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Deliverable D 1.1 Application layer requirements for Communications systems in railway

environments (stream a)

Reviewed: (yes)

Project acronym: EMULRADIO4RAIL Starting date: 01/12/2018 Duration (in months): 18 Call (part) identifier: H2020-S2R-OC-IP2-2018-03 Grant agreement no: 826152 Due date of deliverable:

Month 03

Actual submission date:

29-04-2019

Responsible/Author: Juan Moreno - MdM Dissemination level: PU Status: Issued

Ref. Ares(2019)2986592 - 04/05/2019

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Document history Revision Date Description 1 22/02/2019 First draft 2 22/02/2019 2nd draft with additional contributions sent to reviewers 3 27/02/2019 revision from DTU and IKL 4 07/03/2019 Final version 5 25/04/2019 Revision based on comments from S2R

Report contributors Name Beneficiary Short

Name Details of contribution

Juan MORENO Metro de Madrid (MDM)

Deliverable leader, Sections 1-4,6 and 14

Marion BERBINEAU, Christophe GRANSART

IFSTTAR (IFS) Sections 5 and 6

Alessandro VIZZARRI Radiolabs (RDL) Sections 7-14 Raul TORREGO IK4-Ikerlan (IKL) Review José Soler, Ying Yan Technical University of

Denmark (DTU) Review

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Table of Contents Table of Contents ............................................................................................................................... 3

Index of tables ................................................................................................................................... 4

Index of figures .................................................................................................................................. 5

1. Executive Summary ................................................................................................................ 6

2. Abbreviations and acronyms .................................................................................................. 7

3. Background ............................................................................................................................. 9

4. Objectives ............................................................................................................................ 10

5. Summary of related projects ............................................................................................... 11

6. Characterization of services for the considered scenarios.................................................. 12

6.1. Railway market segments (railway scenarios)..................................................................... 12

6.2. Railway applications ............................................................................................................ 15

7. Data Traffic models for the communication services .......................................................... 18

8. IP-layer parameters ............................................................................................................. 22

9. Quality definitions in communication networks ................................................................. 24

10. Main Standard Technical Recommendations on QoS ......................................................... 28

10.1. IP-based fixed networks ................................................................................................... 28

10.2. Wireless networks ............................................................................................................ 28

11. Metrics and Class of Service (CoS) ....................................................................................... 31

12. QoS assessment in LTE ......................................................................................................... 33

13. Involved standardization Bodies.......................................................................................... 34

14. Conclusions .......................................................................................................................... 35

15. References ........................................................................................................................... 37

Appendix A: Official documents on QoS/QoE standardization for communication networks ...... 40

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Index of tables Table 1 Definition of Railway Scenarios [5] (p. 28) ......................................................................... 12 Table 2: Characterization of services [9] ........................................................................................ 19 Table 3: Summary features of NP, QoS and QoE ............................................................................ 27 Table 4: Service types identified for UMTS [30] ............................................................................. 29 Table 5 Quality requirements for Interactive Services [30] ........................................................... 29 Table 6: Class of Service (CoS) identified for IP networks [15] ....................................................... 31 Table 7: Class of Service (CoS) identified for UMTS [15] ................................................................ 32 Table 8: LTE QCI list [31] ................................................................................................................. 33

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Index of figures Figure 1: High-speed trains [12] ..................................................................................................... 13 Figure 2: Grades of automation [13] .............................................................................................. 14 Figure 3: Telecoms system boundary and Protocol stack interfaces [9, p47] ................................ 16 Figure 4: Concept of Operation [9] ................................................................................................. 20 Figure 5: Telecom system boundary [9, p. 46] ............................................................................... 21 Figure 6: Top to bottom QoS Scheme ............................................................................................ 22 Figure 7: Relationship between NP and QoS [17] .......................................................................... 24 Figure 8: Four viewpoints of QoS [20] ............................................................................................ 25 Figure 9: Architectural views of QoS building blocks [22] .............................................................. 26 Figure 10: QoE Dimension [23] ....................................................................................................... 26 Figure 11: Relationship among NP, QoS and QoE [23] ................................................................... 27 Figure 12: End-to-End QoS Architecture in UMTS [34] .................................................................. 30

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1. Executive Summary To avoid a complicated validation process with costly on-site testing for new Train-to-Ground (T2G) communication systems, the European EMULRADIO4RAIL Project will provide an innovative emulation platform for tests and validation of various radio access technologies (RAT) like Wi-Fi, GSM-R, LTE, LTE-A, 5G and Satcoms. The emulation platform will combine simulations of the communication core network and emulation of various RATs thanks to the coupling of discrete event simulator such as RIVERBED Modeler, Open Air Interface, several radio channel emulators, models of IP parameters and real physical systems. The number of RATs to be considered will be aligned with the X2RAIL-3 project. Therefore, GSM-R is not included within the scope. This initial deliverable focuses on defining application layer requirements for Communication systems in railway environments. The document will first summarize the related projects that have proposed application-layer requirements. Then the document describes scenarios to be covered (high-speed, urban, regional, etc.) and services (CBTC, video surveillance, ETCS, etc.). Some data traffic models for the considered communication services are introduced. IP layer parameters are presented and the main involved standardization bodies. The document will then recall the quality of service definition in communication networks. Technical recommendations for UMTS and LTE are given as examples. Proposed quality metrics to be considered are detailed. Finally, some service characteristics at application layer are provided.

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2. Abbreviations and acronyms

Abbreviation / Acronyms

Description

3GPP 3rd Generation Partnership Project ACS Adaptable Communication System AMBR Aggregate Maximum Bit Rate ARP Allocation Retention Priority ATO Automatic Train Operation CBTC Communication-Based Train Control CCTV Closed-Circuit Television CONNECTA CONtributing to Shift2Rail's NExt generation of high Capable and safe TCMS

and brAkes COS Class of service CS Circuit Switched DTG Distance-to-Go DTO Driverless Train Operation EDGE Enhanced Data rates for GSM Evolution eLDA enhanced Location Dependant Addressing EMU ElectroMechanical Unit eNB evolved NodeB ERTMS European Rail Traffic Management System ETCS European Train Control System GBR Guaranteed BitRate GEO Geostationary Earth Orbit GERAN GSM EDGE Radio Access Network GNSS Global Navigation Satellite System GoA Grade of Automation GPRS General Packet Radio Service GSM Global System for Mobile communications HSL High-Speed Line HSR High-Speed Railway IEEE Institute of Electrical and Electronics Engineers IETF Internet Engineering Task Force IoT Internet of Things IPDV IP Packet Delay Variation IPER IP Packet Error Rate IPLR IP Packet Loss Ratio IPTD IP Packet Transfer Delay ITS Intelligent Transport System KPI Key Performance Indicator KSR Key System Requirements LTE Long Term Evolution MBR Maximum Bit Rate MME Mobility Management Entity

