safe architecture for robust distributed application ... · ta-2 & e 4 l-2 24/01/2020...

CONtributing to Shift2Rail’s

NExt generation of high

Capable and safe TCMS.

Phase 2

SAFE architecture for

Robust distributed

Application Integration

in roLling Stock 2

© CONNECTA-2 & Safe4RAIL-2

The projects CONNECTA-2 and Safe4RAIL-2 have

received funding from the European Union’s Horizon

2020 research and innovation programme under grant

agreement No. 826098 (CONNECTA-2) and No.

826073 (Safe4RAIL-2) respectively. The information

and views set out in this document are those of the

author(s) and do not necessarily reflect the official

opinion of Shift2Rail Joint Undertaking. The JU does

not guarantee the accuracy of the data included in this

article. Neither the JU nor any person acting on the

JU’s behalf may be held responsible for the use which

may be made of the information contained therein.

Igor Lopez, CAF [email protected]

Jérôme Härri, EURECOM [email protected]

Technical Seminar on Advanced Architectures and Components for Next-Generation TCMS

January 21st 2020, Brussels

mailto:[email protected]


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CONtributing to Shift2Rail’s NExt generation of high Capable and safe TCMS. Phase 2 | SAFE architecture for Robust distributed Application Integration in roLling stock 2

• Introduction

• Wireless Train Backbone (WLTB)

Concept

Network Architecture and integration in NG-TCMS

Wireless Train Inauguration over WLTB

• Wireless Consist Network (WLCN)

Concept

Wireless Network Architecture and integration in NG-TCMS

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• Wireless Technology Selection

Candidates technologies for WLTB

Candidates technologies for WLCN

• Prototyping for CONNECTA-2 demonstrators

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• WLTB (WireLess Train Backbone) & WLCN (WireLess Consist Network)

• Provide wireless communication

between coupled consists

inside the consist/vehicle

in Operator-Oriented Services (OOS) and TCMS domains

between end devices, such as control units, displays, sensors, actuators, and

smart devices

• Goal

Reduce cabling and connector failure/maintenance

Ease the installation of NG-TCMS systems in existing fleets

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• Substituting wired ETB (IEC 61375-2-5) by wireless communications

• Pre-requirements

Should be compatible with the NG-TCN architecture defined by CONNECTA

WP3 which is an evolution of the existing IEC 61375-2-5.

Having in mind Wireless Safe Train Inauguration.

Maximum delays of 3 x Cycle Time.

Up to 860 meters.

Up to 32 consists.

• Selected topology: Mesh with multihop packet forwarding

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CONtributing to Shift2Rail’s NExt generation of high Capable and safe TCMS. Phase 2 | SAFE architecture for Robust distributed Application Integration in roLling stock 224/01/2020 6

• WLTBN is divided in Adapted-ETBN (AETBN) and Radio Devices (RD)

AETBN

Railway specific functions: Inauguration, R-NAT, ECSP and TTDB Manager interface, etc.

Independent to underlying radio technology

Railway lifecycle

RD

Wireless networking specific functions: packet forwarding, secure association, secure data

transmission, etc.

Adapted to the telecommunication evolution pace

• WLTBN splits two domains:

TCMS domain forwards through RD with low-latency and reliable capability

OMTS domain forwards through RD with high throughput capability

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WLTBNWLTBN

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• Divided in two phases:

Wireless Train Inauguration over WLTB WLTBN

TTDP HELLO removed. Adjacent neighbour info retrieved from RFID transponders:

the consist identifier (consist id) of the local consist

the direction information (end in direction 1 or end in direction 2) of the local consist

the identifier of the WLTB and WLTBN

Train Inauguration Validator CCU

From independent sensors: Train lines or independent RFIDs

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• Wireless Train Inauguration over WLTB WLTBN

Adapted TOPO_FRAME (including info retrieved by RFIDs) with a cycle time of

40 ms.

Neighbour aliveness status implicitly with TOPO_FRAMEs.

