NTT Technical Review
June 2013 Vol. 11 No. 6
Feature Articles:
NTT Tsukuba Forum 2012 Workshop Lectures
Latest Topics in Optical Fiber Technology Research
R&D Trends in Communications Infrastructure
to Achieve Safe and Secure Access Networks

Regular Articles
A Comparison of Approaches to Incident Response
in Japan and the United States and an Introduction to
the International Standard ISO 22320

Global Standardization Activities
Recent Trends in Standardization ofJapanese Character Codes

Practical Field Information about
Telecommunication Technologies
A Study of a Noise Measurement Method for
Efficient and Smooth Troubleshooting

External Awards

Feature Articles: NTT Tsukuba Forum 2012 Workshop Lectures

Latest Topics in Optical Fiber
Technology Research
Yuji Azuma
Abstract

This article introduces some of the latest research topics related to new
optical fiber technologies. These technologies enable functional and efficient operation and maintenance of networks while maintaining high reliability, and will support future high-speed, high-capacity networks. The
Feature Articles in this month’s issue are based on lectures given at the
NTT Tsukuba Forum 2012 workshop held on October 19, 2012.

1. Forty years of optical fiber
technology research
It has been 40 years since the NTT Research andDevelopment Center was opened in 1972 in Tsukuba.
The research and development of optical fiber technology also has a history of roughly 40 years. The
current optical broadband service infrastructure,
which connects 17 million customers, is the result ofdeveloping technologies such as single-mode fiber,
optical cables, optical interconnects, and operationand maintenance systems. Initially, optical fiber
equipment was intended to create an optical fiber
network that was as easy to handle as wired networks.
However, to obtain high speed and a wide bandwidth,
sophisticated skill or knowledge was often needed tobuild, maintain, and operate the equipment, and,depending on the amount of information being transmitted, the additional care resulted in time-consuming work. The situation was gradually improved
through technical innovations, but several issues
remained. By resolving these issues and achievingease of use comparable to or better than that of metal
cable, we will be able to provide services of even better quality and at lower cost compared with the efficiency benchmark of working with wire.
2. Rapid fault handling
Optical access equipment extending outward from
communications buildings is designed to be highly

reliable and to withstand harsh environments. However, in extremely rare cases, faults can occur thatinterrupt service. To repair such faults and quickly
restore service, the location and cause of the fault
must be narrowed down as much as possible before
sending maintenance staff to the site. To achieve this,
we are working on three new approaches that willallow us to categorize such faults remotely (Fig. 1).
2.1 A ccurate measurement of remote fault
pointsThe optical time domain reflectometry (OTDR)
technique currently used in the field to measure thedistances to fault points is not highly accurate, so it istherefore difficult to determine the precise locationand cause of a fault. The phase-noise-compensatedoptical frequency domain reflectometry (PNCOFDR) technique that we are researching overcomes
these problems. In addition to locating faults, we canalso detect tiny identification (ID) patterns embedded
in remote connectors, creating the potential for
entirely new facility operation scenarios.
2.2 M
 easurement to distinguish fault points
below a splitter
In passive optical networks (PONs), optical splitters are placed at locations close to the customers toincrease the efficiency of equipment sharing. However, if a fault occurs between a splitter and the customer’s residence, the location of the fault cannot be
determined correctly using conventional OTDR. We
NTT Technical Review

Feature Articles

100 m

C-OTDR

OTDR
10 m

MAC address Equipment and information relationshipmapping

Resolution

1m
10 cm
1 cm

PNC-OFDR

C-OFDR
1 mm

Separate tests, below branch lines

Separate tests
below splitter

More distant, more detailed

OLCR

1m
Device test

10 m

100 m

LAN, on-premises

1 km
Access line

10 km

100 kmTrunk line

Ocean line

Measured distance
C-OFDR: coherent optical frequency domain reflectometry
C-OTDR: coherent optical time domain reflectometry
LAN: local area network

MAC: media access control
OLCR: optical low coherence reflectometry
PNC-OFDR: phase-noise-compensated optical frequency domain reflectometry

Fig. 1. Three approaches to categorize remote fault locations.

have devised a principle that enables us to obtainmeasurements below individual splitters using aphysical phenomenon called Brillouin scattering*,
which occurs within the optical fiber, and have demonstrated this principle for the first time. If thisapproach can be implemented practically, it will overcome one of the major difficulties with PONs.
2.3 I nformation linkage between an optical fiber
and transmission systems
When a fault occurs, we use different instruments
and systems to diagnose the fault in each transmission path (optical fiber) and transmission system. We
have focused on measuring the round-trip times
between an optical line terminal (OLT) and each optical network unit (ONU). This approach is often
employed with PON systems, and we have shownthat we can convert the measurement data to an optical fiber length and map ONU MAC (media access
control) addresses to the location of reflections at theend of an optical fiber. By establishing this technology, we will be able to use it both to locate faults and*Brillouin scattering: Optical scattering that occurs within a medium due to phonons (sound waves) and that involves changes infrequency.

Vol. 11 No. 6 June 2013

to detect potential faults, thus providing preventative
maintenance.
3. Building an equipment database, andsafe and secure work navigation
Communication services are provided throughvarious types of equipment. This equipment is complex, and there is a large amount of it, so a lot of work
is involved in carefully managing and maintaining a
database for each type of equipment. If we are toincrease the efficiency of this administration work,
we must construct an inexpensive mechanism thatcan build and update the database autonomously
without requiring manual intervention. The mechanism must assign a unique ID to each element of theequipment. We are conducting applied research on an
equipment management system using image processing and augmented reality (AR) technologies as aneffective means of achieving this. An example of theuse of AR technology on optical patch panels in acommunications building is shown in Fig. 2. The
optical patch panel has connector terminals densely
arranged with 4 × 7 mm spacing. The positions ofmarkers attached to the patch panel beforehand areFeature Articles

MarkerConnector terminal board

Connector toolwith camera and monitor
AR image

Fig. 2. Navigating on-premises terminal panels using AR technology.

captured with a camera. Then an AR image of theterminal matrix is drawn on the monitor based on aunique ID, and this can be used to direct the work.
Also, because the state of the work is being monitored, the database can be built and updated autonomously. Moreover, failsafe functions can be implemented to prevent errors. Thus, we are progressing
with research and development (R&D) of a navigation system that can maintain a database that isalways up to date and that facilitates safe and securemaintenance work.
4. Flexible branching of an optical fiberWith metal cables, current flows as long as there iscontact, so branches can be established anywhere. If
optical fibers could be similarly branched, it would
expand the range of operations and maintenance scenarios in which they could be used. Local light injection technology involves placing a probe fiber near abent section of optical fiber and injecting lightthrough the probe fiber (Fig. 3(a)). Light radiatingfrom the optical fiber passes through the insulation,so some corresponding losses are unavoidable. However, the system should be practically usable if a stable level of coupling efficiency that is suitable for theoperational application can be ensured by optimizing
the refractive-index-matched materials, optical lenses, and probe position. For example, until now, it wasnecessary to have a person in the communications
building who would inject optical test signals into
fibers. However, this line illumination work wouldchange significantly if such test signals could be
injected at arbitrary locations. We are also studying
applications for tasks such as checking the link status


of a line, and for short-interruption optical media
switching, which is described below.
5. Switching optical media in the broadband era
Twenty years ago, when telephone services were
dominant, if work was undertaken only when lines
were not being used, there was little effect on customers. Now, however, in the optical broadband era,
information flows nonstop, 24 hours a day, 365 daysa year, via Internet, cloud computing, video distribution, and other services. Therefore, the old approachcannot be used without affecting customers. We areconducting R&D to find ways of switching optical
media that are appropriate for the modern era.
5.1 U ninterruptible optical access line switchingsystemApproximately four years ago, we conceived principles that enable media to be switched without thedisconnection or suspension of services and wereable to demonstrate the practical implementation ofthis approach. Our technique involves (1) connecting
an optical fiber (the detour path) of approximately thesame length as the current optical fiber (the mainpath) in parallel with it, (2) disconnecting the main
path and transmitting the optical signal over the
detour path, (3) performing the switch work while themain path is offline, (4) adjusting the length of the
detour path while it is transmitting the signal so that
it is approximately the same as that of the main path
after switching, (5) reconnecting the main path as the
new line in parallel with the detour path, and (6) disconnecting the detour path. All of the steps in thisprocedure can be performed without interrupting the
NTT Technical Review

Feature Articles

Bent section for
injecting light into main line

1.3 µmCurrent line signal1.55 µm

Bent section ofshort-interruption switch

1.3 µm

1.3 µm1.55 µm1.55 µm

Current line signal

1.3 µm1.55 µm

Switch

1.3 µmProbe fiber

Test light
1.65 µm

Probe fiber
1.55 µm58.7 ms- Local light is injected with bending radius
within a range where current line signal is
not affected.

