link performance for a satellite-based communications system … · 2019-07-24 · 01.10.2004 dlr,...

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DLR, Institute for Communications and Navigation 1

Link Performance for a Satellite-Based Communications System for Fast Trains: Analysis of Trials and Measurements

Sandro Scalise, Josep Huguet Guasch, DLRVincenzo Schena and Fabrizio Ceprani, Alenia Spazio

Speaker: Harald Ernst, DLR

6th European Workshop on Mobile/Personal Satcoms & 2nd Advanced Satellite Mobile Systems Conference

21-22 September 2004, Noordwijck, NL

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Outline

4 Overview of the FIFTH Project

4 FIFTH Demonstrator and Measurement Setup

4 The Railroad Satellite Channel

4 Results of Measurements and Trials

4 Conclusions

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FIFTH (Fast Internet for Fast Trains Hosts) Objectives

4 Specify and evaluate the FIFTH System, i.e. a multi-segment network infrastructure for the provision of high quality Internet (IP and MPEG over IP) and digital TV services to passengers of top-class, high-speed trains (the extension to other categories of trains and passengers is also envisaged).

4 Study and design a robust satellite radio link which reacts to the impairments caused by obstacles located along the railway.

4 Identify proper Gap fillers for shadowing areas (e.g. railway tunnels or large train stations).

4 Study and design a wireless LAN (W-LAN) based system to distribute the signal inside the train coaches.

4 Complement the study and design phase for all involved radio links with an exhaustive measurement campaign on-field utilising real railroad infrastructures and high speed trains.

4 To design and develop a Ku band demonstrator

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FIFTH Terminal Functional Blocks

Interface Bus

W-LAN STA

SaT

GPS Antenna

TE 1 TE 2

Router 4-7

IEEE802.3 card

IEEE802.3 card

Modules:•Mobility Support•QoS Support•Protocol Conversion •Admission Control

Coach 1TE PTE 3

TE 1 TE 2

Coach 2TE PTE 3

TE 1 TE 2

Coach N TE PTE 3

….

Mobile Surrogate Server

Trai

n D

istr

ibut

ion

Net

wor

k

Navigation UnitT-IWU

GPS: Global Positioning SystemSaT: Satellite TerminalSTA: StationT-IWU: Terminal Inter-working UnitTE: Terminal EquipmentGF: Gap Filler

W-LAN Ant enna

SaT Antenna

Antenna Driver

GPS Module

GF STA GF AntennaIEEE802.3 card

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FIFTH Demonstrator General Prototype Layout

Monitoring& Control

Local ServiceServers

N-IWU-SatelliteGateway

M.IWU

SupportingWorkstation

Switch

Fast Train

Access Server

GeostationarySatellite

Interactive Channel

Forward Channel

Navigation Unit

Train’s LAN Service Centre

GPS

INTERNET &Leased Line

User.1

User.2

User.n

Inertial System.

OnboardServers

Antenna & Platform

Firewall

N-IWU: Network Interworking UnitM-IWU: Mobile Interworking UnitETH: Ethernet

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Demonstrator Target Coach Implementation Design

TrenitaliaFIFTH

UIC-Z1 Baggage VanRadome

Considering the satellite link geometry (elevation and azimuth) to respect the Italian Railway Network, a suitable adaptation of the UIC-Z1 baggage van roof has been designed and implemented to host the final antenna and platform sub-system under the roof.

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TrenitaliaFIFTH

ETR500Compartme

ntEmulation

Radome

CollectiveDisplays

PC “Totem”

Laboratory

Base BandRack

ETR500Compartment Show Room

UIC-Z1 Baggage Van

FIFTH Demonstrator Train Composition

TrenitaliaFIFTH

Baggage Van (Target Coach) ALE-601Ballast Coach ALE-601 Electric Train

Demonstrator Target Train

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50.0

cm

Maximum elevation angleMaximum antenna high

104.8 cm

45.0 cm

Antenna & Platform Details

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Integration Phase in the Target Coach

Antenna Installed Under the Target Coach Roof before the Radome Installation

Final Antenna Installation under the Radome Indoor EquipmentArrangement into the Coach Lab. Section

Detail of the Radome on theTarget Coach Roof

Radome Installedon the Coach

Roof

Wi-Fi Base Station

ConfigurationPC

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Mobile Train Terminal Prototype (MTTP) Layout

Outdoor SectionIndoor Section

Navigation andControl

Unit

GPS Module GPS Antenna

Ku/KaSatelliteModem

Ku/KaIF/RF.

Ku/KaSatelliteModem

Ku/KaIF/RF.

GEOAntenna

&Platform

Inertial System

M-IWU

LAN

Switch

SatServer

TU-LA

N W-LAN IF/RF.W-LAN IF/RF.

GapFiller IF/RF.GapFiller IF/RF.

