NTT Technical Review
June 2011 Vol. 9 No. 6
Feature Articles:
Services for Hikari Era: Terminal Component Technologies
Service and Terminal Component Technology Development Initiatives for
the Optical Fiber Broadband Era (Hikari Era)
Voice Processing Technology for
Realistic-quality Voice and Rich Telecommunication Services
Visual Softphone: New Ways to Communicate
Software H.264 Encoder Engine forOnline Video Delivery Service Cost Reduction
Network Processing Technology for
Terminals Enabling High-quality Services

Regular Articles
Cabling Technologies Providing More Optical Cabling Potential
in Multi-dwelling Unit Buildings
Lower-cost Cicada-resistant Optical Fiber Drop Cable
with Better Workability

Global Standardization Activities
Standardization Activities for Cloud Computing

Practical Field Information about Telecommunication
Technologies
Fault Cases and Countermeasures against
Damage to Access System Facilities Caused by Wildlife

External Awards/Papers Published inTechnical Journals and Conference Proceedings
External Awards/Papers Published inTechnical Journals and Conference Proceedings

Feature Articles: Services for Hikari Era: Terminal Component Technologies

Service and Terminal Component
Technology Development Initiatives
for the Optical Fiber Broadband Era(Hikari Era)
Hirohito Inagaki†, Takehiko Ohno, Atsushi Sato,
Koyo Nitta, Hisashi Uematsu, Akira Nakagawa, andShinichiro Chaki
Abstract

In the optical fiber broadband era (hikari era), which has just begun, optical fiber is being used totransmit large amounts of digital information at high speed. It enables the provision of a great variety ofservices to users and this variety will increase even more in the future. We introduce various research anddevelopment activities for terminal component technologies.

1. Introduction
The functionalities of terminals can be divided into
three broad types: human interface functions, processing functions, and network functions. Our main
aim for terminal research and development (R&D) in
the optical fiber broadband era (hikari* era), which
has just begun, is to make use of communications
media, freely handle multiple types of media, havevarious types of media processing, and exploit all ofthese fully for the provision of many services of various types. For example, while the conventional communications terminal, an analog phone, can transmit
only 3.4-kHz sound, hikari-era terminals will support
a diverse range of medium types such as photographs,
video, and data at any time as well as a diverse range
within each medium (e.g., wideband or multichannelsound, high-resolution images, and video). Furthermore, in addition to supporting person-to-person
communications, terminals will also need to exchange
various types of data with servers. Hikari-era termi† NTT Cyber Space Laboratories
Yokosuka-shi, 239-0847 Japannals will provide various services using large amountsof various media over the network for person-to-person and person-to-server communication.
2. Terminal component elements
Terminal functions can be divided into humaninterface, processing, and network functions, butthese are implemented in either hardware or software.
Terminal component elements are shown in Fig. 1.
Interface functions are implemented by a combination of the terminal shape and mechanisms that terminals are equipped with, touch panels, displays, handsets, keys, and other input/output devices.
Network functions can be implemented using software or with a network processor to utilize the highspeed of hardware. In particular, in the hikari era, it
must be possible to process high-volume media suchas video (consisting of streams of large packets) without excessive delay and fixed-length packets such as
VoIP (voice over Internet protocol) packets (within adelay of a few milliseconds, without any packet loss).
*

Hikari is the Japanese word for light.

NTT Technical Review

Feature Articles

STB for IPTV
Gateway

Softphone
IP telephone (videophone)

Telephone

Humaninterface
functions
Processing
functions

NetworkfunctionsWideband telephoneLifesupport

IPTV

TV

…

Case
Software: application
Middleware,
protocol, codec engine
Operating system

SIP

UPnP

DLNA

Audio
codec

Video
codec

Networkprocessor

EmbeddedCPU

Browser…

…

Hardware: input/output device,other devices
Chip, LSI

Graphics
processor

Codec…
(hardware)

Board
Functionality ofterminal

Basis components

Examples of components
CPU: central processing unit
LSI: large-scale integrated circuit
STB: set-top box
TV: television
UPnP: Universal Plug and Play

Fig. 1. Terminal component elements.

Because of this, network processor technology able
to process packets at high speed is very important.
The Feature Article in this issue entitled “Network
Processing Technology for Terminals Enabling Highquality Services” [1] provides an introduction tothese technologies.
Each processing function in a terminal is implemented with middleware and application software,
but for sound, video, and other media processing inparticular, the codec (coder/decoder) technology isvery important. To implement a VoIP service withwideband sound, one must use appropriate audio
codecs and input/output devices such as microphones
and speakers to transmit and receive sound. Technology components for new hikari-era VoIP terminals
that surpass ordinary 3.4-kHz analog sound are introduced in the article “Voice Processing Technology for
Realistic-quality Voice and Rich Telecommunication
Services” [2].
Moreover, in addition to audio codecs, video codecs
are also important for communication by means ofvideo. There are many possible applications for video
codecs, from realtime bidirectional communication
Vol. 9 No. 6 June 2011

such as video-telephony to services distributing videofrom a server. Comfortable communication by video
telephony and other bidirectional applications
requires a low delay and high video quality, whileservices that distribute a variety of video content,such as IPTV (Internet protocol television) shouldhave high video quality and a low distribution cost.
The characteristics of the codec used must match theapplication. Video codec technologies for distributing
video are described in the article “Software H.264
Encoder Engine for Online Video Delivery Service
Cost Reduction” [3].
To enable the handling of various types of media,
codecs alone are not enough. Also important are
middleware, such as session initiation protocol (SIP)
for call control functions and software based on
Digital Living Network Alliance (DLNA) protocols
for handling media, and specifications for how thecodecs and middleware will be used when terminals
communicate with each other. Specifications governing communications between terminals are called
teleservice specifications. It is necessary to define theusage of low-layer network attributes as well asFeature Articles

Analog telephone

NGN
and other
networks

Gateway

IP telephone (videophone)
STB for IPTV

Television

Personal computer
Mobile phone
Game terminal

NGN: Next Generation Network

PrinterFig. 2. Example of terminal connections in a home environment.