(a) Optical injection, tested at arbitrary location- Forced switching of current line signal- Fiber is bent to its strength limit to achievestrong coupling effect with local light
injection/detection.
(b) Short-interruption optical media

Fig. 3. Local optical injection/detection technology.

signal. The system is complex and requires precise
control of path lengths, measurements, loss compensation, and the cancellation of interference. We are
therefore undertaking R&D to build a system that iscompact, smart, and compatible with a variety of
scenarios in the field. If this system can be realized,
we will be able to change an optical access line at any
time.
5.2 M
 omentarily interrupted optical access line
switching system
We are also conducting R&D on another approachto switching media. We can mechanically switch thetransmission path in an instant by using a local light
injection technique that involves bending the opticalfiber close to its breaking limit to maximize the efficiency of the optical link. This approach does not
require us to cut the optical fiber (Fig. 3(b)), but it
causes a momentary interruption. We have alreadyconfirmed the ability to switch within approximately
60 ms. This can only be applied to certain types of
optical fiber, but if this simple system is realized, it
will be applicable to many work scenarios including
cable switching or replacing an OLT.

Vol. 11 No. 6 June 2013

6. Expanding applications ofbending-loss-resistant fiber
Our free-bending optical cord has overturned thecommon belief that optical fiber cannot be bent. In
the past, great care had to be taken not to bend opticalfiber, but we have expanded the range of application
scenarios with the implementation of hole-assisted
fiber (HAF), which produces almost no losses evenwhen bent. Recently, these optical fibers have evenbeen passed through narrow gaps such as thosearound doors and window sashes. There is a maintenance and operability trade-off with these technologies, but by applying HAF where it is needed, interruptions due to bending can be eliminated, and it may
be possible to simplify the optical cable structure.
7. Next-generation optical fiber research forthe ultrahigh-speed, high-capacity era
Internet traffic is increasing exponentially with theaccelerating spread of services such as social networking and video content services. The bandwidthof optical fiber communications systems that form
the backbone for this communication is also being
increased yearly. However, there are limits to theincrease in bandwidth and speed that can be achievedFeature Articles

Multicore fiber
Transmission capacity
multiplied by N by arranging N
independent cores in samefiber

Few-mode fiber
Transmission capacity
multiplied by M bytransmitting M types (modes)of light through single core

Conventional optical fiber(single-core, single mode)

Base mode

High-order mode

Fig. 4. Next-generation fiber for space-division multiplexing.

with the single-mode optical fiber currently in use,
and it is estimated that these limits will be reached inten years. Therefore, a new transmission medium that
overcomes these limitations will need to be created.
We are focusing on ways to spatially extend the transmission area of optical fiber, which is one way to
overcome these limitations (Fig. 4). Current opticalfibers transmit optical signals using a single mode,through a single core (transmission path) within astrand of quartz glass. However, optical fiber design
and production technology is advancing because of
the employment of complex cross sections such ashole structures, and digital transmission processing
technology. Fiber with multiple cores in a single
strand of quartz glass, and multi-mode fiber capableof transmitting stable signals with multiple modes ina single core are presenting new possibilities fornovel fiber structures with higher spatial multiplexing. We have continued to demonstrate the possibilities of multicore fiber with, for example, a successful
1-Pbit/s transmission over a single 12-core opticalfiber of 52 km, which is a world record (ECOC(European Conference on Optical Communication)
International Exhibition, Sept. 2012, and NTT News
Release).



ProfileCareer highlights
Executive Manager, Senior Research Engineer,
Supervisor, Access Media Project, NTT AccessNetwork Service Systems Laboratories.
Yuji Azuma received the B.E. degree in electrical engineering from Doshisha University, Kyoto,in 1984. He joined Nippon Telegraph and Telephone Public Corporation (now NTT) andengaged in research on the characteristics of multicore optical fiber and fiber nonlinearity. From
1989, he was engaged in the troubleshooting anddevelopment of optical fiber networks and IP
networks. He moved to NTT Access Network
Service Systems Laboratories in 2006 and has
been engaged in R&D of access media and equipment maintenance. He is a member of the Institute of Electronics, Information and Communication Engineers.

NTT Technical Review

Feature Articles: NTT Tsukuba Forum 2012 Workshop Lectures

R&D Trends in Communications
Infrastructure to Achieve Safe andSecure Access Networks
Fumihide Sugino
Abstract

NTT Access Network Service Systems Laboratories is working on the
Civil Systems Project, which involves conducting research and development (R&D) on infrastructure facilities such as conduits and manholes.
This article reviews the current state of infrastructure facilities, provides
details of our current R&D, and touches on future developments. This
article is based on a lecture given at the NTT Tsukuba Forum 2012 workshop held on October 19, 2012.

1. Environment surrounding
infrastructure facilities
In 2012, NTT Access Network Service Systems
Laboratories marked 40 years since its predecessor,
the Construction Technology Development Laboratories, was established in Tsukuba (Fig. 1). At the timeof establishment, a lot of construction was being done
to install telecommunication infrastructure such as
cable tunnels, manholes, and conduits throughout
Japan, so construction technology was the main focusof research and development (R&D). The period
from the mid-1960s to the end of the 1970s was atime of rapid construction, and approximately 80% ofNTT’s conduits and manholes were built during thattime. Consciousness of environmental issues increasedin the 1980s, and during this time, the focus shifted todeveloping technology to build conduits without having to excavate, and as the amount of construction
gradually decreased, R&D themes shifted from construction to maintenance. Currently, maintenancetechnologies such as inspection, diagnosis, and repair
are the major R&D themes.
1.1 Advancing deterioration of facilities
If current trends continue, in 20 years, approximately 80% of all conduits and manholes will bemore than 50 years old and entering their old age(Fig. 2). Approximately half of existing conduits aresteel and have advanced rust and corrosion, which is
becoming an obstacle in installing cable. Moreover,
weakening of concrete components such as manholes
and cable tunnels due to cracking, peeling, and corrosion of rebar is becoming a concern. It would be ideal
to handle these age-related issues by systematicallyrenewing the facilities, but the cost and time required
to renew the large amount of infrastructure buried
underground would be huge, and it is therefore notpractical. Excavation of roadways also significantly
disrupts the surrounding environment. Accordingly, amajor R&D issue is determining how to enable continuous use of old facilities without renewing them.
1.2 T he need to earthquake-proof existing facilities
Developing technology for earthquake-proofing
infrastructure facilities has been an ongoing theme at
the laboratories ever since its inception. Many large
earthquakes have occurred since then, and the knowledge gained from each experience has been accumulated and used to improve earthquake-proofing technologies. The 1964 Niigata earthquake, the 1978
Miyagi earthquake, and the 1995 Kobe earthquake inparticular provided opportunities to radically revise
NTT Technical Review

Feature Articles

1972
Construction Technology
Development Lab.
established

1980

1990

2000

2010

From “construction” to “maintenance”

Construction(capacity, efficiency)