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ID-1 ID-2 ID-3

ID-2 ID-3 -

- ID-1 ID-2

ID-1 ID-2 ID-3

ID-2 ID-3 -

- ID-1 ID-2

ID-1 ID-2 ID-3

ID-2 ID-3 -

- ID-1 ID-2

- ID-1 ID-2

ID-3 ID-2 ID-1

- ID-3 ID-2

ID-C1 Own-ID ID-C2Train Network

Directory

Train Network

DirectoryTrain Network

Directory

Train Network

Directory

Train Network

Directory

Train Network

Directory

direction same

direction same

direction same

direction inverse

direction inverse

direction inverse

direction same

direction same

direction inverse

consist with the smallest identifier is defined as front

end of the train

ECN

ID-1

1 2RFID

ED

ECN

ID-2

Wireless Train Backbone

2 1RFIDRFID

ECN

ID-3

2 1RFID

ED

WLTBN

ED

ED Safe End Device

Topology TelgramTopology Telegram from ID-3

Topology Telegram from ID-1

Topology Telegram from ID-2

…

…

...

…

Matched IDs

Matched IDs

WLTBN WLTBN

ECN

ID-1

1 2

RFID RFID

WLTBN ED

EDED

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ECN

ID-1

WLTBN1_1 WLTBN1_2

RFID

2

EDED

RFID

1ECN

ID-2

WLTBN2_1 WLTBN2_2

RFID

2

EDED

RFID

1

TOPO_FRAME TOPO_FRAME

WLTB-2

WLTB-1

• Example of wireless inauguration over redundant WLTBN:

OperationalTrain

Inauguration

IP Routing

ETB ControlService

TTDB Info Service

DNS Service

Adapted ETBN

EthernetSwitching

Time Sync

Forwarding

Wireless device

WD Neighbour Discovery

Low SIL capable device

No SIL requirement

Security

Radio Interfaces

Ethernet Interface

RFID info retrieval

Time Sync

WLTBN

AETBN Neighbour Discovery

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• Approach in CONNECTA-2

define additional general requirements for WLCN (input Roll2Rail and

CONNECTA)

preselect suitable wireless technologies

support by complementary action / Safe4RAIL-2 to evaluate preselected

wireless technologies in regard to requirements

select wireless technologies

specify WLCN with state of art wireless technologies

Define evolved Architecture (Roll2Rail, CONNECTA)

Define ED Interfaces

Evaluate Safety and Security Aspects

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• Assumption: A mix of technologies is used.

Technology preferences: Wi-Fi, LTE, ZigBee (for sensors)

• WAP (Wireless Access Point) device

provides access for wireless end devices to

the consist network

• WAP may house different

wireless technologies

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cableinterface

radio interface

WAPradio ETH

WAP

ETHsubsystem

A

radio ETH

radio

radiosubsystem

A

radiosubsystem

B

ETH

Network Processor

ETHsubsystem

B

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State of the art:

• ECN extended by WAP, constituting WLCN

WAP are added to the cable-based ECN,

building the wireless network

each car contains WAP

each ECN plane has a separate WLCN

classic and safe wireless devices (WED)

are connected to WAP

most practicable solution,

various wireless technologies could be

integrated/used

ETBN-1ETBN-1

WED

ETBN-2ETBN-2

ECN-PLANE-A

ECN-PLANE-B

ETB Line B

CONSIST - 1

ETB Line A

WED WED

WED

WAP-2WAP-2

WAP-1WAP-1

WED-S

ED

CS-1CS-1

CS-2CS-2

ED-S

CS-3CS-3

WAP-3WAP-3

CS-5CS-5

WAP-5WAP-5

WAP-4WAP-4

CS-4CS-4

WAP-6WAP-6

CS-6CS-6

ED

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Future:

• Fully WLCN (MESH)

Approach with a complete

wireless ECN

all EDs are wireless (WED)

WAPs are using MESH technology

according IEEE 802.11s,

using IEEE 802.11 technology

Approach with the most significant

savings in cabling

Technical protection regarding security and network stability needed

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ETBN-1ETBN-1

WED

ETBN-2ETBN-2

WCN-PLANE-A

WCN-PLANE-B

ETB Line B

CONSIST - 1

ETB Line A

WED

WAP-2WAP-2

WAP-1WAP-1

WED

WED

WED-S

WAP-3WAP-3 WAP-5WAP-5

WAP-4WAP-4WAP-6WAP-6

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WIRELESS TECHNOLOGIES

REQUIREMENTS LTE-V2X

[2,3] ITS-G5 [1] Wi-Fi [4,5,6,

7] VLC

[8,9,12] BLE

[10,11] DOT11BD NR V2X

Max. Bit rate

100 Mbps per traffic

type 27 Mbps 27 Mbps

(1) <2.4 Gbps (2) <6.5Gbps (mmWave)

