Radio Systems for Railways 2014-03-21 KTH Kista

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Speaker

• Jonas Lindh System and Operations Manager at Trafikverket for Radio and Operative Telephony solutions

• Jonas have worked with telecommunications solution for the railways in Sweden the last 30 years. Experience in fibre optic, transmission, data communication, radio and telephony systems

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Radio System for Railways

• What is the needs for Radio Communications in the railway environment - Voice - M2M - GSM-R

• ERTMS (European Rail Traffic Management System) - Signalling system (ETCS) - Radio system (GSM-R)

• Differences in legal approach in Europe between telecommunications and transport sector (rail) - Rail interoperability - Radio Spectrum Policy Program - Standardisation in Europe

• Co-existence with public operators of UMTS and LTE systems - Unwanted emissions - Strong wide band signals - Improved GSM-R terminal

• Future Radio System for the railway

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What is the needs for Radio Communications in the railway environment

Voice Driver <-> Dispatcher PtP, Group call, Functional addressing <-> Driver <-> Onboard Maintenance <-> Maintenance PtP, (Group call) Dispatcher Requirement: Very high availability, specially in disturbed or jammed traffic situations

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What is the needs for Radio Communications in the railway environment

M2M CS data for ERTMS at least to 2022, after that migration to IP based communication Very high availability and quality 100% of the time, everywhere and at all speeds. Drop call rate less than 1/100h even at high speed approx. 12 return trips between Sundsvall and Umeå (all reasons counted including mobiles and application level) Packet domain Communication for maintenance system, passenger information system, SCADA system, power meters, eco driving

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GSM-R have been in operation since year 2000 on the line between Malmö and Copenhagen The number of subscriber is 7000 today The system handle 300 000 call/month 40 000 call/month to train 90 000 call/month to traffic controllers 5000 ETCS call/month Trafikverket have invested 2 billion SEK in the radio system and it is a condition for ERTMS (25 billion SEK to 2030

14 year with GSM-R in Europe and Sweden

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Dimensioning rules for high availability

• Core system in well protected sites with geographical redundancy • Duplicated transmission in physical separated routs to all BTSs • Duplicated TRX in all BTSs • Duplicated antenna system • All BTS sites have at least 10 h of UPS • Power supply on core sites is protected with duplicated UPS and

duplicated diesel generators

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RADIO COVERAGE

BTS BTS BTS BTS BTS BTS

BSC BSC

Loop configuration for BTS-BSC communication

Opto cable CU cable

MSC eTRAU eTRAU BSC-MSC transmission med 1 + 1 configuration

Redundancy / recilience

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ERTMS L2

With ERTMS L2 the signals is removed and all movement authoritys is send by the Radio Block Central over GSM-R to the engine. ERTMS is in operation at Botniabanan since August 2010. Today Botniabanan, Västerdalsbanan, Ådalsbanan and Haparandabanan are in operation. Availability requirement on GSM-R is increased when ERTMS is introduced

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Lesson learned • Radio in tunnels is not easy, issues to handle are

train speed, redundancy, availability and dynamics in the up- and downlink radio path

• You must have tools to see what is going on in the system (GEM)

• Forget standard parameter setup in cells you need to set parameters on cell basis

• Many new interface to handle Get the ETCS, GSM-R and IP people together to solve the “ERTMS issues”

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R Roa RBC

HLR MSC

BTS 1-5 ABIS 1

BTS 6-9

BTS ....

ABIS 2

ABIS ....

BTS 126-130

ABIS 26

IN (SCP)

RBC Roaming Partner

Rail PABX + dispatcher

TRAU* 1

4 E1 (A-IF)

SGSN

Gn Eth

BSC 1

BTS 1-5 ABIS 1

BTS 6-9

BTS ....

ABIS 2

ABIS ....

BTS 126-130

ABIS 26

BSC 11

TRAU* 11

Asub

Asub

4 E1 (A-IF)

2 E1 (Gb)

2 E1 (Gb)

4 E1 (SINAP7M+)

30 E1 (ISDN)

10 E1 (ISDN)

PSTN

2 E1

(ISUP&MAP)

10 E1 (ISUP&/MAP)

GGSN

2 E1 (SS7/Gr/Gs)

10 Eth (Gi)

SMSC

2 E1

(MAP)

VMS/VIP2000

2 E1 (ISUP)

Ställverk Ställverk

Spårobjekt Spårobjekt

Interface to monitor

OBU

*11 TRAU ersätts av 2 E-TRAU

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OSI model

The OSI model is a construction that attempts to make an incredibly complicated system understandable to a greater audience. It can be approached even by the novice networker, to gain the most basic idea of what goes on between networked computers, or it can be used by the most advanced engineer, as an organizing tool for studies of extraordinary detail and complexity

HDLC LAPB

X.224

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ERTMS = ETCS + GSM-R

• GSM-R is the physical bearer of messages in ERTMS • GSM-R is using the radio transmission technology of GSM • GSM-R is a frequency neighbour to the Public Mobile Operators in

the 900 MHz band • New emerging wide-band technologies (UMTS / LTE) cause

interference problems to the GSM-R operation • In Sweden the regulator, PTS, has issued license conditions for the

Public Mobile Operators helping to protect GSM-R operation from harmful interference

• What are the prospects of interference free GSM-R operations when exposed to the public mobile operators wide-band signals?

