(ORDO NEWS) — Several international airlines have recently canceled flights to some US airports over concerns that the rollout of 5G mobile phone technology could interfere with some aircraft’s equipment.
Following warnings of a potential problem from aviation executives and the Federal Aviation Administration, telecommunications companies AT&T and Verizon have delayed the activation of some 5G masts at US airports.
But how can 5G interfere with airplanes? And can the problem be solved? Let’s get a look.
5G is currently being rolled out in several countries around the world and represents the fifth generation of mobile phone technology. It can increase the network speed by 100 times compared to 4G.
To provide high speeds with the widest possible coverage, AT&T and Verizon planned to create 5G internet using so-called C-band frequencies, a type of radio frequency (or radio wave) between 3.7 and 3.98 gigahertz (GHz).
These frequencies are close to those used by modern aircraft for measuring altitude. An important piece of aircraft equipment, called a radio altimeter, operates on C-band frequencies in the 4.2-4.4 GHz band.
Pilots rely on radio altimeters to land aircraft safely, especially in poor visibility conditions such as when an airport is surrounded by high mountains or in foggy conditions.
The concern is that due to the narrow gap between 5G and radio altimeter frequencies, radio waves from 5G towers near airports can cause interference. That is, people using 5G on their phones may inadvertently distort or damage the radio altimeter signal.
If this happens even for a few seconds, it may mean that the pilot is not receiving correct information during landing. It is for this reason that the US Federal Aviation Administration has expressed concern.
So what can be done?
Other countries deploying 5G are using C-band frequencies that overlap or are close to radio altimeter frequencies, with no reported problems. For example, in the UK, 5G operates at frequencies up to 4 GHz. The absence or few mountains around airports reduces the risk.
Some other countries are using their 5G at a frequency slightly further than that of aviation equipment. For example, in the European Union, 5G operates up to 3.8 GHz. This may be a good option for US airports.
A better option in the long run would be to use a much higher band for 5G, such as 24GHz to 47GHz. At these frequencies, the data rate is much higher, although the coverage area of each cell will be much smaller (so more towers will be needed).
There is also the option to reduce signal strength from towers around airports, which has been reportedly done in France and Canada. It’s not about changing the frequency – signal strength is measured in decibels, not GHz – but limiting signal strength can reduce the likelihood of interference with adjacent bands.
Another potential solution would be to adjust the frequency range of the radio altimeters. But this will take a long time and is likely to be resource intensive for the aviation industry.
While the risk of in-flight complications due to 5G interference can be very low, since we are talking about human safety, we must take any possible risks very seriously.
Sufian Yousef, Principal Lecturer, Director of the Telecommunications Engineering Research Group, Faculty of Science and Engineering, University of England.
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