high-layer attributes available between terminals
equipped with these network functions when they
connect to each other. With ISDN (integrated services
digital network), the main teleservices included telephony, fax, videotelephony, and telex, but in the
hikari era, services will freely allow switching
between various types of media in addition to theconventional ISDN teleservices. The article “Visual
Softphone: New Ways to Communicate” [4] introduces the visual softphone as a terminal for the hikariera. The visual softphone can communicate using
various types of data including photographs andvideo, while also handling voice and videophone
communication.
The technical development of these various terminal components, from hardware to middleware, isbecoming more important for achieving rich newservices.
3. Home environments
In the hikari era, how will the various terminals be
placed in the home and how will they be connected
together? In the analog and ISDN eras, homes were
wired with telephone and ISDN cables to connect
telephones, but in the hikari era, optical fiber cable
will be brought right to the home and connected to ahome gateway, and various types of terminals will beconnected to this home gateway. An example of terminal connections in a home environment is shown inFig. 2. Multiple terminals will be connected and multiple types of media (video, sound, data, etc.) will be
used over IP channels in addition to voice. Various
existing IP communications technologies can also be
utilized, from existing Ethernet cables to various
wireless technologies (IEEE 802.11a, b, g, n, etc.),
power-line communications, coaxial communications, etc.
With the increase in the number of choices for users
and the ability to wire a home according to conditions
there, it is becoming increasingly difficult to maintainthe home environment. Wiring for conventional analog telephones or ISDN was simple, but in the hikariera, each room in a house can hold various types ofterminal and each can be connected in various ways,
creating a multitude of possibilities. Conventional
office local area networks could be managed using
protocols such as simple network management protocol (SNMP), but there is no standard management
protocol like SNMP for home devices. This makes it
difficult to determine what devices are connected to
the network and the state of each device. Even thoughprotocols such as Universal Plug and Play (UPnP)and DLNA provide some information about deviceson the network, not all devices support these protocols, and the information they provide is limited.
Therefore, we are developing a home network diagnosis tool [5] that makes it easier to obtain information about what devices are present and whether or
not they are operating normally at the IP level by
NTT Technical Review

Feature Articles

analyzing packets flowing between them on the network. This tool will enable engineers to detect problems in home networks and repair them quickly.
Expert knowledge is generally required for network
maintenance, and it is difficult to find highly skilled
maintenance workers. This technology makes maintenance much easier by providing support functions
such as rule-based interactive diagnostics and aneasy-to-understand network map of connected devices designed for maintenance people with less experience.

References
[1]

[2]

[3]

4. Concluding remarks[4]

We have provided a simple introduction to the stateof R&D activities for terminal component technologies for the hikari era and home environments wherethese various terminals will be used. In the future, wewill continue to conduct R&D of various services andterminal component technologies to promote thespread of these terminals in the hikari era.

Vol. 9 No. 6 June 2011

[5]

Y. Nishida and K. Koike, “Network Processing Technology for Terminals Enabling High-quality Services,” NTT Technical Review, Vol. 9,
No. 6, 2011.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2011
06fa5.html
H. Ohmuro, M. Okamoto, S. Saito, S. Emura, and S. Sakauchi, “Voice
Processing Technology for Realistic-quality Voice and Rich Telecommunication Services,” NTT Technical Review, Vol. 9, No. 6, 2011.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2011
06fa2.html
M. Kitahara, N. Ono, and A. Shimizu, “Software H.264 Encoder
Engine for Online Video Delivery Service Cost Reductions,” NTT
Technical Review, Vol. 9, No. 6, 2011.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2011
06fa4.html
K. Kanaya, H. Ohata, D. Ando, M. Moriuchi, H. Jinzenji, and J. Ikedo,“Visual Softphone: New Ways to Communicate,” NTT Technical
Review, Vol. 9, No. 6, 2011.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2011
06fa3.html
T. Ohno, K. Saito, M. Miyamoto, and Y. Kato, “Support for Problem
Solving in Ill-structured Problem Space: An Empirical Study in Home
Network Troubleshooting,” IPSJ Journal, Vol. 2009-HCI-134, No. 7,
pp. 1–8, 2009.

Feature Articles

Hirohito Inagaki

Executive Research Engineer, Speech, Acoustics and Language Laboratory, Project Manager,
NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from Keio University, Kanagawa, in 1984 and 1986, respectively. Sincejoining NTT Electrical Communication Laboratories in 1986, he has been engaged in R&D ofnatural language processing and its applications.
From 1994 through 1997, he was on transfer to
NTT Intelligent Technology Co., Ltd., where heengaged in the development of information security systems and multimedia systems. His
research interests include network appliancearchitectures. He is a member of the Institute ofElectronics, Information and Communication
Engineers (IEICE).

Takehiko Ohno

Senior Research Engineer, Supervisor, Human
Interaction Project, NTT Cyber Solutions Laboratories.
He received the B.Sc. and M.Sc. degrees from
Tokyo Institute of Technology in 1992 and 1994,
respectively. His fields of research include
human-computer interaction, human-centeredsystem design, gaze tracking technology and its
applications, cognitive modeling, information
appliances, computer-mediated communication,and usability studies. He is a member of the
Association for Computing Machinery, Information Processing Society of Japan, Japan Cognitive Science Society, and IEICE.

Atsushi Sato

Senior Research Engineer, Supervisor, First
Promotion Project, NTT Cyber Space Laboratories.
He received the B.S. degree in mechanical sciences and engineering and the M.E. degree in
information processing from Tokyo Institute ofTechnology in 1987 and 1989, respectively. After
joining NTT Human Interface Laboratories in
1989, he was mainly engaged in R&D of computer vision and medical image processing systems. Recently, he has been engaged in thedevelopment of visual (multimedia) communication systems.

Koyo Nitta

Senior Research Engineer, NTT Cyber Space
Laboratories.
He received the B.E. and M.E. degrees in information science from Kyoto University in 1993
and 1995, respectively. In 1995, he joined the LSILaboratories, where he engaged in R&D of avideo encoder architecture and parallel signal
processing.

Hisashi Uematsu

Senior Research Engineer, NTT Cyber Space
Laboratories.
He received the B.E. and M.E. degrees in 1991
and 1993 and the Ph.D. degree in information
science in 1996 from Tohoku University, Miyagi.
In 1996, he joined NTT Basic Research Laboratories, where he worked in the field of perception
processes of the human auditory system. He iscurrently engaged in R&D of basic technologies
and architectures for user equipment. He is amember of the Acoustical Society of Japan(ASJ).

Akira Nakagawa

Senior Research Engineer, NTT Cyber Space
Laboratories.
He received the B.E. and M.E. degrees from
Kyushu Institute of Technology, Fukuoka, in
1992 and 1994, respectively. In 1994, he joined
NTT Human Interface Laboratories, where heengaged in R&D of echo cancellation. He is amember of ASJ.

Shinichiro Chaki

First Promotion Project Manager, NTT CyberSpace Laboratories.
He received the B.E. degree from Sophia University, Tokyo, and the M.E. degree from Waseda
University, Tokyo, in 1986 and 1988, respectively. In 1988, he joined NTT Switching System
Laboratories, where he worked on the development of an ATM traffic control scheme and thefirst commercial ATM switching system forframe relay service. From 1998, he worked on
the standardization of the VB5 interface in ITU-T
and the development of a B-PON system for the
ATM Mega-data link service in NTT AccessNetwork Service Systems Laboratories. In 2002,
he joined NTT Service Integration Laboratories,
where he engaged in basic network design for
FLET’S Hikari Premium service based on IPv6
technology. In 2004, he engaged in R&D ofadded-value functions for the transport network.
He also designed a logical IP network for the
NGN. He is currently engaged in R&D of basic
technologies and architectures for user equipment. He is a member of IEEE and IEICE.

