VDL Mode 2 Capacity and Performance Analysis

Transcription

1 November Introduction: VDL Mode 2 Capacity and Performance Analysis The objective of this paper is to deliver the background and results of the SESAR Joint Undertaking (SJU) study on. 2. Background: High quality data communications capabilities, consistent and dependable, are essential enablers to support the implementation of efficiency and capacity improvements required by the Single European Sky. The mandated solution in Europe, Regulation (EC) No29/2009 as amended by Implementing Regulation (EU) 2015/310, is based on VDL mode 2 technology. However, as the operational use of VDL mode 2 for ACARS and CPDLC using ATN was progressively reaching the intended operational usage, certain performance degradation issues were observed that raised concerns on the overall usability of the system. These concerns led the European Commission to request EASA to investigate into the observed performance issues of this technology. The resulting EASA report included a ten point Action Plan involving proposals for simulations, performance assessment campaigns, flight trials and deployment planning needed before an informed decision on the future of VDL 2 implementation could be done. In this context, the SJU launched two projects focusing on VDL Mode 2: The is an SJU initiative launched prior to the EASA investigation. It was conducted between June 2014 and July The main objective of the study was the identification of the time horizon by which VDL Mode 2 (assuming usage of up to 4 frequencies) should reach its operational limits in Europe. The study was performed by a consortium led by ENAV depicted in figure 1. Figure 1: " "Consortium The results and conclusions are detailed in section 3 whilst the final report is available in the attachment (section 4). The strategic aim of this study was to assess the capability of VDL2 to support SESAR services on the long term and to determine the point in time by which the next generation datalink technology should be available. The VDL Mode 2 Measurement, Analysis, Testing and Simulation Campaign (also referred to as the ELSA Consortium study) was launched by the SJU further to a European Commission request. It addresses the EASA recommendations 1 to 6 related to the identification of the problem root cause and the provision of potential fixes. It aims at further analyzing the end to end VDL Mode 2 issues experienced today (through simulation and flight testing campaigns), defining potential technical solutions for multi-frequency deployment and VDL Mode 2 potential improvement (protocol optimization, etc.). The project started in February 2015 and is due to deliver the final report mid It is performed by a consortium led by NATS and actively involving a wide representation of stakeholders. The consortium is depicted hereafter in figure 2.

2 Figure 2: ELSA Consortium 3. Main findings of the : This section gives an overview of the. It aims at and providing guidance on the interpretation of the results. How to read the results: The results of the capacity study are based on assumptions, detailed within the document, proposed by the consortium as representing the most realistic scenarios until The VDL Mode 2 protocol considered was the one currently used by many European ANSPs/CSPs and required by the European Commission Regulation (EC) No 29/2009 requirements on data link services for the Single European Sky. Multi- Frequency options are proposed by the consortium, in terms of frequencies usage for better utilization of the four VDL Mode 2 channels. The ongoing ELSA study is expected to further develop the Multi- Frequency options and to conclude within its report on the final Multi-Frequency solution. It should be noted that the results of the study are valid within these assumptions. Dates where the VDL2 should reach the capacity limits highly depend on implementation options and on technical configurations. Changes to these assumptions (e.g., change of topology, introduction of more than 4 frequencies, and use of a complementary media to VDL2) are likely to impact the results. The main findings: Looking to a time window from 2015 until 2040 and considering various traffic growth expectations in Europe, the study defined the expected growth of ATS and AOC datalink traffic over that period. Based on in depth modelling of all the Air and Ground components, the simulation determined the VDL Mode 2 performance at the network level and also at each individual Ground Station level. The results enabled conclusions on where and when the VDL Mode 2 link would suffer from quality degradation making it no longer usable especially for ATS purposes. The main conclusions and recommendations that emerge from this report are summarized hereafter. o VDL2 over one single frequency would already reach its capacity limits in Therefore, Multi-frequency deployment in Europe is a MUST as of today (2015). o o o A 4 frequencies implementation is a minimum requirement to support VDL2 deployment until 2025 in high density area. Further optimisation options under investigation by ELSA may extend the viability of VDL2 over 4 frequencies beyond 2025 in high density area. It is highly recommended to anticipate the evolution of the European datalink infrastructure in the ATM masterplan and to prioritize the development of the next generation datalink technology within SESAR. These conclusions represent the main outcome of the study and do not represent formal recommendations to the European Commission on the next steps.

3 November The report: The detailed report of the is available hereafter.

4 VDL Mode 2 Capacity and Performance Analysis Document information Project Title Project Number Project Manager Deliverable Name Deliverable ID SESAR_CFT_0096 ENAV Edition Template Version Task contributors SESAR_CFT_0096 ENAV (Project Manager of the consortium), University of Salzburg, ENAIRE, DFS, NATS, LFV and supported by: DSNA, EasyJet, Air France, Lufthansa, SITA and Airbus. Abstract

