35th AIAA ICSSC Colloquium: High Throughput Satellite (HTS) Broadband Opportunities: Orbits, Architectures, Interference and Markets Trieste, October 16, 2017 What are the Challenges? 30min Talk Glyn Thomas : Lead Engineer Airbus VHTS & Active Antenna Programme
What are the Challenges? Generic Flexible design Aggregate EIRP Faster Time to market Reduced CAPEX Per Gbps Orbit & Payload Service Area Size DC Power Efficiency Dissipation Gateway / Feederlink Costs Terminal Waveform Design Network IP routing Latency Ground Segment Future HTS Launch / Servicing Launcher Cost / Cadence Frequency Reuse Launcher Capability GTO Fairing In orbit Servicing Assembly
Frequency Reuse Antenna Challenge Applicable to all Orbits Multi-mission (DTH and data) Large Geostationary Satellite Data MEO Satellite (O3B) Constellation Data LEO Satellite (Oneweb) Constellation More capacity implies more bandwidth implies more beams. Classically more beams implies more hardware / mass
Frequency Reuse Generic Flexible design Faster Time to market Reduced CAPEX Per Gbps Heritage HTS missions have used single feed per beam antenna s Coverage flexibility is very limited Capacity flexibility can be offered through the application of beam hopping. Amount of payload hardware / mass / cost is linearly proportional to number of beams / capacity Gateway to user beam flexibility is difficult to provide Digital beam-formed active antennas offer the potential to provide thousands of beams from fewer feeds Digitally beam-formed active antennas offer the potential for generic faster lower cost payloads
Service Area size Antenna Challenge Applicable to all Orbits Service Area size (or scan angle) represents an challenge to the antenna design in all orbits. Direct Radiating Arrays offer greatest flexibility and scan angles. However generating small spot-beams to support high AEIRP often leads to complex arrays with large numbers of elements Application of Terrestrial technology being developed for LEO / MEO scanning phased arrays could help.
Service Area size Capacity Flexible Design Reduced CAPEX Per Gbps Example of a Beam Hopping sequence on a AA architecture Adequacy to traffic demand 1000000 Average served capacity per beam vs demand per beam Scenario 0 - Offered capacity Scenario 0 - Demand Average capacity per beam [Mbps] 100000 10000 1000 100 10 1 0.1 0.01 0.001 0.0001 0 500 1000 1500 2000 2500 Beam Beam hopping is a means to provide flexible allocation of capacity to time varying demand. Beam hopping also allows for simpler payload solutions in respect of number of repeater paths Beam hopping can be implemented on SFPB, or active arrays. Annex E of DVBS2X provides standards for the implementation of beam hopping.
Frequency Reuse Aggregate EIRP DC Power Efficiency Dissipation More capacity implies more spectrum which implies more Aggregate EIRP Aggregate EIRP is the product of HPA power and Antenna Gain In DBFN systems processor / SSPA are integral parts of the antenna and contribute to the overall efficiency Studies show that antenna gain is an important driver to achieving high AEIRP whilst limiting platform DC / Dissipation
Frequency Reuse Aggregate EIRP DC Power Efficiency New Generation Array / Processor Low DC Power High QTY ports Low cost QTY of HPA / Elements High Frequency Sampling Wideband Ports DBFN Processor Regen / IP routing (LEO) ISL capable Efficient DBFN high Frequency reuse DBFN Processor N Ports per pol N HPA RF Power N Element Array per pol Industrialised For Mass Production Active Array HPA Technology Element Technology New Generation processor and Antenna are key technologies in the dream of a generic HTS payload Complex design trade-offs need to be respected. DC power, mass and industrialization are key requirements.
Orbital Layers for applications 5G Spaceweb Common Technology New Generation Array / Processor GEO 36,000km FS = 204dB One way Latency = 120ms Platform Power circa 25kW No Satellites for Global = 3 Simple user terminals Targeted Coverage & point to multipoint MEO ~8000km FS = 191dB Latency = 26ms Platform Power = 1.5kW?kW No Satellites for Global = N/A Tracking user terminals Medium latency and very high Point to point capacity Every orbit has an Important role to play. LEO can offer lowest latency and high aggregate EIRP, ISL can provide low latency paths MEO can offer a compromise in latency and provides high throughput for premium services GEO is king for point to multipoint latency insensitive data The same payload technology challenges and solutions exist in each orbit. LEO ~800km FS = 171dB Latency = 2.6ms Platform Power = 0.5kW -?kw No Satellites for Global = 648 Low latency Low free space loss Very high aggregate capacity
Feeder Link Challenge Applicable to all Orbits Gateway / Feederlink Costs Q and V band W band Ku band Kaband Number of Gateways required can be come large hence investment in mass produced G/W The application of Q and V band can increase the BW per RF gateway and free spectrum for user beams. Diversity systems are needed to manage the impact of rain fade on any given GW location Optical offers the potential to provide high capacity systems with few GW locations Regenerative processing on the uplink, has the potential to reduce the Nb of RF gateways. For constellations this is also a driver, ISL can help extend reach and provide low latency routes
User Terminals Terminal / Waveform Phasor Flat Panel Antenna GEO orbit offers simple static user terminals. Waveforms / Coding and modulation such as DVBSX are established and offer growth potential in respect of 256APSK / Gateway precoding / Beam-hopping. MEO and LEO require scanning terminals. Huge progress is being made in this domain. Further potential exists for 5G approaches include edge processing and MMIO.
Launch New Glen Space X Falcon Heavy / BFR Ariane 6 Launch cost and cadence remains a major part of the overall HTS business case Especially important for constellations Strong Innovation ongoing from both US and European Players. More capable rockets, re-use, larger fairing, direct GTO injection All reducing cost of entry to space
Servicing Make in Space Servicing & Make in Space Challenges Made in Space Airbus Opportunity to build antennas / payloads with out constraints of launcher. Opportunity to upgrade or refuel existing space assets. Opportunity to support debris removal and or de-orbiting.
What are the Conclusions? Orbit & Payload GEO Future HTS Ground Segment Launch / Serving MEO LEO Future HTS represents a golden new era for telecom satellite All the challenges are being solved by our industry. GEO MEO and LEO all have an important role to play Satellite will be a core part of the future 5G space wide web.