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MPTCP Multi Path Transmission Control Protocol MT Mobile Termination NaaS Network-as-a-Service NGTC Next Generation Train Control NP Network Performance OAI Open Air Interface OCC Operation Control Centre P2P Point-To-Point PDN Public Data Network PLMN Public Land Mobile Network PS Packet Switched PSTN Public Switched Telephone Network QCI QoS Class Identifier QoE Quality of Experience QoS Quality of Service RAT Radio Access Technology REC Railway Emergency Call RTCP Real Time Control Protocol RTP Real-time Transport Protocol S/P-GW Serving Gateway, Packet Data Network Gateway S2R Shift2Rail SATCOM Satellite Communication SDN Software-Defined Networks T2G Train-to-Ground TC Test Cases TCMS Train Control & Management System TE Terminal Equipment TMS Traffic Management System TRL Technology Readiness Level UIC Union Internationale des Chemins de fer UMTS Universal Mobile Telecommunications System UTRAN UMTS Terrestrial Radio Access Network UTO Unattended Train Operation Wi-Fi Wireless Fidelity (IEEE 802.11 WLAN)

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3. Background This document constitutes the Deliverable D1.1 “Application layer requirements for Communications systems in railway environments” according to Shift2Rail Joint Undertaking programme of the project titled “EMULATION OF RADIO ACCESS TECHNOLOGIES FOR RAILWAY COMMUNICATIONS” (Project Acronym: EMULRADIO4RAIL , under Grant Agreement No 826152). In December 2018, the European Commission awarded a grant to the EMULRADIO4RAIL consortium of the Shift2Rail / Horizon 2020 call (H2020-S2RJU-OC-2018 S2R-CFM-IP2-01-2015). EMULRADIO4RAIL is a projected connected to the development of a new Communication System planned within the Technical Demonstrator TD2.1 of the 2nd Innovation Programme (IP2) of Shift2Rail JU: Advanced Traffic Management & Control Systems. The IP2 “Advanced Traffic Management & Control Systems” is one of the five asset-specific Innovation Programmes (IPs), covering all the different structural (technical) and functional (process) sub-systems related to control, command and communication of railway systems. The document has been prepared in the framework of the EMULRADIO4RAIL project (GA 826152), WP1/Task 1.1. These requirements will be considered as a basis to build data-traffic models as representative as possible of the railway applications. These data-traffic models will be injected in the EMULRADIO4RAIL platforms developed within WP3 in order to obtain the IP impairments models, which are the outputs of the WP2.

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4. Objectives This document has been prepared to provide some application-layer requirements for communication systems for railways for different use cases considered in X2RAIL-1 and X2RAIL-3 projects, like high-speed lines, regional trains, urban, freight, etc. This has been done by taking into account the diversity of railway-related services at the application layer, such as CBTC (Communications-Based Train Control), ETCS (European Train Control System), CCTV (Close Circuit Tele-Vision).. Therefore, the main objectives of the document are:

• To define, in a detailed way, the railway scenarios to be covered, communication-based services (applications) and the input received from related projects like NGTC [1], FRMCS [2] and X2RAIL-1 [3].

• To present some possible data traffic models for the services proposed by these related projects.

• To recall various definitions of IP parameters and QoS indicators. • To define different metrics/parameters, to be measured by the EMULRADIO4RAIL

platforms in order to obtain the IP impairments models foreseen at the end of WP2.

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5. Summary of related projects The predicted obsolescence of GSM-R by 2030 [2], combined with the long-term life expectancy of ETCS (2050) [2] and the railway business needs, have led to the European railway community to start working to identify a successor for GSM-R. The successor has to be future proof, learn from past experiences / lessons and comply with Railway requirements. For these reasons, Shift2Rail JU multi-annual action plan [4] has given high priority to the development of a new Communication System (TD 2.1). This system should be able to overcome the shortcomings in current ETCS and CBTC, mainly the lack of capacity for higher data rate and the offer of new operational services. The development of a new adaptable communication system (ACS) is ongoing within the S2R members’ projects X2RAIL-1 [3] and X2RAIL-3 [5]. These projects will deliver an adaptable train-to-ground communication system for train-control applications in all market segments (high speed/main line, regional, urban, freight). Packet switching/IP technologies (GPRS, EDGE, LTE, Satellite, Wi-Fi, etc.) are considered as underlying solution, in accordance with the NGTC (Next Generation of Train Control system) project [6],[7] and user requirements of the FRMCS (Future Railway Mobile Communications System) project [8]. The foreseen communication system will enable an easy migration from existing systems (mostly GSM-R). In order to cope with ETCS and CBTS identified limitations, the new ACS will provide enhanced throughput, safety and security functionalities to support the current and future needs of signaling systems. It will also provide extra resilience to interferences and will be open to radio technology evolution [8]. The focus will be as well in supporting the shift from “network as an asset” to “network as a service” model vision. The term "Network-as-a-Service" (NaaS) is often used along with other marketing terms like cloud computing. NaaS describes services for network transport connectivity [37]. NaaS involves the optimization of resource allocations by considering network and computing resources as a unified whole [38]. Backwards compatibility with ERTMS will be ensured as well. The user requirements public report of X2RAIL-1 project [9], is based on FRMCS and NGTC documents [6], [7], [8]. It is also possible to consider Unisig document [10] for ETCS traffic model and ETSI document [11] for CBTC traffic model. They will constitute the basis for EMULRADIO4RAIL application requirements as the more complete and up-to-date documents available at the moment of writing the document. More information about representative data-traffic models, for the X2RAIL-1 applications, has been required to the X2RAIL-3 partners and will be discussed with them. All the services, users and stakeholders are described in [5] (on its Table 4.5 p. 23), thus in this deliverable we decided not to duplicate the work. The data traffic models chosen at the end for the development of IP impairments models foreseen in the Emulradio4rail project will be detailed in D2.2.

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6. Characterization of services for the considered scenarios

6.1. Railway market segments (railway scenarios) There are different ways to characterize railway services but, in particular, [5] refers on its page 27 to the following four scenarios or “market segments” that have been defined and parameterized as shown in Table 1 (Table 5.1 of [5]). All four “market segments” are representative of railway operating scenarios relevant to Shift2Rail.

• Mainline: A dedicated (high-speed) passenger line / train that spans between cities and possibly across nations.

• Metro/Urban: A dedicated urban (mass transit) passenger line / train that spans part or all of a city and possibly as far as the neighboring towns (with sections both above and below ground).

• Regional: A remote low-capacity passenger line with few connections that spans between cities.

• Freight: A dedicated freight line (no passengers) that spans between cities and possibly across nations.

Mainline Metro/urban Regional Freight

Max. number of passengers per train 1000 500 120 0 Average number of passengers per train 4000 300 35 0 Average number of staff per train 4 1 1-2 1 Average number of cameras per train 16 18 8 0 Average traffic density (trains per hour per direction)

15 30 1-2 1

Maximum train speed (km/h) 500 160 160 120 Average train speed (km/h) 160 80 60 80 Average line length (km) TBD 18 TBD TBD Average number of stations TBD 16 TBD N/A Average distance between stations (km) 60 1-2 10 N/A Headway (s) 85-240 85-130 60-120 120-240

Table 1 Definition of Railway Scenarios [5] (p. 28)

a) High-Speed and mainline The first high-speed line was constructed in Japan in the 1960’s, not as an upgrade of existing lines, but was built from scratch. Their success made possible that many European countries developed their own technology shortly after, with the remarkable examples of France and Germany (which built new lines for high-speed trains and upgraded conventional ones as well). More recently, other countries like China and Spain have built a few thousands of kilometers of high-speed lines, being the first and second largest networks in the world, respectively. The most relevant aspect of high-speed lines is the maximum speed (up to 350 km/h). Therefore, to achieve very-high-speed train aerodynamics, tracks need to be properly designed to fulfil some requirements, such as smoothness of curves (usually limited to a minimum radius of 7000 m) and ramp slopes (which shall not exceed 2.5-3 ‰). These two limitations force high-speed lines to have frequent tunnels,

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viaducts and cuttings, implying a very diverse set of physical scenarios, which are mostly rural, including suburban when leaving the metropolitan areas and, in some cases, urban (when entering to the city).