Construction,
maintenance(effective use)

Construction(environment, city support)

Construction
technology

Inspection,
maintenance

Maintenancetechnology- ACEMOLE construction - High reliability conduits(compact excavation- Fleece access- Empty ductless technology)
single-pipe methodrenovation- SAPIC construction(TM lining)- Advanced MH(entry-less conduit
installation)- MH tapered steel plate- STIC construction - SR system(Reuse of earth removed
in construction)- FTC (Fire prevention)- Hardened PVC pipes- Ductile iron pipes- Split block MH- Resin block MH

Inspection
technology- Pipe camera- Espar(Excavation-lessunderground facility
inspection)- Cable tunnel
management systems- Shield construction(large-scale
non-excavation
technology
Earthquake-proofing
technology- Duct sleeve- Flexible joints- Duct sockets- Insertion joints- Stopper joints

FMS: facility management system
FTC: fire tight compartment
MH: manhole
PVC: polyvinyl chloride
SAPIC: safe pipe construction- Optical fiber sensing- FMS(Marios)- Flexible building-entry
conduit- MH duct SFRC
- Flexible joints for
excavation tunnel- Technology forwashing ductswith cables- Lining technology- Simple MH sidewall reinforcing
technology- Macroscopic
ultrasonicconcrete
inspection- Flexible shield pit
connectors- Collapse prevention forstandard private bridges

SFRC: steel fiber reinforced concrete
SR: soil recycling
STIC: shield tunnel interfaces with conduits
TM: thick membrane

Fig. 1. Trends in infrastructure R&D.

0

5

10

15

(10,000 km)
20
25

0

5

10

15

(10,000 sites)
20
25

(km)
0

50

100

150

–1955
–1960
–1965
–1970
–1975
–1980
–1985
–1990
–1995
–2000
–2005
–2010

Steel pipe
PVC pipe
Other(a) Conduits

Site-castConcrete block
Resin block
Other(b) Manholes

ShieldExcavation(c) Cable tunnels

Fig. 2. Amount of infrastructure construction, indicated in 5-year periods.

Vol. 11 No. 6 June 2013



Feature Articles

Mission of NTT Information Network Laboratory Group
Sustainable(continuous connection)

Communications infrastructure
equipment R&D concept

Operate infrastructure equipment efficiently
at minimal cost (reduce OPEX/CAPEX)
Earthquake-proof
Safe, secure facilities
facilities(measures against(earthquake-proofing)
deterioration)
Maintain/improve reliability

Smart(smart connection)

Maintenance*

Simple(simple connection)(a) Concept

Amount of maintenanceneeded in the future(result)

Extend lifetime.
Reduce required
maintenance.

Efficiency
automation
Amount of maintenance currently possibleYear(b) Approach*Maintenance: measures against deterioration; earthquake-proofing.

Fig. 3. Infrastructure construction R&D concept and approach.

earthquake-proofing capabilities because of theextent of the damage that occurred.
The Great East Japan Earthquake in 2011 was thelargest in recorded history in Japan, and it provided
an opportunity to evaluate the performance of infrastructure earthquake-proofing technology applied up
to that point. The evaluation revealed that only 1–3%
of infrastructure facilities were damaged in mostcases, a very low figure. This verified that underground facilities are highly earthquake-proof infrastructures. Furthermore, the facilities that were damaged were built during periods when older standards
applied and earthquake-proofing capabilities werelacking. This also confirmed the effectiveness of current standards. In fact, there are still many older
facilities that were built before the current standards
were introduced. However, even if the renewal ofsuch facilities was restricted to those along majorroutes and in areas where earthquakes were expected
to occur, the cost of renewing all of them to current
standards would still be prohibitive and impractical,
just as it is in the case of aging infrastructure. Consequently, we expect that developing effective methodsof predicting damage to facilities and applying earthquake-proofing measures where they are most needed
will be an important R&D theme in the future.
2. Current R&D
In order for customers to use NTT services with

confidence, the infrastructure supporting these services must, itself, be safe, secure, and very resistantto earthquakes. Measures against aging and earthquakes, as described above, must be steadily advanced
in order to ensure this, but in view of the intenselycompetitive communications market surrounding
NTT and the declining number of skilled specialists
in this technology in the industry, the role of R&D is
to create technologies that can implement these measures quickly, effectively, and at minimal cost.
Currently, the amount of inspection and maintenance work carried out to address the aging of facilities is limited because of the required cost and labor.
However, this aging continues nonetheless, and thenumber of facilities requiring work increases eachyear. R&D will use two approaches to fill in this widening gap (Fig. 3). The first one involves the use of
automation and optimization technologies to increase
the number of facilities that can be inspected andmaintained. The other one involves the use of technology to extend the lifetime of facilities or makethem maintenance-free, which will reduce the number of facilities requiring work. Next, we introduce
some technologies used in these approaches.
2.1 C oncrete pole inspection technology (automating and streamlining inspection)
NTT has approximately eight million concrete
poles nationwide. Inspections of these poles are done
mainly by visually inspecting them for cracks, which
NTT Technical Review

Feature Articles(a) Crack detection using image analysis
Capture remotelywith camera.

Analyze images on computer.

Transfer

Results of analysis(b) Millimeter-wave detection of cracks underanti-posting sheet
Millimeter-wave sensor(c) Analysis of percussive vibration to assess
soundness
Earphones

Accelerometer

Strike around perimeter.

Analysis

Cracks, other
deterioration
Vibration sensor
StrikeAnalysis result
Anti-posting
sheet
Scanning jig

Battery

Analyzer

Fig. 4. Technology for inspecting concrete telephone poles.

requires a certain level of skill. Furthermore, theupper part of concrete poles must be checked using
binoculars, which is labor intensive and raises concerns that problems could be overlooked. Three technologies have been developed to enable this inspection work to be done more efficiently and effectively(Fig. 4).
The first is a technology to detect cracks using
image processing. Software is used to eliminate factors such as cables and dirt, which obstruct the detection of cracks, from the color and texture of images
captured using an off-the-shelf digital camera. This
enables automatic detection of cracks.
The second technology uses millimeter-wave radiation to detect cracks underneath the anti-posting sheet
placed on the concrete pole. The previous image-processing technique is unable to detect cracks hidden byVol. 11 No. 6 June 2013

the anti-posting sheet, but millimeter waves arereflected by cracks and scattered in all directions, andthis can be used to automatically detect cracks thatare concealed by the anti-posting sheet.
The third technology is used to assess the conditionof the pole by analyzing the vibrations that result
from striking it. The purpose of this is not to detectcracks, but to measure the characteristic frequencies
generated when striking the concrete with a hammer
to automatically determine if the pole’s rigidity has
decreased.
2.2 P
 IT (pipe insertion type) new-conduit method
for facility repair, maintenance-free conversion, and earthquake-proofing
One problem with conduit facilities is deteriorationof steel pipes. Over 60% of conduits, where multiFeature Articles

Thin 1000fiber cable

φ28

φ28

φ35

Existing 1000-fiber cable(3) Push in.
(2) Fit coupler.
(1) Fit main
section.

Degraded
conduit
Lining material

Existing cable

Fig. 5. PIT new-conduit method.

cable installations are planned, are diagnosed as
faulty. Most of this is due to rust and corrosion ofsteel pipes. Technology to repair empty conduits thatwere faulty due to rust and corrosion already existed,
but there was no way to repair them after the cable
had been installed. The PIT new-conduit method
resolves this issue (Fig. 5).
This method involves inserting a PVC inner pipe
into a metal conduit that already has a cable installed.
This new pipe encompasses the existing cable. The
duct is replaced by the PVC pipe, so rust is no longer
an issue, and no further maintenance is required. Useof this method can create capacity for three cables in
one duct. The space for the existing cable (35 mm indiameter) accommodates up to a 1000-fiber opticalcable, and the remaining two spaces (28 mm in diameter) can accommodate two new thin 1000-fiber
cables, for a total capacity of 3000 fibers. The innerconduit also protects the cables, which increases theearthquake resistance of the conduit. This enables
conduit earthquake-proofing without having to do theconstruction work of excavating roadways.
We are currently studying ways to expand the range
of application areas for this technology. This includes
reducing the diameter of the PVC pipe to apply it tonarrower conduits that are weak or deteriorated,
increasing the lengths of spans in which installationis possible, and supporting use in colder regions
where cables must be protected from freezing
groundwater.