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European Railway Agency, an agency of the European Union • The construction of a safe, modern integrated railway network is one

of the EU’s major priorities. Railways must become more competitive and offer high-quality, end-to-end services without being restricted by national borders.

• The European Railway Agency was set up to help create this integrated railway area by reinforcing safety and interoperability.

• The Agency also acts as the system authority for the European Rail

Traffic Management System (ERTMS) project, which has been set up to create unique signaling standards throughout Europe.

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Problem issues

GSM-R

Frequency (downlink) MHz

Pow

er le

vels

4m

abo

ve

rail

track

dB

m/5

MH

z

1

2

921-925

Blue line indicate Power level from public base-station UMTS/LTE

1 GSM-R equipment (CAB & EDOR) can not handle strong wide bands signals from 3G/4G mobile networks in adjacent frequency bands

2 Unwanted emissions from 3G/4G base stations into the GSM-R frequency band

Public 900-band

5 MHz

-23

-107

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Interference issue - GSM-R & 3G/4G systems in the 900 MHz-band

Contains two problems: • Unwanted emissions from 3G/4G base stations into

the GSM-R frequency band: – Solution: To overcome the increased noise level, the signal

level in the GSM-R network will be generally raised, also filtering has to be done at the 3G/4G base stations to minimize the unwanted emissions in the GSM-R frequency band.

• GSM-R equipment (CAB & EDOR) can not handle strong wide bands signals from 3G/4G mobile networks in adjacent frequency bands

– Solution: Installing protective filters at the GSM-R equipment (CAB & EDOR). The filter excludes signals from 3G/4G base stations to reach the GSM-R equipment.

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Situation before 2011

-82dBm

-95dBm

Signal level GSM-R

<-110dBm

-82 dBm is the lowest planned signal level in the Swedish GSM-R network -95 dBm is lowest planned signal level when a BTS fails

Noise

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-82dBm

-95dBm

<-107dBm

12dB

Technical restrictions for the public operators

The values below concern a 0 dBi antenna 4 metres above the railway tracks in the GSM-R. Base stations and repeaters transmitting in the frequency band 925 - 960 MHz must – within the frequency band 921 – 925 MHz – not generate a signal level exceeding -107 dBm/200kHz.

Signal level GSM-R

Interference Noise

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-82dBm

-95dBm

<-107dBm

12dB

For circuit switched data there is a demand for better than 12dB S/N (signal to noise ratio) If above shall apply at a BTS failure the emission from the public network may not exceed -107dBm/200kHz The interference from the public network will appear as noise in the GSM-R band

Allowed interference according to regulations <-107dBm in the GSM-R band

Signal level GSM-R

Interference Noise

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-83 dBm Noice

<-95 dBm

UMTS interference

Fältstyrka GSM-R

Trafikverket have to increase the signal strength along the track wit 12 dB to a estimated cost of 200 MSEK Noise floor increased up to maximum -95 dBm

12 dB

Unwanted emission from public mobile operators (UMTS/LTE) in GSM-R frequency band (according to PTS decision 2011-07-04)

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Future for GSM-R MobiSIR

• Increased traffic mainly for ERTMS, other M2M communications and operational procedures

• Even higher focus on high availability Refarming of 900 MHz band and new technology in public networks

• GSM-R will be the railways operational radio system beyond 2020, maybe to 2030.

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Future railway radio Present situation Old engine CABRADIO

Voice

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Future railway radio Present situation Cargo engine

CABRADIO GSM-R

Electricity meters GPS

Remote control

Maintenance

Voice

GSM-R GPRS or public

Not GSM-R

GSM-R or public

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Future railway radio Near future Cargo engine

CABRADIO GSM-R

TCC supported eco driving

EVC

EDOR EDOR

STM

Electricity meters GPS

Remote control

Maintenance

Voice

GSM-R CS-data

GSM-R CS-data

GSM-R GPRS/CS-data

Not GSM-R

GSM-R GPRS public

GSM-R GPRS or public

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Future railway radio Migration alternative 1 CABRADIO

TCC supported eco driving

EVC

EDOR EDOR

STM

Electricity meters GPS

Remote control

Maintenance

SDR both GSM-R and LTE

IP GPRS/LTE

Not GSM-R/ IP LTE Red equipment need replacement and all Radios and radiomodem

IP GPRS/LTE

IP GPRS/LTE

IP GPRS/LTE

IP GPRS/LTE

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Future railway radio Migration alternative 2

CABRADIO

TCC supported eco driving

EVC

IP IP

SDR radio

Electricity meters

Redundant IP- net work

Remote control

Maintenance

GSM-R

Not GSM-R/ IP LTE

New equipment in red

SDR radio Prim ary IP- net work

VOIP Driver MMI In parallel during migration

LTE with Migration over GPRS/EDGE

LTE with Migration over GPRS/EDGE

GPS

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Future railway radio Application strategy

IP-based radio network with QoS for ETCS and the other onboard equipment

Servers for applications “Killer” application is ETCS/RBC Location Dependent Addressing Functional Addressing eco driving

Voice over IP Data-transmission for ETCS, eco driving, maintenance supervision remote control, location with GPS power consumption

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Future railway radio Railway emergency call

IP-based radio network with QoS for ETCS and the other onboard equipment (VoIP)

Servers for railway emergency call Positions server updated true GPS and TCC-system VoIP server with conference bridge for VGCS

Voice over IP No PTT or special requirements on terminal

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