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GSM-R Packet Switched Technology Introduction of GPRS/EGPRS for ETCS. Status GSM-R Air-Interface Capacity ETCS data application widely used in low density areas (track) What about high density areas like stations? Voice capacity demand increases!
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GSM-R Packet Switched Technology Introduction of GPRS/EGPRS for ETCS
Status GSM-R Air-Interface Capacity 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 (1) Packet Mode for ETCS Motivation Track High Density Area Stations High Density Area-Border Region Germany France Packet Mode- Shared Channel Circuit Mode- Dedicated Channel Switzerland
Circuit Mode (CS-Mode) Dedicated transmission resource per ETCS session Sufficient transmission robustness (Radio Network design) Low traffic channel capacity utilisation (10-20%) PS PS CS PS PS CS CS CS ETCS ETCS ETCS ETCS ETCS ETCS ETCS ETCS (2) GSM-R ETCS Bearer Circuit Switched (CS) versus Packet Switched 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
(3) GSM-R ETCS Bearer Circuit (CS) versus Packet Switched (PS) Mode
(4) GSM-R GPRS/EDGETest Cases(O-3023v0.73) Boundary Test Conditions Specific Test Conditions Test Case Focus Variation of Radio Channel Conditions(Optimum 320km/h) • GSM System • 3GPP Features to improve PS-Mode: • Radio Resources Allocation • respecting ETCS application • Mobility behaviour (Cell Change) • Ensure ETCS application precedence • over non-ETCS traffic CS-Mode and GPRS/EDGE co-existence Variation of Channel Coding (GPRS/EDGE) Variation of Radio Traffic Channel quantity GSM Feature Gain Variation in ETCS Session quantity sharing one Radio Traffic Channel GPRS/EDGE robustness • 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 • Traffic Model 1/2 + non-ETCS data • Network Registration Multiplexing Gain of one Radio Traffic Channel IP-performance for transport layer parameterization
(5) GPRS/EDGE Bearer Optimisation - Testing Procedure Track (Ø 50km/h up to 320km/h Measurement Tool LAB Phase 1 (Optimum Radio) LAB Phase 2 (Optimum Radio) Feature Gain IP-Performance Final-LAB Parameter Timer Robustness Parameter Timer Control of min. 4 concurrent Mobile Modules Performance Reference “Best Effort” Radio Access Technology Independent Tool Qualification GSM Feature Activation GSM Feature Qualification Traffic Model Emulation • ETCS Traffic Model • Traffic Model 1 • Traffic Model 2 Timestamp generation • Automated Cell Change Transfer Delay Computation Mixed Traffic (ETCS/Non-ETCS) Reporting Finished Finished
PS PS PS CS PS PS ETCS ETCS ETCS ETCS ETCS ETCS (7) GPRS/EDGE - ETCS Bearer Results: • 4 concurrent ETCS sessions • @320km/h • 6 concurrent ETCS sessions • under static conditions Multiplexing Gain one GSM-R Traffic Channel • Co-existence guaranteed- • matter of GSM-R capacity • planning • Requires min. one dedicated • Packet Mode Traffic Channel PS-Mode • Impact • Circuit • • Packet Mode CS-Mode • 3GPP GSM features improves • transfer delay significantly • (TTD) equal/better than • Circuit Mode for ETCS • Recovery of erroneous packets • faster than in Circuit Mode Transmission Transfer Delay / Robustness
(8) GPRS/EDGE - ETCS BearerRelated Documents • Transport Channel qualification • Transfer Delay • (Transmission Interference – • Transport Protocol impact) • Multiplexing Gain –New! Subset093 Bearer Service QoS • Operation of the required • features • Planning recommendation • (Min. Packet Switched capacity, • Channel Coding) PS-Mode Engineering • 3GPP GSM feature specification • MRM/Network • PS-Mode functions • Full Qualified Domain Name(s) • RBC / OBU Identification • IP Addressing Scheme EIRENE SRS/FRS
(9) GPRS/EDGE - ETCS Bearer Conclusion(s) Future Radio Access Technologies GSM-R Technology Transformation Best Effort “QoS Transmission System ” 3GPP Features Standard features are sufficient to fulfil application QoS requirements 4G Robustness Faster detection and retransmission of erroneous radio blocks with less impact to higher layers Digital Radio Access Independence IP 5G PS-Mode (GPRS/EDGE) provides a capacity improvement especially in high density - railway traffic areas! Unlicensed Mobile Access • Radio Access Technology Independent Measurement Tool • ETCS / non-ETCS Traffic Emulation • Transport Channel – System Qualification (i.e. Transfer Delay/Multiplexing Gain)