Figure 1: High-speed trains [12]

High-speed lines link populated areas, separated 100-600 km, but this may vary largely. Trains are usually around 200 m. long, sometimes 400 m. when two are coupled together, carrying up to 550 people for each of the 200 m. sections. Headways are not as critical as in metro lines, but they can vary from few minutes for lines equipped with ERTMS L2, to half an hour for other systems. Usually, the headway is not limited by the technology but by the demand. Power supply in high-speed lines is usually 25 kV at 50 Hz (60 Hz in Japan).

b) Metro Metro lines are mostly urban but can cover suburban areas as well. Typically, the maximal speed does not exceed 110-120 km/h. In some cases, it could be a little higher (up to 140 km/h, mostly for suburban trains). It is very unlikely for these lines to have a shared track infrastructure with other transportation systems (i.e. automotive) and the majority of the tracks are inside tunnels. Obviously, old lines or old railway networks are built on a different way and the cross-section of the tunnels is radically different (old ones followed cut-and-cover methodology and new lines are built using boring machines). This means that old tunnels have very frequent changes in their cross-section but new ones not. The scenarios for this type of trains are suburban areas, urban-outdoor (sometimes at ground level, sometimes overpasses) and, mostly, tunnels.

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Stations are separated 0.5-2.5 km from each other with an average of around 1 km, sometimes with a high deviation from this mean. This implies a need for considerable accelerations-decelerations in the rolling stock (1-1.2 m/s2). These trains are ready to carry up to 4-6 people/m2, which means capacities above 1000-1200 people per consist (depending on the number of cars within the consist). Headways can go from 50-60 seconds in the best case (for CBTC/DTG lines) up to 15 minutes at valley hours, but in this case it is highly dependent on non-technical aspects (like policies). All metro trains are electric (more generally 1500 VDC and old lines sometimes are 600 VDC) usually with overhead catenary, but the third-rail is very common. Regarding the signaling system, metro trains are usually more automated than all the other types of railway lines. This means that most of them are ATO-operated (i.e. GoA 2 [13]) with a driver that does not control the speed of the train but does certain functions, such as opening and closing the doors. In recent years more and more have become driverless (i.e. GoA 3) or even fully unmanned (GoA 4). The operational grade of automation has implications in the communications system needed to connect both the on board and wayside signaling systems. In Figure 2 a summary for the different grades of automation is depicted.

Figure 2: Grades of automation [13]

c) Regional The travel range for regional trains is between the one for mainline (which covers larger distances with few stops) and the one for commuter trains (shorter distances with more stops). Usually they link large cities with several stops between them. Their frequency is low, because they usually are not intended to carry people from home to work (commute). Good examples for this type of services are the “Regionales” (now “Media Distancia”) in Spain, “Train Express Regional” (TER) in France or “Regionalbahn” in Germany. The rolling stock here is very diverse because many lines are not electrified, therefore diesel trains are very common, as well as electrical (mostly electromechanical units or EMUs). Their maximum speed is not high (up to 140 km/h, but sometimes even lower) mostly due to limitations in both the track profile and the power, of the rolling stock.

d) Freight Finally, freight trains are those, which are not used for passenger transportation. These services can run on dedicated lines or together with passenger services (mixed traffic). In the first case the

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limitations for the track are less tight (slopes of 2.5-3 ‰) than in the second one (usually around 1.5%, with some exceptions). Trains are formed by a large set of wagons with few locomotives and the total length could be up to 7.3 km for some Australian trains. Usually this length is significantly shorter, i.e. 400-850 m in some European countries. The average weight per axle is between 22.5-50 Tm (significantly higher than passenger trains which go from 15 Tm in metro trains and 17.5 Tm for high-speed trains. Regarding the operational aspects, they depend heavily on the type of service, but for mixed traffic, freight trains are usually able to run up to 100-120 km/h like regional trains, in order to not impact the performance of passenger trains. In other cases, freight trains are only allowed to run during the night (for example, in some high-speed lines).

6.2. Railway applications The user and system requirements reported in [9] distinguish the following communication related applications:

• Critical Communications • Performance Enhancing Communications • Business Enhancing Communications • Critical Support • Performance Support

The definition of the words Critical, Performance and Business is defined in [8] as follows: • Critical: applications that are essential for train movements and safety or a legal

obligation, such as emergency communications, shunting, presence, trackside maintenance, ATC, etc.

• Performance: applications that help to improve the performance of the railway operation, such as train departure, telemetry, etc.

• Business: applications that support the railway business operation in general, such as wireless internet, etc.

• Communications related with these classes of applications are described in [8] from chapter 5 to chapter 10.

Figure 2 from [9] depicts the concept of operation of the envisaged adaptable communications system. The figure is based on the Key User Requirements [9] and it includes contextual aspects such as the use of ETCS/CBTC, user types and railway scenarios. Consequently, the figure incorporates mainline, freight, regional and urban/metro railway operating scenarios. It also incorporates a range of services requiring telecommunications for effective operation, these are: passenger information; on-board systems; passenger connectivity; passenger data; driver voice; train crew connectivity; safety and security; CCTV; signaling; autonomous and remote vehicle operation; maintenance staff connectivity; electronic signage; wayside objects and sensors; level crossings; and virtual coupling. In the following section, we will consider only a subset of all these services. In addition, extracted from [9] p18, it is important to mention 5 key user requirements:

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1. The system will be adaptable in terms of bearer selection and configuration, as required

by prevailing QoS demand and availability, and scale in terms of performance, reach and number of users.

2. The network will provide convenient means for technology migration, upgrade and maintainability, co-existence and backward compatibility, when required.

3. The network will be able to support safety-critical communication for railway applications, and be able to provide connectivity to selected third-party users, such as primary emergency services.

4. The system will be resilient to service disruption, for example, through equipment failure, malicious events, or interference. This includes the ability to provide and maintain an acceptable level of service, even in case of any kind of interference (including out-of-band interference)

5. The system requirements should allow for the design of a system that lowers energy consumption and environmental impacts, when compared to existing solutions.

Figure 3, Figure 4 and Figure 5 come from [9]. They present the different boundaries and interfaces of the system the EMULRADIO4RAIL project will consider.

Figure 3: Telecoms system boundary and Protocol stack interfaces [9, p47]

Functional user requirements and Functional and non-functional system requirements matrices are given respectively in Annex 4 and 5 of [9]. As explained in X2RAIL-3 project [5], technical demonstrators will cover the following scenarios:

• Mainline and high-speed line: taking into account some related applications like ETCS, voice, CCTV. The considered bearers are both GSM-R and LTE.

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• Urban & suburban line: taking into account CBTC, ETCS (for commuter trains), CCTV, voice, access to the Internet for passengers. The considered bearers are both LTE and IEEE 802.11 (Wi-Fi).

• Regional and freight trains: taking into account ETCS, GNSS-based positioning, train, integrity monitoring (on board), voice railway emergency call (REC) and remote maintenance. The considered bearers are Public Land Mobile Networks (PLMNs) and SatComs.