5 Authoring & Approval Prepared By - Authors of the document. Name & Company Position & Title Date Michele Carandente / ENAV Project Manager 26/05/2015 Carl-Herbert Rokitansky / Uni of Salzburg Project Member 26/05/2015 Reviewed By - Reviewers internal to the project. Name & Company Position & Title Date Michele Carandente / ENAV Project Manager 26/05/2015 Carl-Herbert Rokitansky / Uni of Salzburg Project Member 26/05/2015 Jan Stibor / LFV Project Member 26/05/2015 Jerome Condis / Airbus Project Member 08/05/2015 Marc Speltens / SITA Project Member 08/05/2015 Luc Rochard / AirFrance Project Member 22/05/2015 Alan Pirovano / ENAC Reviewer 10/07/2015 Approved for submission to the SJU By - Representatives of the company involved in the project. Name & Company Position & Title Date Michele Carandente / ENAV Project Manager 26/05/2015 Carl-Herbert Rokitansky / Uni of Salzburg Project Member 26/05/2015 Raphael Pascal / Airbus Project Member 05/06/2015 Mario Garcia / ENAIRE Project Member 03/06/2015 Armin Schlereth / DFS Project Member 08/06/2015 Jan Stibor / LFV Project Member 26/05/2015 Marc Speltens / SITA Project Member 28/05/2015 Alan McNab / NATS Project Member 08/06/2015 Document History Edition Date Status Author Justification /04/2015 Draft M.Carandente Monofrequency outputs /04/2015 Draft M.Carandente Refinement of the strawman /05/2015 Draft C.-H. Rokitansky Summary of Results /05/2015 Draft C.-H. Rokitansky Multi-Frequency results and Update /05/2015 Draft M. Carandente Proposed Final /06/2015 Final M. Carandente Added reviews from partners /08/2015 Final M. Carandente Max Ehammer C.-H. Rokitansky /08/2015 Final M. Carandente Resolution of external comments (EASA, ECTL, ENAC, etc.) General review of the document /09/2015 Final M. Carandente Acknowledgement /10/2015 Final M. Carandente Added details on chapter 6 2 of 151

6 Table of Contents EXECUTIVE SUMMARY INTRODUCTION PURPOSE OF THE DOCUMENT INTENDED READERSHIP INPUTS FROM OTHER PROJECTS ACRONYMS AND TERMINOLOGY CONTEXT OF THE STUDY (OBJECTIVES) OBJECTIVE OF THE STUDY SIMULATION SETUP METHODOLOGY ASSUMPTIONS AND VARIANTS Assumptions on air traffic growth Assumptions on topology Assumptions on network subscription rate Assumptions on simulation time period Assumptions on aircraft equipage rate Assumptions on frequency management Assumptions on alternative communications means Assumptions on AOC and ATS Traffic Load SIMULATION SCENARIOS DESCRIPTION SIMULATION SCENARIOS SINGLE FREQUENCY SIMULATION SCENARIOS MULTI-FREQUENCY SUMMARY OF THE RESULTS VDL MODE 2 CAPACITY ASSESSMENT CRITERIA SINGLE-FREQUENCY DEPLOYMENT High traffic area Medium traffic area MULTI-FREQUENCY DEPLOYMENT High traffic area Medium traffic area CONCLUSIONS HIGH TRAFFIC AREA (LILLE) MEDIUM TRAFFIC AREA (ROME) REFERENCES APPENDIX A PROGRAMME MANAGEMENT A.1 WORK BREAKDOWN STRUCTURE A.1.1 WP1 Management A.1.2 WP2 Characterization of Applications A.1.3 WP3 Scenario Definition A.1.4 WP4 Simulation and reports A.2 DELIVERABLES A.3 SCHEDULE APPENDIX B SIMULATION MODELS DESCRIPTION B.1 MOBILITY MODEL B.1.2 Air Traffic data file B.2 TOPOLOGY MODEL B.2.1 Area of interest B.2.2 Ground Station characteristics of 151

7 B.2.3 Link Budget Model B.2.4 Mobility Management B.2.5 Deployment Options B.3 DATA APPLICATION MODEL B.3.1 ATS data traffic B.3.2 AOC data traffic B.3.3 End-to-End TRTD estimation B.4 PROTOCOL SIMULATION APPENDIX C DETAILED SIMULATION RUNS of 151

