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Richard Locke Director, Advanced Systems Engineering 27 January 2015 Satellite Communications: Challenges and Opportunities of Future Air Interfaces “Highway Painting” by Marc Meynadier (unmodified) Creative Commons Licence
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Transcript of Satellite Communications: Challenges and Opportunities of ... · PDF fileSatellite...
Richard LockeDirector, Advanced Systems Engineering
27 January 2015
Satellite Communications:Challenges and Opportunities of Future Air Interfaces
“Highway Painting”by Marc Meynadier
(unmodified)Creative Commons Licence
And so it begins… (again)
Inmarsat-6(2020)
Next and Previously…2020
Inmarsat-6
1990
Inmarsat-2
(We are here)
2016
2010
Inmarsat-4
2005
2000
Inmarsat-3
1996
Pre-LaunchDesignPeriod
Pre-LaunchDesignPeriod
1993
Inmarsat-5
The Challenge of Time and Space
2020
Inmarsat-6
2016
Pre-LaunchDesignPeriod
Key link budget parameters are frozen 3 to 4 years ahead of launch at time of satellite procurement …
2030
…and you have them for the next 15 years.
What Drives Satellite Radio Air Interface Design?
Four comparative words.
The Satellite Radio Air Interface Engineer’s Mantra™.(L-Band Version)
Repeated for decades…
The Satellite Radio Air Interface Engineer’s Mantra™L-Band Version
(Repeat)
(Forever)
Smaller.
Faster.
Lighter.
Cheaper.
The Challenge of a Connected WorldEnd user expectations are driving satellite strategy…
4G (and 5G)
Proliferation of Mobile Devices
Bandwidth Hungry Applications
Cloud Computing
Interactive Behaviour
The “Internet of Things”
The “expectation gap” is increasing for satellite communications…
The First Era:Inmarsat-2 and Inmarsat-3
2020
2010
2000
1990
Inmarsat-4Inmarsat-3Inmarsat-2 Inmarsat-6
2016
1993
2005
1996
Solitude.
Air Interface Design ThemesThe First Era: Inmarsat-2 and Inmarsat-3
Earlier on:A B C D D+ E H H+ I M mini-M
An alphabet soup of multiple, separate, incompatible air interfaces in parallel. Each is tailored for specific markets or applications (land, maritime, aeronautical, paging, safety services).
Circuit switched voice and data, PSTN/ISDN and other data network (e.g. X.25) compatibility.
Focus on voice coding technology.
User data rates generally from 2.4 to 9.6 kb/s. Inmarsat-B offered high speed data services at 56-64 kb/s (fixed installation).
Air Interface Design ThemesThe First Era: Inmarsat-2 and Inmarsat-3
Later on:M4 MPDS
Multiple, parallel air interface developments gradually converged into one based on the B/M/mini-M air interface, with adaptationsfor other market segments.
Our first use of turbocoding technology in M4 brought speeds for portable user equipment up to 64 kb/s.
MPDS was our first purpose-built IP data transport service based on the M4 physical layer.
But in this era, all air interfaces were completely proprietary. Until …
The Second Era:Inmarsat-4
2020
2010
2000
1990
Inmarsat-4Inmarsat-3Inmarsat-2 Inmarsat-6
2016
1993
2005
1996
Part of a community. Almost.
Air Interface Design ThemesThe Second Era: Inmarsat-4
Fundamental shift from developing proprietary air interfaces to hybrids with industry standards.
Circuit switched and packet switched applications, with focus on IPv4 transport.
Regional BGAN: GMR-1 [Hughes]GPRS Release 97 with proprietary physical layer for satellite
Desire for compatibility/interoperability with existing 2G/3G terrestrial networks.