3. R&D in the future
NTT currently uses a preventative maintenanceapproach in managing the maintenance of infrastructure facilities. Preventative maintenance reduces therisk of equipment failure because periodic inspections are conducted of all equipment comprehensively, uniformly, and indiscriminately, and repairs
and renovation are carried out as needed. However,with NTT’s large amount of infrastructure and withthe advancing deterioration, even conducting only theinspections entails a high cost and a large amount ofwork. As such, future R&D will continue to focus onfinding ways to reduce the cost and the amount ofwork required for inspections and repairs as much as
possible so that preventative maintenance can bedone smoothly. We will also take on the challenge ofredefining what maintenance the facilities will
require in the future and revise it if necessary. Maintenance standards based on a preventative maintenance approach are already established, but whencompared to people, it is like applying the same
medical examination to all patients regardless of theirage, physical condition, lifestyle, or medical history.
The fact that a facility is old means that useful datafor individual evaluation have been gathered fromthat facility.
Analytical technology is advancing throughout theindustry. More advanced preventative maintenance ispossible by evaluating the state of each facility,
NTT Technical Review

Feature Articles

Repair cost/risk of accidents, etc.
×After-the-fact
maintenanceFuture areas of focus

Current state

Advanced preventative
maintenancePreventative maintenance- Comprehensive, uniform- Fixed intervals- Individual evaluation- Prioritization

Amount ofInspection
Future tasks

Continuing tasks- Optimize timing of inspections and repairs
through individual evaluations.
- Adjust inspections and repairs basedon estimates of deterioration anddisaster.

- Inspect large numbers of facilities efficiently.
- Conduct effective and inexpensive maintenancebased on state of deterioration.
- Carry out maintenance with longer inspection cycles(Our goal is to achieve maintenance-free equipment).
- Aim for robust, earthquake-proof facilities(earthquake-proof hardware).

Fig. 6. R&D in the future.

estimating the degradation or damage, and conducting inspections and repairs effectively at the optimal
times. We have already begun initiatives in this area.
For example, we are researching ways to prioritize
manhole inspections for manholes that are likely to
be in more advanced states of deterioration by doinga rough estimate of their condition (soundness anddeterioration) based on type of construction, installation environment, and external load conditions. This
enables us to find deteriorated equipment quickly andto control inspection costs. We are also researching
methods to evaluate the level of earthquake resistanceby estimating the susceptibility to earthquake damage
for each span of a conduit based on factors such as
conduit line type or ground conditions. This enables
us to apply effective earthquake-proofing measures
starting where they are needed most (Fig. 6).
4. Future development
Currently, most initiatives in infrastructure facility
R&D involve so-called hard technologies such as
inspection tools and maintenance methods. In the
future, research and development will advance inareas such as facility management based on specialist

Vol. 11 No. 6 June 2013

knowledge and past experience in order to manage
infrastructure facilities appropriately while minimizing cost. We hope that the NTT Group will be able tocontribute in these areas.

ProfileCareer highlights
Executive Research Engineer, Civil Engineering Project, NTT Access Network Service Systems Laboratories.
Fumihide Sugino received the B.E. degree incivil engineering from Hokkaido University in
1987, after which he joined NTT. He has studied
ACEMOLE construction technology, which is amethod of construction without road excavation.
He has also worked at NTT Access Network Service Systems Laboratories and NTT EAST,
where he mainly worked on telecommunication
infrastructure including cable tunnels and underground pipeline systems. He has been in his present position since 2012. His current work involves
studying NTT infrastructure.

Regular Articles

A Comparison of Approaches to
Incident Response in Japan and theUnited States and an Introduction to
the International Standard ISO 22320
Mitsuhiro Higashida, Naoko Kosaka, and Yuji Maeda
Abstract

NTT Secure Platform Laboratories has been researching and developing incident responses for whendisasters occur. We introduce the approaches to incident response taken in the United States and comparethem with those in Japan. We also introduce the disaster management standard ISO 22320: Societal
security––Emergency management ––Requirements for incident response, issued by the International
Organization for Standardization (ISO) in November 2011.

1. Introduction
Natural disasters occur regularly in Japan, andevery year there is a great loss of lives and property
due to these events. Additionally, the tendency forheavy downpours to occur throughout the country is
increasing and seems to be a long-term trend.
It has been pointed out with a great sense of urgency that Japan may be struck by large-scale earthquakes in the next few decades in areas such as the
Nankai Trough and inland in the Tokyo area. The
Central Disaster Management Council has estimatedthe potential damage for 18 types of Tokyo Inland
Earthquakes. The Council assumes that an earthquakewith a magnitude (M) of 7.3 with an epicenter in thenorthern part of Tokyo Bay would cause extensive
damage and result in a death toll of approximately
11,000 people, a total collapse of 85,000 buildings,
and a maximum economic loss of 112 trillion yen.
We cannot prevent the occurrence of natural disasters. Therefore, disaster mitigation is necessary inorder to recover as quickly as possible from the damage caused by a disaster. This means to be preparedby implementing both structural and non-structural
measures and by considering how we should prepare
for a disaster. In this article, we discuss the concept ofcrisis management in the future.
2. Activities to improveincident response capabilities
The International Organization for Standardization(ISO) issued ISO 22320 as an international standard
for incident management in November 2011. Incident
response consists of various response operations bydifferent institutions and organizations. In somecases, activities need to be carried out throughout thecountry. Consequently, effective incident response
requires structured command and control, as well as
coordination and cooperation among the variousorganizations. ISO 22320 specifies the minimum
requirements to carry out an efficient and effective
incident response. Before this standard was issued,
incident response was considered separately by different organizational units in Japan. With the introduction of ISO 22320, incident response plans aregradually being standardized. In the following sections, the approach toward incident response in the
United States (U.S.) is introduced and compared withthat in Japan. Then, an overview of ISO 22320 isgiven.

NTT Technical Review

Regular Articles

Command (Incident Commander)
Public information
SafetyLiaisonOperations
Staging areas
Branches Air operations branch
Air support group
Divisions &Air tactical group
GroupsStrike teams
Task force
Single resource

Planning
Resources unit
Situation unit
Demobilization unit
Documentation unit

Logistics
Service branchCommunications unit
Medical unit
Food unit
Support branch
Supply unit
Facilities unit
Ground support unit

Finance/Administration
Time unit
Procurement unit
Compensation/Claims unit
Cost unit

Fig. 1. ICS structure.

