20th Airport Technical Report, November 22th 2019

Airport MCA Radio Systems in Times of Disaster and Future Prospects
Yoshikazu Takahashi
President and Chief Executive Officer
NIPPON AIRPORT RADIO SERVICES CO., LTD.

2.2.
Airport MCA radio in times of disaster
When the Great East Japan Earthquake occurred on
March 11, 2011, PSTN and mobile phone calls weremade impossible or difficult in a vast region ofeastern Japan, including Narita International Airport
because of failures of communication equipment andcongestion of phone traffic. By contrast, the airport
MCA radio systems remained in operation without
being affected by these circumstances.
Number ofcommunications

Call waiting rate

Call waiting rate

Number of busy-hourcommunications(550 communications/10
minutes)

10 minutes

Hour

Figure 1 Number of calls and call waiting rate at the time of theGreat East Japan Earthquake

Number of calls

2.
Airport MCA Radio Systems
2.1.
Background
Before 1990, airport radio communication systems
were deployed by individual companies andorganizations and had problems such as interference
and low radio wave use efficiency. In 1985, efforts
began to develop and standardize radio systems
utilizing multiple radio channels and, in 1990, analog
MCA systems were introduced to the airports in
Narita, Haneda, Naha, and Kansai. Starting in 2004,
they were upgraded to digital systems one after
another. Over the next 10-plus years, these systems
served as the radio communication infrastructure atfive airports (the above-mentioned four airports andChubu Airport),
supportingthebusiness
communication of domestic and foreign airlines,
airport-related companies, affiliated organizations,etc.
In the meantime, a new public safety radio system,TETRA, was increasingly accepted as aninternational standard and began to be deployed in
airports and other facilities mainly in Europe. In

Japan, discussions also took place to consider
deploying TETRA as the successor to the airport
MCA radio system. Since Narita International Airport
introduced the new system for the first time in 2016,
Naha, Haneda, and Chubu Airports have replaced
their systems with TETRA.

Number of calls

1.
Introduction
Airport MCA, “Multi Channel Access”, radio
system is a communication system for groundservices at airport. It is provided by dedicated basestation equipment and frequencies. Its features
include high radio wave use efficiency, flexible groupcall settings, and reliability in times of disaster. When
the Great East Japan Earthquake hit Narita
International Airport in 2011 and a typhoon damaged
Kansai International Airport in 2018, the MCA radio
systems in these airports remained in operation,
contributing to disaster response efforts in therespective airports.
Currently, the use of public safety radio systems
known as TETRA is growing globally. Airport MCA
radio systems in Japan are also being replaced withTETRA.
This report outlines the airport MCA radio systemand describes its features at the times of disaster aswell as the status of deployment of TETRA up to now.
It also discusses the latest trends and the issues andfuture prospects of airport radio systems in disastersituations.

Hour

Figure 2 Number of calls made before, on, and after the day ofthe earthquake120th Airport Technical Report, November 22th 2019

Figure 1 shows the number of calls and call waiting
rate for the MCA system at Narita International
Airport on March 11, 2011. During the 10-minuteperiod immediately after the earthquake occurred at
14:46, more than 750 calls were made, which was 1.4
times as many as the regular busy hour. This raised
the call waiting rate (the ratio of calls waiting to beconnected after the pressing of PTT) to around 10%
temporarily, although it dropped to the normal levelsoon. When compared to the number of calls madebefore and after the day of the earthquake in Figure 2,
the number of calls decreased immediately after theearthquake of March 11 as the airport was closed. On
the following days, however, the number returned to
the normal level as flight services resumed. At thetime, the MCA system of Narita International Airport
served approx. 3,500 wireless terminals over a totalof 97 communication channels. It was operated
efficiently to handle high volumes of traffic during
the disaster.
On September 9, 2019, the Tokyo metropolitan area,
primarily Chiba Prefecture, was struck by Typhoon
No. 15, leaving as many as 13,000 people stranded at
Narita International Airport. At the time, mobile
phone users in Chiba Prefecture had difficulty ingetting connections, while the airport MCA radio
system continued operation without being affected.
Sept.8

Sept.9When Typhoon No. 21 passed the Kinki region ofJapan in September 2018, a tanker collided with theconnecting bridge of Kansai International Airport,
damaging the communication cable between the
airport and the mainland and thus shutting down thelines connecting mobile operators' base stations to thecore networks. This accident made the mobile phoneservice unavailable inside Kansai Airport while, incontrast, the MCA radio system of the airport
remained in operation without being affected.
The airport MCA radio system utilizes a dedicatedfrequency. It is designed based on the radio wave
environment of the airports and the style of work. It
is also operated in a manner best suited to airport
facilities. These ensure high reliability andavailability, making the system vital communication
infrastructure to support communication in case of adisaster or other unexpected event.
3.
Deployment of TETRA in Airports
3.1.
About TETRATETRA is the name of the digital mobile
communication system (1) for public safety that the
ETSI (European Telecommunications Standards
Institute) standardized in 1994. In 2014, the ARIB
(Association of Radio Industries and Businesses)
developed a standard for Japanese airports as"Airport Digital Mobile Telecommunication System
TYPE 2" STD-T114(2).

