ANTARES: Communication System Design Figures of Merit Iris Information Event - Prague

Transcription

1 : Communication System Design Figures of Merit Iris Information Event - Prague May 26-27th, 2010

2 INDEX 01 Objectives 02 Design drivers 03 Figures of Merit Definition 04 Communication System Technologies Overview 05 Figures of Merit Assessment 06 Verification Test Bed 07 Conclusions 2

3 Communication System Design Objectives Specification of a new satellite-based Air-Ground Communication Standard To cope with the future Air Traffic Services (ATS) and Airline Operational Control (AOC) communication needs Based on the COCR requirements (Application definition, traffic profile). Design of the Communication System consisting in: Communication Standard (CS) with the specification of physical and link layers Address User (traffic), Control and Management plane, with the signaling needs between the system elements. Verification of the CS in the frame of the ANTARES project 3

4 Communication System Design Drivers System requirements and traffic profiles from the COCR requirements (and any refinement of COCR along the project) Flow down of requirements to the Communication System design Precise definition of Applications to consolidate the traffic profile Implications from Aeronautical scenario Efficient use of limited L-band spectrum resources User terminal design (omni-directional aircraft antennas, limited amplifier power) Design for high system efficiency and availability (> 5 nines) Flexibility to support decentralized service provision Preferably technologies free of IPR (Intellectual property rights) CS specification aimed for a global standardization process 4

5 CS Design: Figures of Merit Definition Figures of merit to identify the communications system technologies that better fulfil the requirements Identification of figures of merit related to: System efficiency, maximize bit/s / bandwidth System capacity, technologies that better support the requested traffic Increase system availability, taking into account the propagation channel and the aeronautical mobile scenario Compliance with applications latency requirements Optimize power needs in the User terminal and Payload Support the adequate level of information security and provide robustness in front of interferences 5

6 CS Design: Technologies Overview All techniques related to the physical and link layers and to the control and management planes, as for example: Forward / Return Link Modulation and Channel Coding Adaptive Coding Modulation for the forward link Forward and Return Link Medium Access Control Redundancy Security Measures Handover Procedures Diversity Techniques 6

7 CS Design: Figures of Merit Assessment System efficiency ( bit / sec / Hz ) Forward Link Modulation and Channel Coding based on MPSK and with adaptability to channel variations Maximize capacity using Adaptive Coding & Modulation, but increasing the signalling overhead Forward / Return Medium Access Control with an efficient use of scarce radio resources Frequency reuse among beams to increase efficiency Overhead due to synchronization, guard time, guard bands and detection needs Impact on efficiency due to signalling overheads from: Redundancy mechanism Handover procedures to assure service continuity Security mechanism Procedures for allocation of resources of the satellite network 7

8 CS Design: Figures of Merit Assessment Maximize the system capacity Forward and Return Medium Access Control schemes Evaluation of capacity of Demand based access (Time, Frequency or Code Multiplex) and Random Access schemes Limitations caused by multiple access interference. Techniques based on frequency reuse among beams limited by interferences from adjacent beams f R =3 N=12 Beams =17dB 8

9 CS Design: Figures of Merit Assessment Increase system availability Modulation and coding exhibiting low Packet Error rate: Combined modulation (MPSK, OQPSK, CPM) and channel coding (Turbo, LDPC, BCH) Performances with impairments from the mobile channel, Satellite and User Terminal amplifier characteristics Optimize required signal-to-noise ratio for forward and return links Redundancy (Space and Ground segment) Avoid single points of failure and improve the system availability. Properly design of switch-over protocols (hot redundancy) Linked to ground segment architecture and interfaces Handover mechanism Support of seamless mobility between beams, GES s and satellites. Performance as service continuity (minimise delay and interruption) and signalling overheads 9

10 CS Design: Figures of Merit Assessment Increase system availability (cont): applicability of Diversity techniques Improve system availability by using different uncorrelated communication channels Diversity techniques: satellite, GES site, polarization, space time coding and UT antenna The use of the techniques is under evaluation, based on complexity and performance (diversity gain) (Feeder link ) (User link ) Rain Solar Outages Multipath Scintillation Geometric link 10

11 CS Design: Figures of Merit Assessment Optimize power needs in the User terminal Return link Modulation and Coding: modulations (OQPSK, CPM) that minimises power requirements for the UT amplifier Undesired out of band power: limited by regulation constraints and causing interferences to adjacent channels Compliance with applications latency requirements Forward and Return Multiple Access schemes, assuring delay requirements Efficient synchronization and detection techniques Packet retransmission necessary after packet lost due to channel propagation effects 11

12 ANTARES Verification Test Bed - Concept Mapping between VTB and CS architecture 12

13 Verification Test Bed - Architecture VTB overall preliminary architecture PTS Physical Simulations (SW based) LTE Logical Emulations (SW based) PTE Physical Emulations (HW based) 13

14 Communication System Design - Conclusion ANTARES Communication System Design activity To specify a global communication standard Maximize system capacity, assuring reliability Adapted to the aeronautical scenario Efficient support of applications Communication Standard validation Development of a Verification Test Bed to validate the Communication Standard User Terminal to be prototyped and integrated in the Verification Test Bed in the frame of ANTARES project 14

15 Thank you for your attention Joan Manuel Cebrian Indra Espacio, S.A. Telecommunication and Navigation Solutions Roc Boronat, Barcelona, SPAIN 15