3. Incident Command System
The Incident Command System (ICS) is a standardized on-scene incident management concept designed
specifically to allow responders to adopt an integratedorganizational structure that can meet the complexityand demands of any single incident or multiple incidents without being hindered by jurisdictional boundaries.
The original ICS was established in the mid-1970s
by the U.S. Forest Service and a number of California
agencies. It was designed to improve and help coordinate responses to catastrophic wildfires in California. The ICS was developed to manage rapidly moving wildfires and to address the following problems:
too many people reporting to one supervisor; different emergency response organizational structures;lack of reliable incident information; inadequate andincompatible communications; lack of structure forcoordinated planning among agencies; unclear lines
of authority; terminology differences among agencies; and unclear or unspecified incident objectives.
Federal officials transitioned the ICS into a national
program called the National Incident Management
System (NIMS), which became the basis of a
response management system for all federal agencies. Since then, many federal agencies have endorsed
the use of ICS, and several have mandated its use.
The ICS divides an emergency response into five
manageable functions essential for emergency
response operations: Command (Incident Commander), Operations, Planning, Logistics, and Finance andAdministration. A typical ICS structure is shown in
Fig. 1.
Vol. 11 No. 6 June 2013

The Incident Commander (IC) is responsible for all
aspects of the response, including developing incident objectives and managing all incident operations.
The ICS defines various information processing
forms required for an incident response, which are
known as ICS Forms. ICS Forms are designed toassist emergency response personnel in the use of ICS
and the corresponding documentation during incident
operations.
In addition, many ICT systems have been set up to
support ICS activities. Training programs are conducted in various institutions in order to prepare fordisasters, for example, HSEEP (Homeland Security
Exercise and Evaluation Program), and a grant program to support these activities has been establishedby the U.S. government.
As described above, the response management system in the United States is based on ICS.
In Japan, the Self-Defense Forces, National Police
Agency, and National Fire Department have established a command and control system. When the
Great East Japan Earthquake struck in 2011, theseorganizations were able to respond quickly to thedisaster area by sending units that are dispersed
across the country. By contrast, local governments inJapan do not have a system like this.
4. Difference in incident response approaches
between Japan and the United States
The Local Disaster Management Plan is common
in Japan. This is a plan established by each prefecturaland municipal disaster management council, subject
to local circumstances and based on the BasicRegular Articles

Incident

Feedback andcontrol

Implementation ofdecisions

Information
gathering andsharing
Assessment ofsituation andforecasting

Decisionmaking andsharing
Planning

Fig. 2. Command and control process specified in ISO 22320.

Disaster Management Plan.
By contrast, ICS in the U.S. is applied nationally. It
is flexible and can be used for incidents of any type,
scope, and complexity. ICS allows its users to adopt
an integrated organizational structure to match thecomplexities and demands of single or multiple incidents.
ICS is used by all levels of government—federal,state, tribal, and local—as well as by many nongovernmental organizations and the private sector. It isalso applicable across disciplines.
In Japan, the role of state agencies is limited, andthey do not have a system to perform disaster
responses in place of local governments.
The role of state agencies is to provide support tothe local governments.
Furthermore, in Japan, disaster responses areplanned based on an extension of command and control operations during ordinary times. Thus, the disadvantage is that the response may not be sufficientduring a disaster that is beyond the response capacity.
In contrast, in the United States, the correspondingorganization expands according to the size of thedisaster. The organization also has the authority tocommand and control the response operations.
In addition, there are full-time professional disaster
response teams in the United States. However, disaster response personnel change every few years inJapan.



Evaluation

Dissemination andintegration

Analysis andproduction

MissionProcessing andexploitation

Planning anddirection

Collection

Feedback

Fig. 3. P rocess of providing operational information(ISO 22320).

5. ISO 22320
ISO 22320 is an international standard that wasissued to enhance the ability of private and publicorganizations to handle all kinds of emergencies suchas flooding, earthquakes, and accidents.
The standard specifies the following requirements
for an effective incident response:a) Requirements for command and control (Fig. 2)b) Requirements for operational information (Fig. 3)c) Requirements for cooperation and coordination
NTT Technical Review

Regular Articles

ServerPrefecture “X”

Cloud

Knowledge
database

Local government “B”

Plan
Do

Information sharing/reporting
Local government “A”

SeeInternet

Staff on site
Disaster area

Incident
response
knowledge

Ordering/reporting /information sharing
See

Do

Plan

EOC (emergency operations center)
Input data to
the form

Evacuation
centerExecutive
outside EOC

Disaster prevention
office near disaster area

Departments and agencies

Fig. 4. Strategic emergency management support system.

Photo 1. Screen shots of strategic emergency management support system.

Thus, ISO 22320 is a standard that allows interorganizational cooperation among the involved organizations, agencies, and other parties.
After ISO 22320 was issued, a committee wasformed in 2012 by the Japanese Standards Association (JSA) to establish Japanese Industrial Standards(JIS), which will be issued in the summer of 2013 at
the earliest.
Vol. 11 No. 6 June 2013

6. Conclusion
Until now, there was no common agreement on how
to implement an incident response in Japan. Therefore, ISO 22320 will play an important role in thestandardization of a domestic incident response planin the future. We will work on developing a strategic
emergency management support system based on ISO
Regular Articles

22320 (Fig. 4). Key personnel will use the support
system to prepare a common operational picture andcarry out effective emergency management throughthe summarizing, managing, and sharing of information and foresight utilizing incident response knowledge (Photo 1). If the system is provided on a cloud,users can use it whenever necessary, including during
training. As a result, local governments that have not

Mitsuhiro Higashida

Senior Research Engineer, Medical and
Healthcare Information Systems Development
Project, NTT Secure platform Laboratories.
He received the Ph.D. degree in social informatics from Kyoto University in 2008. He joined
NTT in 1993. He is currently studying disaster
information systems. He is a member of theInstitute of Social Safety Science and the Japan
Society for Natural Disaster Science.

Naoko Kosaka

had any experience in dealing with disasters can utilize the knowledge of other local governments stored
on the knowledge database of the system.
NTT Secure Platform Laboratories is continuing toresearch and develop ways to improve incident
response capabilities through the management support system based on ISO 22320.

Yuji Maeda

Senior Research Engineer, Supervisor, Medical and Healthcare Information Systems Development Project, NTT Secure platform Laboratories.
He received the Ph.D. degree in systems information science from Future University Hakodate, Hokkaido, in 2013. He joined NTT Telecommunication Networks Laboratories in 1991.
He is currently supervising a development project on medical and healthcare information systems and disaster resilient information systems.
He received the Scholarship Encouragement
Award from IEICE in 1998. He is a senior member of IEICE, and a member of IEEE, the Human
Interface Society, and the Japanese Telemedicine
and Telecare Association.

Engineer, Medical and Healthcare Information
Systems Development Project, NTT Secure Platform Laboratories.
She received the B.E., M.E., and Ph.D. degrees
in engineering from Tokyo Institute of Technology in 1995, 1997, and 2004, respectively. She
joined NTT Human Interface Laboratories in1997 and moved to Secure Platform Laboratories
in 2010. She is currently studying an emergency
management support system using incident
response knowledge. She is a member of theInstitute of Electronics, Information and Communication Engineers (IEICE).

NTT Technical Review

Global Standardization Activities

Recent Trends in Standardization ofJapanese Character Codes
Taichi Kawabata
Abstract

Character encodings are a basic and fundamental layer of digital text that are necessary for exchanging
information over the Internet. Character codes are used in plain text files as well as in structured text files
such as XML (extensible markup language), MIME (multipurpose Internet mail extensions), and HTML
(hypertext markup language).
This article explains the basic architecture of character encodings and reviews Japanese and International standardization activities.

1. Overview of character code
standardization history
Character codes are used everywhere on the Internet. They form the most basic layer of the digital text
hierarchy. This means that above the plain raw character codes lie layers of variant glyph encodings, text
encoding formats such as HTML (hypertext markup
language) and XML (extensible markup language),
and instructions for the placement of such charactercodes, such as those given in CSS (cascading style
sheets), as shown in Fig. 1.
The first attempt to standardize character codes forelectronic information interchange was initiated in
the early 1960s by the International Organization forStandardization (ISO), followed by the American
Standards Association (ASA, now called the ANSI(American National Standards Institute)) and theEuropean Computer Manufacturer’s Association(ECMA) as 6-bit and 7-bit character codes. Since
then, character codes have been standardized by individual countries or organizations*1. The first 2-byte(14-bit) character coding system was standardized by
Japan in 1978. Later, China, Korea, and Taiwan also
standardized their own 2-byte character codes. Thesevarious character codes were not compatible witheach other. As a result, some characters were doubly
encoded in different character encodings, thus making their combined use practically difficult.
In the late 1980s, some software companies began
an attempt to unify these various character codes intoa single coding system, which was called Unicode.
Similar attempts were also made within the ISO, andwith some vicissitudes, these two attempts achieved apari passu (literal meaning: on equal footing) advance, resulting in two technically identical standards, namely, ISO 10646 and Unicode. Since then,both ISO/IEC (International Electrotechnical Commission) and Unicode have continued to publish
technically identical standards to this day.
The first version of ISO 10646, whose official nameis the Universal Coded Character Set (UCS), waspublished in 1993. Since then, it has gradually been
disseminated all over the world. In Japan, JIS (Japanese Industrial Standards) and its variant character
encoding systems (such as Shift_JIS) have been
widely adopted, but now UCS prevails on the Japanese Internet*2. Today, Japan has already ceased creating its own standards and now proposes new characters to UCS*3. A brief history of the standardizationachievements over the years is shown in Fig. 2.
2. Architecture of UCS
The UCS character coding system consists of 17
planes; each plane has 65,534 character code points,
which are numerical values representing the code
*1	 Basic character encoding frameworks were standardized internationally as ISO 646 or ISO 2022.
*2 Except for email, in which the JIS coding system is still widely
employed.
*3 The JIS translation of UCS is referred to as JIS X 0221.

