Copyright © 2011 Open Geospatial Consortium
107 FI and EXI are very easy to put in place or integrate to a SAX parser XML reader.
8 Perspective on real world use cases
8.1 Best compaction candidate for small files or “datalink” messages
8.1.1 Understanding onboard systems constraints and datalink limitations
8.1.1.1 ATC Datalink “en route”
If cabin communications are relatively open, datalink communications between DSP and cockpit are very structured and driven between 4 main actors: Boeing, Airbus, Arinc and
SITA. Buses between CMU datalink user and VDR radio is also very structured and does not evolve very often. Every time a new datalink media is proposed, 10 years run
between the first running mockup and a global installation in a majority of planes. That’s why, DataLink are never up-to-date compared to the kind of communications publicly
available LTE, wifi, high speed internet through satellite with a dish antenna,…
As Airframe manufacturers and DSP begin to install VDL-2 to replace POA DL, the throughput of VDL-2 is only 31.5 kbps compared to legacy 2.4kbps ACARS. Of course
in dense area multiple frequencies can be used up to 3 to increase the global throughput.
So it’s reasonable to think that in the next years, a bandwidth beneath 100kbps is the maximum reachable for VHL datalink or SatCom using omni-directional antennas. New
datalinks both VHF LDACS1,2 and SatCom IRIS are studied by SESAR, but they are still at very early stages and won’t offer MBs by plane throughput anyway.
As VHF bandwith is shared between all the plane of a region radius around 100NM, and a sender cannot use the radio channel too much time for a message regarding fairness to
other planes communications., the time when we will be able to send big volumes of data to a flying plane has not come yet.
8.1.1.2 AOC AAC datalink grounded
However, when the plane is grounded or flying not too fast and near the ground, some commercial techno can be used such as LTE, WiMax, or even Wifi. Some companies
already offer such services like ThalesGateSync or Teledyne.
Anyway theses usages as they may interest companies willing to synchronize their EFB, or update their IFE once grounded, present no much interest for D-NOTAM updates as
they are ground based, deployed only on some planes, on some airports, for only several companies.
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8.1.1.3 AOC datalink “en route”