8 List of tables Table 1 - SITA Ground Stations Table 2 - ARINC Ground Stations Table 3 - ENAV Ground Stations Table 4 - Network subscription rate assumptions Table 5 - Aircraft equipage rate assumptions Table 6 - Frequency management assumptions Table 7 - Equipage rate with respect to all simulated flights Table 8 - Alternative communication means assumptions Table 9 - Brief resume of main assumptions Table 10: Summary of parameter settings for simulation stream 01 as discussed previously Table 11: Single Frequency (SF) Scenario compilation Table 12: Summary of parameter settings for simulation stream 02 as discussed previously Table 13: Multi Frequency Scenario compilation Table 14 - Capacity Limitations values, Single-Frequency (SF), optimistic traffic growth, high traffic area Table 15 - TRTD values, Single-Frequency (SF), optimistic traffic growth, high traffic area Table 16 - Overall results, Single-Frequency (SF), optimistic traffic growth, high traffic area Table 17 - Capacity Limitation values, Single-Frequency (SF), optimistic traffic growth with AOC Migration, high traffic area Table 18 - TRTD values, Single-Frequency (SF), optimistic traffic growth with AOC migration, high traffic area Table 19 Overall results, Single-Frequency (SF), optimistic traffic growth with AOC migration, high traffic area Table 20 - Capacity Limitations values, Single-Frequency (SF), median traffic growth, high traffic area Table 21 - TRTD values, Single-Frequency (SF), median traffic growth, high traffic area Table 22 Overall results, Single-Frequency (SF), median traffic growth, high traffic area Table 23 - Capacity Limitation values, Single-Frequency (SF), optimistic traffic growth with AOC Migration, high traffic area Table 24 - TRTD values, Single-Frequency (SF), median traffic growth with AOC migration, high traffic area Table 25 Overall results, Single-Frequency (SF), median traffic growth with AOC migration, high traffic area Table 26 - Capacity Limitation values, Single-Frequency (SF), optimistic traffic growth, medium traffic area Table 27 - TRTD values, Single-Frequency (SF), optimistic traffic growth, medium traffic area Table 28 Overall results, Single-Frequency (SF), optimistic traffic growth, medium traffic area Table 29 - Capacity Limitation values, Single-Frequency (SF), optimistic traffic growth with AOC Migration, medium traffic area Table 30 - TRTD values, Single-Frequency (SF), optimistic traffic growth with AOC Migration, medium traffic area Table 31 Overall results, Single-Frequency (SF), optimistic traffic growth with AOC Migration, medium traffic area Table 32 - Capacity Limitation values, Single-Frequency (SF), median traffic growth, medium traffic area Table 33 - TRTD values, Single-Frequency (SF), median traffic growth, medium traffic area Table 34 Overall results, Single-Frequency (SF), median traffic growth, medium traffic area Table 35 - Capacity Limitation values, Single-Frequency (SF), median traffic growth with AOC Migration, medium traffic area Table 36 -TRTD values, Single-Frequency (SF), median traffic growth with AOC Migration, medium traffic area Table 37 Overall results, Single-Frequency (SF), median traffic growth with AOC Migration, medium traffic area Table 38 - Capacity Limitation values, SF, Multi-Frequencies, optimistic traffic growth, high traffic area Table 39 TRTD values, SF, Multi-Frequencies, optimistic traffic growth, high traffic area Table 40 Overall results, Single-Frequency (SF), optimistic traffic growth, high traffic area of 151

9 Table 41 - Capacity Limitation values, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, high traffic area Table 42 - TRTD values, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, high traffic area Table 43 Overall results, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, high traffic area Table 44 - Capacity Limitation values, SF, Multi-Frequencies, median traffic growth, high traffic area Table 45 - TRTD values, SF, Multi-Frequencies, median traffic growth, high traffic area Table 46 Overall results, SF, Multi-Frequencies, median traffic growth, high traffic area Table 47 - Capacity Limitation values, SF, Multi-Frequencies, median traffic growth with AOC migration, high traffic area Table 48 - TRTD values, SF, Multi-Frequencies, median traffic growth with AOC migration, high traffic area Table 49 Overall results, SF, Multi-Frequencies, median traffic growth with AOC migration, high traffic area Table 50 - Capacity Limitation values, SF, Multi-Frequencies, optimistic traffic growth, medium traffic area Table 51 TRTD values, SF, Multi-Frequencies, optimistic traffic growth, medium traffic area Table 52 Overall results, SF, Multi-Frequencies, optimistic traffic growth, medium traffic area Table 53 - Capacity Limitation values, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, medium traffic area Table 54 - Capacity Limitation values, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, medium traffic area Table 55 Overall results, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, medium traffic area Table 56 - Capacity Limitation values, SF, Multi-Frequencies, median traffic growth, medium traffic area Table 57 - TRTD values, SF, Multi-Frequencies, median traffic growth, medium traffic area Table 58 Overall results, SF, Multi-Frequencies, median traffic growth, medium traffic area Table 59 - Capacity Limitation values, SF, Multi-Frequencies, median traffic growth with AOC migration, medium traffic area Table 60 - TRTD values, SF, Multi-Frequencies, median traffic growth with AOC migration, medium traffic area Table 61 Overall results, SF, Multi-Frequencies, median traffic growth with AOC migration, medium traffic area Table 62: Expected number of flights of mobility scenarios from 2015 to Table 63: Evaluated SITA network relevant for area of interest with high data link usage Table 64: Evaluated ARINC network relevant for area of interest with high data link usage Table 65: Evaluated SITA & ARINC network relevant for area of interest with low data link usage Table 66: Parameters used for link budget calculation Table 67: Frequency Option 1: Single frequency Table 68: Frequency Option 2: Multi frequency deployment with two frequencies Table 69: Frequency Option 3: Multi frequency deployment with three frequencies Table 70: Frequency Option 4: Multi frequency deployment with four frequencies Table 71: ATS Communication profile B2 / B List of figures Figure 1 - Existing and possible future communication systems aligned with SESAR deployment Figure 2 - High Level view of simulation tool chain Figure 3 - Traffic Growth within ECAC Area Figure 4 - European VDL Mode 2 GS topology and simulated reference area Figure 5 - Number of flights within selected areas of interest Figure 6 - Peak instantaneous aircraft count (PIAC) for the ECAC region Figure 7 - ATS and AOC data whole simulation zone (30N010W 60N025E) Optimistic Traffic of 151