In a first stage, in order to facilitate the development within the EMULRADIO4RAIL partners in different locations, different EMULRADIO4RAIL platforms to emulate the Radio Access technologies and the associated networks will be designed in accordance to the technical demonstrators developed within X2RAIl-3 project. At the final stage of the project, integration of the different platforms is foreseen.

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7. Data Traffic models for the communication services In order to analyze the influence of the radio environment and network subsystems on the performance of applications, we need to generate appropriate traffic flows, representative of those related to train-to-ground services. The traffic models based on the generic packet-data transmission paradigm are the following [9bis]:

• HTTP • FTP • Near Real Time Video Streaming • VoIP • Gaming

These general traffic models will be considered when no specific traffic model is available. In order to assess the performance of the adaptable communication systems developed within X2RAIL-3 project, it is important to define several traffic models for the data transmitted. The traffic (packet size, packet periodicity) model should be a simple model that resembles the real behavior of the communication between the train (On board Unit) and the ground (Radio block centre-RBC). The traffic model will be used to transmit realistic IP traffic into the different radio bearers and to obtain the perceivable effect at application level. With the emergence of 4G communication systems, methodologies to evaluate Radio Access Performance were proposed and adopted [35], [36].[35] (Next Generation Mobile Networks Radio Access Performance Evaluation Methodology), describes metrics as well as some generic traffic models to consider in order to evaluate new radio access technologies. The metrics are:

• Uplink and Downlink data rates for a network as a whole assuming all cells are interference limited

• Spectrum efficiency • Core latency • RAN latency • E2E latency • Mobility support with service continuity through different speed

In [36] the authors propose a new traffic model for IEEE 802.16j-06/013. In the framework of the EMULRADIO4RAIL project, it is important to take into account standard methodologies and data traffic models coming from the telecommunications world in order than our results can be recognized in the telecommunication domain. This will be also very important if other specific railway data-traffic model is not available. Different data traffic models for railway cases are available in [10] and [11]. The figures presented in table 2 are extracted from [9]. The table highlights some characteristics useful to build specific

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data-traffic models for the five applications listed. Some figures are unfortunately missing and are part of the ongoing discussions with X2RAIL-3 partners.

max

latency (s)

min data rate

max jitter (ms)

max connection set up time

(s)

Vmax (km/h)

Max. Frequency of Use (mean #users / hr /

km)

packet loss (%)

ETCS 3.5 s 4 kbits/s 3 s 500 0.11 CBTC 0.1 s 128 kbits/s 5 s 160 2.0 Critical voice 0.15 s

23.85 kbits/s 20-30 ms 1 s 500 8.5 0.1%

Critical video 0.1 s 5 Mbits/s 30 ms 1 s 500 TBD critical data 0.1 s 100 kbits/s 1 s 500 45000

Table 2: Characterization of services [9]

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Figure 4: Concept of Operation [9]

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Figure 5: Telecom system boundary [9, p. 46]

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8. IP-layer parameters Quality of Service (QoS) is the capability of a network to provide performance differentiation to selected network traffic over various underlying technologies. We can identify it as the feature enabling the network to differentiate between different classes of traffic and treat them differently. QoS in an entire network involves capabilities in the:

1. End system software running on a computer (e.g. the operating system) or on the edge/access of the network;

2. The networks that carry the data being sent back and forth from one end host to another.

The most important technical parameters to define and quantify QoS are: 1. Delay: The time taken by a packet to travel through the network from one end to another. 2. Jitter (referred to Delay): Jitter is the variance in the inter arrival time between packets,

measured at reception. 3. Throughput: The rate at which packets are transmitted through the network. 4. Packet loss rate: The rate at which packets are dropped, get lost or become corrupted

(some bits are changed in the packet without possible correction) while going through the network.

Any network design should try to minimize 1 and 4, reduce 2, and try to eliminate 3. QoS strategies, may be applied at different layers in the communication stack, implying a multilayer or Top to Bottom (T2B) approach, if considered form the user or application layer. This per layer T2B approach contributes to the overall end to end (E2E) QoS provision. Figure 6 shows the two different approaches to QoS, from the top to the bottom, depending on the different input to analyze and goal to reach.

Figure 6: Top to bottom vs End to End QoS Schemes

Current data networks need to support multiple kinds of traffic over common network paths. Two different methodologies for provision of E2E QoS are defined in the realm of packet data networks:

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Integrated Services (IntServ) vs Differentiated Services (DifServ). The Integrated Services methodology is based on resource reservations. In an IP protocol stack this is based on Resource Reservation protocol (RSVP). In practice, IntServ is not used as the reservations are initiated by the final users and this prevents operators to have full control of their resources. Furthermore, it creates billing and resource isolation issues in multi-domain scenarios. In the Integrated Services methodology, different types or classes of services are defined, and based on them operators provide differential treatment to the data flows falling in the categorization. As there is no resource reservation nor interdomain coordination needs, this is the methodology used in practice, although it provides no real guaranties in multidomain scenarios. Under different kinds of traffic may demand different treatments from the network. Therefore, much of the bulk of network traffic have to flow through lines where first class traffic and other classes of traffic have to share the bandwidth (just like economy class passengers share the airplane with first class passengers). We can only differentiate at places where the traffic flows through active network elements, which have the capability to differentiate (e.g. routers, switches and gateways). Therefore, today's data networks need to:

1. deliver multiple classes of service (that is they should be QoS conscious); 2. be scalable in many aspects (i.e. capacity, so that network traffic can increase without

affecting network performance; i.e. size, having more nodes, routers, etc.); 3. support emerging network intensive, mission critical applications which will be the key

determinant of a company’s success in the global world.

The aim of building a QoS enabled network architecture is to bring end hosts closer, by increasing performance and reducing delay of the underlying network. In order to do this the network should implement service models so that network performance is adequate to each and every application the network is serving to.

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9. Quality definitions in communication networks Network Performance (NP) is defined in ITU-T Recommendation E.800 [17] as “The ability of a network or network portion to provide the functions related to communications between users”. It is defined slightly different way in ITU-T Recommendation E.417 [18] as “The performance of a portion of a telecommunications network that is measured between a pair of network-user or network-network interfaces using objectively defined and observed performance parameters”[18]. Both definitions focused on the portion of network responsible for communication and information exchange between users [19]. Moreover, the second definition introduces the necessity of measuring NP in terms of numerical parameters (Key Performance Indicators, KPIs). These values are used by network providers for the purposes of system design, configuration, operation and maintenance. In this way NP should be defined independently of terminal performance and user actions. Quality of Service (QoS) is defined in ITU-T Rec. E.800 [17] as "the collective effect of service performance which determines the degree of satisfaction of a user of the service." In particular QoS comprises both network performance and non-network related performance (non-NP) information, since including performance of Terminal Equipment (TE) used by end user, both in transmission and reception phases. Examples of NP KPIs are bit error rate, latency, etc., and for non-NP KPIs we can mention the provision time, repair time, range of tariffs and complaints resolution time, etc. Figure 7 shows the relationship between QoS and network performance (NP).

