Key components of metro rail communications network
Source: Prasanth Aby Thomas, Consultant Editor
Broadly speaking, the communication systems in rail networks
can be classified into wireless
and wired. Both have their purpose in the rail network and have standards to comply with. Here is a look at the requirements to make each system robust.
Karsten Oberle, Global Practice Lead for Railway business at Nokia
, points out the following factors that should be ensured for a solid wireless system.
- The intrinsic reliability of the equipment itself. For example, a consumer or enterprise-grade network switch won’t have the same reliability as that of a mission-critical grade switch that has redundancy built-in
- High network capacity to move a massive amount of data from different applications
- Network resiliency features to maintain the overall functionality of the communications network even if there are link or node failures
- Traffic separation and quality of service capabilities to ensure that each sub-system utilizing the network has priority and performance guarantees and won’t affect the performance of another sub-system. For example, a user retrieving a file from a network server shall not congest the network and affect the performance of the CCTV system
- Finally, expandability. Since the bandwidth needs are growing at an astonishing rate, a communications system must be able to accommodate such growth without major modification or replacement of key components
“Considering these critical points that listed, the technology that can meet these requirements is mission critical IP/MPLS network solution,” Oberle said.
As for a wireless network
, in addition to the wired network requirements, there are problems with security and multiuser scenarios. Securing a wireless network isn’t trivial.
“If we look in the past years, many wireless networks were compromised due to loopholes or even social engineering,” Oberle said. “Network and cybersecurity are key characteristics that must be considered.”
The multiuser, multiapplication scenario is also an important consideration. Since the same wireless access link is shared by several users and applications, it is important to use a wireless network solution that implements mechanisms that guarantee all users and applications can be served with resources from the wireless network and that, in case of congestion, mechanisms exist to assure the performance of the network.
A technology that meets all these requirements outlined is LTE. By having a private LTE network, a rail system can leverage a secure wireless network that delivers the best experience to their staff to perform their duties.
Widespread network and secure devices
According to Timo Harju, Business Development Manager for Vertical Markets at Airbus Secure Land Communications
, it is essential to have a reliable and widespread radio network in difficult areas such as tunnels, depots, stations, and their vicinity. The core network must be redundant, and a network management system must always be implemented in order to monitor the network.
“Two other fundamental points are to possess trustworthy, robust and secured devices (terminals) equipped with state-of-art applications which allow end users to benefit from data communication, location tracking, group communication and dispatching for the Operations Centre,” Harju said.
Airbus’ Tetra technology, he added, can offer tailored solutions according to specific requirements and needs, such as network element specific redundancy schemes, network topology, routing and spare route solutions within the Tetra network, disaster recovery plans, radio access solutions, and application-related redundancy solutions.
Complying with industry standards
Adhering to standards is critical to ensure the secure and efficient functioning of communications systems. Oberle points out that both wired and wireless solutions in use are standardized.
“IP/MPLS standards are specified by IETF and IP/MPLS networks are widely deployed worldwide by communications service providers as well as mission critical industry operators including railways,” Oberle said. “LTE technology is standardized by the 3GPP forum and is present everywhere. It is the technology that powers the world’s cellular networks, and private LTE solutions are in use by many industries today.”
In recent years, there have also been increased concerns on cybersecurity. It is now important to comply with relevant cybersecurity regulations and best practices to secure these critical networks against cyber attacks and to implement a robust cybersecurity strategy. Railway operators can avoid potential loss of revenue and enhance their reputation as reliable providers of hassle-free, on-time service.