10 Figure 8 - AOC percentage (%) whole simulation zone (30N010W 60N025E) Optimistic Traffic Figure 9 - AOC with migration % whole simulation zone (30N010W 60N025E) Optimistic Traffic Figure 10 - ATS and AOC data High Traffic Area (Lille) Optimistic Traffic (ScA) Figure 11 - AOC percentage (%) High Traffic Area (Lille) Optimistic Traffic (ScA) Figure 12 - AOC with migration % High Traffic Area (Lille) Optimistic Traffic (ScA) Figure 13 - ATS and AOC data Medium Traffic Area (Rome) Optimistic Traffic (ScA) Figure 14 - AOC percentage (%) Medium Traffic Area (Rome) Optimistic Traffic (ScA) Figure 15 - AOC with migration % Medium Traffic Area (Rome) Optimistic Traffic (ScA) Figure 16 - ATS and AOC data whole simulation zone (30N010W 60N025E) Median Traffic Figure 17 - AOC percentage (%) whole simulation zone (30N010W 60N025E) Median Traffic. 31 Figure 18 - AOC with migration % whole simulation zone (30N010W 60N025E) Median Traffic Figure 19 - ATS and AOC data High Traffic Area (Lille) Median Traffic Growth (ScC) Figure 20 - AOC percentage (%) High Traffic Area (Lille) Median Traffic Growth (ScC) Figure 21 - AOC with migration % High Traffic Area (Lille) Median Traffic Growth (ScC) Figure 22 - ATS and AOC data Medium Traffic Area (Rome) Median Traffic Growth (ScC) Figure 23 - AOC percentage (%) Medium Traffic Area (Rome) Median Traffic Growth (ScC) Figure 24 - AOC with migration % Medium Traffic Area (Rome) Median Traffic Growth (ScC) Figure 25 - Capacity Limitations, Single-Frequency (SF), optimistic traffic growth, high traffic area Figure 26 - Capacity Limitations, Single-Frequency (SF), optimistic traffic growth with AOC Migration, high traffic area Figure 27 - Capacity Limitations, Single-Frequency (SF), median traffic growth, high traffic area Figure 28 - Capacity Limitations, Single-Frequency (SF), median traffic growth with AOC Migration, high traffic area Figure 29 - Capacity Limitations, Single-Frequency (SF), optimistic traffic growth, medium traffic area Figure 30 - Capacity Limitations, Single-Frequency (SF), optimistic traffic growth with AOC Migration, medium traffic area Figure 31 - Capacity Limitations, Single-Frequency (SF), median traffic growth, medium traffic area 51 Figure 32 - Capacity Limitations, Single-Frequency (SF), median traffic growth with AOC Migration, medium traffic area Figure 33 VDL Mode 2 ground station network performance - Single Frequency scenarios years 2015, 2020, 2025, 2030, 2035 and Figure 34 VDL Mode 2 ground station network performance - Single Frequency scenarios years 2015, 2020, 2025, 2030, 2035 and Figure 35 - Capacity Limitations, SF, Multi-Frequencies, optimistic traffic growth, high traffic area Figure 36 - Capacity Limitations, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, high traffic area Figure 37 - Capacity Limitations, SF, Multi-Frequencies, median traffic growth, high traffic area Figure 38 - Capacity Limitations, SF, Multi-Frequencies, median traffic growth with AOC migration, high traffic area Figure 39 - Capacity Limitations, SF, Multi-Frequencies, optimistic traffic growth, high traffic area Figure 40 - Capacity Limitations, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, medium traffic area Figure 41 - Capacity Limitations, SF, Multi-Frequencies, median traffic growth, medium traffic area. 77 Figure 42 - Capacity Limitations, SF, Multi-Frequencies, median traffic growth with AOC migration, medium traffic area Figure 43: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 44: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 45: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 46: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 47: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year of 151

11 Figure 48: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 49: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 50: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 51: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 52: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 53: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 54 - VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 55: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 56: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 57: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 58: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 59: VDL Mode 2 GS network performance Optimistic Traffic - Single- (SF) and Multi- Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 60: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 61: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 62: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 63: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 64: VDL Mode 2 GS network performance Median Traffic - Single- (SF) and Multi-Frequency scenarios: FO2, FO3, FO4, MF4 Year Figure 65 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, optimistic traffic growth, high traffic area Figure 66 - Overall results, Single-Frequency (SF), optimistic traffic growth, high traffic area Figure 67 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, high traffic area Figure 68 Overall results, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, high traffic area Figure 69 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, medium traffic growth, high traffic area Figure 70 Overall results, SF, Multi-Frequencies, median traffic growth, high traffic area Figure 71 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, medium traffic growth with AOC migration, high traffic area Figure 72 Overall results, SF, Multi-Frequencies, median traffic growth with AOC migration, high traffic area Figure 73 - High Traffic Area - ARINC Stations Baseline Year 2014/ Figure 74 - High Traffic Area - SITA Stations Baseline Year 2014/ Figure 75 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, optimistic traffic growth, medium traffic area Figure 76 Overall results, SF, Multi-Frequencies, optimistic traffic growth, medium traffic area Figure 77 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, medium traffic area Figure 78 Overall results, SF, Multi-Frequencies, optimistic traffic growth with AOC migration, medium traffic area Figure 79 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, medium traffic growth, medium traffic area of 151

