China Railway Eryuan
China Railway Eryuan, founded in 1952, is affiliated to China Railway Group Limited, which is listed in the top 500 global brands and companies. China Railway Eryuan, one of the largest comprehensive engineering survey and design enterprises in China, was once awarded State Top Scientific and Technological Award twice. China Railway Eryuan owns the Grade-A engineering design qualification and provides design services for 21 industries. With its unparalleled competence, China Railway Eryuan undoubtedly is Huawei's key partner. In their cooperation, China Railway Eryuan provides consulting, design, integration, and service capabilities, and Huawei provides information and communications technology (ICT) products and solutions. They bring their industry influence into full play and launch the mass transit eLTE multi-service and unified bearer solution with dedication to joint solution design and market expansion. This solution provides LRT users with operation communications services.
Huawei mass transit eLTE multi-service and unified bearer solution
Against the backdrop of fast railway service development, scheduling services based on the traditional wireless communication technology face severe challenges:
Centralized scheduling: Central dispatchers need to communicate with station on-duty personnel and train drivers. As the operation efficiency increases, the departure interval decreases, raising more concurrent scheduling communication requirements. The traditional wireless communication system adopts the single-channel analog modulation and cannot meet the requirements of wide area scheduling and concurrent calling requirements.
High-speed and heavy-load: Trains need to rely on a reliable and secure wireless communication network to transmit security data, such as ETCS-2 train control data, high-load train synchronous control data, and electrical air brake data. The traditional wireless communication system cannot bear these data because the system is incapable of transmitting system data and lacks security protection measures.
Huawei leverages its proprietary GSM-R, transmission, and IP products and partners with industry's leading auxiliary product suppliers to provide the operation communications solution for the railway industry customers and deploy a highly reliable, flexible, and scalable digital wireless communication system.
China Railway Eryuan provides the signal control, ground control, and ticketing systems and integrates the systems with Huawei's communication subsystem to roll out the joint solution. The following figure shows the architecture of the joint solution.
This solution has the following highlights:
Adheres to the high availability, reliability, and security design standards and provides multiple proprietary technologies and protection mechanisms to ensure secure and reliable scheduling communication services.
Uses Huawei-proprietary automatic frequency control (AFC) algorithm and industry's unique commercial distributed base station technology to increase the switching success rate, reduce the switching frequency, improve the quality of radio signals, and prevent call interruption, signal device degrade, or train stop caused by the communications network disconnection.
Provides the future-proof operation communications system that can be smoothly evolved to protect the existing investments.
Customizes the highly-flexible operation communications system for the railway industry, which features perfect adaption to the complicated railway environment, easy deployment and management, and lowered site investments and operating expense (OPEX).
The LRT operation has unique features: low construction costs, simple services, no dispatcher, simply structured train, multiple sets of devices unsuited, and compliance with centralized scheduling in the control center. Therefore, the LRT project needs a new wireless broadband mobile communication technology. Such a technology shall provide the broadband, rapid, and reliable train-to-ground wireless transmission and simultaneously carry multiple security services (such as signal control and ticketing). The major requirements are as follows:
Multiple services carried by only one network: A wireless communication network converges multiple separate networks used for wireless scheduling, signal control, and ticketing. This approach reduces network construction and operation and maintenance (O&M) costs and improves utilization of resources, for example, spectrum.
High bandwidth for improving the operation efficiency: After the operation in a sector is complete, the sector can automatically upload vehicle ticket data to the control center's ticketing system within 10s.
Excellent anti-interference capability: The network can suppress or avoid interference from external wireless systems, such as open WLAN hotspots, Bluetooth, microwave, medical devices, and carrier wireless networks. This perfectly solves interference problems and challenges faced by the existing private wireless local area network (WLAN).
The following figure shows the architecture of the operation communications solution. China Railway Eryuan provides the part in the dashed box and the integration service for all subsystems.
This solution brings the following benefits:
- Integration of multiple networks for lowered costs: A train-to-ground wireless broadband network integrates multiple networks of different modulations used for wireless scheduling, signal control, and ticketing. Such integration helps reduce construction costs.
- Fewer devices for easy maintenance: The LTE network has a simplified flattened architecture with a small number of network elements (NEs). A single cell can cover a long distance, making possible zero base station in tunnels With all these highlights, maintenance workload is greatly reduced.
- End-to-end quality of service (QoS) guarantee: Based on refined hierarchical service management and air interface resource management, this solution implements end-to-end QoS guarantee and allocates transmission resources to high-priority services preferentially.
- Increased operation efficiency: This solution automatically downloads ticketing data to improve the operation efficiency.