NTT Technical Review

Global Standardization Activities

Text positioning and decoration:
Document structure:
Fonts:

Variants and glyphs:
Character codes and attributes:

CSS (W3C)
HTML (W3C), XML (OASIS),
SGML (ISO/IEC)
WebFonts (W3C)
OpenType (Apple, Adobe)
UnicodeUnicode, ISO/IEC 10646

ISO/IEC: International Organization for Standardization/International Electrotechnical Commission
OASIS: Organization for the Advancement of Structured Information Standards
SGML: standard generalized markup language
W3C: World Wide Web Consortium

Fig. 1. Digital text hierarchy showing character/coding characteristics and details related to their standardization.

International movement

Japanese movement

1963: ISO IRV, ASCII standardized
1969: JIS Kana standardized

1973: ISO-2022 standardized

1978: JIS Kanji standardized(revised in 1983, 1990, 1997)

1980: Chinese GB code
1986: Korean KS Code1990: Unicode 1.0 proposed
1993: Unicode 2.0 & ISO/IEC 10646:1993
are published.

1995: JIS X 0221 standardized(translation of ISO/IEC 10646)
2000: JIS X 0213 standardized(This is the last original JIS standard.
Now, all Japanese characters are
standardized via UCS.)

2002: ISO/IEC 10646-2(Standardization of Extension-B,
incorporating JIS X 0213 ideographs)
2006: UTR#37 officially published2010-2012: Registration of Hanyo-Denshi
collection to IVD
2012: Proposal of Japanese Kanjicharacters for administrative use to
Extension-F work

2012: Work on Extension-F has begun.

ASCII: American Standard Code for Information Interchange
IRV: International Reference Version

IVD: Ideographic Variation Database
UTR: Unicode Technical Report

Fig. 2. Brief history of character encoding standardization.

space. This results in nearly 1.1 million code points
for all 17 planes, as shown in Fig. 3. In the UCS,
unique code points are assigned to characters from allover the world. Today, approximately 100,000 character code points have been assigned, as shown in the
figure*4.
The UCS code points are represented in the form of
U+XXXX, where XXXX is a 4 to 6 hexadecimal digit.
Vol. 11 No. 6 June 2013For example, the Latin character a is assigned thecode point U+0061, and the kanji character 漢 isassigned the code point U+6F22. Since its standardization in 1993, most characters in modern scripts
have been encoded; however, efforts to assign archaic*4 About 70% of them are CJK (Chinese/Japanese/Korean) Unified
Ideographs.

Global Standardization Activities

65,536∗ × 17

Plane 0

U+0000–U+FFFF

Basic Multilingual Plane

Plane 1

U+10000–U+1FFFF

Supplementary Multilingual Plane

Plane 2

U+20000–U+2FFFF

Supplementary Ideographic Plane

1.1 million

Planes 3 to 13 are undefined.

Plane 14

U+E0000–U+EFFFF

Plane 15

U+F0000–U+FFFFF

Supplementary Special-Purpose Plane

Supplementary Private-Use Area
Plane 16

U+100000–U+10FFFF∗ This number includes non-character code points.

Fig. 3. Planes of UCS character coding system.

E6 BC A2

漢(character)U+6F22(UTF-8)

E6 BC A2

(UTF-8)

6F 22(UTF-16BE)

6F 22(UTF-16)

22 6F(UTF-16LE)

00 00 6F 22 (UTF-32)

Code point
Encoding forms

00 00 6F 22 (UTF-32BE)
22 6F 00 00 (UTF-32BE)
Encoding schemes

Fig. 4. E xample of a character and its codepoints and encoding forms/schemes.

characters and scholarly symbols are still continuing.
For actual communication or memory storage ofcharacters, code points must be encoded and serialized. This means that these character code points will
be converted to one or more 8-bit or 16-bit code unit
sequences. UCS defines three encoding forms, namely UTF (UCS Transformation Format)-8, UTF-16,
and UTF-32, and seven encoding schemes, namely,
UTF-8 , UTF-16 , UTF-16BE , UTF-16LE , UTF-32 ,UTF-32BE, and UTF-32LE. An example of their use
is shown in Fig. 4.
Among these, UTF-8 is upward compatible withASCII (American Standard Code for Information
Interchange) character codes and is widely used in
UNIX-based operating systems (OSs) and in communication over the Internet. Windows OS and JavaVM (Virtual Machine) have adopted UTF-16 for theirinternal representation and storage.
UTF-8 will encode UCS code points to one to four
8-bit code units. UTF-16 will encode UCS code
points to one or two 16-bit code units. The correspondence between UCS code points and their UTF-8
encodings are shown in Table 1. As shown in thistable, the first unit of UTF-8 code units can be easily
distinguished among the remaining code units.
3. Ideographic Variation Databaseand its selectors
UCS is used to encode abstract characters. For
example, the ideograph 葛 would have the same character code regardless of its shape or font. However,for some special scholarly, publishing, or administraNTT Technical Review

Global Standardization Activities

Table 1. UTF-8 codepoints.
Codepoints
U+0000–U+007F

Bit arrays

Byte sequences

0xxx xxxx

00-7F

U+0080–U+07FF

110yyyyx 10xxxxxx

C2-DF 80-BF

U+0800–U+FFFF

1110zzzz 10yyyyyy 10xxxxxx

E0-EF 80-BF 80-BF

U+10000–U+10FFFF

11110uuu 10uuzzzz 10yyyyyy 10xx xxxx

F0-F7 80-BF 80-BF 80-BF

tive usages, slight differences in shape that would
otherwise be ignored during encoding have sometimes resulted in significant differences.
For example, in Japanese administrative systems,
Katsushika Ward in Tokyo (葛飾区) and KatsuragiCity (葛城市) in Nara Prefecture would have thesame character “葛” with ordinary character encoding, yet they might be displayed differently in official
administrative documents.
UCS provides a method to differentiate such variants that would otherwise be unified with the Ideographic Variation Database (IVD) and Ideographic
Variation Sequence (IVS). IVD was introduced in2006 as the Unicode Technical Standard (UTS) #37.
This scheme involves attaching the variation selector after the character code, which makes it possible
to represent ideographic variations.
In the above examples of 葛 (Katsushika) and 葛(Katsuragi), the different variations can be specified
as U+845B U+E0103 and U+845B U+E0102, respectively, as shown in Fig. 5. There are 240 variation
selectors for ideographs assigned from U+E0100 to
U+E01EF of the UCS 14th plane.
Currently, the IVD is maintained by the Unicode
Consortium, a nonprofit organization that develops
the Unicode Standard.
According to UTS #37, when someone wants toregister a variation of an ideograph, he/she applies forregistration of variations along with its name to theUnicode Consortium (along with the requested variants).
Then the Unicode Consortium opens the application to public review for three months. After the public review has closed and comments have beenreflected in the application, the Unicode Consortium
will assign an IVS to each glyph.
Currently, two collections are registered: AdobeJapan1 and Hanyo-Denshi. The latter collection ofvariants is registered by the Hanyo-Denshi committeeof Japan for the administration systems of national
and local Japanese governments.