12 Figure 80 Overall results, SF, Multi-Frequencies, median traffic growth, medium traffic area Figure 81 - Capacity Limitations and TRTD values, SF, Multi-Frequencies, medium traffic growth with AOC migration, medium traffic area Figure 82 Overall results, SF, Multi-Frequencies, median traffic growth with AOC migration, medium traffic area Figure 83 Comparison of Offered Load for various scenarios High traffic vs. Medium traffic area Figure 84 - Medium Traffic Area - ENAV Stations Baseline Year 2014/ Figure 85 - Work Breakdown Structure Figure 86 - GANTT of the project Figure 87: High Level view of simulation tool chain Figure 88: Number of Flights within ECAC Area (peak day 2014; 2015 to 2050 (forecast)) Figure 89: Number of flights on reference day (Aug. 29 th 2014) Figure 90: Simulated area including areas of interest with high and low data traffic Figure 91: Interference Figure 92: Possible trigger events of a simulated flight Figure 93: Application instance and corresponding dialogues Figure 94: Calculation of maximum execution time for a dialogue Figure 95: AOC application message exchanges for different subscriber levels Figure 96 - AOC messages assumed to be exchanged between air and ground for the years 2020 to Figure 97: Markov Model to estimate Technical Round Trip Delay (TRTD) for end-to-end data traffic Figure 98: Simulation protocol stack of VDL Mode 2 performance and capacity study of 151

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14 High quality data communications capabilities, consistent and dependable, are essential enablers to support the implementation of the Single European Sky. The Commission Regulation (EC) No 29/2009, which lays down the requirements on Data Link Services for the Single European Sky (also known as the Data Link Regulation), entered into force on 6 February 2009, became applicable from 7 February 2013 and has subsequently been amended in February Its essential objective was to increase Air Traffic Control capacity by supplementing voice communication by air-ground data link communications. It addresses both the airborne and ground environment with obligations of data link capability for both operators of aircraft and air navigation service providers (ANSP's). The mandated solution is based on VDL mode 2 technology. However, as the use of VDL mode 2 for ACARS over AVLC (AOA) and CPDLC using ATN has become more widespread, certain performance issues were observed that raised concerns on the usability of the system. These concerns led the European Commission to sponsor an EASA investigation into the observed performance issues of this technology. The resulting final report included a ten point Action Plan involving proposals for simulations, performance assessment campaigns, flight trials and deployment planning. SJU launched two studies focussing on VDL Mode 2: the first one the Capacity and Performance Analysis, covered by this document, is dealing with the identification of the time horizon by which VDL Mode 2 should reach its operational limits in Europe, while the second study VDL Mode 2 Measurement, Analysis aims at further analysing the end to end VDL Mode 2 issues experienced today (through lab and flight testing campaigns) and to define potential technical solutions for multifrequency deployment and VDL Mode 2 improvement (protocol optimization, etc). Both studies are complementary coordinated together. The objective of the, presented here, is the identification of the limits of the operational performance of VDL Mode 2 in terms of the Comparison Throughput to Offered Load and its operational usage for ATS purposes. Since the VDL mode 2 technology provides neither the mechanisms for separation of ATS and AOC traffic nor a prioritization scheme for messages with respect to parameters such as safety criticality, it is an accepted consensus that in its current implementation, the technology will at some point reach the limit of its usefulness as a technology from an ATC point of view. Air Traffic Management requires a robust, responsive and trustable datalink technology to help offload traffic off existing voice R/T channels whilst at the same time increasing the overall level of air safety. Currently VDL Mode 2 is operating over one single VHF frequency. From a technical viewpoint, the study sought to reveal whether and if so, at what point, the VDL Mode 2 link, operating on up to 4 VHF frequencies, will reach a performance level commensurate with degradation of service that would objectively be judged as unacceptable for the purposes of the provision of ATC services. The reference document used for this evaluation is CFC/Datalink/PMP "Link DLS CRO Performance Monitoring Requirements", Eurocontrol / Network Manager Directorate, David Isaac, Ed. 1.3, 19 May Looking to a time window from 2015 until 2040 and considering various traffic growth expectations in Europe, the study defined the expected growth of ATS and AOC datalink traffic over that period. Based on in depth modelling of all the Air and Ground components, the simulation determined the VDL Mode 2 performance at the network level and also at each individual Ground Station level. The results enabled conclusions on where and when the VDL Mode 2 link would suffer from quality degradation making it no longer usable especially for ATS purposes. 11 of 151

15 A cross-year analysis has also been detailed, to provide an understanding of how the VDL Mode 2 datalink performances will decrease in comparison to increases of usage. Two areas of interest have been deeply analysed, one representing the busiest airspace in Europe (including London, Paris and Brussels airports and centred on Lille) and an area with medium traffic (centred around Rome). The topology model for this simulation reflects the existing geographical location of the Ground Stations (GS) in Europe. Although, the simulation did not consider the geographical redistribution of the stations, performance details per antenna are provided and the GS that are not performing well can clearly be identified for further investigation. The simulations produced a considerable wealth of technical data, amounting to thousands pages of simulation run results and available on SJU extranet for reference and detailed study. The key findings of the study are that: On the high density area, single frequency implementation is insufficient to service contemporary (2015) bandwidth demand. Progressive extension of VDL2 implementation to the four frequencies already allocated will alleviate the negative trend and postpone the bandwidth exhaustion horizon until 2025, or even later if a suitable network load balancing policy is implemented. On the medium density area, single frequency implementation will support service demand for another few years but not beyond Multi-frequency implementation, utilizing dedicated channels per traffic type (Airport, TMA/En-route) as well as dual squitter solution now pioneered by ENAV will postpone the sunset date to at least 2030, perhaps more if a suitable network load balancing policy is implemented. 12 of 151

