Regarding all the subjects, technologies and challenges presented in this chapter, several scientific barriers can be identified. First of all, the emphasis was placed on the spectrum management, which represents a great challenge regarding the necessity to optimize the utilization of the frequency spectrum.
For instance, dynamic allocation of frequency spectrum is initiated in the CR works presented above. A large number of wireless communication systems are operating at different frequencies and railway system’s efficiency would be improved by integrating all these heterogeneous wireless networks.
A second important feature is to take into account the Electromagnetic Compatibility (EMC) aspects. The multiplication of telecommunication systems in the transportation environment results in the increase of potential sources of electromagnetic interference. In addition, the continued diminution of power levels necessary for the operation of electronic systems tends to make them more vulnerable.
The EMC represents then a foundation to improve the availability, reliability and integration of communication devices. EMC can rely on characterization and modeling of the electromagnetic environment and the behavior of electronic equipment and telecommunication systems.
EMC activities deal with interferences that can be intentional or not. In the former case, we talk about cyber-attacks. Systems have then to be equipped with a cybersecurity layer. Due to the amount of sensitive information on networks and the vulnerability and porosity of railway systems, an optimal level of cybersecurity has to be achieved to fight the different threats for the railway signaling and telecommunication systems. Cybersecurity has also to fight cyber-attacks and advanced persistent threats from outside. The challenges are to set up a system that is sustainable, integrated, interconnected and supported by the network.
Cybersecurity systems rely on threat detection, identification, modeling and monitoring. The different threats can be electromagnetic jamming, eavesdropping, denial or service attacks, spoofing attacks and equipment infection attacks. The fight against attacks can rely on the adaptation of security layers of the communication systems, suitable for railway context.
As presented in this section, SDN can be used as an enhanced technology to set up a high performance and scalable intrusion detection system and to block traffic. Works on physical layer and multipaths can also be performed to resist to jamming for instance. In another hand, cybersecurity vulnerability increases when using standards components on the market, but also implementing large systems combining critical and non-critical applications or multiple/combined networks. So enlarging the radio paths capability and the system complexity/conflgurability might also enlarge the vulnerabilities.
The security in the context of Cognitive Radio was also addressed in this chapter. Indeed, Cognitive Radios cause unique security issues, due to the observation of a huge amount of information or the extensive use of collaboration for the spectrum sharing for instance. Finally, innovative solutions for cryptography and safe key management systems can be developed to reduce complexity of large-scale systems, such as railway systems with a large number of connected objects.
A complete policy has to be defined and set up on the cybersecurity issues for railway domain. The current networks are usually heterogeneous and not protected. The communication systems already standardized are not flexible, cost effective and sustainable with an already planned obsolescence of the used cryptographic techniques. The set up of a security system will ensure high availability, authentication and integrity of the railway systems. Safety and security are quite related and safety can not be ensured without security.
Finally, it is important to notice that the telecom system is not only radio path, but also onboard and wayside networks connected by routers. So combining the radio path has an impact on the complete chain and may provide risk to link a critical domain with a non-critical domain. Moreover, the cybersecurity objectives may give severe constraints to the systems, like some potential physical segregation, or access limitation or configuration limitation. Cybersecurity must then be a key driver for the telecom evolution.
Energy management represent a big challenge for the railway sectors. The trends are to reproduce models from other sectors and adapt them to the railway one. For instance, some works on smart metering are initiated in the context of the In2Rail European project, as presented in Chap.2. The objective is to manage the energy flows in order to minimize the global consumption.