Figure 7: Relationship between NP and QoS [17]

QoS can be analyzed from different perspectives for evaluating the quality of the functions, which are involved in service providing. In fact, ITU-T E.800 and G.1000 [20] recommendations introduce four different views to be taken into account (Figure 8) and adopting a top down approach based on user (customer):

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• Customer's QoS requirements; • Service provider's offerings of QoS (or planned/targeted QoS); • QoS achieved or delivered; • Customer survey ratings of QoS.

Figure 8: Four viewpoints of QoS [20]

Customer's QoS requirements states the “targeted” Quality Level (QL) typically required of a particular service. The customer is not concerned with any aspects of the involved network. QoS offered by the service provider states the “theoretical” QL expected to be offered to the customer by the service provider (expressed by values assigned to QoS parameters). Each service would have its own set of QoS parameters (as in the QoS Classes of ITU-T Rec. Y.1540 for IP service offers). [21] QoS offered by the service provider can be used in planning documents, to specify measurement systems and also can be used to form the basis of the Service Level agreements (SLAs). QoS delivered by the service provider states the “real” QL achieved and delivered to the customer expressed by values assigned to parameters. Comparing theoretical QL with real QL gives the opportunity to assess the level of performance achieved. QoS perceived by the customer states “experienced” QL perceived by customer usually in terms of degrees of satisfaction and not in technical terms. Perceived QoS is assessed by customer surveys and comments on “experienced” QL. Ideally, there would be a 1:1 correspondence between delivered and perceived QoS. In order to analyze different elements involved in QoS assessment, ITU-T Y.1291 Recommendation [22] defines different QoS building blocks organized into the following three planes (Figure 9):

• Control Plane: contains control mechanisms during communication between end user, e.g. admission control, QoS routing, and resource reservation;

• Data Plane: contains mechanisms directly involved in exchanging user data, e.g. buffer management, congestion avoidance, packet marking, queuing and scheduling, traffic classification, traffic policing and traffic shaping;

• Management Plane: contains mechanisms regarding operation, administration, management aspects of the network, e.g. Service Level Agreement (SLA), traffic measuring, policy.

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Figure 9: Architectural views of QoS building blocks [22]

Quality of Experience (QoE) refers to a subjective perspective usually used by end user for estimating Quality Level. ITU-T Rec. P.10/G.100 (2006) Recommendation defines QoE as “The overall acceptability of an application or service, as perceived subjectively by the end-user.” [23] QoE is quite different from QoS for several aspects, but the most important is related to the adopted approach. First, QoE is based on a subjective approach since it takes in account perception of service by end user. It is dependent by factors as static or dynamic service fruition, positive or negative emotions, etc. QoS is only focused on mechanisms of service delivering across the network. For this reason, it is based on an objective approach and then it is dependent by factors as network transport condition or service functionality, etc. Figure 10 shows Quality of Experience (QoE) Dimension [24].

Figure 10: QoE Dimension [23]

Considering the relationship among NP, QoS and QoE, it is evident QoE realizes a strong link between user’s service perception with service’s parameters measured by QoS. Then, QoE should be impacted from the QoS while NP is limited into a network domain. Figure 11 shows the relationship between NP, QoS and QoE.

Control Plane

Data Plane

QOSRouting

AdmissionControl

ResourceReservation

Buf ferManagement

CongestionAvoidance

PacketMarking

Queuing &Scheduling

Traf f icShaping

Traf f icPolicing

Traf f icClassif ication

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Figure 11: Relationship among NP, QoS and QoE [23]

Comparing key features of NP, QoS and QoE, it is also evident that:

• QoS and QoE are based on user’s perspective, while NP on provider’s perspective; • QoS is characterized by measurable service specifics while QoE by user subjective specifics.

Table 3 lists key features of NP, QoS and QoE. [25]

Quality of Experience Quality of Service Network Performance

User oriented Provider oriented

User behavior attribute Service attribute Connection/Flow element attribute

Focus on user-perceived effects

Focus on user-observable effects

Focus on planning, development (design), operations and maintenance

User subject Between (at) service access points

End-to-end or network elements capabilities

Table 3: Summary features of NP, QoS and QoE

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10. Main Standard Technical Recommendations on QoS

10.1. IP-based fixed networks In ITU-T Recommendation E.800 (1994) [17] International Telecommunication Union (ITU) started to study and define Quality of service (QoS) in transmission networks. First formulations of QoS were applied to the telephony sector and based on Support, Operability, Accessibility, Retainability, Integrity and Security. ITU-T Recommendation X.902 (1995) included a definition of the OSI reference model. [26] In 1998 the ITU published a document discussing QoS in the field of data networking. X.641 offers a means of developing or enhancing standards related to QoS and provide concepts and terminology to assist in maintaining the consistency of related standards. [27] ITU-T Recommendation Y.1540 is the recommendation defining the basic common performance parameters for evaluating network performance for IP networks. The specifications of these common parameters are the basis for quantitatively evaluating, measuring, and comparing network QoS performance. Y.1540 was last revised in 2007. [21] ITU-T Recommendation Y.1541 is the recommendation specifying the objectives of end-to-end network performance, or performance between user network interfaces (UNI’s), based on Y.1540 parameters. [28]. ITU-T Recommendation Y.1542 describes some ideas regarding how the end-to-end performance objectives specified in Y.1541 can be achieved in multiple-carrier environments. Notably, Y.1542 is a framework recommendation, it does not include anything to mandate and it simply discusses approaches for achieving end-to-end performance objectives. [29] It mainly describes two different approaches: (1) Impairment Allocation, which assigns a subset of end-to-end performance objectives to each provider on the path, thus achieving the total end-to-end performance objectives, and (2) Impairment Accumulation, which accumulates the sum of the performance budget commitment from each provider on the path and evaluates whether the end-to-end QoS requirements are fulfilled. ITU-T Recommendation Y.1543 specifies the measurement methodology for a network with a multi-provider environment. [30] An exhaustive list of major official documents on QoS/QoE standardization is available in Appendix A.

10.2. Wireless networks In this paragraph, we give examples of QoS parameters defined at ETSI level for wireless networks. ETSI TS 122.105 defines QoS parameters for bearer services and teleservices, and sets expectations for measures such as delay, delay variation, loss, etc. for each of the service types identified for UTMS service (Table 4) [30].

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Table 4: Service types identified for UMTS [30]

ETSI TS 122.105 also defines end user performance expectations. Table 5 lists quality requirements for Interactive Services (e.g. web browsing).