16 1 1.1 Purpose of the document In order to anticipate the evolution of the European datalink infrastructure, considering the expected ATS and AOC traffic growth from 2015 until 2040, this study identifies the time horizon by which VDL Mode 2 should reach its operational limits in Europe. Simulation scenarios considered the use of one single frequency as well as up to four frequencies. The aim of this document is to summarize the results of the study and main findings. It provides clear evidences of the identified operational VDL Mode 2 limits, based on results coming from simulations. 1.2 Intended readership The complete ATM community will be interested to check result of this study, so to better understand VDL Mode 2 limits and drive future investments. Institutions can also identify well in advance which appears to be communication future needs for the European airspace, identifying perhaps which may be new technologies that may complement the VDL Mode 2 link and their required performances. 1.3 Inputs from other projects This study has been done on such a way that is really not strictly related to any other study done in the past on this matter. Anyway, in order to identify the criteria that allowed us to determine VDL Mode 2 operational limits; we have used as reference some documents: Link DLS CRO Performance Monitoring Requirements, edition 1.3 Eurocontrol Requirements for monitoring through VDL Mode 2 channels edition, Eurocontrol 1.4 Acronyms and Terminology Term Definition ATM Air Traffic Management ACARS Aircraft Communication Addressing and Reporting System ACSP Air/Ground Communications Service Provider AOC Aeronautical Operational Communications APT Airport Domain ATN aeronautical telecommunications network ATS Air Traffic Services CPDLC Controller-Pilot Datalink Communications CSC Common Signalling Channel DLS Data Link Service ENR En-Route FANS Future Air Navigation System GS VDL Mode 2 Ground Station i4d Initial 4D trajectory LME Link Management Entity MF Multi Frequency OI Operational Improvements PA Provider Abort SESAR Single European Sky ATM Research Programme SESAR Programme The programme which defines the Research and Development activities and Projects for the SJU. SF Single Frequency SJU SESAR Joint Undertaking (Agency of the European Commission) SJU Work Programme The programme which addresses all activities of the SESAR Joint 13 of 151

17 Term Undertaking Agency. TMA Terminal Area TRTD Technical Round Trip Delay USBG University of Salzburg VDL Mode 2 VHF Data Link mode 2 Definition 14 of 151

18 2 Figure 1 - Existing and possible future communication systems aligned with SESAR deployment Figure 1 depicts the SESAR communication infrastructure roadmap which is reflected in the European ATM master plan. This roadmap clearly shows the need to progressively transition from the existing infrastructure towards new datalink solutions. This transition is related to when the current (also called legacy) communication systems will become saturated and new communication systems need to be developed and deployed. Therefore, it is important to identify when data link systems and especially VDL Mode 2 becomes saturated with respect to growing air traffic and new data based operations for ATM. 2.1 Objective of the study The aim of this study is to match aircraft future ATS and AOC traffic requests with foreseen traffic growth, and so to determine when the VDL Mode 2 technology, on monofrequency or multifrequencies, will reach performances that are such to let the link considered as not usable for ATS purposes, that has more stringent requirement than AOC traffic. Simulations provided an incredible amount of data that will be available as annex of this report. Other technical material will be uploaded on SJU extranet. On the main body of this document, main results are summarized, with the help of graphs that give a clear understanding of when the study will foresee this VDL Mode 2 capacity limit. The scope of the study address the capability of mono and multi-frequency VDL Mode 2 to support Datalink services across a number of scenarios. In particular, the analysis determines the capability (capacity and performance) of VDL Mode 2 to support the implementation of evolving datalink services within increasing traffic scenarios. It clearly demonstrated the point at which VDL Mode 2 will no longer be able to support the operational usage of ATS services foreseen within the SESAR Concept. The results enable then the determination of the time horizon by when the introduction of more advanced datalink services will require greater datalink capacity & performance that VDL Mode 2 can offer. This addresses the evolution of traffic and datalink implementations. Datalink services considered are: Existing datalink Services (including Link ) 15 of 151

19 Airline Operational Communication (AOC) ATN Baseline 2 (including initial 4D ) The analysis addresses the time period 2015 through to 2040, with 5 year intervals. The study is giving evidence of technical system loads/key parameters on typical aircraft, operating in dense continental airspace as well as a less busy continental airspace, in line with SJU call for tender requirements and KoM agreement. The following metrics are monitored (always minimum, maximum, average, 95 percentile, 99 percentile, standard deviation, sample count): Application Layer o User Data Rate o User Success Rate o Application Delay o Application Loss / Drop Rate Management Layer (VME) o Logged on Aircraft o Link Establishment Delay o Hand Offs o Broadcast Message Receivers Data Link Services (DLS) o Roundtrip Time o AVLC Frames Medium Access Control (MAC) o MAC Delay o TM2 Occurences o N2 Occurences o T1 Occurences Physical Layer o Channel Occupancy o Offered Load o Throughput o Loss o Transmission Delay o Transmission Distance o Signal Quality Parameter o Collisions o Cause of Failure Taking account of services, link budgets, data volumes and timing, the predicted utilisation analysis clearly show how the evolution and take-up of services will drive utilisation and performance. The analysis indicates clearly when VDL Mode 2 reaches its limitations, the consequence of reaching them and the assumptions being made. 16 of 151