NTT Technical Review

Feature Articles: Services for Hikari Era: Terminal Component Technologies

Voice Processing Technology for
Realistic-quality Voice andRich Telecommunication Services
Hitoshi Ohmuro†, Manabu Okamoto, Shoichiro Saito,
Satoru Emura, and Sumitaka Sakauchi
Abstract

This article describes the speech coding, acoustic design, and signal processing technologies for thehigh-quality telephone service that NTT provides over the Next Generation Network (NGN). Since theconventional telephone system uses a limited frequency range less than that of the human voice, voice
individuality and clarity are sometimes insufficient. On the other hand, the high-quality NGN telephoneservice enables realistic-quality voice communication. A stereo conference phone under development
for future services is also described.

1. Realistic-quality voice
In 2008, NTT launched a new IP (Internet protocol)
telephone service called HIKARI DENWA*1 [1] over
FLET’S HIKARI NEXT [2], its optical fiber subscriber line service. This is a telephone service basedon voice-over-IP (VoIP) technology, and it optionallyprovides multimedia communications that enables auser to make calls in the same way as normal telephone calls. One of the optional services is a highquality telephone service. Conventional telephones
use only the human voice components in the frequency range from 300 Hz to 3.4 kHz. This limitation
sometimes leads to insufficient individuality andsimilar words may be misheard. High-quality telephones use components in the range from 50 Hz to 7
kHz: twice the width of conventional telephones.
This enables telecommunication with realistic-quality voice.
2. Speech coding technology
To enable speech signals to be transmitted over
† NTT Cyber Space Laboratories
Yokosuka-shi, 239-0847 Japan

digital or packet networks, speech coding technology
is used. The encoder and decoder together are calleda codec. The legacy analog telephone system uses
ITU-T G.711 codecs at subscriber switchboards(ITU-T: International Telecommunication Union,
Telecommunication Standardization Sector). By contrast, in the HIKARI DENWA system, the codec is
implemented in each terminal, i.e., an IP phone terminal or home gateway. When a user makes a normal
telephone call over HIKARI DENWA, the G.711
codec is used, as in the conventional telephone service; when a user makes a high-quality telephone
call, a wideband codec is used. The codec to be used
for a telephone call is determined automatically by
negotiation between the calling and receiving terminals by means of session initiation protocol (SIP)
signaling. One well-known wideband codec is ITU-T
G.722, which has been used for video and audio conferencing systems over ISDN (integrated services
digital network) and IP networks and has recently
begun to be used for IP phones.
Even when a wideband codec is used for a telephone call, the same functions as in a conventional*1	 Hikari is the Japanese word for light; denwa is the Japanese word
for telephone.

NTT Technical Review

Feature Articles

Power

50 Hz

7 kHz

Wideband speech

300 Hz3.4 kHz

LegacytelephonespeechLower-band
enhancement

Higher-band
enhancement

Layer 2

Enhancement bits
(16 kbit/s)

Layer 1

Enhanchment bits
(6 kbit/s)

Layer 0G.711 bits
(64 kbit/s)

Frequency bandwidth

Higher-band
enhancement layer
Lower-band
enhancement layerCore layercompatible withlegacy telephone
speechBitstream structure

Fig. 1. Scalable coding.

Handset receiving characteristics
30

20

20

Response (dB)

Response (dB)

Handset sending characteristics
30
10
0
−10
−20
−30
100

1000
Frequency (Hz)10,000

10
0
−10
−20
−30
100

1000
Frequency (Hz)10,000Fig. 2. Transmission characteristics for wideband telephone in CIAJ standards (CES-Q004).

telephone service, e.g., call waiting and call transfer,should be provided. However, codec negotiation isoften problematic in this case. Codec negotiation was
not considered before because there was only one
codec: G.711. However, when G.711 and a wideband
codec are used together, the codec should be switchedappropriately.
To solve this problem, NTT Cyber Space Laboratories developed a scalable codec that extends the conventional G.711 and standardized it as ITU-T
G.711.1. As shown in Fig. 1, this scalable codec hasa multilayer structure consisting of a G.711 layer,
lower-band enhancement layer, and higher-band
enhancement layer. The G.711 layer is compatible
with the conventional G.711 codec. This structure canbe understood in terms of building blocks. G.711 andG.711.1 are easily converted to each other by extracting some blocks or by adding required blocks. Therefore, the use of G.711.1 enables wideband speech tobe easily applied for conventional call functions, suchas call waiting, call transfer, and multipoint teleconferencing [3].
Vol. 9 No. 6 June 2011

3. Design strategy for high-quality handset
A handset is the most basic acoustic device for atelephone. A high-quality telephone cannot be madejust by implementing wideband speech codec software. A normal handset is designed for narrowband(from 300 Hz to 3.4 kHz) speech, and it cannot pickup or reproduce over-3.4-kHz speech. We need ahandset design for wideband speech and a standard
for its characteristics.
The Communication and Information Network
Association of Japan (CIAJ) standardized transmission characteristics for wideband (from 150 Hz to 7kHz) digital handset telephones as CES-Q004 in
2007. CES-Q004 requires a wideband telephone to beable to send speech with a frequency range from 125
Hz to 6.3 kHz and receive speech ranging from 160
Hz to 6.3 kHz. The characteristics required for thehandset are shown in Fig. 2.
We can use acoustic design knowledge for audio
and broadcasting to design hands-free devices forcommunication using over-3.4-kHz speech. However,Feature Articles

Sound holes
Microphone unit
Air cabinet

Earphone
Microphone (cross section)

Fig. 3. High-quality telephone for NGN trial (NP-1).

this knowledge cannot be used for handsets: thedesign of a wideband handset is a new endeavor. The
selection of a microphone and an earphone driverunit, the method of enclosing these units in a handset,
noise suppression by circuit design, and equalizationof frequency characteristics by signal processing areimportant for a high-quality handset design.
We developed the first high-quality telephone NP-1
for a trial of the Next Generation Network (NGN) in
2007. The handset uses microphone and earphone
driver units intended for audio products rather thanfor telephones. The units were enclosed, and wemade a small air cabinet in front of each unit. We
adjusted the volume and shapes of the cabinets andthe placement of sound holes for the earphone(Fig. 3). As a result, the handset achieved flat frequency characteristics up to 7 kHz. Generally, a flatfrequency earphone is more difficult to design than aflat-frequency microphone. The best design method
differs according to the acoustic driver units that canbe used. Therefore, when designing a handset, onemust leave room for making sound holes and an air
cabinet.
Noise suppression is not considered for the under300-Hz or over-3.4-kHz frequency ranges in the circuits of a normal telephone. For wideband use, thecircuits must be redesigned. If standard characteristics are not satisfied by the microphone and earphone
designs, then the use of additional signal processing
is an efficient measure.
We developed a high-quality Wi-Fi telephone as aprototype in 2009 (Fig. 4). It has a very small bodyfor portability and does not have air cabinets. For ahigh-quality handset design, only large sound holes
were added. The standard characteristics were satisfied by selecting an acoustic driver unit and by equalizing sound through signal processing.

