Smart Connectivity with 5G and Wi-Fi 5 Wave 2

To be prepared for future requirements, the railway companies cannot avoid deploying 5G and Wi-Fi 6 technology. This benefits not only indoor Wi-Fi coverage but also train-to-ground communications. This is because the data traffic per passenger and, thus, the total data volume generated on the train will increase immensely in the future. For example, a passenger is expected to generate up to 1.5 GB of data per day, and the vehicles many times of that amount. Therefore, the challenge now is to realize the highest bandwidths for a large number of simultaneous accesses to the Internet and network services with unprecedented speed and reliability.

It is essential especially for data-intensive applications, such as 4K/8K video streaming, HD online gaming, or cloud access, to provide passengers simultaneously with guaranteed transmission quality at maximum available bandwidth. The IEEE 802.11ac Wave 2 and IEEE 802.11ax Wi-Fi standards enable more devices than ever to connect without sacrificing speed or compromising reliability. The short transmission times and high quality of service (QoS) of 5G technology ensure real-time capability, which is also required for safety-relevant and time-critical applications such as autonomous driving.

In contrast to industry, railway companies have different requirements for smart connectivity components which is reflected, for example, in the so-called railway standard: The DIN EN 50155 (and its international equivalent IEC 60571) must be applied to electronic equipment on and in rail vehicles – only then the products are "suitable for railway application". ELTEC's railway-certified products enable Wi-Fi on trains, the exchange and storage of infotainment content and operational data via train-to-ground connections, and the implementation of wireless backbone networks across carriages for upgrading in retrofit programs. As a technology driver, ELTEC develops application-oriented system solutions based on innovative hardware and software for high-performance smart mobility and connectivity solutions. The application focus is on railway and road transport. The product portfolio includes wireless access points, routers and gateways, data loggers, Ethernet switches and I/O modules.

The company recently added the CyBox RT 3-W, a 5G high-speed router with a combined Wi-Fi 5 Wave 2 interface, to its product line. In combination with the wireless 5G gateway, CyBox GW 2-P, this provides railway technology with one of the most advanced solutions for 5G transmission technology. The first series systems were already delivered to customers in December 2020. The wireless 5G gateway, CyBox GW 2-P, offers four slots for various 5G/LTE and Wi-Fi module combinations and an integrated SSD for storing media content.

This maintenance-free router certified according to EN 50155 for applications in railway technology is specially designed for 5G communication and, thus, for high-speed Internet applications in the mobile radio standard of the future. The device provides reliable, secure, and broadband 5G and LTE connections to enable passengers to download, share, and store information and entertainment content faster. The 5G high-speed router supports 5G with up to 2.4 Gbps download and 500 Mbps upload or LTE Cat 18 with up to 1.2 Gbps download and 225 Mbps upload. When using two 5G modules in parallel operation, the bandwidth even increases to up to 4.8 Gbit/s. The device has four SIM sockets per 5G/LTE interface for multi-provider support with the best network coverage and least cost routing.

Short latency and the associated high quality of service ensure the router's real-time capability while taking functional security into account – both aspects play an important role in safety-relevant and time-critical applications. The integrated GNSS module of the 5G router allows position determination via navigation satellites with an accuracy of up to 1.5 meters. The CyBox RT 3-W is designed for an operating temperature range of -40 °C to +70 °C and is suitable for worldwide use in any type of train.

The CyBox RT 3-W has two sockets for communication modules that can be equipped with either 5G, LTE Cat 18 or Wave 2. The parallel use of two 5G channels enables a maximum data throughput of 4.8 Gbit/s. Alternatively, a Wave 2 interface can be combined with a 5G interface to efficiently distribute the radio data on the train to the end devices via Wi-Fi.

Thanks to the optional Wave 2 interface with 4x4 multi-user MIMO, the router can simultaneously transmit data to a large number of clients at up to 1,733 Mbps. For this, a high-performance dual-core processor optimized for network communication provides sufficient power reserves. The configurable stateful firewall, the multilevel client isolation, and the hardware-accelerated encryption according to current standards ensure the best possible security for communication.

In addition to the firewall, the cross-device client isolation also provides reliable protection for all Wi-Fi participants on the train. Unlike usually, the CyBox RT 3-W not only prevents unauthorized access from mobile end devices that are dialed-in at the same access point (AP), it also prevents access from end devices at different ELTEC access points – the security concept now extends across the entire train.

Another plus point is that the configuration of the access point cannot be influenced via Wi-Fi. With AP isolation, each device operates as an independent unit. This prevents mobile devices from communicating with each other. This reliably prevents potentially harmful network traffic and increases security in the network. A hardware-accelerated encryption engine that supports SNMPv3, WPA3 and OWE standards ensures secure data transmission.

To increase data throughput and improve connectivity through redundancy, multiple transmission channels can be interconnected in the cellular and Wi-Fi networks thanks to multipath TCP (MPTCP) support. This results in high-performance, uninterrupted data transmission on the train. Mobile device users benefit from this when, for example, they start an online video on the Wi-Fi network, which continues seamlessly and without noticeable interruption on the cellular network when they leave the network's range. Users can switch from network to network in a convenient and transparent manner, while also saving costs.