Medium Application Degree of symmetry

Data Rate

Key Performance Indicator

One-way delay Delay Variation

Information Loss

Audio Voice Messaging Primarily one-way

4-13 kbit/s

< 1 s for playback < 2 s for record < 1 ms < 3% FER

Data Web Browsing – HMTL

Primarily one-way < 4 s /7 page N.A. Zero

Data Transaction Service (e.g. e-Commerce)

Two-way < 4 s N.A. Zero

Data email Primarily one-way < 4 s N.A. Zero

Table 5 Quality requirements for Interactive Services [30]

ETSI TS 123.207 develops the QoS framework for the UMTS bearer service using an end-to-end view, as shown in Figure 12. [31]

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Figure 12: End-to-End QoS Architecture in UMTS [34]

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11. Metrics and Class of Service (CoS) In case of IP networks, ITU-T Y.1541 [28] defines the following measurable parameters: IP Transfer Delay (IPTD): measures the end-to-end delay of a service, and consists of contributions from several sources. These delays are additive, so the total IPTD value is the sum of all of these contributions. Certain delays are fundamental (such as propagation delay), whereas other contributors are tractable to design trade-offs, such as transport delay (where queuing and scheduling can have an effect) and jitter buffer delay. IP Delay Variability (IPDV) o Jitter: measures the variation in the end-to-end delay between a minimum and maximum (strictly the 99th percentiles, rather than absolute maximums); IP Loss Rate (IPLR): measures the ratio of loss to delivered packets, including packets loss through network congestion (typically dropped by intermediate routers) and packet loss through late arrival at jitter buffers. IP Packet Error Rate (IPER): measures packets delivered to the correct destination but with errors in the packet. In case of a voice over IP (VoIP) application, the Call Setup Time (CST) is the most important QoS metric to monitor. The official definition of Call setup time is given by ITU-807 [19] as the period elapsing from the sending of a complete destination address (target telephone number) to the setting up of a call to the receiving terminal. The call setup time is measured entirely from the user terminal, which originates the call. Typical Call Setup Time is 3 to 5 seconds. ITU-T Y.1541 also defines a set of classes of services and proposes thresholds for QoS parameters analyzed for each of them, as shown in Table 6. Network Performance Parameters (KPI)

Y.1541 QoS Classes

Class 0 Class 1 Class 2 Class 3 Class 4 Class 5

IPTD 100 ms 400 ms 100 ms 400 ms 1 s -

IPDV 50 ms 50 ms - - - -

IPLR 1 ∙ 10-3 1 ∙ 10-3 1 ∙ 10-3 1 ∙ 10-3 1 ∙ 10-3 -

IPER 1 ∙ 10-4 -

Table 6: Class of Service (CoS) identified for IP networks [15]

Voice Signaling

Interactive Data

Streaming Video

Video Streaming

Example Service Mapping

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In case of wireless networks, 3GPP ETSI TS 123-107 [34] also defines classes of service to deliver over UMTS network, as shown in Table 7.

Traffic class Conversational class Real Time

Streaming class Real Time

Interactive class Best Effort

Background class Best Effort

Fundamental characteristics

Preserve time relation (variation) between information entities of the stream

Conversational pattern (stringent and low delay)

Preserve time relation (variation) between information entities of the stream

Request response pattern

Preserve payload content

Destination is not expecting the data within a certain time

Preserve payload content

Description Conversational pattern with very low delay and jitter. This is the most delay-sensitive traffic class.

Delay and jitter requirements are not as strict as with conversational traffic class.

Interactive class enables prioritization between packet data protocol (PDP) contexts, which allows end-user or service prioritization. Interactive class is associated with a traffic handling priority (THP). THP values can be 1 through 3.

Interactive class enables prioritization between packet data protocol (PDP) contexts, which allows end-user or service prioritization. Interactive class is associated with a traffic handling priority (THP). THP values can be 1 through 3.

Example of the application

Voice and real-time multimedia messaging such as VoIP and video conferencing.

Streaming type applications such as video on demand.

Streaming type applications such as video on demand, Web browsing, and Telnet.

Background type applications such as e-mail and FTP.

Table 7: Class of Service (CoS) identified for UMTS [15]

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12. QoS assessment in LTE QoS is characterized in LTE [33] by the following main parameters:

• QoS Class Identifier (QCI) • Allocation Retention Priority (ARP) • Maximum Bit Rate (MBR)

QCI is a scalar indicating QoS requirements to be guaranteed by the network during service delivering to the end user. The standardized QCIs are nine. Each for them is assigned to a particular service, in terms of guaranteed bitrate (GBR) or non-guaranteed bit rate (Non-GBR). Table 8 shows LTE QCI list.

QCI Resource Type Priority Packet Delay Budget

Packet Error Loss Rate Example Services

1

GBR

2 100 ms 0,01 Conversational Voice

2 4 150 ms 0,001 Conversational Video (live streaming)

3 3 50 ms 0,001 Real-Time Gaming

4 5 300 ms 0,000001 Non-Conversational Video (buffered streaming)

5

Non-GBR

1 100 ms 0,000001 IMS Signaling

6 6 300 ms 0,000001

Video (Buffered Streaming) TCP-based (e.g., web, e-mail, chat, FTP, point-to-point file sharing, progressive video, etc.)

7 7 100 ms 0,000001 Voice, Video (Live Streaming), Interactive Gaming

8 8

300 ms

0,001 Video (Buffered Streaming), TCP-based (e.g., web, e-mail, chat, FTP, point-to-point file sharing, progressive video, etc.)

9 9 0,000001

Table 8: LTE QCI list [31]

ARP is a parameter used for the management of the access procedures in the case of congestion of the cell and affects the priority with which connections are established for the various users. However, once the connection is established, this parameter has no influence on how the network manages the flow of information associated with it. The MBR parameter specifies instead the maximum bit rate supported by a virtual channel to transport IP packets (bearer). The maximum limit in terms of bit rate allowed for a particular transmission is indicated by the initials instead AMBR (Aggregate Maximum Bit Rate).

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13. Involved standardization Bodies This paragraph lists the different standardization bodies. International Telecommunication Union (ITU) is the international organization formed by 193 members and deputed to deal with the standardization, regulation and development of telecommunications technologies in the world, both fixed and mobile. Its commitment is valid worldwide [14]. ITU’s headquarter is in Geneva, with about 20 regional offices located all around the world. ITU members are both ITU States (Member States) and public and private entities (Sector Members) operating in the telecommunications sector. ITU was established in 1932 and the main goals are focused on promoting cooperation between Member States in order to improve the rational use of telecommunications and providing technical assistance to developing countries. Within ITU Organization a special study group 12 (SG12) was created and focused on Quality of Service (QoS) and Quality of Experience (QoE) issues and the relationship between them. European Telecommunications Standards Institute (ETSI) is the European organization officially recognized by the European Union (EU) and the European Free Trade Association (EFTA), responsible for providing and managing universally applicable standards in the ICT world, including fixed, mobile, broadcast and Internet networks [15]. Created in 1988 by the CEPT (European Conference of Postal and Telecommunications Administrations), ETSI members consist of 700 entities belonging to organizations from 62 different countries spread over five continents. Its headquarter is located in Sophia Antipolis (France). Third Generation Partnership Project (3GPP) is a collaboration agreement, formalized in December 1998, between different kinds of members: Organizational Partners (external standards organizations), Market Representation Partners and Individual members. 3GPP commitment is focused on all aspects of cellular networks, as standard requirements, transmission techniques and QoS/QoE issues [16].

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14. Conclusions In the last years, communication systems for railway applications were affected by a great revolution. The interest of railway operators has also moved from dedicated technologies (as GSM-R) towards Public Land Mobile Networks (PLMNs), as 4G/5G and satellite networks. Satellite networks can guarantee wide coverage areas and are used for serving several trains in the same area where terrestrial networks are not available. Satellite networks implement the IP protocol for delivering applications as broadcast. 4G/5G terrestrial networks are very innovative because they are the first 3GPP wireless communication systems based on the IP protocol. They are fully-IP end-to-end technologies. This means:

1) They are based on a single communication paradigm: They are only packet-switched (without the circuit-switched component).

2) The traffic they carry out is typically “best effort” with Quality of Service (QoS) mechanisms.