Sound holes

Fig. 4. High-quality Wi-Fi telephone.

4. Echo canceller
Hands-free speakerphones are useful for conversation and for sharing information among several people, while phone calls via a handset are suitable for
one-to-one communications because the voice isheard only by the far-end speaker. Hands-free phones
did not used to be widely utilized except for specificsituations such as business teleconferences. In recent
years, however, high-performance mobile terminals
like netbooks or smartphones have become prevalent,and hands-free calls using those small devices havebecome more popular.
When you talk on a hands-free telephone (Fig. 5),
the voice of the far-end speaker emitted from theloudspeaker is picked up by the microphone and sent
back to the far-end speaker. In other words, the farend speaker hears his or her own voice like an echo.
To avoid this phenomenon, most hands-free speakerphones and conferencing systems are equipped withecho cancellers, which decrease or eliminate the echothrough signal processing. If the environments at
both ends are quiet enough and the echo is not too
NTT Technical Review

Feature Articles

Loudspeaker
Hello

Hello
Echo
canceller

Echo

Network

Echocanceller

Echo

Hi

Hi
Microphone

Fig. 5. Hands-free telephone.

Far-end speaker’s voice x ω ( k )Frequency
Echo model
Noise model

Updatecontroller0

Echo
calculation

Echo
Near-end speaker’s voiceeω

Histogram of ratio
between error andfar-end speaker’s voicexω
Error signal e ω ( k )NoiseFig. 6. Noise-robust echo cancellation.

loud, most of these echo cancellers work properly.
However, echo cancellation in small devices such as
smartphones has two technical problems: the treatment of ambient noise and appropriate hardware
design for the device.
Ambient noise deteriorates the echo canceller’s
performance, especially the adaptive filter’s performance. An echo canceller usually has an adaptive
filter for estimating the acoustic echo path and calculating the pseudo-echo signal. This estimation is done
only when the loudspeaker emits sounds and thenear-end speaker does not talk. The microphone picks
up only the echo signal, and the adaptive filter estimates the acoustic echo path so that the calculated
pseudo-echo can be made equal to the observed signal. If the acoustic echo path is estimated precisely,
the echo canceller can eliminate the echo from thesending voice even when the speakers at both ends
talk simultaneously (called the double-talk state).
However, if the observed signal is contaminated byVol. 9 No. 6 June 2011

ambient noise, the estimated echo path has a large
amount of error. As a result, the echo canceller cannot
eliminate the echo and the remaining echo interfereswith communication.
Our new technology, noise-robust echo cancellation (Fig. 6), enables echo path estimation by meansof an adaptive filter that is less sensitive to ambient
noise. This technology uses the ratio of the noise in
the microphone signal and controls the update speedof the acoustic echo path. Specifically, the update
controller in Fig. 6 calculates the ratio between the
far-end speaker signal and the error signal. It thendetermines whether the noise is dominant within theerror signal on the basis of the ratio’s statistical distribution. The more noise included in the error signal,
the more the update controller decreases the update
speed. An echo canceller using this technology cancels echoes three times as much as the conventionalecho canceller in a noisy environment, and this performance is suitable for most conditions for hands-freeFeature Articles

Point-to-point conferencing(Stereo sound makes conferencing immersive.)

Multipoint conferencing(You can immediately recognize who is talking from where.)

Osaka

London

New York

Network
Tokyo

Fig. 7. Typical usages of stereo conference phone.

telephone calls.
The other problem is hardware design. In a small
device, the loudspeaker and microphone are locatedmuch closer together than in ordinary videoconference systems, and the echo signal is too large toeliminate. Therefore, some ingenuity is needed tomake an echo canceller that works well. One solution
is to use a directional microphone and locate its lowsensitivity direction toward the loudspeaker in order
to avoid picking up echoes. In addition, sound propagating directly along the device’s housing to themicrophone must be reduced. Adding a rib tostrengthen the housing structure, dividing the space
between the loudspeaker and microphone, and attaching the microphone to the housing by rubber orsponge mountings, for example, are effective ways toreduce the propagation of vibration from the loudspeaker. It is very difficult to know what the optimalecho cancellation structure is or how to design the
hardware; the current design is mainly based on experience. We are considering calculating the optimal
structure by computer simulation in the future.
We have now achieved echo cancellation in a small
device with performance equivalent to that of an ordinary (large) hands-free telephone. The HIKARI
FLET’S phone VP3000 [4], which uses the technologies described above, is now available from NTT
EAST and NTT WEST.
5. Stereo conference phone
In recent years, audioconferencing and videocon

ferencing have been in strong demand in order to cut
the cost of business trips and reduce the environmental load. Though audioconferencing (using telephones) is inexpensive, easy to use, and more popularthan videoconferencing, it has two drawbacks: it ishard to judge who is talking at the remote site and itis hard to sense the atmosphere at the remote site.
To address these drawbacks, we are developing a
new stereo conference phone with 14-kHz stereo
sound that corresponds to the quality of FM (frequency modulation) radio. The use of wideband stereo sound makes it easier for people to understand thesituation at the remote site.
The stereo conference phone has three features: a
14-kHz audio codec, automatic gain control, and amultimodal display. We extended the 7-kHz codec
G.711.1 to 14 kHz. This codec is already standardized as G.711.1 Annex D (G.711.1 SWB). Automatic
gain control improves listenability by adjusting voicelevels moderately depending on whether the talker is
far from or close to the conference phone. The multimodal display uses light emitting diodes and changes
their lighting pattern according to the balance
between the left and right channels and the levels of
stereo sound. This helps users determine who is
speaking where at the remote site.
Typical uses of the stereo conference phone areshown in Fig. 7. In point-to-point conferencing, FMquality stereo sound can deliver not only voices but
also ambient sound in the remote site vividly. The
multimodal display visually assists users in determining who is talking at the remote site. This makes
NTT Technical Review

