Ali Sabra | Université de Bourgogne (original) (raw)
Papers by Ali Sabra
IEEE sensors journal, 2024
IEEE Access
Validation measurements for the Future Railway Communication System in railway environments is a ... more Validation measurements for the Future Railway Communication System in railway environments is a very challenging task and should be reduced to a minimum for cost and time efficiency. ''Zero-on-site testing'' consists of using simulation/emulation tools and testing procedures to allow validation and verification activities in the laboratory to avoid complex and expensive trials with trains on real-world sites. A solution to test a communication network in a laboratory under realistic conditions consists of injecting perturbations at the IP level (such as additional delay, packet losses, or jitters). It is essential to correlate the IP impairments with the radio environment, their effects on end-to-end transmission, and how the network and its elements react. To do so, IP impairments (or the conditions that lead to them) should be generated in such a way that allows assessing their impact on the performance of transmissions. This paper presents the results of an experimental research based on an original emulation platform (Emulradio4Rail platform), able to emulate and test wireless systems taking into account both physical layer as well as IP traffic in realistic railway environments. Different types of IP traffics are injected at the application layer and go through the platform. The work aimed at extracting various statistical distributions of classical IP metrics (delay, packet loss, jitter, throughput) versus time, as a function of radio channel conditions for Wi-Fi and LTE transmissions in typical railway environments. Then, the modeled IP impairments statistical distributions can be considered at the IP level to test very easily wireless system modems. The results and methodology can be considered for the evaluation of the Future Railway Mobile Communication System modems. INDEX TERMS IP metrics, railway communications, tapped-delay-line models, channel emulator, open air interface, LTE. The associate editor coordinating the review of this manuscript and approving it for publication was Jesus Felez .
IEEE Access, 2021
In the automotive and rail domains, vehicles are entering the era of full automation thanks to wi... more In the automotive and rail domains, vehicles are entering the era of full automation thanks to wireless sensors and communication systems, shifting control functions from a human driver to computers. High data rate, robustness, high reliability and ultra-low latency wireless communications are required in the context of autonomous train and safety critical applications. Today, the Future Railway Mobile Communication System (FRMCS) is under development at European level within the International Union of Railways (UIC). This system will answer all the current and future needs of rail. It will be IP based, multi-bearer and resilient to technology evolution. In the context of the development of different FRMCS prototypes by industry, it is crucial to be able to test them in representative Railway radio environments thanks to laboratory tools. Characterization of radio channels in railway environments, by measurements or simulations, is a very active field. In this article, based on broad literature survey, we show that not all the published models are suitable for performance evaluation. Then, we propose a selection of typical Tapped-Delay-Line channel models to be implemented in an original hardware and software testing platform capable to reproduce the effect of representative Railway environments in laboratory, with real time emulation at RF (Radio Frequency) level. Preliminary results in Hilly 3 taps and Cutting 5 taps channel models are presented as a proof of concept of a ''zero on site testing'' approach, allowing for time and cost savings in the validation of railway communication systems. INDEX TERMS Radio channel modelling, railway communications, tapped-delay-line models, channel emulator, open air interface, LTE.
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)
The European Train Control System (ETCS) relies today on the 2nd generation cellular system GSM-R... more The European Train Control System (ETCS) relies today on the 2nd generation cellular system GSM-R. GSM-R obsolescence has triggered the evolution of the current European Railway Traffic Management System (ERTMS) to the Future Railway Mobile Communication System (FRMCS), under development. FRMCS considers the use of several radio access technologies in parallel such as Wi-Fi, LTE, Satellite and 5G. Testing new communication systems along railway tracks is time and money consuming. Consequently, it is important to develop a zero-on-site-testing approach thanks to the development of emulation platforms. These platforms, combining hardware and software, are able to reproduce in laboratory real railway infrastructure behavior and scenarios. This paper presents the EMULRADIO4RAIL platforms, developed in the framework of Shift2Rail program and gives examples of results obtained.
