Inflight connectivity: from Wi-Fi to 5G

In an increasingly connected world, the inside of an aircraft cabin remains limited when it comes to on-demand connectivity. Restricted to in-flight Wi-Fi, made worse by slow download speeds, patchy coverage and high expenses, in-flight connectivity is far removed from the seamless connections we have on ground. However, with the development of 5G technology and high-speed communication systems, the way we connect in-flight is set to transform.

Jean-Christophe Schiel, Senior Expert in Wireless Communications at Airbus Secure Communications, has spent over 15 years working on military telecommunications and public safety projects, including the adaptation of multiple civil technologies for the military sector using 4G and now 5G.

Hear from Jean-Christophe as he discusses how 5G is providing better inflight-service for the aviation industry. 

Inflight Wi-Fi – how does it work?

Whether travelling for business or pleasure, many rely on inflight Wi-Fi to work or to be entertained. Despite the high demands, inflight Wi-Fi relies on external connectivity of the aircraft. And this external connectivity has with limited capacity and high costs, diminishing the quality and accessibility for the end user.

Inflight Wi-Fi connectivity is provided by one of two methods: Air to Ground or Satellite.

Air to Ground
Working in a similar way to mobile phone connectivity, as airplanes travel, the onboard antenna connects to the nearest ground-based tower, acting as a hotspot for passengers to connect to the Internet. However, due to the limited spectrum and coverage, it only works when flying over, or close to land. Currently some ATG networks are deployed using 4G technology, mainly in the US, Europe (EAN) and Saudi Arabia.

Satellite
When travelling across the oceans, aircrafts must receive data through an onboard antenna connected to satellites in geostationary orbit, which passengers then connect to through an onboard router.

On average, aircraft are receiving a few Mbits per second and they share the resources from the same satellite. While sending of emails and web browsing is possible with inflight Wi-Fi, video streaming remains a desire, and with the increase in users, the bandwidth continues to become more congested. Also the high latency does not help.

The satellite has the main advantage of almost ubiquity for the conventional non polar aircraft’s routes, but with very high latency and low data rate compared to a good 5G ATG system.

Fortunately, inflight connectivity is set to improve with the incorporation of 5G NTN technology. NTN - Non terrestrial Networks - is the 3GPP 5G standardization work for 3D networks, so mainly above the ground. This includes satellites LEO / MEO / GEO and HAPS, balloons, aircrafts and helicopters. A first version of NTN is already standardized but having a commercial solution will happen only in a few years or maybe 6G.

Also we will get improvements with the existing and future LEO constellations – such as OneWeb, as latency with lower orbits is reduced and the link budget is allowing better throughput with the LEO power capabilities.

Both technologies are complementary for long-haul flights.

The future of 5G inflight connectivity 

5G will have a wider impact compared to 4G and before, as it englobes more areas and especially the “verticals”, the kind of users and use-cases that were not under consideration before – only the commercial service was. Additionally the technology offers also different faces, sort of all-in-one network for broadband communication, Internet of Things, connected objects and ultra-reliable and low latency uses-cases. Typically covering our factories with 5G will enable to make IoT sensors, video cameras, broadband connection for employees and Virtual Reality headsets work on a same network. Before several ones were needed for all these applications, so it is a sort a mini-revolution!

Similarly with the idea of non-terrestrial networks within the 5G standardization body to expand 5G to satellite and airborne networking, it is quite straightforward also to try to connect airplanes with 5G. 4G aviation networks are reliable but a quite high density base station network is needed and achievable data rates are of a few tens of Mbps. Going to 5G will broaden the spectrum access and thus the data rate. With a very good deployment, the gigabit barrier per aircraft could be achieved, but a few 100s of Mbps would be already a huge step forward. 5G shares indeed the same drawbacks as the 4G, as it requires a modem able to deal with high speed of the aircraft – well above the high-seed train specifications of the 5G Standard (500km/h).

Also a very good coverage of the aircraft routes is needed to provide a great quality of experience to the passengers. This good coverage is at the expense of the number of ground base stations – so deploying a European large network means then probably 1000s of base stations.

5G Air to Ground Project 

Air to Ground is a collaboration project between Airbus experts across Europe and the China Innovation Center (ACIC). Created with the aim to interconnect a civil airplane from the ground with 5G, it is set to provide passengers with inflight high-broadband connectivity and provide real-time sharing of flight and maintenance data to the ground.

Designed initially for A320 aircraft seating up to 300 passengers, Air to Ground is expected to provide between 1 and 2Mbit of data per person if all were to use the network simultaneously meaning high definition inflight video streaming would become a reality.

Using a mixture of ground antennas when flying over land and satellite connectivity when over water, the aircraft will receive upwards of 500Mbit of data through a dedicated 5G network link. The connection is possible due to the onboard antennas being designed to adapt to the change in altitude and transmission angle required. The onboard modem has also been adapted to work with the high-speed flight (up to 1200km/h) of the aircraft.