Feature Articles

phone conferencing increasingly immersive. In multipoint conferencing, our new stereo conferencephone can reproduce sound from each site at a separate position. This overcomes the problem of ordinary
multipoint conference phones, which mix voices intomonaural sound with the result that you cannot
immediately distinguish who is talking from where.
Our stereo conference phone makes conferencing
more efficient and productive. It can also be used asexternal hands-free audio equipment with videoconferencing software for a personal computer (PC).
Since this audio equipment is self-contained and notuning is necessary, it will make PC-based high-defi-

Hitoshi Ohmuro

nition videoconferencing tools more convenient.
References
[1]
[2]
[3]

[4]

HIKARI DENWA.
http://flets.com/english/hikaridenwa/index.html
FLET’S HIKARI NEXT
http://flets.com/english/next/index.html
S. Sasaki, T. Mori, Y. Hiwasaki, and H. Ohmuro, “Global Standard for
Wideband Speech Coding: ITU-T G.711.1 (G.711 wideband extension),” NTT Technical Review, Vol. 6, No. 8, 2008.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2008
08le1.html
HIKARI FLET’S Phone (in Japanese).
http://flets.com/fletsphone/VP3000/

Satoru Emura

Senior Research Engineer, Supervisor, Promotion Project 1, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from Nagoya University,
Aichi, in 1988 and 1990, respectively. Since joining NTT Human Interface Laboratories in 1990,
he has been researching speech coding. He contributed to ITU-T G.711.1 standardization. He iscurrently developing VoIP applications and terminals. He is a member of IEEE, the Institute ofElectronics, Information and Communication
Engineers (IEICE), and the Acoustical Society ofJapan (ASJ).

Senior Research Engineer, Promotion Project
1, NTT Cyber Space Laboratories.
He received the B.E., M.E., and D.E. degrees
from the University of Tokyo in 1992, 1994, and1997, respectively. Since joining NTT Human
Interface Laboratories in 1997, he has been
researching adaptive signal processing. He is amember of IEEE, IEICE, and ASJ.

Manabu Okamoto

Sumitaka Sakauchi

Senior Research Engineer, Supervisor, Promotion Project 1, NTT Cyber Space Laboratories.
He received a masters degree in design from
Kyushu Institute of Design, Fukuoka, in 1991
and a doctor’s degree in design from Kyushu
University, Fukuoka, in 2007. Since joining NTT
Electrical Communication Laboratories in 1991,
he has been researching the acoustic design ofvarious kinds of teleconferencing systems. He isa member of IEICE and ASJ.

Senior Research Engineer, Promotion Project
1, NTT Cyber Space Laboratories.
He received the B.S. degree in physics from
Yamagata University in 1993, the M.S. degree inphysics from Tohoku University, Miyagi, in
1995, and the Ph.D. degree in engineering from
Tsukuba University, Ibaraki, in 2005. Since joining NTT Human Interface Laboratories in 1995,
he has been researching acoustic echo cancellers
and noise reduction. He received the Best Paper
Award from IEICE in 2001. He is a member of
IEICE and ASJ.

Shoichiro Saito

Engineer, Speech, Acoustics and Language
Laboratory, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees fromthe University of Tokyo in 2005 and 2007,
respectively. Since joining NTT Cyber Space
Laboratories in 2007, he has been engaged inresearch on echo cancellers and the developmentof hands-free telephone terminals. He is a member of IEEE, IEICE, ASJ, and the Information
Processing Society of Japan.

Vol. 9 No. 6 June 2011

Feature Articles: Services for Hikari Era: Terminal Component Technologies

Visual Softphone:
New Ways to Communicate
Koichiro Kanaya, Hironori Ohata, Dai Ando,
Machio Moriuchi, Hiroshi Jinzenji, and Jotaro Ikedo†
Abstract

NTT is providing a visual softphone for use on Windows personal computers as a tool for expanding
the means of communication. This article provides an overview of it and describes various communication formats that it can provide.

1. Softphone with OAB-J number capability
The visual softphone is a software-based telephone
terminal that can run on Windows personal computers (PCs). It is being provided by NTT EAST and
NTT WEST free of charge to HIKARI DENWA*1
users of FLET’S HIKARI NEXT broadband service
under the name HIKARI Softphone. The initial version of the visual softphone was provided in February
2009 and a content transfer function supporting data
connections (enabling data files to be sent andreceived by a PC) was added in July 2010.
Although Skype and other softphone products areavailable on the market, achieving a short end-to-end
delay has been a difficult problem to solve. At present, only a few softphones (including NTT’s visualsoftphone) can achieve a delay of 150 ms, which is
specified as a requirement for using 0AB-J numbers(10-digit numbers starting with 0).
2. Architecture
In general, software on a PC operates by receiving
instructions (input) from the user, performing various
types of processes, and returning results to the user.
In contrast, a softphone operates not only by receiving instructions from the user but also by recognizing
and processing an incoming call. A softphone mustalso support a variety of commercially available† NTT Cyber Space Laboratories
Yokosuka-shi, 239-0847 Japan

external devices such as headsets and cameras. In
addition, a softphone by its very nature achieves mostof its functions by software, which means that it supports the addition of diverse functions and modification of its operations in a relatively easy manner. To
exploit this feature to the maximum, we need to use
an architecture that can simplify function additionand specification modification as much as possible
without sacrificing overall performance.
With these characteristics taken into account, thevisual softphone can be broadly divided into utility,
control logic, and graphical user interface (GUI) elements, as shown in Fig. 1.
The utility element enables the visual softphone tosupport various external devices by concealing differences in PC hardware components, and it uniformly
supports incoming calls by performing SIP (session
initiation protocol) processing and general-purpose
processing such as media RTP (Real-time Transport
Protocol). The logic element controls all softphone
operations and controls input/output according to thestate of the software. The GUI element handles input/
output with respect to the user.
3. Main functions
The main functions of the visual softphone arelisted in Table 1. Its functions for videoconferencing,broadband telephony, and content transfer greatly*1	 Hikari is the Japanese word for light; denwa is the Japanese word
for telephone.

NTT Technical Review

Feature Articles

Table 1. Main functions.