Sept. 10

Number of communications
Hour

Figure 3 Number of calls made via the MCA system of Narita
International Airport before, on, and after September 9

Figure 4 Airports TETRA is deployed (as of July 2018;according to our own research)

Figure 3 shows changes in MCA traffic at Narita
International Airport before, on, and after September
9. Then, the staff in the airport needed to deal withthe stranded passengers, the number of calls
increased during the evening hours from the eveningof the 9th until flight services resumed on the 10th.
However, calls were not concentrated to any specifictime zone, and the quality of communication was notaffected by any problems.

TETRA has been deployed mainly in Europe andAsia as common radio communication infrastructure
primarily for mission-critical fields such as police,
fire departments, transportation, military, and plants.
It is used in more than 80 airports around the world(Figure 4). In Japan, roughly 20 local governments,
in addition to airports, have adopted TETRA for theirdisaster prevention wireless system.
2

20th Airport Technical Report, November 22th 2019

3.2.
Migration to TETRA
While the deterioration of old MCA system became
an issue, discussions on the next system began inearnest in 2013. TETRA as well as the U.S. standard
APCO-P25 were compared and considered. As aresult, TETRA was adopted as it featured highscalability and had a proven track record in European
nations similar to Japan in size. First, Narita
International Airport upgraded its system to TETRA.

the relocation of the control tower, etc. In April 2019,
Haneda Airport also migrated to TETRA.
In 2019, Chubu Centrair International Airport also
completed its migration to TETRA. The airport
officials had been considering the next system as thetime drew near to upgrade the previous MCA systeminstalled when the airport was opened. In considering
the next system, they made disaster control a major
priority, with the typhoon damage suffered by KansaiInternational Airport in mind. They chose TETRA
from the perspective of system reliability. Design,
construction, and relevant procedures began in June
2018, and equipment installation was complete in
April 2019. After a three-month period of the parallel
operation of the old and new systems, the changeoverfrom the old system was complete on July 1 of thesame year. In September, relay amplifiers were
installed to ensure sufficient radio field strength in the
newly built second terminal and the exhibit hall
"FLIGHT OF DREAMS."

Figure 5 TETRA radio base station at Narita International
Airport

3.3.
System configuration and the reliability
Figure 6 shows the current system configuration of
TETRA deployed in the airports.
Base stations are installed in Narita, Naha, Chubu,
and Haneda, with those of Naha and Chubu
connected to the controller in Narita via dedicatedlines.
While each airport provides the necessary area
coverage through the use of base stations andantennas, a radius of approx. 5 kilometers is actually
covered mainly with outdoor antennas, making it
possible to make calls even in related facilities aroundthe airport.
Figure 7 shows the results of radio wave
measurements conducted in and around Chubu
Centrair International Airport. The system not only
covers the entire island on which the airport is locatedbut also provides sufficient radio signal strength toDuring the system migration at Narita International
Airport, the new system was assigned the same
frequency band as the existing system, 400 MHz, andtwo base stations were set up. The airport operated
the old and new systems in parallel temporarily, thus
avoiding the suspension of the radio service andgiving users time to get accustomed to the newterminals. The migration was complete in October
2016 (Figure 5).
After that, Naha Airport replaced its MCA systemwith TETRA in July 2017 and added antennas andother equipment when it expanded terminal facilities
in 2019. The airport is now planning to scale up thesystem in response to an increase in the number offlights, the start of operation of the second runway,

Figure 6 TETRA system configuration3

20th Airport Technical Report, November 22th 2019

communicate even in Tokoname City on the opposite
shore except in weak signal areas (black spots) suchas behind buildings. This suggests that the system cancontribute to the sharing of information between thelocal government and the airport in future disastersituations.

communicate.
At Narita International Airport, the electric power
to the base stations is supplied from the power supply
in the NTT Building and, at the other airports,
uninterruptible power supply (UPS) systems in therespective airport buildings are used. Since a UPS is
installed individually at every location where a basestation resides, the base station can continue its
operation for as many as two hours even if the power
supply in the building fails. Furthermore, adjusting
the number of radio waves according to traffic
enables the base station operation to continue for up
to five hours.

