5G Risks and Challenges for Aviation

anil chopra, air power asia, 5G, Aviation Risk

5G in telecommunications, is the fifth generation technology standard for broadband cellular networks, which cellular phone companies began deploying worldwide in 2019, and is the successor to the current 4G networks. 5G networks are predicted to have more than 1.7 billion subscribers worldwide by 2025. Like its predecessors, 5G networks are cellular networks, in which the service area is divided into small geographical areas called cells. All 5G wireless devices in a cell are connected to the Internet and telephone network by radio waves through a local antenna in the cell. The main advantage of the new networks is that they will have greater bandwidth, giving higher download speeds, eventually up to 10 gigabits per second (Gbit/s). Due to the increased bandwidth, it is expected the networks will not exclusively serve cellphones, but also be used as general internet service providers for laptops and desktop computers, competing with existing ISPs such as cable internet, and also will make possible new applications in internet of things (IoT) and machine to machine areas. 4G cellphones are not able to use the new networks, which require 5G enabled wireless devices.

5G in Aviation Market Analysis, Insights and Forecast, 2019-2026. Image Source: prnewswire.com

In local urban communities there would be a 5G cell tower approximately every 500 feet along every street. As bad as these small cell towers might seem from the standpoint of constant exposure to radio frequency (RF) radiation in close proximity to the source, perhaps an even more alarming prospect will be the beaming of millimeter length microwaves at the earth from thousands of new communication satellites.

The increased speed is achieved partly by using higher-frequency radio waves than previous cellular networks. However, higher-frequency radio waves have a shorter useful physical range, requiring smaller geographic cells. For wide service, 5G networks operate on up to three frequency bands — low, medium, and high. A 5G network will be composed of networks of up to three different types of cells, each requiring specific antenna designs, each providing a different trade-off of download speed vs. distance and service area. 5G cellphones and wireless devices connect to the network through the highest speed antenna within range at their location.

Image Source: globalrecharge.guru

Low-band 5G uses a similar frequency range to 4G cellphones, 600-850 MHz, giving download speeds a little higher than 4G, at around 30-250 megabits per second (Mbit/s). Low-band cell towers have a range and coverage area similar to 4G towers. Mid-band 5G uses microwaves of 2.5-3.7 GHz, allowing speeds of 100-900 Mbit/s, with each cell tower providing service up to several kilometres in radius. This level of service is the most widely deployed, and should be available in most metropolitan areas in 2021. Some regions are not implementing low-band, making this the minimum service level. High-band 5G uses frequencies of 25–39 GHz, near the bottom of the millimetre wave band, although higher frequencies may be used in the future. It often achieves download speeds in the Gbit/s range, comparable to cable internet. However, millimetre waves (mmWave or mmW) have a more limited range, requiring many small cells. They have trouble passing through some types of materials such as walls and windows. Due to their higher cost, plans are to deploy these cells only in dense urban environments and areas where crowds of people congregate such as sports stadiums and convention centres. The above speeds are those achieved in actual tests in 2020, and speeds are expected to increase during rollout.

Application Areas

The three main application for the enhanced capabilities of 5G are Enhanced Mobile Broadband (eMBB), Ultra Reliable Low Latency Communications (URLLC), and Massive Machine Type Communications (mMTC). Only eMBB is deployed in 2020; URLLC and mMTC are several years away in most locations. The eMBB uses 5G as a progression from 4G LTE mobile broadband services, with faster connections, higher throughput, and more capacity. This will benefit areas of higher traffic. The URLLC refers to using the network for mission critical applications that require uninterrupted and robust data exchange. The mMTC would be used to connect to a large number of devices. 5G technology will connect some of the 50 billion connected IoT devices. Most will use the less expensive Wi-Fi. Drones, transmitting via 4G or 5G, will aid in disaster recovery efforts, providing real-time data for emergency responders. Most cars will have a 4G or 5G cellular connection for many services. Autonomous cars do not require 5G, as they have to be able to operate where they do not have a network connection. While remote surgeries have been performed over 5G, most remote surgery will be performed in facilities with a fibre connection, usually faster and more reliable than any wireless connection.