20 3 Within this section we briefly describe the simulation methodology, assumptions and variants taken to assess the VDL Mode 2 capacity breakeven point more detailed descriptions about the simulation modules and parameters used can be found in the annexes. 3.1 Methodology During the introduction of new standards for data communication in aviation (i.e. mainly VDL mode 2, mode 3, and mode 4) a lot of research on the topic of VDL Mode 2 has been published; a paper called characteristics and capacity of VDL Mode 2, 3, and 4 sub-networks 1 gave a good overview of the performance of each of those systems. Also, Eurocontrol conducted a study called VDL Mode 2 Capacity Simulations and published results in late ; USBG was part of this study. Air Traffic Growth Reports Air Traffic in ECAC Area Ground- Station Information Topology Configuration Data Scenario Configuration Application Data Profiles.xls.mdb.txt.txt.txt.xls Mobility Model.xml Topology Model.xml VDL2 Protocol and Channel Simulator.xml.xml.xml.xml.xml.xml D 2.1 D 2.2 D 2.X Seed 1 Seed 2 Seed n.doc VDL2 Report Generator.doc Input Data Final Report D3 MS Word Report D 2.X Figure 2 - High Level view of simulation tool chain 1 Steven C. Bretmersky, Robert R. Murawski, and Vijay K. Konangi. "Characteristics and Capacity of VDL Mode 2, 3, and 4 Subnetworks", Journal of Aerospace Computing, Information, and Communication, Vol. 2, No. 11 (2005), pp /WGM09WP05_VDL2_Capacity%201%20Channel%20Oct04.ppt 17 of 151

21 The approach of the is based on a simulation tool chain where each element provides input to the next element of the chain. Each tool is based on a discrete event based simulation. The first tool (NAVSIM 3 : Air Traffic Calculation) provides the mobility of aircraft of a complete day 4 (i.e. 24 hours). The information of each aircraft is updated in discrete steps of 3 seconds 5. Thereby, important aspects such as position (i.e. longitude, latitude, and altitude), vertical intent, current domain (i.e. APT, TMA, ENR, or ORP), and current sector information are provided. Aircraft are generated for the core area of Europe. The amount of aircraft is extrapolated to the desired scenario (i.e. year and growth scenario). The second tool (VDL Mode 2 Topology Calculation) takes this information and calculates distances of individual aircraft to neighbouring aircraft and visible ground stations. The distances are updated in the same discrete steps as the granularity of the aircraft mobility model. Neighbouring aircraft are all aircraft which are within the radio horizon. The same is true for visible ground-stations. The second tool requires input data such as ground-station positions (latitude, longitude, and altitude), operating frequency, and parameters necessary for link budget calculation such as transmission power or antenna gain. Due to the geographical areas that have been assessed we did not consider any digital elevation model as obstacles are not expected within the evaluated area. The third tool (VDL Mode 2 Protocol and Channel Simulation) takes the mobility, topology, data model, and additional scenario configuration parameters and produces VDL Mode 2 performance data. Each simulation scenario is simulated with multiple different initial seed settings, thus providing confidence intervals for all results. The gained performance data is stored for each seed in a separate xml file. The fourth and final tool (VDL Mode 2 Report Generator) takes all performance data of a single scenario setup and calculates performance figures. These figures are then provided in separate simulation reports. These reports are auto-generated. For concluding comparisons the VDL Mode 2 Report Generator keeps data of interest for the final report. 3 NAVSIM ATM/ATC/CNS Simulation Tool developed by Mobile Communications R&D (MCO) in close co-operation with University of Salzburg (USBG) 4 based on data provided by Eurocontrol/NM (former CFMU) for a reference day (whole ECAC area) 5 might be simulated or derived (interpolated) from time steps of about 1 minute (e.g. Consolidated Position Report (CPR) data) 18 of 151

22 3.2 Assumptions and variants This subsection presents briefly the assumptions and variants taken to compile a representative set of scenarios. The following main simulation variants are taken into account: Air traffic growth Topology Network subscriber rate Simulation time period Equipage rate & data traffic Frequency deployment & management Alternative AOC communications means Assumptions on air traffic growth The air traffic reference (mobility) data has been provided on courtesy by Eurocontrol/NM. The following describes the main characteristics of the reference air traffic data: Reference Day: August 29 th, 2014 (last Friday in August; high/peak day of year 2014) Type of Flights: All IFR Flights (within / to / from) ECAC area on reference day Number of Flights: (within 24 hours) Main data provided for each flight: Figure 3 - Traffic Growth within ECAC Area Callsign / Operator Type of Aircraft Departure and Destination Aerodrome ETD, CTD, ATD (Estimated, Calculated, Actual Time of Departure) ETA, CTA, ATA (Estimated, Calculated, Actual Time of Arrival) Flight Route by Point Coordinates (Latitude, Longitude and Altitude / FL) Flight Route by Air Space Profile (Entry / Exit Time) 19 of 151