Figure 7 Radio wave signal strength and around Chubu
Centrair International Airport

Moreover, efforts are underway to improve theradio wave environment to prevent dead zones fromforming in airport buildings and other locations. In
Narita, about 50 amplifiers and about 100 indoor
antennas have been installed (Figure 8) and leaky
coaxial cables are used in some tunnels tocomplement the radio field strength. Also, antenna
facilities are added as needed to deal with dead zones
that form as buildings are expanded and renovated.

Figure 9 Mobile base station of TETRA system

In addition, a mobile base station is deployed in
anticipation of a risk that both the commercial power
and the UPS system in the building may become
unavailable for an extended period of time (Figure 9).
When operated in or near the airport, this mobile basestation provides seven channels on two radio waves
for emergency use.
The provided wireless terminals for TETRA arerobust and waterproof and capable of noise
suppression. They can also communicate directlywith one another, bypassing the base station.

Figure 8 Indoor amplifier and antenna

One base station of TETRA has multiple
transmitting and receiving parts, which are all maderedundant along with the control part. The receiving
antenna features a triple-diversity for enhanced
receiving sensitivity. Four channels are supported perradio wave and, excluding control channels, a total of
89 communication channels on 23 radio waves are
currently provided in Narita. Highly reliable
dedicated lines are used to connect the base stations.
Even if the base stations are isolated, their radio relay
function is maintained, thus allowing wirelessterminals inside the airport to continue to

4.
Trends of Airport Radio Systems
Narrowband business radio systems, including
TETRA, have proven highly reliable in lifethreatening emergencies. Diverse wireless terminals
are also available for use in specific usage scenes.
Therefore, these systems are being increasingly
deployed in mission-critical fields. For example,
Guarulhos International Airport of São Paulo, Brazil,
was plagued by interference and information leaks
because airport-related companies choose radio
systems independently, and it also had concerns about
information sharing in case of a disaster. The airport4

20th Airport Technical Report, November 22th 2019

officials solved all these problems by deploying
TETRA as a common radio system for the entire
airport (3).
On the other hand, advances in mobile broadband
technology have prompted 3GPP and otherorganizations to discuss ways to apply its
convenience to the field of public safety, andstandardization efforts are underway.
In fact, PS-LTE (Public Safety LTE) systems towhich dedicated frequencies are assigned are coming
into wider use as common radio communication
infrastructure for police, fire department, and otheremergency organizations in the U.S., the U.K., andSouth Korea (4). Discussions are ongoing in Japan aswell on the integration of public safety radio systems
using PS-LTE (5).

There are two types of users of radio wave in
airports (one used by humans is assumed here): 1)
general visitors who come to the airport for such
purposes as to go on travel or send off passengers and2) airport workers. General visitors mostly use public
networks provided by telecom carriers via mobile
phones, smartphones, or other devices. While thelater type of users - airport workers - mainly rely on
MCA and other business radio systems. In recent
years, even airport workers, they have come to use
public network-based services including Push to talkon cellular, “PoC”, smartphones, and tablets.
When a disaster hits an airport, general visitors
simultaneously use their mobile phones and otherdevices to check the safety of their family members
or flight and other transportation information. This
causes temporal and spatial concentration of traffic,
resulting in congestion degrading the quality ofcommunication. Failures of telecom carriers'
equipment also have a direct impact to them. In suchcircumstances, PoC, smartphones, and other devices
used for business compete against general visitors forlimited telecommunication resources. In fact, it
became difficult to get PoC connections at the
typhoon-damaged Kansai and Narita Airports and theearthquake-hit Shinchitose Airport.
By contrast, business radio systems that use
dedicated equipment and frequencies, such as airport
MCA radio systems, allow reliability measures to betaken as appropriate for the purpose of use. Even
during a disaster, these systems can continue tooperate unless their equipment, power supply, andother hardware components are affected. On top of
that, the use of the system does not impact thecommunication of general visitors.

Figure 10 Private LTE base station in Charles de Gaulle
Airport of ParisAt the airports in Paris, Vienna, Helsinki, and other
European cities, LTE-based demo experiments ofvideo communication are being conducted using
vehicle-mounted cameras and tablets (Figure 10). In
each of these cases, reliability and security are
ensured by a private LTE system, instead of the public
network, and such a system can be expected to be
useful in grasping damaged status and sharing theinformation via video in a disaster situation. Atinternational conferences on critical radio
communication, discussions are held about theinterworking technology that takes advantage of thefeatures of both the stable narrowband and the new
broadband communication (6) and the application of
5G technology to critical communication (7) among
other topics.
5.
5.1.