Vol. 11 No. 6 June 2013

Fig. 5. Registered Hanyo-Denshi variation of “葛”.

4. Relationship between domestic andinternational standardization committees
The character coding system is one of the standards
in the information technology (IT) field. International
standards in the IT field are currently established by
Joint Technical Committee One (JTC 1) of the ISO
and the IEC, which is referred to as ISO/IEC JTC 1.
There are about 20 subcommittees in JTC 1, and thesubcommittee working on character encoding standardization is subcommittee 2 (SC 2). SC 2 has one
working group, called WG 2, which is working on
ISO/IEC 10646. WG 2 has entrusted the Ideographic
Rapporteur Group (IRG) with specifically creating
the repertoire of CJK Unified Ideographs for standardization. These committees and subcommittees
are often referred to by their abbreviations. For
example, WG 2 is officially known as ISO/IEC
JTC 1/SC 2/WG 2.
In Japan, the Information Technology Standards
Committee of Japan (ITSCJ), a division of the Information Processing Society of Japan (IPSJ) and
entrusted by the Ministry of Economy, Trade andIndustry, is a corresponding domestic standardizationbody for most subcommittees of ISO/IEC JTC 1.
SC 2 in Japan is working with ISO/IEC JTC 1/SC 2,
SC 2/WG 2, and SC 2/WG 2/IRG, to reflect the Japanese concerns and requirements in international character codes. The relationship between the inter­Global Standardization Activities

Unicode Consortium
Liaison

TC 1
ISO

SC 2

IRG

WG 2

TC 246

International
committees

Joint TC 1

SC 29

TC 1
IEC

SC 39

Japan’s
domestic
correspondence

TC 146
Japanesedomestic
committees

SC 2 of Japan
IPSJ
ITSCJ

TC
SC 39 of Japan

Fig. 6. International and Japanese committees working on character code standardization.

national organizations and the Japanese organizations
is shown in Fig. 6.
5. Future outlook
Most kanji (CJK Unified) ideographs needed forJapanese governmental administration systems areproposed to the IRG as part of Extension F standardization efforts*5. They are expected to be standardized
within the next several years.
As devices such as e-books and studies on thedigital humanities evolve, the character encodings forkanji ideographs used in classical documents will
follow the same path of standardization that ideographs needed for administration systems have. In thecurrent work being done on Extension F, the kanji
ideographs that appear in the classical Buddhist
canon Taisho– Revised Tripit.aka are in the process of
being standardized. These efforts mean that many
more classical documents will be available on ebooks or the Internet in the future.
Emojis (Japanese-style pictorial characters) werealso developed by Japanese mobile phone carriers,
but their standardization in the UCS was initiated byApple and Google, who have developed operating*5 Standardized CJK Ideographs are currently grouped into Unified
Repertoire and Ordering (URO) character sets identified with Extensions. Extensions A to D have already been standardized. Extension E has just passed the vote and will be officially publishednext year. The work on Extension F has just begun.

systems for cellular phones. Emoji characters also
have numerous variations, and to date, nearly 700
characters have been standardized as emoticons andpictographs.
NTT recognizes that standards and technologies
related to character encodings will be crucial in applications involving the web, email, and e-books andservices, and will therefore stay engaged in this technology.

Taichi Kawabata

Research Engineer, Ubiquitous SoftwareGroup, Ubiquitous Service Systems Laboratory,
NTT Network Innovation Laboratories.
He received the M.S. degree in computer science from the University of Tokyo in 1997 andjoined NTT in the same year. He has mainly been
engaged in researching the usage of personal dataon network systems, and has also worked onstandardization activities on character, text
encoding, and related standards in ISO, IEC, andW3C standardization organizations.

NTT Technical Review

Practical Field Information about
Telecommunication Technologies

A Study of a Noise Measurement
Method for Efficient and SmoothTroubleshooting
Abstract

This article describes a study carried out on a noise measurement method in telecommunication lines
to make fault troubleshooting more efficient and smooth. This is the seventeenth in a bimonthly series
on the theme of practical field information on telecommunication technologies. This month’s contribution is from the EMC Engineering Group, Technical Assistance and Support Center, Maintenance andService Operations Department, Network Business Headquarters, NTT EAST.

1. Introduction
Measures for saving energy in electrical and electronic equipment have become more sophisticated inrecent years. Such measures include the adoption ofenergy-saving inverter circuits in the power-supply
parts of equipment. The energy-saving performanceof such circuits is high, but the level of radio interference can also be high if no anti-noise measures aretaken. Noise can also be generated as a result of faults
or insufficient insulation in the power-supply part.
Such noise can penetrate telecommunications equipment in a user’s building or home via a power-supply
line or space and can cause malfunctions in asymmetric digital subscriber line (ADSL) or very-highspeed DSL (VDSL) modems or in the generation of
audible noise.
Measuring the voltages between a telecommunication line and earth (VL1-E or VL2-E) in telecommunication lines when inspecting telecommunication equipment for noise-related faults is one of the most important means of troubleshooting the causes of such
faults. However, this method unfortunately results inthe measurement of noise components not in isolation, but as components of telecommunication signals. As a result, there are times when the noise cannot be clearly identified, which makes it all the moredifficult to troubleshoot the causes of noise. We propose a simple method for separating the external
noise and the signals and have developed a separation
probe as a prototype product incorporating this method. We describe the results of tests that were conducted in our laboratory and in the real field to evaluate the effectiveness of the noise-separation method
and the separation probe in troubleshooting noiserelated faults.
2. Background
The measurement of common mode noise in telecommunication lines when troubleshooting noise
faults is shown in Fig. 1. This method measures voltage between the telecommunication line and a ground(VL1-E or VL2-E). When the telecommunication line is
not in a communication state, the common mode voltage is equivalent to voltage caused by noise. An
example of the results of measuring common modenoise is shown in Fig. 2. In this case, only the noise
waveform was measured, which made it relatively
easy to check for noise. Next, the common modenoise was measured when noise was superposed onan ADSL/VDSL line when the line was in a communication state (Fig. 3). In this case, a signal is continuously applied on the telecommunication lines sothat the measured common mode voltage corresponds
to the signal + noise. An example of the results ofmeasuring common mode noise associated with adropped link in the ADSL service is shown in Fig. 4.
The measured waveform shows that noise is superposed on the signal, which makes it difficult to check
NTT Technical Review

Practical Field Information about Telecommunication Technologies

Noise superposed on analog circuit(common mode)+10

5 ms/div.

Noise(Voltage)

Telecommunication line
L1
Noise

0

L2
VL2-E

VL1-E
–10

Ground (E)(Time)

Fig. 1. Noise measurement on analog line.

Fig. 2. N oise waveform superposed on analog line.

Noise superposed on telecommunicationlines (common mode)+4

20 ms/div.

Noise

Telecommunication line
L1

Noise
Signal(Voltage)

Signal0

Dropped link

L2
VL2-E

VL1-E

Ground (E)–4(Time)

Fig. 3. Noise measurement on ADSL/VDSL line.

Fig. 4. Noise waveform superposed on ADSL line.

for the presence of the noise and adds to the timerequired for fault troubleshooting. A device such as aseparation probe was therefore needed that could
make fault troubleshooting more efficient by separating and extracting the fault-causing noise from thesignals.

determined by Eq. (1) according to the definition ofcommon mode voltage [1].