LED dependent up (2Mbps-

60Mbps) up to

2Mbps estimation:

(1) <2-3Gbps

(2) <20Gbps

estimation:

(1) <2-3Gbps (2) <20Gbps

Max. Latency 16-500ms 50-100ms 1-20ms

(1) 1 - 20ms (2) 5-250ms

20-40ms 50ms-1000ms

estimation: (1) 1 - 20ms (2) 5-250ms

estimation: (1) 1 - 20ms (2) unknown

Medium Access

Deterministic

Mode 3: Determinist

ic Mode 4

Non-Determinist

ic;

Non-Determinist

ic Non-

Deterministic Non-

Deterministic

Deterministic Non-

Deterministic

Non-

Deterministic

(mode 2(b)) &

Deterministic (mode 2(d))

Communication Range

up to 820m 300m-1000m

300m-1000m

(1) > 200m (2) < 2m

5m-20m 50m-200m estimation:

<1000m estimation:

<1000m Group

Communication

Multicast/Group - - (2) DOT11y - Clusterin

g Multicast/groupcast

Multicast/groupcast

Mesh Capabilit

ies up to 32 nodes - Geonet/16

09.3 DOT11s - inter-cluster Geonet/1609.3 -

Freq. reuse 1 / car SL-subpools

(2-3) - ISM, mmWave Directional ISM Carrier

aggregation (Mx10Mhz)

SL-subpools (2-3)

Protect. against

interferences

- - - (1) DSSS+Freq

Hopping (2)

BeamForming Beam

Forming Freq.

Hopping BeamForming BeamForming

Note 1: General assumptions for each technology (frequency band, environment (LOS/NLOS), evaluation methodology,..) are described in the cited papers. Note 2: Performance of VLC technologies are assumed in a vehicular context and strongly depend on the receiver LED and modulation [11,12]. Note 3: The required WLTB communication range includes optional multi-hop forwarding.

• VLC and BLE are unsuitable technologies for the

WLTB considering a Mesh architecture. BLE is

unsuitable due to low performance.

• Wi-Fi could be used for non-critical and high-data-

rate WLTB traffic, but cannot support critical traffic.

• LTE V2X/D2D could be used but need to merge

D2D and V2X features, leading to 3GPP non-

compliant systems. Irrespectively, it would need a

deterministic scheduler to handle critical traffic.

• ITS-G5 could be used, but would need a

deterministic scheduler to handle critical traffic.

• NR V2X offers better performances and mechanisms

for deterministic scheduler. But, NR V2X rel. 16 is not

ready yet.

• DOT11BD offers better performances than ITS-G5,

but a same Listen-Before-Talk (LBT) MAC.

OMTS

TCMS

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ITS Band at 5.9GHz in EU for both LTE V2X and

ITS-G5 [source: 5GCAR]s

3GPP Band Number

Uplink (MHz) Downlink (MHz) Duplex Mode

Combined with ITS Band

3 1710-1785 1805-1880 FDD Yes

7 2500-2570 2620-2690 FDD Yes

8 880-915 925-950 FDD Yes

20 832-862 791-821 FDD Yes

LTE Uu Frequency Bands (for LTE V2X mode 3)

5G Frequency bands [source: 5GCAR]

Uplink: 876MHz-880MHz (4Mhz)

Downlink: 930MHz-934MHz (4Mhz)

GSM-R Frequencies

Spectrum for WLTB critical traffic needs strong lobbying… !!

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• Reactive Ad-hoc MESH technologies are

unsuitable technologies for the WLTB due to delay.

• Geographic (position-based) MESH

technologies are unsuitable technologies for the

WLTB due to strong GPS requirement and to the

native stateless approach. Notably, ETSI Geonet

native stateless.

• Proactive Ad-hoc MESH technologies are most

suitable technologies for the WLTB.

OLSR: defined at IETF, well used in the community. Candidate

MESH technology for platooning in France (SCORE@F)

B.A.T.M.A.N. improved version of OLSR. Large community

in MESH WiFi.