5G Wireless Internet Service Satellite Signal Imgae Source: strangesounds.org

5G Impact Aviation – Weather Satellite Signal

The spectrum used by various 5G proposals will be near that of passive remote sensing such as by weather and Earth observation satellites, particularly for water vapour monitoring. Electro-magnetic interference will occur and will potentially be significant without effective controls. An increase in interference already occurred with some other prior proximate band usages. Interference to satellite operations impairs numerical weather prediction performance with substantially deleterious economic and public safety impacts in areas such as commercial aviation. The issues are under consideration with NOAA, NASA, and U.S. DoD, and warning of harmful impacts to national security. 5G out-of-band emissions could produce a 30% reduction in weather forecast accuracy and that the resulting degradation in weather forecast model performance. It could mean failure to predict weather phenomenon including and track storms.

At the 2019 quadrennial World Radio Communication Conference (WRC), atmospheric scientists advocated for a strong buffer of −55 dBW, European regulators agreed on a recommendation of −42 dBW, and US regulators (the FCC) recommended a restriction of −20 dBW, which would permit signals 150 times stronger than the European proposal. The ITU decided on an intermediate −33 dBW until September 1, 2027 and after that a standard of −39 dBW. This is closer to the European recommendation but even the delayed higher standard is much weaker than that pleaded for by atmospheric scientists, triggering warnings from the World Meteorological Organization (WMO) that the ITU standard, at 10 times less stringent than its recommendation, brings the “potential to significantly degrade the accuracy of data collected”. A representative of the American Meteorological Society (AMS) also warned of interference, and the European Centre for Medium-Range Weather Forecasts (ECMWF), sternly warned, saying that society risks “history repeating itself” by ignoring atmospheric scientists’ warnings. In December 2019, a bipartisan request was sent from the US House Science Committee to the Government Accountability Office (GAO) to investigate why there is such a discrepancy between recommendations of US civilian and military science agencies and the regulator, the FCC.

5G to be ‘revolutionary’ – yet security concerns remain high. Image Source: itbrief.co.nz

Security Concerns

Concerns over Chinese involvement in 5G wireless networks and criticism of Huawei and espionage and security concerns are in public domain for some time. A report published by the European Commission and European Agency for Cyber-security details the security issues surrounding 5G. The report warns against using a single supplier for a carrier’s 5G infrastructure, especially those based outside the European Union. Interestingly, Nokia and Ericsson are the only European manufacturers of 5G equipment.

On October 18, 2018, a team of researchers from ETH Zurich, the University of Lorraine and the University of Dundee released a paper entitled, “A Formal Analysis of 5G Authentication”. It alerted that 5G technology could open ground for a new era of security threats. The paper described the technology as “immature and insufficiently tested,” and one that “enables the movement and access of vastly higher quantities of data, and thus broadens attack surfaces”. Simultaneously, network security companies such as Fortinet, Arbor Networks, A10 Networks, and Voxility advised on personalised and mixed security deployments against massive DDoS attacks foreseen after 5G deployment.

IoT Analytics estimated an increase in the number of IoT devices, enabled by 5G technology, from 7 billion in 2018 to 21.5 billion by 2025. This can raise the attack surface for these devices to a substantial scale, and the capacity for DDoS attacks, crypto-jacking, and other cyber-attacks could boost proportionally.

Due to fears of potential espionage of users of Chinese equipment vendors, several countries including the United States, Australia and the United Kingdom as of early 2019 had taken actions to restrict or eliminate the use of Chinese equipment in their respective 5G networks. Chinese vendors and the Chinese government have denied claims of espionage. On 7 October 2020, the U.K. Parliament’s Defence Committee released a report claiming that there was clear evidence of collusion between Huawei and Chinese state and the Chinese Communist Party. The U.K. Parliament’s Defence Committee said that the government should consider removal of all Huawei equipment from its 5G networks earlier than planned.

