Wireless mmW communications for Railway – mmW4Rail

The mmW4Rail project is organized in five interconnected Work Packages over 48 months. The scientific barriers will be solved with simulations and with experimentations. WP1 consists in radio channel characterisation and modelling in specific railway areas for T2T and T2I communications. WP2 will focus on antenna integration in the specific context. In WP3 we will first define the requirements for T2I and T2T wireless communications in the railway context based on existing documents. We will define the key performance indicators (KPI) to consider in the evaluation process. The channel characterisation will be performed at Centre d’Essais Ferroviaire (CEF) at Petite Forêt (59). Specific rail-road vehicles on tracks will be considered.

Since the beginnng of the project, A channel sounder has been developped and tested. Preliminary tests at Centre d'essais ferroviaire were performed in July and preliminary results but promizing are under analysis.

Two directions are followed in WP2. First we investigate the possibility to design and realize a specific reflecting surface to help the deployment. In addition, we are considering the design and development of a multiple standards, multiple ports antenna for FRMCS and other systems in the mmW band.

Regarding the task on physical layer enhancement design for T2T/T2I communication, literature search on state-of-the-art physical layer enhancement techniques and beamforming codebook designs were conducted. An algorithm for radio resource management in a multi-hop heterogenous railway communication network was proposed, and performance evaluations were performed.
Regarding the task on system level simulation and technologies evaluation for mmW train radio, a specification of the deployment, simulation scenario and detail parameters was drafted.

The work will progress on the 3 WPs during the second period of the project.

1. S. Mabrouki, I. Dayoub, Q. Li and M. Berbineau, «Codebook Designs for Millimeter-Wave Communication Systems in Both Low- and High-Mobility: Achievements and Challenges,« in IEEE Access, vol. 10, pp. 25786-25810, 2022, doi: 10.1109/ACCESS.2022.3154016.
2. Q. Li, J. -C. Sibel, M. Berbineau, I. Dayoub, F. Gallée and H. Bonneville, «Physical Layer Enhancement for Next-Generation Railway Communication Systems,« in IEEE Access, vol. 10, pp. 83152-83175, 2022, doi: 10.1109/ACCESS.2022.3192971.
3. Marion Berbineau, Nicholas Attwood, François Gallée, Patrice Pajusco, Quianrui Li, Hervé Bonneville, Semah Mabrouki, Iyad Dayoub, Divitha Seetharamdoo, « Millimetric waves communications for Railways », Accepted for oral presentation at TRA2022, Lisbon, September
4. ATTWOOD Nicholas, GALLEE François, PAJUSCO Patrice, BERBINEAU Marion, MmW channel sounder for dynamic SIMO measurement, Journée URSI France,
5. Q. Li, A. Charaf, N. Gresset, H. Bonneville, “Radio Resource Management in Next-Generation Railway System with Heterogeneous Multi-hop Relaying Deployment”. In International Workshop on Communication Technologies for Vehicles (pp. 59-70), 2021, November, Madrid.

Trains are entering the era of full automation thanks to wireless systems shifting control functions from the human driver to computers. High data rate, robustness, high reliability and ultra-low latency are required. The Future Railway Mobile Communication System (FRMCS) is under development at European level. It will be IP based, multi-bearer and resilient to technology evolution and interferences.
One of the main problems for railway control and command applications is spectrum scarcity. Only very small bands are allocated in the 900 MHz, 1900 MHz band and 5.9 GHz, but mainly reserved for urban rail. This motivates the exploration of the millimeter-wave (mmW) frequencies in the 5G developments. This band can answer specific needs for railways in addition to or for complementing the current telecommunication standards. This is foreseen in well-defined and restricted areas (e.g. train stations, shunting yards, high-speed lines), while possibly sharing existing infrastructures, and for specific use cases such as virtual coupling of trains, platooning, remote driving of trains, downloading maintenance data, etc. The objective in considering mmW is to improve the communication system adaptability for full bearer independency.
The bands foreseen for 5G NR standard are located at 28-30 GHz, 38-40 GHz, the free-licensed band 57–64 GHz, extended to 71 GHz. The 60 GHz band is of great interest for railway in case of very high data rate and very low latency requirements. The environment (ballast, cutting, tunnels, high voltage near the antennas, dust, interferences, etc.) as well as the constraints (vibrations of the trains, non-line of sight situations, crossing of trains, cohabitation with other systems, etc.) are very specific and will impact the performances of the wireless links for both Train-to-Infrastructure (T2I) and Train-to-Train (T2T). The propagation conditions and channel behaviour have to be well known to avoid communication outages particularly in the context of mobility. Dedicated channel models for mmW in railway environments are needed.
Solutions to enhance T2T and T2I performances in the mmW band should be developed and analysed. Optimization of radio resources management considering the train-specific security, latency and reliability constraints; deployment enhancement and radio condition monitoring in the mmW band, are important topics to study. Optimization of the wireless link thanks to integration of multiple antenna array with different potential application (beamforming, diversity and/or spatial multiplexing) should also to be considered taking into account the impact of integration on antenna performances with the specification and the definition of new models for antenna.
The mmW4Rail project focuses on three fundamental research topics: in the mmW band characterization and modelling of radio channels for dynamic scenarios, antenna specification; design and prototyping; and enhancement of reliability of the communications at Physical layer. We will consider three typical and representative use cases:
• T2I links along high speed line with infrastructure sharing;
• T2I links in specific areas for remote driving of trains;
• T2T links for virtual coupling and platooning applications.
The mmW4Rail results will contribute actively to the development of wireless communications in mmW to answer specific needs for railways. The mmW communication system will be deployed to complement current standards, improving the system adaptability in view of full bearer independency as foreseen by railway operators. The consortium will disseminate the results at international level, at 3GPP, ETSI and UIT-R. The proposed works in the mmW4Rail project are in line with Shift2Rail multi annual plan and they should provide a foundation for future developments and deployments of alternative communication systems.