23 Figure 3 shows the expected number of flights within the whole ECAC area for the years 2014 to 2050; Scenarios A, C, and D) based on the reference day (August 29 th ) of year While scenario A is assumed to be optimistic, scenario C seems to be a realistic growth model for the coming years. Consequently, we decided to investigate those two scenarios. Variants Baseline Scenario: Year 2015 Air Traffic Growth Scenario A (years 2020, 2025, 2030, 2035 and 2040) Air Traffic Growth Scenario C (years 2020, 2025, 2030, 2035 and 2040) Assumptions on topology Figure 4 - European VDL Mode 2 GS topology and simulated reference area Figure 4 gives an overview of the simulated reference area and the involved data link topology. The black lines indicate simulated air traffic tracks. The red ellipses show the areas of interest for a high data link usage environment (High density area) and a medium data link usage environment (Rome area), respectively. These areas are represented as ellipses as the Mercator projection distorts the circular area of interest with a radius of roughly 150 nautical miles. Each available VDL Mode 2 ground station within the simulated reference area is simulated, however, evaluated are only those which are located within the areas of interests for high and low data link usage, respectively. These ground station positions are represented as orange circles the remaining ground stations are represented as green circles. The areas of Lille and Rome have been selected to represent high and medium data link usage environments, respectively. The area with high air traffic density is the area with roughly 150 nautical miles (nm) radius around Lille, France. All major airports within the capital areas of London, Paris, Brussels and Amsterdam lay within this area. Figure 5 highlights the number of flights within selected 20 of 151

24 areas of interest. This figure clearly shows that the High density area contains most flights across Europe while Rome reflects an area with comparably low air traffic. Figure 5 - Number of flights within selected areas of interest NOTE: Details on the link budget calculation is given in ANNEX B Evaluated ground stations of SITA network in high data link usage environment: Code City Airport Country OWNER FRQ Power AMS7 Amsterdam Schiphol Netherlands SITA 136, W BRU7 Brussels National Belgium SITA 136, W CDG7 Paris CDG France SITA 136, W CDX Paris CDG France SITA 136, W DUS7 Düsseldorf Int l Germany SITA 136, W LCY7 London City UK SITA 136, W Airport LGW7 London Gatwick UK SITA 136,975 5 W LHR7 London Heathrow UK SITA 136, W NWI7 Norwich Int l UK SITA 136, W ORY7 Paris Paris France SITA 136, W Orly PAR7 Paris No France SITA 136, W Airport PARU Paris No France SITA 136, W Airport Table 1 - SITA Ground Stations Evaluated ground stations of ARINC network in high data link usage environment: Code City Airport Country OWNER FRQ Power AMS Amsterdam - Netherlands ARINC 136, W BRU Brussels - Belgium ARINC 136, W CDG Paris - France ARINC 136, W LGW London - UK ARINC 136, W LTN London - UK ARINC 136, W ORY Paris - France ARINC 136, W 21 of 151

25 Code City Airport Country OWNER FRQ Power STN Paris - France ARINC 136, W Table 2 - ARINC Ground Stations NOTE: for all SITA and ARINC VDL Mode 2 ground station antennas a loss attenuation of -3dB is assumed. Evaluated ground stations of SITA/ARINC network in low data link usage environment: Code City Airport Country OWNER FRQ Power Ciampino - Italy ENAV 136, W Fiumicino - Italy ENAV 136, W ATCR-33S Fiumicino - Italy ENAV 136, W SMR-B Napoli - Italy ENAV 136, W Table 3 - ENAV Ground Stations NOTE: for all VDL Mode 2 ground station antennas in Italy a loss attenuation of -4.5 db is assumed. NOTE: In Italy all ground stations are operated by ENAV and have been manufactured by Selex-ES. Those ground stations have adopted criteria named Dual Squitter : The MGS Multi-Squitter is able to manage traffic for all the supported services (ATS and AOC) and for all the aircraft connected regardless the ACSP they belong, on a single VDL Mode 2 radio channel. This will reduce concurrency/collisions and hidden terminals by factor of 2 (more or less). This is achieved thanks to the serialization of the uplinks (ATS, AOC ACSP1 and AOC ACSP2) over the same AVLC links, using a single radio and antenna. The MGS is configured to broadcast different GSIF in using the same VDL Mode 2 radio in order to reach and connect all the aircraft. The simulator has been setup in a way to consider this particular behaviour of ENAV antenna. NOTE: The transmit power level of the VDL Mode 2 ground stations in Italy are either significantly higher (50 Watt for Fiumicino SMR-B and Napoli) compared to the transmit power level of maximum 20 Watt (for ARINC and SITA stations in the high traffic area (Lille)) or are at the low end (10 Watt for Ciampino). Variants No variants for the topology with respect to ground station positions and ground station transmission characteristics have been investigated Assumptions on network subscription rate In Europe SITA and ARINC have different subscriber rates that have been considered in the following way, based on info received by SITA and with the assumptions that the difference between CSP subscriptions will evolve in the future SITA Subscribers 70 % 68 % 66 % 64 % 62 % 60 % ARINC Subscribers 30 % 32 % 34 % 36 % 38 % 40 % Table 4 - Network subscription rate assumptions Table 4 shows an expected slight shift of the market share of about 2% every 5 years up to the year 2040 with a share for SITA and ARINC of 60% and 40% respectively in year Due to the fact that we have not taken additional ARINC ground stations into account, the impact on the study is a further slight degradation of the VDL2 link performance for those stations. The VDL2 performance 22 of 151