HealthRisks not Confirmed, But protests are on. A protestor poster of proposed radiation damage. Art by Shelley Masters. (Sammy Shaktah/KTVL)

Health Issues

The scientific consensus is that 5G technology is safe. Misunderstanding of 5G technology has given rise to conspiracy theories claiming it has an adverse effect on human health. There is a level of disinformation in the media and online regarding the potential health effects of 5G technology. Some have linked 5G to harmful health effects which “lack scientific support”, such as “brain cancer, infertility, autism, heart tumours, and Alzheimer’s disease”. In 2019, 180 scientists from 36 countries wrote to the European Union requesting a pause on 5G rollout, because of their concerns about possible health risks. In April 2019, the city of Brussels in Belgium blocked a 5G trial because of radiation rules. In Geneva, Switzerland, a planned upgrade to 5G was stopped for the same reason. The Swiss Telecommunications Association (ASUT) has said that studies have been unable to show that 5G frequencies have any health impact. The US FDA is quoted saying that it “continues to believe that the current safety limits for cellphone radiofrequency energy exposure remain acceptable for protecting the public health. The World Health Organization published a mythbuster infographic to combat the conspiracy theories about COVID-19 and 5G.

5G Operationalisation

On April 3, 2019, South Korea operationalised 5G. Same day Verizon launched its 5G services in the United States. In June 2019, the Philippines became the first country in Southeast Asia to roll out a 5G network. AT&T brought 5G service to consumers and businesses in December 2019 ahead of plans to offer 5G throughout the United States in 2020. In January 2020 Belarus launched test zones, with Huawei and Cisco equipment. Later in February, Huawei became the equipment supplier. In May 2020 A1, in partnership with ZTE, launched the first 5G SA network in Belarus.

V2V communications mandate. Image Source: enterpriseiotinsights.com

5G Automobiles

5G Automotive Association have been promoting the C-V2X communication technology that will first be deployed in 4G. It provides for communication between vehicles and infrastructures.

5G Connectivity at Airports and With Aircraft

         While major civil airports are gearing up for 5G connectivity for their operations and logistics chains, it would mean installing more antennae on large airports. By deploying a private wireless network over 5G the airport can operate a cable-free, autonomous network environment with its devices and third-party clients operating on a separate frequency from the public mobile networks. This could have its own dynamics of EM interference. The same is being studied. Companies are looking at designing and building 5G base stations (ground towers) specifically for 5G air-to ground (ATG) networking. Connecting and maintaining a consistent connection with an aircraft traveling at 500-plus miles per hour at altitudes of 35,000-plus feet is incredibly challenging. Managing handovers from tower to tower with no drops and managing Doppler Effect are difficult on an aircraft moving at such high speeds and distances.

How 5G-powered robots are helping Chinesew airports fight coronavirus. Image Source: smartcitiesworld.net

Meanwhile, some airports and aircraft maintenance providers are looking at using 5G network to enable collaborative virtual engine inspections between engineers at workshops and customers in different locations. Lufthansa Technik describes the 5G-enabled concept as its “Virtual Table Inspection” project, where airline maintenance engineers will not have to travel to their facility in Hamburg, instead they use the network for high-definition video trainings.

New 5G Plan Could Jam Radar Altimeters. Image Source: avweb.com

Direct Aviation Concerns

The US Federal Communications Commission, early this December began auctioning a portion of C-band electromagnetic spectrum. But, in the weeks leading up to the auction, more than a dozen commercial aviation groups warned the sale could, as one study put it, lead to “catastrophic failures” with the potential for “multiple fatalities.” At the core of the concerns are radar altimeters, a critical piece of aviation technology used by military, commercial and civil aircraft of all types, including helicopters and unmanned aerial systems, to measure the distance between an aircraft and the ground. Worry is of interference that may cause inaccurate readings on altimeters or cause their failure outright, and leaving pilots unaware of how far they are from the ground and potentially leading to crashes. The Pentagon has yet to determine the effect on military aircraft and has not established any formal position on the spectrum sale. Major radio altimeter producers like Honeywell Industries, have been asked to study and comment. If the concerns are proved right, it could mean spending millions of dollars and thousands of man hours to redesign, procure and install new radar altimeters across the military’s fleet of airborne systems.

Says Aerospace Industries Association. Image Source: ia-aerospace.org

There is a concern that the frequency band that 5G will use is adjacent to a band used by the Global Positioning System (GPS) and poses a strong risk of interference with GPS signals, including the potential interruption of GPS signals at low altitudes. Cockpit systems such as Terrain Avoidance and Warning Systems (TAWS) use GPS signals to accurately display position reports to pilots. Even though the satcom system is mainly used in oceanic operations, the pilot needs to make sure it is working before the aircraft departs. But if you have a Ligado station near the airport, it may cause interference. If you cannot lock on your satcom, you cannot verify that the system is operational so you may not be able to depart.

