Network Architecture For Smart Railways: The requirements of the network architecture for railways are different from those of the public mobile communication network in many aspects.
First, the network architecture for railways should be a dedicated communication transmission network that connects the dispatching center at all levels.
This ensures that all elements interact with each other through different modes of information, such as voice calls between train driver and dispatching center, train operation control data, and video monitoring data for smart rail infrastructure.
In addition, the rail communication network strives to establish an integrated and reliable emergency command system that would take realtime scene information as the decision- making base during emergencies (e.g., natural disasters or traffic accidents).
Furthermore, the specific performance requirements of the train operation and control are embodied in reliable business, specialized equipment, timely transmission, and other aspects.
The biggest challenge for 5G-R is how to ensure the operational safety and reliability of the train and the reliability of MBB communication for passengers at high-moving speeds and complex scenarios.
In addition, the compatibility of legacy operational management systems should not be ignored.
Accordingly, to protect the current infrastructure investments and to ensure normal operation during evolution, there should be no doubt about the long-term coexistence of multiple rail-oriented transportation systems.
In other words, 5G-R will certainly evolve with the legacy networks, as it maintains backward compatibility and smooth transitions.
The design of a 5G-R network architecture mainly involves three parts: access network, CN, and air interface.
Unlike C-RAN, D-RAN, F-RAN, and H-CRAN, the network architecture should fully take into account real-time and high-reliability access and always-online transmission.
It should be capable of executing hybrid networking using both low (below 6 GHz) and high (mmWave) frequency bands.
The CN design should likewise account for 5G-R services and applications, in which the network slicing and SDN/NFV networking architecture are used.
Also, the 5G-R network architecture should support both ultra-reliable train operation control signal transmission and high quality user experience that would satisfy the diverse needs of diversified services.
New CN elements should be added to provide different levels of QoS.
For example, a train group call register needs to be added to the CN, and this should be different from the public mobile communication network. read full pdf here
