Wireless inter-carriage link for train coupling

In refurbishment projects there are typically no possibility to install additional cables for high speed inter-carriage connectivity. Westermo WLAN products offer an optimized solution for high speed wireless inter-carriage coupling avoiding the need of additional cable installation.

Westermo has a long history in designing and delivering IEEE 802.11 technology based products for railway industry and its applications. Westermo wireless carriage coupling solution offers easy installation, high speed communications, reliability and optional redundancy features for all kinds of trains.

Wireless carriage coupling solution

Increasingly intelligent transportation solutions are requiring IP-based train backbones with high data throughput. However, especially in refurbishment projects it is often very difficult or even impossible to add additional cables between the train carriages or compositions. As an alternative for additional cables, Westermo offers a wireless carriage coupling solution.

Wireless carriage coupling requires an intelligent automatic bridged connection establishment between the carriages. It is important that the connection is only established between the carriages that are facing each others. Especially important it is to avoid erroneous connections to carriages that are located at the nearby tracks.

Solution highlights

• Wi-Fi 6E (802.11ax) support with Ibex-3510
• Automatic coupling and decoupling process with easy configuration
• Reliable locating for link establishment during coupling
• Automatic failure recovery
• Completely transparent cable replacement feature
• Support of advanced encryptions (WPA2-PSK, WPA3-SAE, 802.1X)
• Configurable operation in 5 GHz and/or 6 GHz channels
• Data rate up to 4.8 Gbit/s with 4.0 Gbit/s user payload
• Enables full duplex 1.0 Gbit/s train backbone networks
• Redundant and aggregated systems possible
• Supports operation on 5.8 GHz short range outdoor frequencies
• Supports operation on 6.0 GHz very low power outdoor frequencies
• Resistant against movement and vibrations also during driving

Westermo Inter-Carriage Link

Westermo's wireless inter carriage link (ICL) offers high throughput wireless connection between the carriages. The maximum speed is achieved by using 120MHz channel bandwidth and making use of multiple streams of MIMO technology. Efficiently using multiple streams in a short distance application is not easy, but Westermo has implemented a solution for this. That means that the customers can benefit from high speed and reliable links that offer average user data throughput of up to 4.0 Gbit/s for each link in a 4×4 MIMO setup.

The Westermo solution also implements a true cable replacement feature. This feature enabled users to make use of the onboard switches to built redundant and transparent topologies.

Prepared for redundancy and aggregation.

It is possible to install one wireless bridge with two Westermo products. However, if redundancy is required there is an option to multiply the hardware and have two parallel wireless bridges between the carriages. The benefit of using a second Westermo wireless bridge as a backup is that the higher connection data rates and throughput provided by Westermo wireless link can be maintained even in case of a hardware defect. The installation of two separate links enables the operation of a full-duplex 1.0 Gbit/s trainborne network.

The Westermo solution is WLAN based and offers several advantages over 4G, 5G and satellite communication. For example, in a tunnel where both 4G, 5G and satellite fail, WLAN can be deployed as the train to ground communication. WLAN based systems also makes it possible to deploy a privately managed network, which removes mobile operator dependencies, such as bandwidth allocations and mobile data costs.

Being WLAN based and complying with regulations, Westermo's train to ground solution does not required any costly licences for the operation.

Installations and antennas

From carriage to carriage the signal is transmitted using the latest standard IEEE 802.11ax data rates. Westermo Ibex products allow using 2.4 GHz, 5 GHz and 6 GHz bands. In order to prevent interferences between the other communication networks employed within a train environment, the inter-carriage antenna system is usually configured to use the 5.8 GHz or 6.0 GHz band. The use of MIMO antennas allows a higher data rates to be transmitted.

With the compact and easy-to-install Westermo 3×3 MIMO antennas using 120 MHz channel bandwidth, data rates up to 3.60 Gbit/s (3.0 Gbit/s user data throughput) can be achieved. The directional antennas can be installed outside at the end of the carriage in a variety of ways. In order to achieve the best results, the antennas must point to-wards each others and the distance between the antennas should be minimized. This increases the signal levels in comparison to interfering signals and with proper antennas allows the use of higher data rates thanks to multiple MIMO streams.