3. Separation of noise and signals
The conventional method of measuring common
mode noise (VL1-E or VL2-E) involves measuring voltage when the noise and the signal are superposed, as
described above. In order to separate the noise, we
use the results of two measurements: the common
mode voltage between L1 and E and that between L2and E. It is known that noise can be approximately
Vol. 11 No. 6 June 2013noise ≈ VL1-E +VL2-E (1)
2At the same time, the signal can be approximately
determined by Eq. (2).
signal ≈ VL1-E −VL2-E

(2)

4. Separation probe and test results
4.1 Overview of separation probe
Our prototype separation probe achieves the functions expressed by Eqs. (1) and (2). The configurationof the probe is shown in Fig. 5, and an external view

Practical Field Information about Telecommunication Technologies

SignalNoise
CH 1 input(L1-E voltage)

Telecommunication line

VL1-E
CH 2 input(L2-E voltage)

Adder output
Input

Adder

Vnoise(common mode)

HPF switch
1 Hz/500 Hz

Subtractor output
Subtractor

Input
VL2-E

OutputOutputExternal power supply (+/-12 V)
External power
supply input

Ground (E)Battery
Low battery
Power
LED
supplyswitch

DC-DCconverter

Vsignal(normal mode)

Power
LED

OscilloscopeInternal
circuits

CH: channel
DC: direct current
HPF: high-pass filter

Fig. 5. Configuration of separation probe.

of the probe is shown in Fig. 6. The separation probe
consists of input parts, an adder and subtractor, output
parts, and a power supply. In common mode measurement, the L1-E and L2-E voltages are measured byusing a high-impedance probe connected to each of
the input parts. The results of these measurements areprocessed in an analog manner by additive (Vnoise)and subtractive (Vsignal) processing and then output toan oscilloscope. The power supply can be fed to theprobe’s main unit by either an internal battery or an
external power supply from the oscilloscope.
4.2 Results of laboratory test
In order to test the separation probe, we applied an
external 160-kHz sinusoidal wave as common modenoise to the signals of an ADSL line. The measurement results using the separation probe are shown in
Fig. 7. The upper half of the figure shows the noisevoltage waveform and the lower half the signal voltage waveform. These results show that the 160-kHz
sinusoidal wave applied as the noise was able to be
extracted, which made it possible to observe the signal waveform with the noise component separated
from it. In other words, the results of this test demonstrated that the separation probe functioned effectively. For reference, the VL1-E and VL2-E voltage
waveforms measured by the conventional technique
are shown in Fig. 8. These results show that it is difficult to confirm the existence of a 160-kHz sinusoidal wave applied as noise from conventionally measured waveforms.


Main unit
Input(voltagemeasurement)

Output(oscilloscope)Fig. 6. External view of separation probe.

4.3 Results of field test
We also examined the effectiveness of applying ourseparation probe for troubleshooting in the case of a
dropped link in ADSL services. In the following, we
introduce one of three tests that we performed in thefield.
(1) Fault description
Dropped links in the ADSL line in a tenantbuilding frequently occurred between 9:00–
10:00 AM.
(2) Facilities overview and noise measurement
An overview of the actual facilities in the field
is shown in Fig. 9. The ADSL line was connected to the tenant’s ADSL modem via a main
distributing frame (MDF). The noise voltage on
the signal line was measured at the MDF using
the separation probe.
(3) Measurement results
The noise waveform at the time the ADSLNTT Technical Review

Practical Field Information about Telecommunication Technologies+5+5

20 µs/div.

Vnoise0
1 Vp-pAdder output

160 kHz–5+5(Voltage)(Voltage)

0

0

–5

20 µs/div.

VL1-E

–5
+5

20 µs/div.

0
VsignalSubtractor output

–5

VL2-E

(Time)(Time)

Fig. 8. VL1-E and VL2-E measured waveforms.

Fig. 7. Waveforms measured by separation probe.

Tenant’s building
Measurement point

Tenant

MDF
FLET’S ADSL
MORE II (24 M)

ADSL
modem
NV

Splitter

Non-NTTfax

Powertransformer

AC/DC power
supplyadaptor

Hub

PC

Hub

PC

Non-NTT
wirelessrouter

AC100V

AC: alternating current
PC: personal computer

Fig. 9. Overview of actual facilities in the field.

signal is lost is shown in Fig. 10. The upper halfof the figure shows the noise waveform and thebottom half the signal waveform. An examination of the noise waveform on top shows that themeasurement of noise was unaffected by thesignal.
The frequency spectrum obtained by subjecting thisnoise waveform to fast Fourier transform (FFT)
analysis is shown in Fig. 11. When the waveforms of
Fig. 11(a) (with noise) and Fig. 11(b) (without noise)are compared, it can be seen that the noise level isVol. 11 No. 6 June 2013high in the frequency band of 80 kHz–1 MHz. The
noise was found to fall within the frequency band
used for ADSL signals (28 kHz–3.75 MHz). Thisparticular test case therefore clarified that the superposing of the noise on the signal resulted in a dropped
link of the ADSL line. Additionally, we found that the
separation probe used in this test and other tests was
effective for quickly checking for noise and reducing
the time required to troubleshoot faults. In this test
case, moreover, the signal voltage level was 9 Vp-p,
which was much higher than the noise voltage levelPractical Field Information about Telecommunication Technologies–10

Dropped link–20
+5 (a) with noise

–30
–40

0
–5 (b) without noise
+5

(dBV)

(Voltage)Noise

20 ms/div.

with noise–50(a) with noise(b) without noise

–60
–70

Signal 0
–5

–80
–90
1k

ADSL signal(Time)

10 k

100 k
(Hz)

1M

10 M

Fig. 10. Waveforms measured by separation probe.

Fig. 11. Comparison of FFT analysis results.

of 1 Vp-p. This suggests that use of the conventional
method would make it difficult to check for the presence of noise at such a low level and would require
more time to troubleshoot the cause of the fault.

we plan to conduct more evaluations in the field toimprove the accuracy of the probe and to study thefeasibility of commercializing it. We are committed
to developing methods for quickly solving noise
faults and will continue to carry out work that supports the provision of safe and secure telecommunication services.

5. Conclusion
We developed a probe for separating noise from atelecommunication signal and tested it in both thelaboratory and the field using ADSL lines. Test
results showed that the separation probe was effective
in extracting the noise component even if the noiselevel was lower than that of the signal. In the future,

Reference[1]

Y. Ogura, K. Tominaga, Y. Okugawa, H. Itou, and K. Murakawa,“Experimental studies of separation between telecom signal and noiseof common mode noise,” IEICE Technical Reports, Vol. 112, No. 201,
EMCJ2012-58, pp. 35–40, 2012 (in Japanese).

NTT Technical Review

External Awards
International Workshop on Nitride Semiconductors 2012
Best Paper Award
Winners: Yoshitaka Taniyasu†1, Jean-François Carlin†2, Antonino
Castiglia†2, Raphaël Butté†2, and Nicolas Grandjean†2†1	 NTT Basic Research Laboratories†2 Ecole Polytechnique Fédérale de LausanneDate: October 19, 2012
Organization: International Workshop on Nitride Semiconductors
For “AlInN/GaN MQW UV-LEDs”.
Among III-Nitride semiconductors, the AlInN can only be grownlattice-matched to GaN. The lattice-matched AlInN/GaN structure
should be free from cracks and strain-driven defects, which limit theperformance of UV/Visible LEDs and LDs using conventional lattice-mismatched AlGaN/GaN and InGaN/GaN structures. In addi-tion, the AlInN/GaN structure has a larger bandgap discontinuity anda larger refractive index contrast, which more strongly confine theinjected carriers in the quantum wells and the emitted light in theactive region. Thus, the AlInN/GaN structures are expected not only
to improve the device properties but also to increase the design flexibility for novel III-nitride devices. Here we report the achievementof p-type doping in AlInN and describe AlInN-based light-emitting
devices.
Fellowship in the American Physical Society
Winner: William John Munro, NTT Basic Research Laboratories
Date: November 3, 2012
Organization: American Physical Society
For his extensive contributions to applied quantum information.

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