User operations
Graphical user interface layer
Control logic layer

VGA (640x480) @ 30 fps: MEPG-4
Video

Application
layer

QVGA (320x240) @ 15 fps: MPEG-4
QCIF (176x144) @ 15 fps: MPEG-4

Utility layer

Wideband (7-kHz) voice: G.711.1 & UEMCLIP

AudioOperating system

Narrowband (3.4-kHz) voice: G.711

HardwareSimultaneous contents transfer and voice call
Digital contents Simultaneous contents transfer and video call

Network events

Individual contents transfer

Fig. 1. Architecture overview.

fps: frames per second

MPEG-4 codec (DSF)
Camera input signal(RGB)
Resolution
converter
Desktop
image

Input
selector

MPEG-4
video
streamVideo coder

-VGA
-QVGA
-QCIF

DCT + VLC

RGB
→ YUV
converter

Multiplexer

RTP
packetization

Motioncompensation

Output signal(RGB)

Video decoder
YUV
→ RGB
converter

VLD + I-DCT

Demultiplexer

MPEG-4
video
streamRTP
depacketization

DCT: discrete cosine transformDSF: DirectShow Filter
I-DCT: inverse DCT
VLC: variable length coding
VLD: variable length decoding

Fig. 2. Visual softphone’s video processing module.

exceed conventional telephone functions. These
functions can be optimally allocated to suit userneeds.
3.1 Video communications function
The configuration of the visual softphone’s videocommunications processing module is shown in
Fig. 2. This module takes a video signal input from acamera and converts it to a previously set resolution
in the resolution-conversion section. It then passes
the resulting signal to the video coding section where
it undergoes RGB-YUV*2 conversion and compression/coding. The coding system uses an MPEG-4Vol. 9 No. 6 June 2011

based codec developed by NTT Cyberspace Laboratories and achieves high-quality video while suppressing the processing load. Supported video sizes
are VGA (640 pixels × 480 lines), QVGA (320 pixels
× 240 lines), and QCIF (176 pixels × 144 lines). In
general, high-quality videophone communications isprovided using VGA video, but QVGA video, which
generates a somewhat smaller processing load forcoding, is also supported to enable the use of relatively low-performance PCs such as netbook*2 RGB: red, green, and blue; YUV: color space defined in terms of
one luma and two chrominance components.

Feature Articles

Table 2. T erminals that can connect to the visualsoftphone.
Network
NGN

Terminals
HIKARI DENWA terminal
Mobile phone

PSTN

Contents receiver

HIKARI Softphone
Analog terminal

Voice callContents sender

INS voice terminal
050 number IP phone

Session establishment phase (SIP)
TCP connection

PHS (personal handy-phone system)

Capability negotiation phase (HTTP/SOAP)

INS: Information Network System
NGN: Next Generation Network

Contents check (HTTP/SOAP)

Contents transfer phase

3.2 Voice communications function
Call control on the visual softphone is performed
by SIP, and calls can be made to a variety of PSTN
(public switched telephone network) telephone terminals via a home gateway (Table 2).
In addition to the G.711 coding system used by theconventional telephone network for speech coding,the visual softphone is also equipped with the UEMCLIP system developed by NTT Cyberspace Laboratories and the G711.1 wideband speech coding system [2] to provide high-quality voice calls with little
delay.
Switching between these speech encoding systems
is performed automatically by a negotiation process
at the beginning of a call. The user does not need toknow what kind of terminal the other party is using.
It is common to incorporate a fixed-size buffer for

In-channel...

computers. The visual softphone also supports videophone communications with FOMA mobile phones
in the same way as the PC Communicator [1], forwhich QCIF video is used to match the video on theFOMA side.
Although the usual format is for a video signal to be
input from a camera and then compressed and sent to
the other party’s terminal, a desktop sharing function
can also be used. In this case, the input-switching section of the video communications processing moduleswitches the input signal from a camera-fed video
signal to a rectangular portion of the PC’s desktop
screen selected by the user. This signal is then compressed and sent to the other party. This configuration
enables a screen image to be sent to the other party’s
terminal during videophone communications without
the need to switch applications, which leads tosmooth screen sharing.

Out-channel

Disconnect TCP

Disconnect session (SIP)

Out-channel

Fig. 3. Example of the contents transfer sequence.

voice communications that uses Internet protocol (IP)to deal with packet transmission fluctuations andpacket loss. However, this buffer processing is directly related to increases in voice delay. In the visualsoftphone, this problem is dealt with through various
measures such as dynamically controlling the buffer
size and performing buffer processing frequently
with the aim of preventing buffering-related delay asmuch as possible. The visual softphone also prioritizes the allocation of CPU (central processing unit)
resources for voice packet processing to prevent
unwanted effects from other applications.
The visual softphone also incorporates a simple
echo canceller [3]. This enables the user to connect a
microphone and speakers to the PC and perform
hands-free calling in an environment where the distance between the microphone and speakers is no
greater than 2 m.
3.3 Content transfer function
In addition to video and voice communications,
NTT Technical Review

Feature Articles

Visual softphone
File Display Tools Settings Help
Extension no. :3
Contacts

Dial
Incoming log

Outgoing log

Input telephone number and press any of the
button: Call, Message, or Data communication.
(b) Videophone window
Data communication (file sent)

Clear

Call Data com. Message Mail(a) Main window(c) Contents transfer window

Fig. 4. Examples of PC windows.

the visual softphone provides a content transfer
service that supports the sending and receiving ofdigital data such as images and documents using the“m=application” media type in SIP/SDP (SDP:
session description protocol). This service enables
users to send and receive all sorts of digital data in themanner of fax transmission using 0AB-J numbers
and even to send data that must be carefully handledsuch as personal information by utilizing the secure
network characteristic of the Next Generation Network (NGN). In short, the content transfer service is
expected to stimulate the creation of completely newusage formats.
The content transfer service uses technical specifications for content transfer established by NTT Cyber
Solutions Laboratories. The visual softphone canconnect to and transfer content to other devices that
use the protocol specified in these technical specifications. In particular, the specifications prescribe amethod for describing call settings on the basis of
SIP/SDP and an in-channel communication protocolVol. 9 No. 6 June 2011using HTTP/SOAP (HTTP: hypertext transfer protocol; SOAP: simple object access protocol) for use
after the call has been established.
The content transfer service can be used in both anon-calling state and a calling state. An example ofcontent transfer from a non-calling state is shown in
Fig. 3. The session is started by a SIP INVITE command specifying m=application. This causes in-channel communications to begin. The softphone on thesending side connects to the softphone on the receiving side by TCP (transmission control protocol). It
sends a list of digital content specified by the user
(maximum 100 files), transmits the actual digital content, and closes the TCP connection and terminates
in-channel communications. The sending softphone
sends a SIP BYE command to terminate the session.
For content transfer while a call is in progress, thesoftphone sends a SIP reINVITE command with
m=application added to begin in-channel communications. After in-channel communications has been
performed, media deletion by reINVITE(port0) isFeature Articles

performed to return the communications state tovoice/video.
The NGN currently has an upper limit for the number of times that media addition can be performed
during a voice/video call, and when m=application
media addition is performed at the time of content
transfer, a limit can be set for the number of content
items that can be transmitted at one time. We therefore
considered how to exceed such limits in content
transfer by enabling the sending-side softphone toselect whether content transfer will continue after one
transmission. If it does continue, the user can specify
and send new content in the same session by continuing the m=application session.