L2 code availability

• Challenge:

Security: ETSI ITS has a full security framework. Need to define

such one for WLTB Mesh

ETSI Geonet MESH

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• ZigBee, WirelessHART and UWB are unsuitable technologies for the WLCN. ABB’s WirelessHP cannot be

used either, due to the lack of a MAC layer implementation and WISA is no longer supported by ABB.

• ECHORING could be used for low-latency traffic, but WLCN data rate requirements should be relaxed. Several

ECHORING networks should be deployed to cover all nodes in the WLCN.

• Wi-Fi could be used for non-critical and high-data-rate WLCN traffic, such as Audio/Video Data Streaming and

Best Effort Data, as it is a high performance and non-deterministic technology. In order to use Wi-Fi for critical

traffic, a deterministic MAC layer should be added, as has been done in SHARP.

• LTE, despite providing a deterministic access, does not provide enough data rate for Streaming Data traffic,

and it does not provide sufficiently low latency for Process Data and Supervisory Data traffic in the WLCN.

• 5G could be explored as an alternative, but further research would be required to confirm the specified latency

values.

In near future no single technology will meet whole set of requirements at once!

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• 1 / 2 Adapted ETBN from CONNECTA-2

• 1 / 2 Adapted ETBN from Safe4Rail-2

• 2 / 4 C-V2X wireless devices from Safe4Rail-2

• 2 / 4 802.11s wireless devices from CONNECTA-2/Safe4Rail-2

• 1 / 2 RF attenuator from CONNECTA-2/Safe4Rail-2

Channel condition Parameters to tune

Distance between WLTBNs

Attenuation1:

87.70 dB of attenuation (i.e. 100 m).




Tunnel

Packet loss

Delay

Jitter

Open field

Packet loss

Delay

Jitter

Underground station

Packet loss

Delay

Jitter

Open air station

Packet loss

Delay

Jitter

1 Attenuation calculated for Free Space Path Loss (FSPL) without antenna gains and a frequency of 5.8GHz.

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• WLTB Radio device specification for TCMS 1 PC for LTE-V2X (L2) and B.A.T.M.A.N (L2) Connection to AETBN via ETH

LTE-V2X rel.14 Mode 3: two radio front-ends (SL and UL/DL)

Mode 4: single radio front-end (SL)

GPSDO required for 10Mhz synch pulses WLTB independent timing from AETBN

5.9Ghz 10Mhz 23dBm power amplifier

• WLTB Radio device specification for OMTS IEEE 802.11s

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eth0 PC

Radio Front-end

Radio Front-end

GPSDO

Power Amplifier

Power Amplifier

USB3

USB3

Timing: 10Mhz, 1pps pulse

coax

coax

TCMS radio

OMTS radio

COTS 802.11seth0

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• Overlay/Underlay approach

Underlay

OpenAirInterface (OAI) SDR platform

LTE V2X L2 functions (sidelink, broadcast)

ProSe Controller configured for L2 (MESH)

QoS: LTE RB as function of the ProSe PPP

Overlay

Service discovery – Consist-2-Consist Communication

Group communication – Consist Management

Mesh Management – multi-hop

Security

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WLT

B-C

WLT

B-D

L2 -

Underl

ay

L3

-O

verl

ay

DEMO

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Define environment and test cases for WLCN to validate

WLCN specification in general

specific points like:

using wireless technologies in TCMS

deterministic behavior needed

fitting safety aspects

WAP positioning due to lacking propagation models

needed for train design

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RF attenuatorWED

12XX07

WAP

Wire

Radio

Proposed Testbed with RF attenuator and

communication emulator 12XX07

Coordinator:

IKERLAN, Aitor Arriola

[email protected]

+34 943 712 400

© CONNECTA-2 & Safe4RAIL-2

The projects CONNECTA-2 and Safe4RAIL-2 have

received funding from the European Union’s Horizon

2020 research and innovation programme under grant

agreement No. 826098 (CONNECTA-2) and No.

826073 (Safe4RAIL-2) respectively. The information

and views set out in this document are those of the

author(s) and do not necessarily reflect the official

opinion of Shift2Rail Joint Undertaking. The JU does

not guarantee the accuracy of the data included in this

article. Neither the JU nor any person acting on the

JU’s behalf may be held responsible for the use which

may be made of the information contained therein.

Coordinator:

CAF, Igor López

[email protected]

+34 943 189 241


safe architecture for robust distributed application ... · ta-2 & e 4 l-2 24/01/2020...

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