3) In this case the voice service is Voice Over IP (VoIP)

1) and 2) introduce the concept of bearer as the end-to-end virtual channel (at IP layer) to adopt for packet data transmission. They also evidence the crucial role of mechanisms for QoS guaranteeing at IP layer (L3 or network layer). All communication standardization bodies (ITU, ETSI, 3GPP) focus on the necessity to guarantee acceptable QoS levels in IP communication networks, both wireless and wired. This can be achieved through the measurement of standardized network Key Performance Indicators, as: IP Transfer Delay (IPTD), IP Delay Variability (IPDV) or Jitter, IP Loss Rate (IPLR), IP Packet Error Rate (IPER). Network performance indicators are fundamental metrics to measure at IP layer (at network layer), because they are strictly related both to physical parameters (very important in case of wireless communication systems in terms of SNR, SINR and RSSI) and to application parameters (with strong transmission requirements to satisfy, especially for emergencies). In case of VoIP applications, the Call setup time (CST) is the main KPI at application layer to monitor in order to have an intelligible service to the end-user. Different scenarios or “market segments” (in terms of train speed and train environments) and applications characterize the railway sector. Each of them can use different communication systems in terms of bitrate, latency, jitter, bandwidth, etc. The QoS guaranteeing mechanisms are based on metrics measurement in order to monitor the communication quality and then to implement the best solutions able to meet the application requirements. Therefore, to sum up the conclusions reached at this stage and highlighted in this report are the following: - Railways are a very diverse “system of systems” with many particularities to be taken into

account (speed, headway, physical scenario, etc.)

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- Communication services are also very diverse. Some of them require low capacity and high robustness, other are intensive in capacity or demand very low latencies, etc.

- In order to have a flexible platform able to emulate several scenarios for T2G communications the complexity of IP-layer perceived KPIs needs to be carefully considered. To do so we have proposed some data-traffic models but they have to be refined with discussions with X2RAIl-3 partners. The final data-traffic models that we will considered will be detailed in the deliverable D2.2 that will present the IP impairments models.

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15. References [1] NGTC: Next Generation of Train Control System available at http://www.ngtc.eu/ [2] FRMCS: Future Rail Mobile Communications System, available for download at: https://uic.org/frmcs [3] X2RAIL-1 project description online available at: http://projects.shift2rail.org/s2r_ip2_n.aspx?p=X2RAIL-1. Accessed on February 2019 [4] S2R MAAP 2015 available on www.shift2rail.org. Accessed on February 2019 [5] X2RAIL-3 project, available at: https://projects.shift2rail.org/s2r_ip2_n.aspx?p=X2RAIL-3 [6] NGTC - D6.1 Requirements Specifications for IP communication system- NGTC-WP6-D-SIE-089 available for download at: http://www.ngtc.eu/wp-content/uploads/2017/01/D6.1_Requirements_Specifications_for_IPcomm_system_FINAL.pdf [7] NGTC-D6.1_Application_Requirements_v0.5, available for download at: http://www.ngtc.eu/results-publications/ [8] FRMCS user requirements – FU 7100 Version 4.0.0, available for download at: https://uic.org/IMG/pdf/frmcs_user_requirements_specification_version_4.0.0.pdf [9] X2RAIL-1 – D3.1 - User & System Requirements (Telecommunications) – available for download at: http://projects.shift2rail.org/s2r_ip2_n.aspx?p=X2RAIL-1 [9bis] IEEE C802.16j-06/093 - Comments and proposal to replace traffic models in IEEE 802.16j-06/013 [10] UNISIG ERTMS/ETCS - Traffic Model for RBC – Train Communication [11] ETSI CBTC Group contribution - Typical traffic model for a "generic" CBTC system. [12] Images from Wikipedia published under the Creative Commons License. Credit to authors: Sebastian Terfloth, FlyAkwa, ChrisO and 慕尼黑啤酒. [13] IEC 62267:2009, “Railway applications - Automated urban guided transport (AUGT) - Safety requirements”. [14] http://www.itu.int/en/ITU-T/tsbdir/Pages/default.aspx .

[15] http://www.etsi.org/about .

[16] http://www.3gpp.org/about-3gpp/about-3gpp .

[17] ITU-T Rec. E.800: “SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS. Definitions of terms related to quality of service (2008).” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-E.800-200809-I!!PDF-E&type=items

[18] ITU-T Rec. E.417: “SERIES E: OVERALL NETWORK OPERATION, TELEPHONE SERVICE, SERVICE OPERATION AND HUMAN FACTORS. Network management ñ International network management (2001).” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-E.417-200102-S!!PDF-E&type=items

[19] ITU-T Technical Paper: “How to increase QoS/QoE of IP-based platform(s) to regionally agreed standards – ITU-T Technical Paper. How to increase QoS/QoE of IP-based platform(s) to regionally agreed standards (2013).”

[20] ITU-T Rec. G.1000 “SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS. Quality of service and performance. (2001)” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.1000-200111-I!!PDF-

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E&type=items

[21] ITU-T Rec. Y.1540 “SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects. Quality of service and network performance (2011).”https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-Y.1540-201103-I!!PDF-E&type=items

[22] ITU-T Rec. Y.1291 “SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT GENERATION NETWORKS Internet protocol aspects. Architecture, access, network capabilities and resource management. (2004)” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-Y.1291-200405-I!!PDF-E&type=items

[23] ITU-T Rec. P.10/G.100 “SERIES P: TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKS Vocabulary and effects of transmission parameters on customer opinion of transmission quality SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS International telephone connections and circuits – General definitions. (2006)” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-P.10-200607-I!!PDF-E&type=items

[24] ITU-T Rec. G.1080 “SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Multimedia quality of service and performance – Generic and user-related aspects. (2008)” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.1080-200812-I!!PDF-E&type=items

[25] ITU-I Rec. 350 “SERIES I: INTEGRATED SERVICES DIGITAL NETWORK (ISDN) Overall network aspects and functions, ISDN user network interfaces (1988).”https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-I.350-198811-S!!PDF-E&type=items

[26] ITU-T Rec. X.902 “Data networks and open system communications. Open distributed processing.” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-X.902-199511-S!!PDF-E&type=items

[27] ITU-T Rec. X.641 “SERIES X: DATA NETWORKS AND OPEN SYSTEM COMMUNICATION. OSI networking and system aspects. Quality of Service. (1997)” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-X.641-199712-I!!PDF-E&type=items

[28] ITU-T Y.1541 “SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects – Quality of service and network performance Network performance objectives for IP-based services (2011).” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-Y.1541-201112-I!!PDF-E&type=items

[29] ITU-T Y.1542 “SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects – Quality of service and network performance. Framework for achieving end-to-end IP performance objectives. (2010)” https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-Y.1542-201006-I!!PDF-E&type=items

[30] ETSI TS 122.105 “UMTS: Services & Service capabilities. (2008)”

[31] ETSI TS 123.207 “End-to-end QoS concept and architecture. (2003)”

[32] [ITU-807] ITU-T Recommendation E.807: “Definitions and associated measurement methods of user-centric parameters for call handling in cellular mobile voice service”

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[33] ETSI TS 23.203 “Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Policy and charging control architecture. (2010)” http://www.etsi.org/deliver/etsi_ts/123200_123299/123203/08.09.00_60/ts_123203v080900p.pdf

[34] Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Quality of Service (QoS) concept and architecture (3GPP TS 23.107 version 12.0.0 Release 12).