5.2.
Requirements for airport radio systems
The functions that an airport is required to fulfill ina time of disaster such as an earthquake or typhoon
include providing information to people in airport,
guiding them to safety, and achieving rapid recovery
to serve as a base for rescue, transportation of goods,etc.(8) In order to meet these needs, the airport radio
system in particular must satisfy the following
requirements.
(a) To ensure reliable communication and sharing
of information related to rescue and recovery
among airport officials, the system must not beaffected by the failure or congestion of the
public network.
(b) Even if no channels are available due to heavy
traffic, priority interrupts and simultaneous
broadcasts must be possible in an emergency.

Challenges for Disaster Situations
Issues associated with the style of use
5

20th Airport Technical Report, November 22th 2019(c) The system must be installed in a secure,earthquake-resistant,andflood-proof
environment with an uninterruptible power
supply system.
(d) An integrated radio system must be shared toenable communication and information sharing
among different companies and organizations
operating in the airport in the event of a disaster.
(e) In case of a large-scale disaster, the affected
airport and nearby airports serve as rescue bases
and work together in many ways (9). Therefore,
the system must be expandable to a networkthat enables inter-airport communication in adisaster situation.

systems, enhance their convenience through the useof private LTE, 5G, and other technologies, andpropose ways to operate these systems in assumed
disaster situations. Currently, different companies
and organizations use different business radio
systems at most airports. We are going to work ontechnology for connecting different systems as welland build a nationwide inter-airport network. Figure
11 shows the concept of this network.
6.
Conclusion
Airport radio systems are vital communication
infrastructure used not only for daily work but also toensure the safety of passengers and workers in theevent of a disaster. We will continue our ongoing
efforts to maintain the communication environmentthat enables reliable communication even in times ofdisaster and ensure its stable operation. By building
an inter-airport network for the future and applying
new technologies such as LTE and 5G, we hope tocontribute to further improving the disasterprevention capabilities of Japanese airports.

TETRA deployed (as of Oct. 2019)
Examples of connected airports (top10 airports in terms of the number ofpassengers)

References(1) ETSI ETR 086-1 ed.1, “Trans European Trunked Radio(TETRA) systems; Technical requirements specification”
Jan.1994.
(2) ARIB STD-T114 1.0, “AIRPORT DIGITAL MOBILE
TELECOMMUNICATION SYSTEMTYPE 2” Oct. 2014.
(Japanese)(3) Gilson Pozzati, “Benefits of migrating from a multitechnology environment to TETRA to cover all airport
operations, TCCA Critical Communication World 2019, Jul.
2019.
(4) Hong, young Sam, “Korea Public Safety Mobile Broadband
Project Update, TCCA Critical Communication World 2019,
Jul. 2019.
(5) Ministry of Internal Affairs and Communications,“Roundtable report on effective use of radio wave for growthstrategy”, Aug. 2018. (Japanese)(6) Eric Davalo, “How TETRA can work together with the latest
technologies”, TCCA Critical Communication World 2019,
Jul. 2019.
(7) P.Agard, “5G for Public Safety”, TCCA CriticalCommunication World 2019, Jul. 2019.
(8) Ministry of Land, Infrastructure, Transport and Tourism ”
Prepare for an era of disasters!! -Transformation to"Comprehensive disaster management" at airports-” Apr.
2019. (Japanese)(9) Tomoyuki Todoroki, Yuichi Indou , "Disaster and Airports”,
Seizando-shoten Publishing, Feb. 2018. (Japanese)

Figure 11 Concept of the inter-airport network

5.3.
Future actions
The airports that already have TETRA in operation
satisfy the requirements of (a) to (c) above from thefunctional perspective. As for the integration andsharing of airport radio systems by each airport (d)and how to operate the priority interrupt and otherfunctions across multiple organizations (b), they meetthe requirements to different degrees.
With regard to the inter-airport communication
requirement of (e), three airports can currently
communicate with one another via dedicated linesthat control the TETRA base stations. This interairport network will expand as more airports deploy
TETRA in the future. Also, communication between
TETRA and smartphones is made possible, albeit in
a complementary fashion, by leveraging the function
to communicate with the public network.
Our next steps will be to increase the use of TETRA
6