Modular 21

Overview: 

The Modular 21 system is low-cost, completely scalable, and dynamically reconfigures to any train configuration.

Every Internet provisioned carriage is equipped with the same set of compact equipment. There is no need for a “main rack” or “brain car”. In the Modular 21 system, all carriages are equipped with indoor Wi-Fi and outdoor Wi-Fi cellular antennas, so any carriage can act as a self-contained internet on board system.

In addition, when multiple carriages equipped with the Modular 21 system are operated together in a single configuration, the Modular 21 nodes dynamically form a self-configured mesh network in which Internet traffic from any carriage can be transported over the external links from that carriage, or from any other carriage. In this way a total train system derives the advantages of bonding many cellular links, antenna diversity and automatic load balancing.

Specifications: 

Product Components

In a basic “Modular 21 system , every internet carriage is equipped with:

  • 1 Modular 21 Control Unit (“MCU”)
  • 1 Wi-Fi Access Point (“AP”)
  • 1 Indoor Antenna (“!A”)
  • 1 Outdoor Mesh Antenna (“OMA”)
  • 1 Outdoor Cellular Antenna (“OCA”)

Further Access Points and Indoor Antennas can be added to provide better in carriage Wi-Fi coverage. Additional Access Points can network with the MCU via in carriage Ethernet cabling or via an additional OMA.

 The 21Net Modular 21 Control Unit includes:

  • Motherboard running Linux and 21Net software components for Mobile Access Router; Access Control Gateway; Load Balancing, Qos and Traffic Shaping: Remote Management
  • Cellular Modems (typically 2, maximum 4)
  • GPS geo-location

The Modular 21 Access Point and Indoor and Outdoor Antennas are standard industrial Wi-Fi equipment chosen for their suitability to the railway environment, adherence to all relevant standards, and excellent in-service performance and reliability. The Modular 21 Outdoor Mesh Antenna is a 5GHz directional antenna tailored for creating a robust wireless mesh network using a proprietary extension of 802.11a Wi-Fi. The Modular 21 Outdoor Cellular Antenna is a multi-band antenna that combines the signals for GPS and multiple cellular data modems.

Modular 21 System Architecture

All carriages are equipped with Modular 21 are equal peers able to communicate with one another via the Inter-Carriage Mesh Network, and with the Internet via Cellular Data Cards located in any Modular 21 node.

Benefits: 
  • No single point of failure: failure of any one node will not affect performance of Internet in the rest of the train. Failure of a cellular card will not affect Wi-Fi in that carriage as traffic can be routed via neighboring carriages.
  • Scalable and affordable: equip as many or as few carriages as required. Each Modular 21
    node can be equipped with 1 - 4 data cards.
  • Self configures to any train consist: each carriage can immediately offer Wi-Fi as soon as equipped
    with the Modular 21 Internet on Board system.
  • Easy to deploy: as soon as a train leaves the depot the Modular 21 nodes form an inter-carriage mesh network using the rooftop OMAs communicating via 5.8GHz 802.11a Wi-Fi.
  • Single Wi-Fi network inside the train: via the inter-carriage mesh the Modular 21 system creates a single in-carriage wireless network throughout the train. A single public access SSID allows passengers to roam between carriages.
  • Staff network: train staff can access a separate VLAN with different access rights (e.g. prioritized traffic, access to corporate intranet)
  • Per carriage GPS: Every carriage has its own GPS. Modular 21 nodes continuously report their geo-location so that the whereabouts, and running order of carriages in each train consist, is always known.