[35] NGMN alliance white paper, “Next Generation Mobile Networks Radio Access Performance Evaluation Methodology”, January 2008, Guangyi Liu (China Mobile), Shen Xiadong (China Mobile), Jürgen Krämer (KPN / E-Plus), Sadayuki Abeta (NTT DoCoMo), Thomas Sälzer (Orange), Eric Jacks (Sprint Nextel), Andrea Buldorini (Telecom Italia), Georg Wannemacher (T-Mobile)

[36] IEEE C802.16j-06/093, Improve the traffic models in IEEE 802.16j-06/013

[37] ITU Focus Group on Cloud Computing - Part 1. International Telecommunication Union (ITU) Telecommunications Sector. February 2012. Retrieved 16 September 2013.

[38] "Cloud computing in Telecommunications" (PDF). Ericsson. Retrieved 16 December 2012.

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Appendix A: Official documents on QoS/QoE standardization for communication networks

No. Organization Standard Content

1

ITU-T

ITU-T Rec. G.109 Definition of categories of speech transmission quality

2 ITU-T Rec. G.1010 End-user multimedia QoS categories

3 ITU-T Rec. G.1000 Communications quality of service: A framework and definitions

4 ITU-T Rec. E.800 Terms and definitions related to QoS/NP including dependability

5 ITU-T Rec. I. 350

General aspects of quality of service and network performance in digital networks including ISDN

6 ITU-T Rec. X.641 Information Technology-QoS Framework

7 ITU-T Rec. G.107

E- Model. A computational model for use in transmission planning

8 ITU-T Rec. G.1000 Communications quality of service. A framework and Definition

9 ITU-T Rec. E.801 Framework for service quality agreement

10 ITU-T Rec. E 802

Framework and methodology for the determination and application of QoS parameters

11 ITU-T Rec. E.860 Framework of service level agreement

12 ITU-T Rec. P. 10/G.100

Vocabulary for performance and quality of service-Definition of QoE

13 ITU-T Rec. P. 800 Methods for subjective determination of transmission quality

14 ITU-T Rec. P. 862

Perceptual evaluation of speech quality (PESQ). An objective method for end-to-end speech quality

15 ITU-T Rec. Y.1540 IP packet transfer and availability

16 ITU-T Rec. Y. 1541 Network performance objectives for IP-based services

17 ITU-T Rec. Y. 1542 Framework for achieving end-to-end IP Performance Objectives

18 ITU-T Rec. X.140 QoS parameters for public data networks

19

ISO

EN ISO 9000:2000 Quality management systems. Fundamentals and vocabulary

20 EN ISO 9001:2000 Quality management systems. Requirements

21 EN ISO 9004:2000

Quality management systems. Guidelines for performance improvements

22 ETSI EG 202 086 Objectives and principles for "traditional quality" telephone service

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23 EG 201 377-1 Part 1: Introduction to objective comparison measurement methods for one-way speech quality across networks

24 EG 201 377-3 Part 3: Non-intrusive objective measurement methods applicable to networks and links with classes of services

25 EG 201 474 Speech transmission quality across multiple interconnected networks

26 EG 201 769 QoS parameters of voice telephony required under ONP Voice Telephony Directive 98/10/EC

27 EG 202 009-1 Part 1: Methodology for identification of parameters relevant to the Users

28 EG 202 009-2 Part 2: User related parameters on a service specific basis 29 EG 202 009-3 Part 3: Template for Service Level Agreements (SLA)

30 EG 202 057-1 User-related QoS parameter definitions and measurements Part 1: General

31 EG 202 057-2 User-related QoS parameter definitions and measurements Part 2: Voice telephony, Group 3 fax and modem data services

32 EG 202 057-3 User related QoS parameter definitions and measurements Part 3: QoS parameters specific to public land mobile networks (PLMN)

33 EG 202 057-4 User related QoS parameter definitions and measurements Part 4: Internet Access

34 TR 103 138 Speech and multimedia Transmission Quality (STQ); Speech samples and their use for QoS testing

35 ES 202 737

Speech and multimedia Transmission Quality (STQ); Transmission requirements for narrowband VoIP terminals (handset and headset) from a QoS perspective as perceived by the user

36 ES 202 738

Speech and multimedia Transmission Quality (STQ); Transmission requirements for narrowband VoIP loudspeaking and handsfree terminals from a QoS perspective as perceived by the user

37 ES 202 739 Speech and multimedia Transmission Quality (STQ); Transmission requirements for wideband VoIP terminals (handset and headset) from a QoS perspective as perceived by the user

38 ES 202 740

Speech and multimedia Transmission Quality (STQ); Transmission requirements for wideband VoIP loudspeaking and handsfree terminals from a QoS perspective as perceived by the user

39 TS 129 213

Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Policy and charging control signaling flows and Quality of Service (QoS) parameter mapping (3GPP TS 29.213 version 12.6.0 Release 12)

40 TR 125 906

Universal Mobile Telecommunications System (UMTS); Dynamically reconfiguring a Frequency Division Duplex (FDD) User Equipment (UE) receiver to reduce power consumption when desired Quality of Service (QoS) is met (3GPP TR 25.906 version 12.0.0 Release 12)

41 ES 202 718 Speech and multimedia Transmission Quality (STQ); Transmission Requirements for IP-based Narrowband and Wideband Home Gateways and Other Media Gateways from a

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QoS Perspective as Perceived by the User

42 TS 123 107

Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Quality of Service (QoS) concept and architecture (3GPP TS 23.107 version 12.0.0 Release 12)

43 TS 123 207

Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; End-to-end Quality of Service (QoS) concept and architecture (3GPP TS 23.207 version 12.0.0 Release 12)

44 TS 102 250-2 Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 2: Definition of Quality of Service parameters and their computation

45 ES 202 765-2 Speech and multimedia Transmission Quality (STQ); QoS and network performance metrics and measurement methods; Part 2: Transmission Quality Indicator combining Voice Quality Metrics

46 ES 202 765-4 Speech and multimedia Transmission Quality (STQ); QoS and network performance metrics and measurement methods; Part 4: Indicators for supervision of Multiplay services

47 TS 103 220

Speech and multimedia Transmission Quality (STQ); Transmission requirements for Superwideband handheld (handset and hands free) terminals from a QoS perspective as perceived by the user

48 TR 101 578 Speech and multimedia Transmission Quality (STQ); QoS aspects of TCP-based video services like YouTube TM

49 TR 103 114 Speech and multimedia Transmission Quality (STQ); QoS Parameters and measurement methodology for Smartphones

50 TS 103 189 IMS Network Testing (INT); Specification of end-to-end QoS assessment for VoLTE and RCS Interop Events or Plug tests

51 TS 102 250-3 Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 3: Typical procedures for Quality of Service measurement equipment

52 TS 102 250-5 Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in mobile networks; Part 5: Definition of typical measurement profiles

53 EG 202 843 User Group; Quality of ICT services; Definitions and methods for assessing the QoS parameters of the customer relationship stages other than utilization

54

IETF

RFC 1633, QoS in intserv 55 RFC 2475 QoS in diffserv 56 RFC 3031 MultiProtocol Label Switching (MPLS)

57 RSVP 2205-2209 Resource Reservation Protocol (RSVP)

58 3GPP TS 22.105 QoS parameters for bearer services and teleservices 59 TS 23.107 QoS framework for the UMTS bearer service