- Dedicated frequency band for anti-interference: Dedicated frequency bands are used to prevent overlapping public signal frequency bands and interference from external systems, such as Wi-Fi, Bluetooth, public network, and trunking. The inter-cell interference coordination (ICIC) technology is used to suppress neighboring cell interference and improve the quality and bandwidth of channels at cell edges.
Urban LRT project in Country E
In this project, Huawei constructs a unified train-to-ground wireless communication network for City N in Country E. This network can simultaneously transmit train-to-ground communication service data, such as signals, ticketing data, and scheduling voice, and support future service expansion.
As planned, this network covers all LRT main tracks (including stations and tracksides), control centers, and depots, giving solid support for efficient LRT operation in the future.
At present, communication data and signals are transmitted through the narrowband wireless network (Terrestrial Trunked Radio (TETRA) or rented public network) and public frequency band independent network (Wi-Fi). The networks work independently of each other and address only their own train-to-ground transmission requirements. Generally, Country E's LRT project faces the following challenges:
(1) LRT tracks are constructed at lower costs (CNY20 million per kilometer) and provide fewer services than subways, thereby raising common requirements on reliability of the communication and signal systems. However, at present, two wireless bearer networks are used to carry communication data and signals respectively, consuming massive resources, such as spectrum and auxiliary devices. Accordingly, massive resources result in heavy maintenance workload and high construction costs.
(2) The legacy train wireless scheduling system uses the TETRA technology that features clear voice, fast connection, and narrowband data communication. This technology can well meet the train scheduling communication requirements. However, the TETRA technology encounters troubles in its application to the LRT project.
The LRT needs to simultaneously transmit security data (signals) and sensitive data (ticketing data) at a rate lower than 50 kbit/s and 12 Mbit/s respectively, but the TETRA technology supports high density data transmission only at a rate of 9.6 kbit/s. Even if signals and ticketing data are transmitted at the maximum rates (50 kbit/s and 12 Mbit/s), the transmission delay will still amount to 5.2s and 1280s, far from the required service system performance (signal transmission delay < 300 ms and ticketing transmission delay < 10s). Therefore, the TETRA technology is not suitable for the LRT project.
(3) The signal system mainly implements train-to-ground communication using the 2.4GHz public frequency band and WLAN technology. As the widespread application of the WLAN, LRT tracks, just like railways, are vulnerable to more and more interference from external 2.4G systems, certainly impacting LRT operation.
The following figure shows the architecture of the LRT solution in Country E. China Railway Eryuan provides the subsystems marked in red and integrates them with Huawei's operation communications system.
This solution is highlighted by the following features:
1.Professional voice trunking, delivering zero-latency calling experience
This solution utilizes lots of new technologies to provide all professional voice trunking functions and elevates voice trunking service counters to industry's top levels. For example, the group call setup delay is less than 300 ms, the call rights application or preemption delay is less than 150 ms, and a single cell supports even 160 concurrent group calls.
2.Multi-service concurrency, perfectly implementing multimedia scheduling
This solution supports concurrent operations of voice, short message service (SMS), multimedia messaging service (MMS), data, and positioning. Dispatchers thereby can simultaneously perform voice trunking, video scheduling, and graphic instruction transmission through the LTE network. Multi-service concurrency gives full play to multimedia scheduling and promotes integration of more applications, changing the traditional working mode. More importantly, multi-service concurrency renovates the communication and operation modes and improves the production efficiency significantly.
3.Broadband trunking handheld terminals
Handheld terminals are specially designed according to the railway industry's characteristics. A handheld terminal simultaneously supports professional voice trunking, video scheduling, broadband data access, SMS, MMS, and positioning. Undoubtedly, it is acknowledged as the terminal with the industry's most comprehensive functions. Its protection level amounts to IP67. It still works properly after being submerged for 30 minutes one meter underwater. Many other counters such as shock, vibration, and solar radiation reach the industry's highest-level reliability standards, ensuring that the terminal can work perfectly in the harsh environment. As required in the industry, the special noise reduction design is used for the handheld terminal so that it still performs excellently in the harsh noise environment.
4.Multiple protection mechanisms for powerful disaster recovery
China Railway Eryuan official website:
In the past few days, China Railway Eryuan signed a strategic cooperation agreement with Huawei. This agreement regulates their cooperation issues, such as market strategy, market expansion, solution, and professional technology, and specified that their cooperation modes include but would not be limited to joint market research and promotion, technical and training cooperation, overseas project expansion, and intellectual property protection. In the near future, senior executives of China Railway Eryuan and Huawei will periodically visit each other, proactively communicate with the transportation industry customers at home and abroad, and regularly exchange their corporate culture, business management, and marketing experience. All these activities help set up a more robust and harmonious basic platform for extensive cooperation between China Railway Eryuan and Huawei.