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Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
GSM-R Packet Switched Technology
Introduction of GPRS/EGPRS for ETCS
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
France Germany
Switzerland
High Density Area-Border Region
(1) Packet Mode for ETCS Motivation
Status GSM-R Air-Interface CapacityETCS data application widely used in low density areas (track)What about high density areas like stations?
Voice capacity demand increases! ETCS in stations demands additional
Circuit Mode channels! Border regions have to share the
limited number of frequencies Capacity demand conflicts with the limited GSM-R(EIRENE) frequency band resources Increase radio channel multiplexing – keep QoS requirements transition towards packet switched modeCircuit Mode-
Dedicated ChannelPacket Mode- Shared
Channel
Track High Density AreaStations
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
(2) GSM-R ETCS Bearer Circuit Switched (CS) versus Packet Switched
Circuit Mode (CS-Mode) Dedicated transmission resource per
ETCS session Sufficient transmission robustness
(Radio Network design) Low traffic channel capacity utilisation (10-
20%)
Packet Mode (PS-Mode GPRS/EDGE) Shared transmission resource(s) between
several ETCS sessions Bearer Service bandwidth depends on:
Channel Coding (more/less robust against transmission errors caused by Doppler and Delay spread)
Radio Network design
Improved protection algorithms against transmission errors
Multiplexing of several ETCS sessions improves resource utilisation
PS ETCSPS ETCS
PS ETCS
PS ETCS
CS ETCS
CS ETCS
CS ETCS
CS ETCS
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
(3) GSM-R ETCS Bearer Circuit (CS) versus Packet Switched (PS) Mode
CS-Mode Resource
PS-Mode Resource
Demand
Release
Demand
Release ETCS - «LOW» Delay
Other «Best Effort»Applications
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
(4) GSM-R GPRS/EDGETest Cases(O-3023v0.73)
User Area - ETCS traffic emulationTraffic Model 1 - Limit•Reflects high radio traffic channel utilisation•Message frequency
every 3 seconds Train RBC every 6 seconds RBC Train
Traffic Model 2 - Typical•Reflects medium traffic channel utilisation•Message frequency
every 6 seconds Train RBC every 20 seconds RBC Train
Mixed Traffic – Application dependent bandwidth allocation•Traffic Model 1/2 + non-ETCS data Network Registration
Boundary Test Conditions
Var
iatio
n of
Ch
ann
el
Co
din
g
(GP
RS
/ED
GE
)
Var
iatio
n of
Rad
io T
raff
ic
Ch
ann
el
qua
ntity
Var
iatio
n in
ET
CS
Se
ssio
n
qua
ntity
sh
arin
g on
e R
adio
T
raff
ic C
han
nel
Variation of Radio Channel Conditions (Optimum 320km/h)
GSM System3GPP Features to improve PS-Mode: •Radio Resources Allocation respecting ETCS application•Mobility behaviour (Cell Change)•Ensure ETCS application precedence over non-ETCS traffic
Specific Test Conditions
Test Case Focus
GSM Feature Gain
Multiplexing Gain of one Radio Traffic Channel
GPRS/EDGE robustness
CS-Mode and GPRS/EDGE co-existence
IP-performance for transport layer parameterization
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
Track (Ø 50km/h up to 320km/h
LAB Phase 2(Optimum Radio)
LAB Phase 1(Optimum Radio)
(5) GPRS/EDGE Bearer Optimisation - Testing Procedure
Measurement Tool
GSMFeature Activation
Performance Reference “Best Effort”
Feature GainIP-Performance
Final-LABParameter Timer
RobustnessParameter Timer
GSMFeatureQualification
Radio AccessTechnology Independent
Timestampgeneration
Transfer Delay Computation
Traffic ModelEmulation
Control of min. 4 concurrent Mobile Modules
Reporting
FinishedFinished
Mixed Traffic (ETCS/Non-ETCS)
Automated Cell Change
ETCS Traffic Model •Traffic Model 1 •Traffic Model 2
Tool Qualification
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
(6) GSM-R GPRS/EDGE Results: Feature Gain
PS-Mode Resource
Demand
Release ETCS - «LOW» Delay
Other «Best Effort»Applications
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
(7) GPRS/EDGE - ETCS Bearer Results:
• 4 concurrent ETCS sessions @320km/h• 6 concurrent ETCS sessions under static conditions
Mu
ltip
lexi
ng
Gai
no
ne
GS
M-R
T
raff
ic C
ha
nn
el
Imp
act
Cir
cuit
P
acke
t M
od
e
• Co-existence guaranteed- matter of GSM-R capacity planning• Requires min. one dedicated Packet Mode Traffic Channel
• 3GPP GSM features improves transfer delay significantly• (TTD) equal/better than Circuit Mode for ETCS • Recovery of erroneous packets faster than in Circuit Mode
Tra
ns
mis
sio
n
Tra
ns
fer
Del
ay
/R
ob
ust
nes
s
CS ETCS
PS ETCS PS-Mode
CS-Mode
PS ETCS
PS ETCS
PS ETCS
PS ETCS
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
• Operation of the required features• Planning recommendation (Min. Packet Switched capacity, Channel Coding)
(8) GPRS/EDGE - ETCS BearerRelated Documents
0
200
400
140
200
260
350
500
560
620
680
740
800
860
950
1200
1800
• Transport Channel qualification Transfer Delay (Transmission Interference – Transport Protocol impact)• Multiplexing Gain –New!
Su
bs
et09
3B
eare
r S
erv
ice
Qo
SP
S-M
od
eE
ng
inee
rin
g
• 3GPP GSM feature specification MRM/Network• PS-Mode functions• Full Qualified Domain Name(s) RBC / OBU Identification• IP Addressing SchemeE
IRE
NE
SR
S/F
RS
GPRS CS2 EGPRS MCS2 GPRS CS2 EGPRS MCS2subset093 95%subset093 99%
Requirements
1 Traffic Channel 2 Traffic ChannelTransfer Delay
Istanbul, 01.-03. April.2014GSM-R Packet Switched TechnologyIngo Wendler / UIC Project Manager - ETCS over GPRS
(9) GPRS/EDGE - ETCS Bearer Conclusion(s)
Transformation Best Effort “QoS Transmission System ”
3GPP Features Standard features are sufficientto fulfil application QoS requirements
Robustness Faster detection and retransmissionof erroneous radio blocks with less impactto higher layers
PS-Mode (GPRS/EDGE) providesa capacity improvement especially in high density - railway traffic areas!
Radio Access Technology Independent Measurement ToolETCS / non-ETCS Traffic EmulationTransport Channel – System Qualification (i.e. Transfer Delay/Multiplexing Gain)