Huawei Helps Shenyang Metro Create a Brand-New Train-to-Ground Wireless Communications Experience

Shenyang, the capital of Liaoning Province, is a renowned historical city in China. It serves as a crucial transportation hub in northeast China and plays a significant role in the region's development. In 2022, Shenyang invested more heavily in building an urban rail transit network that had clear function layers and could provide seamless and efficient connections, aiming to improve the city's image and its citizens' commutes.

Shenyang Metro Line 1, the city's first ever line, was opened on September 27, 2010. By September 2023, the number of lines had increased to five, with a total operating mileage of 165 kilometers across 122 metro stations. These five lines also connect the city's three railway stations and one airport. Shenyang Metro now operates a network that covers the city center, connects new developments, and runs through important hubs. This provides citizens with convenient, safe, green, and economical transportation services. Once sparse locations feel closer than ever.

Cutting-edge LTE-M ensures stable operations of critical communications services

As Shenyang's metro lines expand, they create more room for the city's development, which boosts economic growth across the regions they connect. Shenyang Metro has upgraded and reconstructed Lines 1 and 2, and is constantly innovating to ensure top-notch metro line operations. Currently, it is upgrading its wireless communications from the conventional Wi-Fi + TETRA mode to LTE-M.

Conventional urban rail wireless communications typically adopt two modes (WLAN and TETRA) and four networks (signal, PIS, CCTV, and dispatch) to carry services together, but face several challenges. First, the control signals of the communications-based train control (CBTC) system, which is carried by Wi-Fi, are prone to interference, leading to poor reliability and stability. Second, the traditional narrowband TETRA solution only supports voice services but fails to meet requirements for video big data services. Third, it is costly to build and maintain multiple networks.

LTE-M (Metro) is a wireless train-to-ground communications solution for urban rail transit based on 4G TDD-LTE. It provides continuous, reliable, secure, and uninterrupted communications support and simultaneously carries a variety of services, such as CBTC, trunking dispatch, PIS, and CCTV. The solution simplifies networking and maintenance, and uses dedicated frequencies and a multi-level QoS mechanism to ensure service security and reliability.

During their early stages, Shenyang Metro Lines 1 and 2 used Wi-Fi and TETRA to carry CBTC and narrowband trunking communications respectively. However, the Wi-Fi had insufficient anti-interference due to the shared spectrum while TETRA had poor network connectivity, and it was complicated to maintain both. Therefore, Shenyang Metro urgently needed an alternative solution that excelled in reliability and performance without its O&M costing too much.

LTE-M delivers a brand-new train-to-ground wireless communications experience

CBTC and trunking communications are vital to the urban rail transit system as they work together to ensure safe train operation and reliable dispatch and command. Shenyang Metro Lines 9 and 10 began operating in 2019 and 2020, respectively, and primarily use LTE-M to carry CBTC services. The lines have benefited from stable train-to-ground communications and smooth train operation as a result. Drawing from its experience in operating Metro Lines 9 and 10, and with the city's overall plan for the metro wireless communications system in mind, Shenyang Metro deployed a single urban rail LTE-M network to centrally carry CBTC and trunking communications in its upgrade and reconstruction of Line 1's train-to-ground wireless communications system.

LTE-M outperforms traditional communications modes in three aspects.

First, LTE-M uses a dedicated 1.8 GHz wireless frequency band to avoid mutual interference between public frequency bands. This also enables seamless handovers when the train is moving at a high speed, ensuring stable transmission of train-to-ground communications signals.

Second, to enhance dispatch efficiency, LTE-M has upgraded from narrowband to broadband trunking and provides audio and multimedia communications like video. It also reduced the number of core production networks from two to one, laying a network foundation for line network dispatch communications and interconnectivity.

Third, a single base station can cover a radius of 1.2 kilometers, reducing the number of trackside devices needed by over 80% compared with WLAN and TETRA solutions. This significantly lowers subsequent O&M difficulty and costs while improving network stability and reliability.

Shenyang Metro now uses one LTE-M network to carry CBTC and broadband trunking services. It has managed to build a simplified, secure, and reliable urban rail train-to-ground communications private network. The network guarantees the safety and reliability of train operations and enables real-time transmission of train control information. As a result, passengers experience fewer delays and incidents caused by interference in train-to-ground communications, and can enjoy efficient, safe, and comfortable travel.

Shenyang Metro has come a long way in upgrading the communications system after choosing LTE-M. It collaborates with Huawei to establish a solid digital and intelligent foundation and continuously evolves its train-to-ground communications technologies and scenarios. The goal is to maintain stable operations of critical communications services, promote the integrated development of multi-tiered rail transport, and ultimately contribute to the construction of a comprehensive and three-dimensional transportation network.

Huawei's smart urban rail LTE-M solution has been implemented across over 120 urban rail lines globally since the world's first metro line to adopt LTE-M in 2013. Huawei and Shenyang Metro signed a strategic cooperation agreement in March 2023 to collaborate in smart urban rail, smart business, and other domains. The two parties will continue to complement each other, broaden their areas of collaboration, and provide full support for efficient business decision-making and scientific governance through top-level planning and the digital and intelligent foundation. Together, they aim to establish intelligence benchmarks for the urban rail transit industry and create an interconnected and comprehensive transportation network. They look to build an integrated hub city that is smart, modern, and people-oriented. This partnership will lead the high-quality development of Shenyang's modern metropolitan areas.

Huawei, a leading global ICT infrastructure provider, has been dedicated to the transportation industry for almost 30 years, and has served over 300 urban rail lines in more than 70 cities worldwide. Moving forward, Huawei plans to collaborate with over 100 industry ecosystem partners in innovative practices. Together they will enhance the security, efficiency, and user experience of smart urban rail systems, and accelerate the urban rail industry's intelligent and digital transformation.