ed by drag-and-drop to facilitate intuitive use similar
to the operation of other Windows applications.
5. Conclusion
This article outlined NTT’s visual softphone, whichenables people to communicate using various typesof new media on the NGN. Looking beyond thevisual softphone’s obvious use as a videophone, we
intend to propose new ways of communicating using
diverse media.
References[1]

4. User interface
The GUI is divided into a main window, telephone
window, and content transfer window (Fig. 4). Information needed at non-calling times, such as contacts
and calling history, is all contained in the main window to minimize the display area occupied during
non-calling times. At the time of a call, the GUI automatically switches to the telephone window; theprocedure for accepting an incoming call was carefully designed to be uncomplicated. The content
transfer window enables files for transfer to be select-



[2]

[3]

H. Takeda, D. Ando, S. Sakauchi, S. Onishi, and H. Jozawa, “Functions of PC Communicator: PC-to-FOMA IP Videophone Technology,” NTT Technical Review, Vol. 3, No. 10, pp. 18–24, 2005.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2005
10018.pdf
S. Sasaki, T. Mori, Y. Hiwasaki, and H. Ohmuro, “Global Standard for
Wideband Speech Coding (G.711 wideband extension),” NTT Technical Review, Vol. 6, No. 8, 2008.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2008
08le1.html
S. Sakauchi, Y. Haneda, M. Okamoto, J. Sasaki, and A. Kataoka,“Echo Canceller with Noise Reduction Provides Comfortable Handsfree Telecommunication in Noisy Environments,” NTT Technical
Review, Vol. 2, No. 3, pp. 59–63, 2004.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2004
03059.pdf

NTT Technical Review

Feature Articles

Koichiro Kanaya

Machio Moriuchi

Senior Research Engineer, Promotion Project
1, NTT Cyber Space Laboratories.
He received the B.E. degree in mechanicalengineering from Waseda University, Tokyo, in
1990. In 1990, he joined NTT Video and Record
Communications Division and has mainly been
engaged in developing video communication
systems.

Senior Research Engineer, Promotion Project
1, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from Tokyo Science University
in 1987 and 1989, respectively. He joined NTT
Electrical Communication Laboratories, Kanagawa, in 1989. He has been engaged in R&D ofvideoconferencing systems.

Hironori Ohata

Hiroshi Jinzenji

Dai Ando

Jotaro Ikedo

Senior Research Engineer, Network Applianceand Services Project, NTT Cyber Solution Laboratories.
He received the B.E. degree in communicationengineering from Tokai University, Kanagawa, in1989. In 1989, he joined NTT Telecommunications Equipment Division and has mainly been
engaged in the development of telecommunications equipment. He is a member of the Instituteof Electronics, Information and Communication
Engineers (IEICE).

Research Engineer, Promotion Project 1, NTT
Cyber Space Laboratories.
He received the B.E. degree in information
technology from Tohoku University, Miyagi, in
1989. In 1989, he joined NTT Human Interface
Laboratories and has mainly been engaged indeveloping video communication systems. He isa member of IEICE.

Vol. 9 No. 6 June 2011

Senior Manager, Network Appliance and Services Project, NTT Cyber Solution Laboratories.
He received the B.E. and M.E. degrees in communication engineering from Osaka University
in 1989 and 1991, respectively. In 1991, hejoined NTT Human Interface Laboratories andhas mainly been engaged in developing customer
premises equipment. He is a member of IEICE.

Senior Research Engineer, Promotion Project
1, NTT Cyber Space Laboratories.
He received the B.E. degree in electronic engineering and the M.E. degree in electrical engineering from Kogakuin University, Tokyo, in
1989 and 1991, respectively. Since joining NTT
in 1991, he has been engaged in R&D of low-bitrate speech coding and wireless transmission. He
contributed to establishing the ARIB STD-27
and ITU-T G.729 standards. He is now developing VoIP systems. He is a member of IEEE,
IEICE, and the Acoustical Society of Japan.

Feature Articles: Services for Hikari Era: Terminal Component Technologies

Software H.264 Encoder Engine
for Online Video Delivery
Service Cost Reduction
Masaki Kitahara†, Naoki Ono, and Atsushi Shimizu
Abstract

This article describes the software H.264 encoder engine that we have developed in NTT Cyber Space
Laboratories. It implements technologies for fast encoding, high compression performance, and reduced
encoder operation cost, which are all important features for reducing the cost of online video delivery
services. In tests, it outperformed conventional encoders. It is also suitable for use in creating content for
online video delivery services.

1. Introduction
Video delivery services such as IPTV (Internet protocol television) and video-on-demand have recently
gained in popularity. Video generally involves much
more data than audio, so the increasing popularity ofhigh-resolution video has led to demands for video
encoding. For example, the amount of data used for
uncompressed HDTV (high-definition television)
video is close to 1 Gbit/s.
Video content delivery over networks requires
video encoding technology that can encode video
with a good compression ratio, which is defined as
the compressed size divided by the original size, so asmaller ratio equates to better performance. To meetthis demand, the use of H.264, which is known toachieve twice the compression performance of
MPEG-2, has spread widely over the years. H.264
can achieve such high performance because it enables
the use of various coding tools, which makes it adaptable to various kinds of video characteristics. However, this means that an H.264 encoder must adaptively select coding tools from a large number ofcandidates according to the characteristics of the
input video in order to achieve a good compression
ratio. In other words, there is a trade-off between† NTT Cyber Space Laboratories
Yokosuka-shi, 239-0847 Japan

compression performance and encoding time: H.264
encoders tend to need long encoding times. To reduce
the service cost of online video delivery services, it isnecessary to encode video with high compression
performance so that the bitrate of the compressedvideo is low in order to reduce storage costs. Therefore, to reduce the encoder operation cost in suchservices, fast encoding is needed. The basic functionalities and system requirements are listed in Table 1.
NTT Cyber Space Laboratories has a long historyof developing codec LSIs (large-scale integrated circuits) and equipment. We utilized know-how acquired
from those past developments and developed technologies for fast encoding, high compression performance, and encoder operation cost reduction, which
are all important for reducing the cost of online video

Table 1. Basic functionalities and system requirements.
Encoding format MPEG-4 part 10 AVC/ITU-T H.264
ProfilesMain Profile, High Profile, High 4:2:2 Profile

Image size

CIF (352 x 288) to 4K x 2K (3840 x 2160)

Systemrequirements

CPU

SSE4.1 or aboveOS

MS-Windows XP SP3

Library Microsoft C/C++ Runtime Library

CIF: common intermediate format
OS: operating system

NTT Technical Review

Feature Articles

Encoding order at each coreFirst macroblock to be encoded at each core
Macroblock A
Macroblock B
Macroblock C