BGAN: IAI-2/Family-SL [Inmarsat]UMTS Release 4 with proprietary access stratum over radio interface for satellite
GSPS (IsatPhone): GMR-2+ [Lockheed Martin]GSM with proprietary physical layer for satellite
1990
Inmarsat-22010
Inmarsat-4
2005
2000
Inmarsat-3
1996
1993
Coverage Global Beam Global Beam+5 Wide Spots
Global+19 Wide Spots+228 Narrow Spots
Mobile Link EIRP 39 dBW 49 dBW 67 dBW
Power Generation 1.2 kW 2.8 kW 14 kW 22 kW
Channelisation 4 channels of 4.5-7.3 MHz bandwidth
46 channels of 0.9-2.2 MHz bandwidth
630 channels of 200 kHz bandwidth
750 channels of 200 kHz bandwidth
Solar Array Span 14.5 m 20.7 m 45.0 m
Satellite Dry Mass 700 kg 1000 kg 3000 kg
Total Launch Mass 1500 kg 2050 kg 5960 kg 6600 kg
Alphasat
The Gift of Inmarsat-4The Second Era: Inmarsat-4
The Third Era ?Inmarsat-6
2020
2010
2000
1990
Inmarsat-4Inmarsat-3Inmarsat-2 Inmarsat-6
2016
1993
2005
1996
6Smaller.Faster.Lighter.Cheaper.
The Challenge of a Connected World(Reprise)
We’re way beyond packet vs. circuit switched now…
Now the connected world wants two inharmonious things at the same time. Future air interfaces must somehow do both well.
Bandwidth Hungry
Applications
Cloud Computing
Interactive Behaviour
The “Internet of
Things”
Infrequent (and slow!) communicationNot conversational
Very low power !Incredibly small !
So unbelievably light !Dirt cheap !
OMG. So many devices !
More frequent and faster communicationVery conversationalHigh powerVery smallVery lightVery cheapMany devices
The Challenge of Relevancein a Connected World
“Satellite is what we use when we don’t have access to conventional terrestrial communications or when they fail…”
“Satellite doesn’t give us the same performance as terrestrial communications services but it is good enough or better than nothing…”
If the expectation gap is increasing, for how long will “good enough” still be good enough? Future air interfaces must maintain the relevance and utility of satellite communications in an increasingly connected world.
(P.S. This is not a bad thing…)
The Challenge of Mass(and other dimensions)
One day we’ll build satellites in space and they will be the size of football pitches…
Until then, the challenges of construction and launch from way down here remain.
And it’s getting harder.
Leaps in raw performance between successive generations may not be as large as they used to be in every dimension. Future air interfaces must anticipate this…
The Challenge of InterferenceThe Undiscovered Country (at least for us anyway).
Now what?
If improvements in some aspects of satellite performance may become more modest in subsequent generations…
… and if there are practical limits on UE EIRP and emissions (and elsewhere in the link budget) …
Interference can’t be treated as a static parameter anymore.
Radio resource management algorithms in future satellite air interfaces need to improve link performance and system capacity through dynamic and adaptive interference management and cancellation.
The Challenge of ChoiceUnnatural Selection.
There are many good and near-optimal radio air interface families out there…
… each tailored for a specific application.
… and not directly interchangeable with each other.
The Big Question: do you continue to evolve what you are using or do you take the cost and schedule penalties and risk from jumping to and then adapting one of the alternatives to your application?
Future air interfaces must be universal.
like DVB, LTE, GMR, BGAN (Family SL)
The Challenge of ScaleEconomy Matters.
Future air interfaces must be universal to support the economy of scale.
Air interface adaptation costs money. And time.
Implementation costs money. And time.
So does integration. And testing. And deployment.
Doing this alone (while everyone else is doing the same for themselves) is silly.
The barriers to adopting a common air interface must be lowered through considered, advance design that simultaneously addresses the needs of many, yet distinct communications applications.
One day we’ll just adopt rather than adapt.
The Third Era ?
2020
2010
2000
1990
Inmarsat-4Inmarsat-3Inmarsat-2 Inmarsat-6
2016
1993
2005
1996
No, not yet. But we’re close…True air interface convergence.
The Challenge of Time and Space
The Challenge of a Connected World
The Challenge of Relevance
The Challenge of Mass
The Challenge of Interference
The Challenge of Choice
The Challenge of Scale
Until then…
Smaller.Faster.Lighter.Cheaper.