W-LANAntenna

Gap-FillerAntenna

Tracking System

4 Satellite front-end– Antennas, LNB– RF/IF Downconv.– Modems

4 NTU– PAT algorithm

based on GPS, gyro and a railway database

4 M-IWU– Manages the

handover between different segments

4 TU-LAN– Allow both wired

and wireless access

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Ku Band Measurement Setup

RF Splitter(-5dB)

RS232

Acquisitions Workstation

PAL Video Signal

MicroCamera

SAT DecoderDigital DisplayGyro

Sensor

SpectrumAnalyser Video

Combiner

GPS

MTTPEquivalent

ProbingAntenna

AntennaControl Unit

(ADCU)

Video Recorder

KuGeo-Satellite

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Stationary / Slow Motion Measurement Results

Suspension Bracket

Electric LinePost

Electric TrellisBridge

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The Railroad Satellite Channel

4 Extremely challenging environment for mobile satellite communications

4 Nearly ON-OFF behavior of the propagation channel at Ku-band

4 Peculiar obstacles typical of the railway environment:

– Electrical Bridges / Trellises– Electrical Posts with Brackets– Catenaries Suspension

Bracket

Electric LinePost

Electric TrellisBridge

Environment A Dg [s] Db [s] c [dB]Highway 0.11 6.2 0.8 18Rural 0.15 3.9 0.7 18Suburban 0.15 4.7 0.8 19Urban 0.56 7.6 9.5 19

Results for the Land MobileSatellite Channel at Ku-Band

(downlink)

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Impairment Effect Due to the Power Line Infrastructure

Good Corrupted Corrupted Good

TrellisSpectrum Analyser

Display

Visible Obstacle

Video output

Post with Bracket

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Trials in Motion

• Test Itinerary:Firenze <–> Campiglia Marittima

• Firenze <-> Pisa, mainly E-W oriented• Pisa <-> Campiglia M., mainly N-Soriented

• Approx. Length: 200 km• Max Speed: 160 km/h

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-82 -81 -80 -79 -78 -77 -76 -75 -74 -73 -72 -71 -70 -69 -68 -67 -66 -65 -64 -63 -62 -61 -60 -59 -580

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S igna l Leve l [dBm]

PD

F

-82 -81 -80 -79 -78 -77 -76 -75 -74 -73 -72 -71 -70 -69 -68 -67 -66 -65 -64 -63 -62 -61 -60 -59 -580

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S igna l Leve l [dBm]

Com

plem

enta

ry C

DF

Trial Results: First Order Statistics

LOS

Blockedstate

“Shadowed” state

Reception threshold for a DVB-S signal with rate 3/4

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Trail Results: Second Order Statistics I

100 101 1020

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1Time Share of Connection (TSC)

Tc [sec]

Pro

vabi

lity

of c

onne

ctio

n

-67 dBm-72 dBm

100 101 10210-4

10-3

10-2

10-1

100Time Sha re of Fade (TSF)

Tf [sec]P

rova

bilit

y of

fade

-67 dBm-72 dBm

TSC (Tc, x) is the probability that an arbitrary time instant belongs to a connecton of duration Tc.

A connection is a time interval where the signallevel remains above a given threshold x.

TSF(Tf, x) is the probability that an arbitrary time instant belongs to a fade of duration Tf.

A fade is a time interval where the signal levelremains below a given threshold x.

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Trial Results: Second Order Statistics II

4,5 %9,7 %46,9 %21,3 %46 m2.2 sec

72 m3.4 sec

500 m25 sec

325 m16 sec

Campiglia -> Florence

2,5 %7,4 %37,8%15,5 %80 m4.5 sec

90 m5 sec

600 m40 sec

350 m20 sec

Florence -> Campiglia

-72 dBm-67 dBm-72 dBm-67 dBm-74 dBm-67 dBm-74 dBm-67 dBm

TSF (Tf = 10 sec)TSC (Tc = 2 min)AFDLCR-1

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- 8 2 - 8 1 - 8 0 - 7 9 - 7 8 - 7 7 - 7 6 - 7 5 - 7 4 - 7 3 - 7 2 - 7 1 - 7 0 - 6 9 - 6 8 - 6 7 - 6 6 - 6 5 - 6 4 - 6 3 - 6 2 - 6 1 - 6 0 - 5 9 - 5 80

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S ig n a l L e v e l [ d B m ]

Com

plem

enta

ry C

DF

w i t h o u t t im e d i v e r s i t yo n e r e t r a n s m is s io n a ft e r 5 m in u t e so n e r e t r a n s m is s io n a ft e r 1 0 m i n u t e stw o r e t r a n s m is s i o n s a ft e r 5 a n d 1 0 m i n u t e s

- 8 2 - 8 1 - 8 0 - 7 9 - 7 8 - 7 7 - 7 6 - 7 5 - 7 4 - 7 3 - 7 2 - 7 1 - 7 0 - 6 9 - 6 8 - 6 7 - 6 6 - 6 5 - 6 4 - 6 3 - 6 2 - 6 1 - 6 0 - 5 9 - 5 80

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S ig n a l L e v e l [ d B m ]

Com

plem

enta

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DF

w it h o u t s p a c e d iv e r s it ys p a c e d iv e r e s it y o f 1 5 m e t e r ss p a c e d iv e r s i t y o f 3 0 0 m e t e r s

Diversity Techniques

– Space Diversity

• 15 m

• 300 m

– Time Diversity

• 5 min

• 10 min

• 5 & 10 min

+ 4 %

+ 9 %

+ 14 %

+ 16 %

+ 20 %

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Conclusion

4 A statistical analysis of the satellite radio link in the railway environment has been performed using the data gathered during direct measurements.

4 Although the results confirm that the railway scenario is extremely challenging, diversity techniques can lead to significant improvements.

Embedded touch screen display

Passenger personal laptop

Collective “totem” PC Collective 22”

Display

Collective 18” LCD display

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Link Performance for a Satellite-Based Communications System for Fast Trains: Analysis of Trials and Measurements

THANKS FOR YOUR ATTENTION!!!

link performance for a satellite-based communications system … · 2019-07-24 · 01.10.2004 dlr,...

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