperatures and high altitudes.

ZTE’s distributed remote RF module R9018R is designed based on the latest ZTE RAN unified platform and supports eight transmit and eight receive channels (8T8R). The R9018R is a dedicated 2.1 GHz-band, 10 MHz bandwidth product customized for China Railway. It can effectively reduce mutual interference with external systems. Advanced technologies such as Doherty, digital pre-distortion (DPD), and power tracking enable the amplifier to dynamically adjust the power supply voltage according to output power requirements, thereby improving amplifier efficiency and reducing total cost of ownership (TCO). The module is compact and lightweight, suitable for wall or pole mounting. Compared with 4T4R, the 8T8R RRU can significantly improve network coverage capability.

Moreover, installing 8T8R on towers  can reduce feeder loss by 3 dB, increase the downlink rate at cell edges by around 27%, and boost the uplink rate by 80% to 100%. Compared with the under-tower solution, the on-tower solution can reduce the cable weight by around 90%. This reduction significantly decreases cable purchase and installation costs, as well as tower load and wind load requirements. Tower installation can also reduce the need for equipment room construction and cooling, thereby lowering air conditioning procurement costs and equipment room energy consumption, which supports green railway construction.

With a series of customized products, the ZTE FRMCS solution can meet the coverage requirements of railway main lines, tunnels, stations, dispatch centers, freight yards, and office buildings. It provides comprehensive coverage solutions for railway communications, achieves full network coverage, and reduces the difficulty and costs of railway wireless network management and O&M (Fig. 2). The deployment of the FRMCS network will greatly improve the intelligence of railway operation and maintenance. All GSM-R services and new broadband services will be carried over the FRMCS network to ensure modern railway operations such as multimedia dispatch communication, train video observation, natural disaster monitoring, and foreign object monitoring.

Multi-level Reliability Solution Ensures Service Continuity

As an important infrastructure for railway transportation, the wireless communication system is responsible for train control and scheduling tasks. ZTE provides a multi-level reliability solution to improve the reliability and security of FRMCS, addressing network, node, link, board, and component levels to ensure the safe operation of railways.

Furthermore, ZTE FRMCS employs the 5G QoS identifier (5QI) technology for precise management of various service types, allowing railway operators to flexibly allocate network resources based on actual needs, ensuring high-priority handling of critical services. 5QI not only improves network resource utilization but also drives innovation and development in railway operations.

Multiple Patented Technologies Ensure Stable Signal Connection for High-Speed Trains

The high-speed moving trains pose challenges to the communication system, mainly including Doppler frequency shift and frequent signal switching. ZTE’s Doppler frequency offset compensation algorithm supports more flexible and adaptive demodulation reference signal (DMRS). This patented technology can detect and compensate for Doppler frequency shifts generated during the high-speed movement of the UE, greatly improving radio link performance and supporting a maximum speed of 500 km/h. To address the signal switching issue, ZTE’s proprietary ultracell technology can significantly reduce handover frequency and optimize mobile performance.

Intelligent O&M Solution Enhances Visibility, Manageability, and Control for FRMCS

The diversity of FRMCS application scenarios and services presents challenges to network O&M and service quality assurance. Leveraging intrinsic intelligence, ZTE’s uSmartNet intelligent network solution achieves multi-scenario intelligence through intelligent computing integration, twin evolution, and intent-driven approaches. It is key to creating visualized, manageable, and controllable FRMCS networks, enhancing intelligence in maintenance and service applications, and facilitating the intelligent development of railway mobile communication networks.

Continuous Innovation Supports FRMCS Evolution

In response to the challenges and pain points in railway services, ZTE actively researches new technologies and solutions to facilitate intelligent, green, and efficient railway operations.

For the train-to-ground data dump service, ZTE is collaborating with railway research institutes to explore the technology and application of millimeter waves for automatic data dumping. Millimeter waves offer ultra-large bandwidth, ultra-low latency, and strong anti-interference capabilities. 5G millimeter waves can be used for vehicle-to-ground data transmission, ensuring complete, secure, and efficient data dumps and enhancing operational efficiency.

In mission-critical communication services (MCx) for railways, there is a significant need for point-to-multipoint information transmission in train operation, management, and maintenance applications, where system transmission bandwidth can become a bottleneck. The 5G multicast and broadcast service (MBS) technology effectively addresses this challenge by allowing multiple application data streams to share a single set of transmission resources. Regarding data transmission in access networks, transport networks, and core networks, ZTE devices support not only point-to-point data transmission but also point-to-multipoint multicast data transmission, significantly saving backhaul network transmission bandwidth.

For monitoring railway equipment and the environment along the tracks, ZTE actively explores RedCap technology to enable real-time monitoring of railway infrastructure and the natural environment. This approach supports low-cost, comprehensive monitoring of railways to ensure safe train operations.

ZTE is a global GSM-R supplier, a key participant in China’s railway FRMCS standards, and an active practitioner of FRMCS. The ZTE GSM-R system covers nearly 20,000 km of railway lines.

In China, as a key contributor to the development of 5G-R standards, ZTE actively participates in the drafting of the General Technical Requirements for Railway 5G-R System and the Temporary Technical Specifications for Railway 5G-R System Base Station Equipment. ZTE is also a core member of the 5G-R specification drafting team.

To further improve its R&D capabilities for the FRMCS technology, ZTE has established the FRMCS Innovation Center in the Xi’an R&D Institute. This center is dedicated to advancing FRMCS research, developing new services, and fostering future innovations.

ZTE will continue to uphold the principles of innovation, reliability, and efficiency to deliver the highest quality railway wireless products and services to the global railway industry. It will work closely with global railway partners to drive digital transformation and intelligent development in the railway industry, working towards a more intelligent, efficient, and sustainable future for railways.