Some of you may remember that couple of years back Ericsson showed an example of using LTE in extreme conditions. The video below shows that LTE can work in these scenarios.
Now there are various acronyms being used for these type of communications but the one most commonly used is Direct-Air-to-Ground Communications (DA2GC), Air-to-Ground (A2G) and Ground-to-Air (G2A).
While for short distance communications, LTE or any cellular technology (see my post on Flying Small Cells) may be a good option, a complete solution including communication over sea would require satellite connectivity as well. As I have mentioned in a blog post before, 75Mbps connectivity would soon be possible with satellites.
For those interested in working of the Air-Ground-Air communications, would find the presentation below useful. A much detailed ECC CEPT report from last year is available here.
The next challenge is to explore whether LTE can be used for Mission Critical Air Ground Air communications. 3GPP TSG RAN recently conducted study on the feasibility and the conclusions are as follows:
There is a common understanding from companies interested in
the topic that:
- Air-to-Ground communications can be
provided using the LTE standards (rel-8 and beyond depending on the
targeted scenarios).
- 3GPP UE RF requirements might need to be
adapted
- It may be possible to enhance the
performance of the communications with some standards changes, but these
are in most cases expected to be non-fundamental optimizations
- Engineering and implementation adaptations
are required depending on the deployment scenario. In particular, the ECC
report [1] comments that from implementation point of view synchronization
algorithms are to be modified compared to terrestrial mobile radio usage
in order to cope with high Doppler frequency shift of the targeted
scenario. In addition, some network management adaptations might be needed.
From engineering perspective the Ground base station antenna adjustment
has to be matched to cover indicated aircraft heights above ground up to 12
km by antenna up-tilt. It is also expected that the inter-site distances
would be dominated by the altitudes to be supported [5].
- A2G technology using legacy LTE has been
studied and successfully trialed covering different kinds of services: Surfing,
downloading, e-mail transmission, use of Skype video, audio applications and
Video conferencing. Related results can be found in several documents from
ECC and from companies [1], [2], [3]. The trials in [1] and [2] assumed in
general a dedicated spectrum, and the fact that the communications in the
aircraft cabin are using WIFI or GSMOBA standards, while LTE is used for
the Broadband Direct-Air-to-Ground connection between the Aircraft station
and the Ground base station.
- It is understood that it is possible to
operate A2G communications over spectrum that is shared with ground
communications. However, due to interference it is expected that the
ground communications would suffer from capacity losses depending on the
deployment scenario. Therefore, it is recommended to operate A2G
communication over a dedicated spectrum.
- It can be noted that ETSI studies concluded
that Spectrum above 6 GHz is
not appropriate for such applications [4].
- LTE already provides
solutions to allow seamless mobility in between cells. Cells can be
intended for terrestrial UEs and cells intended for A2G UEs which might
operate in different frequencies.
- Cell range in LTE is
limited by the maximum timing advance (around 100km). Larger ranges could
be made possible by means of implementation adaptations.
