Presentation on theme: "Quality of Service in a GSM-R PPP Jean CELLMER UIC ERTMS 2014."— Presentation transcript:
Quality of Service in a GSM-R PPP Jean CELLMER UIC ERTMS 2014
The RFF GSM-R project Preliminary study started in 2000 Start of rollout in 2003 with the first supply contract given to Nortel GSM-R scenario: Replacement of analog system : 14,000 km on a total of 32,000 km Unique train radio for new lines : East European High Speed Line first 10 year rollout Radio optimized for 8 Watt cab radios Planned number of users: 10,000 cab radios + 30,000 handhelds ETCS level 2 on high speed lines Architecture: 1 Core Network active (+ 1 back up site) 17 Base Station Controllers, 2,500 Base Stations (radio sites)
The RFF GSM-R network architecture
Why a PPP? June 2004: a new French Law authorising PPP (Public Private Partnership) Why a GSM-R PPP? Rollout time schedule could be reduced RFF and SNCF could benefit from additional competencies in term of rollout and network operation thanks to mobile operators involvement RFF financial risks would be limited since the price is definitely fixed in the Partnership contract Operation costs could be reduced thanks to mutualisation of activities and resources (a common network operating centre) Additional revenues allocated to the private partner, reducing the price paid by RFF RFF CAPEX postponed and partly changed in OPEX.
The main aspects of the French PPP contract A 15 year contract signed in March, 2010 with a new company named SYNERAIL Complete rollout of the GSM-R network Operation of the complete GSM-R network, including the part which was built by RFF (transfered to SYNERAIL in March, 2011) Maintenance, upgrade, replacement of all necessary hardware and software equipment until 2025 New services on the network in order to improve business revenue Future High Speed Lines: connection to the GSM-R national network and support of local GSM-R Base Station Subsystem (the radio sites) A very high grade of service: Train to ground radio, 100% compliant to EIRENE specification ETCS level 2 data transmission on High Speed Lines
What’s not in the PPP Transmission links between network elements are still supplied by RFF. These fiber optic or copper cables already exist and are used for various telecommunication applications. They could not be dedicated to GSM-R and transfered to the GSM-R PPP. This share of responsibilities create some difficulties and needs a good organisation. Fixed telephony is also supplied by RFF. The Private Partner is just responsible for integration of these equipment in the end to end system.
GSM-R PPP: Area of responsibility of SYNERAIL 7 BSS Base Station Subsystem BSC BTS NSS Network Switching Subsystem BSC (7 sites) FTS: SNCF (Primary and secundary controllers) Cab radios Handhelds Lineside Telephone Sets (Base Transceiver Station) (Base Station Controller) SDH Transmission: SNCF SYNERAIL domain Local loop: copper cables and fiber optics: SNCF
A complex contractual organisation 8 RFF Temporary building consortium : SYNERAIL CONSTRUCTION SYNERAIL Stakeholders Banks Consortium for operation and maintenance : SYNERAIL EXPLOITATION MAINTENANCE Sub contractor N Sub contractor N+1 Small companies Sub contractor N Rollout independant Controler Stakeholders contract PPP contract Financing contract Building contractOperation and maintenance contract Sub contract Interface contract Certification of sites Specific contractual relationship Sub contract
Lessons learnt from RFF experience A very complex organisation Managing a PPP contract is all but simple: Financial, operational, technical aspects have to be dealt with by numerous contractors. Too many interfaces RFF is the customer but RFF is also the supplier of transmission links, works along the track safety etc.
Lessons learnt from RFF experience The temptation to over specify In a PPP contract the private partner is responsible for the network design and RFF should have only issued functional specifications, mainly expressing RFF’s needs in term of services, QoS, maps of lines to be covered, railway constraints. But RFF explained very precisely its internal rules: no candidate took the risk of not following RFF’s rules and no one showed creativity. SYNERAIL designs and builds the same network as RFF did.
Quality of Service in a GSM-R PPP network There is a contractual relationship between RFF and the private partner. SYNERAIL is committed to: Guarantee a permanent GSM-R service (train radio and support for ETCS level 2) Instantly inform RFF in case of any loss of service Keep the network as new until the contract end (2025) Pay penalties for every break in the contractual rules RFF is permanently informed of the network status SYNERAIL Exploitation comes from a mobile operator (SFR): Technicians are very professional, well skilled and trained There is an efficient human resource sharing with SFR But sometimes, there is a need to better understand the railway specific environment and constraints / UIC/PTA 23 May
The network Operation Centre is shared with a mobile operator’s / UIC/PTA 23 May SFR operation centre: one table is dedicated to GSM-R
QoS: Level of performance SYNERAIL is committed to deliver the GSM-R service with a contractual level of performance: Radio coverage: minima signal level > - 98 dBm pour train radio and > -92 dBm for ETCS level 2 Handover on Power Budget: > 90% Handover ping pong: < 1% Voice quality: MOS > 3 and RXQUAL < 2 (*) Call drop rate for voice < 1.5% Call drop rate for ETCS < 1 call drop per 100 hours Etc. (*) RXQUAL is a GSM-R parameter which qualifies the received signal quality / UIC/PTA 23 May
Quality of Service: Service availability Three categories of sites Normal sites: Conventional lines Critical sites: High Speed Lines + around 100 sites on conventional lines ETCS level 2 sites For every radio site a maximum downtime per year is specified: 99.51% availability of service for conventional (40 hours cumulative max outage) 99.91% availability of service for critical (8 hours cumulative max outage) 99.99% availability of service for ETCS level 2 (52 mns cumulative max outage) In addition Time To Repair (TTR) per site is limited to 4 hours Every service affecting breakdown must not last more than 4 hours
QoS: Information of RFF and SNCF In case of a service breakdown: SYNERAIL must inform SNCF railway operator in less than 5 minutes of any issue which could have a negative effect on railway traffic They must confirm in less than 20 minutes that the issue is not fixed and explain the consequences in term of affected area, likely duration of the problem, possible reason for this issue to go on etc. After service recovery: SYNERAIL must inform SNCF in less than 5 minutes In case of a Railway Emergency Call: SYNERAIL must provide, on request of SNCF, a provisional technical information in less than 15 minutes (call trace) and complete information in 24 hours, / UIC/PTA 23 May
Some railway specific issues In spite of their professional experience, SYNERAIL technicians are facing some new issues: No alarm out-of-service sites: A Public GSM site is monitored by counters of traffic A GSM-R site (non ETCS) is not used to support permanent traffic In case of loss of service without alarm notification (i.e. antenna) train drivers are the only source of information: no way to fix the issue in less than 4 hours! Very high requested availability: A public network can live with several sites out-of-service for hours/days especially far from peak hours A GSM-R network needs to be permanently in service, all sites (no coverage overlap), especially ETCS sites A strong need to inform railway operators in case of a breakdown and after service recovery: Some outages could lead to a railway traffic stop. / UIC/PTA 23 May
Conclusion Operating a GSM-R network in a PPP mode is a good way to improve the Quality of Service thanks to the presence of mobile operators skilled and well trained people. But these professionals often need a time to fully understand railway constraints and specificity. Questions? / UIC/PTA 23 May