As the C-Band spectrum in the 3.7–3.98 GHz frequency, starts getting auctioned, Satellite operators using the C-Band have agreed to repack their operations out of the band’s lower 300 megahertz (3.7-4.0 GHz) into the upper 200 megahertz (4.0-4.2 GHz), in two stages. They expect to complete the move in December 2023. Currently, the 3.7–3.98 GHz frequency portion of the C-Band is relatively quiet, occupied predominantly by low-powered satellites. For decades, this made the neighbouring 4.2-4.4 GHz frequency a perfect place for the operation of radar altimeters, which are also called radio altimeters. This may not stay quiet for long. Once 5G telecommunications are introduced in the 3.7-3.98 portion of the band, there is a “major risk” that those systems will create “harmful interference” to radar altimeters. Radio altimeters are critical during landings, once an aircraft moves below 2,500 feet from the ground. At that point, no other instruments provide an accurate measurement of a plane’s distance from the ground. The altimeters operate with more than 200 megahertz of separation from the C-band spectrum being auctioned brings risk.

5G likely to mess with weather forecasts, but spectrum auction goes ahead. Image source: arstechnica.com

 Many missions in bad weather or at night that are flown at low level such as troop insertion by a C-130 special operations aircraft or missions by helicopters at low level will be affected. It also effect autonomous operations of UAVs landing on a ship deck or even on a runway. Part of the problem is going to be trying to know whether you’re getting interference or not. Replacing or modifying altimeters will take time and research funding. Till then will it mean restricting pilots of certain aircraft from landing in bad weather or ensuring that pilots of fighter aircraft take off with enough fuel so that they can divert to another airport if their radar altimeter no longer works. The impact is going to be even greater on the commercial airlines than it was on the military.

Possible Solutions

Despite aerospace concerns, NASA is also interested in the potential data sharing and other use cases 5G could enable in low altitude airspace. The agency’s Aeronautics Research Mission Directorate is sponsoring multiple activities to address communications, navigations systems (CNS) needs in what it describes as the Advanced Air Mobility (AAM) market. NASA intends to bring together companies involved in emerging air transportation systems to help inform requirements and best practices for UAM operations, including Federal Aviation Administration certification requirements for electric and hybrid-electric aircraft. NASA is exploring CNS architectures and technologies for AAM that will satisfy safety-critical service requirements for high-volume, high-density operations in and around urban airspace.

FSS and 5G NR uplink sharing scenario in the 28 GHz band. Image Source: esearchgate.net

The satellite operators who currently operate within 3.7-3.98 GHz will receive some proceeds of the sale, allowing them to move to another portion of the spectrum, no funding is set to be given to the civil, commercial and government entities that rely on radar altimeters for safe aerospace operations. As a result, military will have to replace “many or most” of the radar altimeters currently on-board its airplanes, helicopters and drones. And because radar altimeters have all been developed to operate on the same portion of the spectrum, there is no off-the-shelf replacement already on the market for which interference wouldn’t be a concern. If aviation industry has to replace altimeters across its fleet, an estimated price tag of several billion dollars could be on the lower side. That price tag could well jump for the military side, given the complexity of work on military systems. It is easier to swap out a part on a commercial plane than a stealth-coated fighter and the infamous prices of defence procurement.

When you look at any operation, whether its unmanned aerial systems (UAS), or future urban air mobility, ICAO and other national agencies would need to ascertain the safety for each type of mission.

Militaries would need to invest hundreds of millions of dollars into the engineering work necessary to develop new altimeters, procuring those systems, testing and recertifying each platform for normal operations, and finally, installing the new hardware on potentially hundreds or thousands of aircraft across the military’s inventory. It will take many years, if not decades. Protecting the frequency bands used by radar altimeters could be a good solution. Just the US space and aviation industry may have to spend more than the US$ 15 billion that the spectrum auction is going to bring to the US government. The telecom Czars are convinced that when it’s all said and done, the aerospace and defence industries will likely be the number one user of 5G technologies. India has taken a wait and watch approach as the 5G unfold is much faster in USA, Europe and China.

Header Image Source: datascience.aero

Published by Anil Chopra

I am the founder of Air Power Asia and a retired Air Marshal from the Indian Air Force.

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