IEEE sensors journal, 2024
IEEE Access
Validation measurements for the Future Railway Communication System in railway environments is a ... more Validation measurements for the Future Railway Communication System in railway environments is a very challenging task and should be reduced to a minimum for cost and time efficiency. ''Zero-on-site testing'' consists of using simulation/emulation tools and testing procedures to allow validation and verification activities in the laboratory to avoid complex and expensive trials with trains on real-world sites. A solution to test a communication network in a laboratory under realistic conditions consists of injecting perturbations at the IP level (such as additional delay, packet losses, or jitters). It is essential to correlate the IP impairments with the radio environment, their effects on end-to-end transmission, and how the network and its elements react. To do so, IP impairments (or the conditions that lead to them) should be generated in such a way that allows assessing their impact on the performance of transmissions. This paper presents the results of an experimental research based on an original emulation platform (Emulradio4Rail platform), able to emulate and test wireless systems taking into account both physical layer as well as IP traffic in realistic railway environments. Different types of IP traffics are injected at the application layer and go through the platform. The work aimed at extracting various statistical distributions of classical IP metrics (delay, packet loss, jitter, throughput) versus time, as a function of radio channel conditions for Wi-Fi and LTE transmissions in typical railway environments. Then, the modeled IP impairments statistical distributions can be considered at the IP level to test very easily wireless system modems. The results and methodology can be considered for the evaluation of the Future Railway Mobile Communication System modems. INDEX TERMS IP metrics, railway communications, tapped-delay-line models, channel emulator, open air interface, LTE. The associate editor coordinating the review of this manuscript and approving it for publication was Jesus Felez .
IEEE Access, 2021
In the automotive and rail domains, vehicles are entering the era of full automation thanks to wi... more In the automotive and rail domains, vehicles are entering the era of full automation thanks to wireless sensors and communication systems, shifting control functions from a human driver to computers. High data rate, robustness, high reliability and ultra-low latency wireless communications are required in the context of autonomous train and safety critical applications. Today, the Future Railway Mobile Communication System (FRMCS) is under development at European level within the International Union of Railways (UIC). This system will answer all the current and future needs of rail. It will be IP based, multi-bearer and resilient to technology evolution. In the context of the development of different FRMCS prototypes by industry, it is crucial to be able to test them in representative Railway radio environments thanks to laboratory tools. Characterization of radio channels in railway environments, by measurements or simulations, is a very active field. In this article, based on broad literature survey, we show that not all the published models are suitable for performance evaluation. Then, we propose a selection of typical Tapped-Delay-Line channel models to be implemented in an original hardware and software testing platform capable to reproduce the effect of representative Railway environments in laboratory, with real time emulation at RF (Radio Frequency) level. Preliminary results in Hilly 3 taps and Cutting 5 taps channel models are presented as a proof of concept of a ''zero on site testing'' approach, allowing for time and cost savings in the validation of railway communication systems. INDEX TERMS Radio channel modelling, railway communications, tapped-delay-line models, channel emulator, open air interface, LTE.
2021 IEEE 93rd Vehicular Technology Conference (VTC2021-Spring)
The European Train Control System (ETCS) relies today on the 2nd generation cellular system GSM-R... more The European Train Control System (ETCS) relies today on the 2nd generation cellular system GSM-R. GSM-R obsolescence has triggered the evolution of the current European Railway Traffic Management System (ERTMS) to the Future Railway Mobile Communication System (FRMCS), under development. FRMCS considers the use of several radio access technologies in parallel such as Wi-Fi, LTE, Satellite and 5G. Testing new communication systems along railway tracks is time and money consuming. Consequently, it is important to develop a zero-on-site-testing approach thanks to the development of emulation platforms. These platforms, combining hardware and software, are able to reproduce in laboratory real railway infrastructure behavior and scenarios. This paper presents the EMULRADIO4RAIL platforms, developed in the framework of Shift2Rail program and gives examples of results obtained.