GSM-R Packet Switched Technology
Introduction of GPRS/EGPRS for ETCS
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014
(1) Packet Mode for ETCS
Motivation
Status GSM-R Air-Interface
Capacity

Track
High Density Area
Stations
High Density Area-Border Region
Germany
France
Switzerland
Circuit ModeDedicated
Channel
Packet ModeShared
Channel
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
ETCS 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 mode
Istanbul, 01.-03. April.2014
(2) GSM-R ETCS Bearer
Circuit Switched (CS) versus Packet Switched
Circuit Mode (CS-Mode)
CS
CS
 Dedicated transmission resource
per ETCS session
 Sufficient transmission robustness
(Radio Network design)
 Low traffic channel capacity utilisation
(10-20%)
ETCS
ETCS
CS
ETCS
CS
PS
Packet Mode (PS-Mode GPRS/EDGE)
ETCS
ETCS
PS
ETCS
PS
ETCS
PS
ETCS
 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
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014
(3) GSM-R ETCS Bearer
Circuit (CS) versus Packet Switched (PS) Mode
Radio Resource
Allocation/Release
Mobility
• CS-Mode
• Handover (Network commanded)
• dedicated resources in source
and target cell
• End User resource demand
• End User release resource
• PS-Mode
Release
Demand
• PS-Mode
• Cell Change (Reselection)
Mobile self sustaining with/without
Network assistance
• Traffic resources between target
cell and origin cell (Planning Task)
• Handover (Network commanded)
(Neither in Public-GSM nor in
GSM-R Network/Mobile available)
• End User demand
• Network release
Demand
• CS-Mode
• CS-Mode
• Dedicated transmission resource
- allocation – ranking by preemption!
• PS-Mode
• ETCS application
• typical machine to machine
interaction (location measurement
to get track segment permission)
• stringent and low delay  real
time treatment
Applications
Other «Best Effort»
CS-Mode
Resource
PS-Mode
Resource
Application - Priority
based resource
allocation
Release
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
ETCS - «LOW» Delay
Istanbul, 01.-03. April.2014
(4) GSM-R GPRS/EDGE
Test Cases(O-3023v0.73)
•
•
Radio Resources Allocation
respecting ETCS application
Mobility behaviour (Cell Change)
Ensure ETCS application precedence
over non-ETCS traffic
CS-Mode and
GPRS/EDGE coexistence
Variation of Radio
Channel Conditions
(Optimum 320km/h)
User Area - ETCS traffic emulation
Traffic 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
•
Test Case Focus
Variation in ETCS Session
quantity sharing one Radio
Traffic Channel
•
Variation of Radio Traffic
Channel quantity
GSM System
3GPP Features to improve PS-Mode:
Specific
Test Conditions
Variation of Channel Coding
(GPRS/EDGE)
Boundary Test Conditions
GSM Feature Gain
GPRS/EDGE
robustness
Multiplexing Gain
of one Radio
Traffic Channel
IP-performance
for transport layer
parameterization
Traffic Model 1/2 + non-ETCS data
Network Registration
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014
(5) GPRS/EDGE Bearer
Optimisation - Testing Procedure
Track
Measurement
LAB Phase 1
LAB Phase 2
(Ø 50km/h up to 320km/h
(Optimum Radio)
(Optimum Radio)
Tool
Control of min.
Final-LAB
Robustness
Performance
Feature Gain
4 concurrent
Parameter
Parameter
Reference
IP-Performance
Mobile Modules
Timer
Timer
“Best Effort”
Radio Access
Technology
GSM
GSM
Tool
Independent
Feature
Feature
Qualification
Traffic Model
Activation
Qualification
Emulation
ETCS Traffic Model
Timestamp
• Traffic Model 1
generation
• Traffic Model 2
Transfer Delay
Automated Cell Change
Computation
Mixed Traffic
(ETCS/Non-ETCS)
Reporting
Finished
Finished
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014
(6) GSM-R GPRS/EDGE
Results: Feature Gain
Demand
PS-Mode
Resource
Applications
Other «Best Effort»
Release
ETCS - «LOW» Delay
Radio Resource
Allocation/Release
Features:
• Delayed-Downlink-TBF (Network)
• Extended-Uplink-TBF
(Network/Mobile)
•(TBF -Temporary Block Flow)
Mobility
Feature:
• Network Assisted Cell Change
(Network/Mobile)
System Feature Gain Ø
45%
40%
System Feature Gain Ø
35%
35%
20%
30%
10%
5%
0%
up to
•(GBR Guaranteed Bit Rate)
System Feature Gain Ø
33%
15%
0%
17%
-28%
-10%
-20%
25%
20%
Reference feature inactive
10%
0%
40%
25%
15%
Feature:
• Packet Flow Context
(Network/Mobile)
20%
43%
30%
Application - Priority
based resource
allocation
up to
-5%
up to
GBR 2kbps
GBR 3kbps
GBR 4kbps
-30%
-40%
10%
5%
0%
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014
(7) GPRS/EDGE - ETCS Bearer
/
Robustness
Transmission
Transfer Delay
Impact
Circuit
 
Packet Mode
Multiplexing Gain
one GSM-R
Traffic Channel
Results:
• 4 concurrent ETCS sessions
@320km/h
• 6 concurrent ETCS sessions
under static conditions
• Co-existence guaranteedmatter of GSM-R capacity
planning
• Requires min. one dedicated
Packet Mode Traffic Channel
PS
ETCS
PS
ETCS
PS
ETCS
PS
ETCS
PS
ETCS
PS-Mode
CS-Mode
CS
ETCS
• 3GPP GSM features improves
transfer delay significantly
• (TTD) equal/better than
Circuit Mode for ETCS
• Recovery of erroneous packets
faster than in Circuit Mode
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014
(8) GPRS/EDGE - ETCS Bearer
PS-Mode
Engineering
• Operation of the required
features
• Planning recommendation
(Min. Packet Switched capacity,
Channel Coding)
• 3GPP GSM feature specification
MRM/Network
• PS-Mode functions
• Full Qualified Domain Name(s)
RBC / OBU Identification
• IP Addressing Scheme
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
400
200
0
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!
EIRENE SRS/FRS
Subset093
Bearer Service QoS
Related Documents
Transfer Delay
subset093 95%
subset093 99%
1 Traffic Channel
GPRS CS2 EGPRS MCS2
2 Traffic Channel
GPRS CS2 EGPRS MCS2
Requirements
Istanbul, 01.-03. April.2014
(9) GPRS/EDGE - ETCS Bearer
Conclusion(s)
Transformation
Best Effort  “QoS Transmission System ”
3GPP Features
Standard features are sufficient
to fulfil application QoS requirements
Robustness
Faster detection and retransmission
of erroneous radio blocks with less impact
to higher layers
PS-Mode (GPRS/EDGE) provides
a capacity improvement especially in
high density - railway traffic areas!
Radio Access Technology Independent Measurement Tool
 ETCS / non-ETCS Traffic Emulation
 Transport Channel – System Qualification (i.e. Transfer Delay/Multiplexing Gain)
GSM-R Packet Switched Technology
Ingo Wendler / UIC Project Manager - ETCS over GPRS
Istanbul, 01.-03. April.2014