Encoding(multithreaded processing)Core 1

Core 2

Core 3

Input video

Fig. 1. Conventional multithreaded encoding.

delivery services. These technologies are described
below and compared with other encoders.
2. Technology for fast encoding
We have implemented a multithreaded encoding
method that utilizes multicore central processing
units (CPUs), which are common in recent personal
computers (PCs), with negligible degradation in compression performance.
Conventionally, multithreaded encoding has beenachieved by dividing images in the input video into
sub-images and encoding the sub-images independently thread by thread. Such a method is illustrated
in Fig. 1. In H.264, images in the input video are
encoded in units of macroblocks, which are blocks ofpixels that consist of 16 pixels in the horizontal direction and 16 pixels in the vertical direction; when amacroblock is encoded, information about how adjacent already-encoded macroblocks were encoded isutilized in order to achieve high compression performance. Furthermore, encoding begins with the macroblock at the top left of the image (or the sub-image
if conventional multithreaded encoding is used) andeach macroblock in the top horizontal macroblockline is encoded from left to right. When the top right
macroblock is encoded, macroblocks in the horizontal macroblock line below are encoded from left toright, and the rest of the horizontal macroblock line isprocessed in the same way. When the encoding
method described in Fig. 1 is used, at the moment
Vol. 9 No. 6 June 2011

core 2 is encoding macroblock B, core 1 is encoding
macroblock C, assuming that the encoding speed isthe same for all the cores. This means that macro­
block A, which is one of the macroblocks adjacent tomacroblock B, has not yet been encoded by core 1, so
its encoding information is not yet available for use inencoding macroblock B; this results in low compression performance. Since the number of such cases
increases with the number of divided images (fasterencoding), it is not possible to achieve a significant
speedup in encoding in the conventional method
without significant degradation in compression performance. Thus, even if the PC had many cores, itwould not possible to utilize its full potential with theconventional method.
In the newly developed software H.264 encoder
engine, we have implemented a new method createdby applying know-how acquired during encoder LSI
development. In this method, the encoding of macroblocks is pipelined, so that the number of threads canbe increased with negligible loss in compression performance. Thus, it is possible to utilize the full potential of newer multicore CPUs designed for PCs. As aresult, our new H.264 encoder engine can encode at
twice the speed of our conventional one. Furthermore, even faster encoding will be possible in the
future by using PCs with more cores than those on themarket at present.

Feature Articles

Scene change

(a)

I

B

B

P

B

B

I

B

GOP1

(b)

I

B

B

GOP1

I

B

P

B

B

I

B

GOP2

B

B

P

B

GOP2

B

I

B

P

B

B

B

B

GOP3

B

B

P

B

GOP3

B

I

GOP4

Frame that has been changed to I frame from P frame
Frame that has been changed to P frame from I frameFig. 2. Adaptation of GOPs to scene change.

3. Technology for high compression
performance
We have implemented a method that adapts the
structure of groups of pictures (GOPs) to scenechanges to achieve higher compression performance.
In H.264, frames in the input video are grouped
together to construct GOPs. Furthermore, each frame
can be one of three types: intra-coded (I), predictivecoded (P), or bidirectionally predictive-coded (B). I
frames are encoded solely using information inside
the frame to be encoded without reference to otherframes, P frames are encoded using past I or P frames
and are also used as a reference for further prediction,
and B frames are encoded using both past and future
frames. An example where each GOP is of equal
length (6 frames), and there are 2 B frames between
an I frame and a P frame or between two P frames isshown in Fig. 2(a). As shown here, it is common touse I frames for the first frame in a GOP to enablerandom access.
Since P and B frames use past or future frames forencoding, when a scene change occurs in suchframes, the compression performance degrades significantly because there is no correlation between theframe to be encoded and the frame that is used for
encoding. The conventional method for avoiding thiswas to change the frame type of such a frame to an I
frame, leaving the GOP structure basically unchanged.
However, such a simple solution leads to an increase

in the number of I frames. Since the compression
performance of I frames is low, this is not an optimal
solution for coping with scene changes.
An example of the method implemented in the new
encoder engine is shown in Fig. 2(b). When a scenechange occurs, a new GOP is created from that frame.
With this method, the number of I frames can besmaller than in the conventional method. Furthermore, since the GOP length can be limited, thismethod is applicable to the case where the GOP
length needs to be made shorter than a particularvalue, such as in IPTV system specifications.
When this method is used together with the fastencoding technology described in section 2, thebitrate of compressed video can be 20% smaller compared with our conventional software H.264 encoder
engine at the same encoding speed.
4. Technology for encoder operation
cost reduction
In general, when the bitrate of a long section ofcompressed video exceeds the target bitrate, it is
impossible to decode the video within the specified
frame rate because this section of compressed video
takes longer to deliver over a network that has bandwidth equal to the target bitrate. Such cases occur
when the video contains a section of content that iscomplex and difficult to compress; an example is ascene with water splashing. In such cases, the person
NTT Technical Review

Feature Articles

Online video
delivery service
IP
network

Software H.264
encoder engine
Input
moduleMultiplexer
engineAudio encoder
engineStorage

StorageFig. 3. Example of an audio-visual encoder application.

Table 2. Comparison with other encoders.

Compressed bitrate*

1Competitor’s
encoder

Our conventional
encoder engine

Our newly developed
encoder engine

7 Mbit/s

7 Mbit/s

5.6 Mbit/s-

Remarks

Encoding time*2

x3.3

x5.2

x2.6

Encoder processing time at
the same bitrate

Automatic retry of
encoding

No

No

Yes

-

Encoding in 4:2:2 format
video

Yes

No

Yes

-

*1 Bitrate able to provide the video quality of digital terrestrial television broadcasting in Japan*2 Encoder processing time relative to the actual video length when HDTV video was encoded

operating the encoder must encode the video again
using different encoder parameters to decrease thebitrate of the complex parts. One problem with this isthat the changed encoder parameters can influenceother parts of the video, resulting in the video having
degraded video quality. Another problem is that since
encoding with different parameters can occur multiple times and the encoder operator must check thequality of the video each time, the encoder operation
cost is higher.
In our new H.264 encoder engine, we have implemented a method that automatically detects anomalies during encoding and automatically encodes suchparts with different encoder parameters multiple
times. This method avoids quality degradation of thewhole video and achieves a lower encoder operationcost.
5. Use of the H.264 encoder engine forapplication development

is solely for encoding images. To develop an application that can encode video content containing both
images and sound, one needs other components suchas an audio encoder engine and a multiplexer engine.
An example of the architecture of such an audiovisual encoder application is shown in Fig. 3.
6. Comparison of performance andfunctionalities
The performance and functionalities of our new
software H.264 encoder engine are compared withthose of our conventional encoder engine and acompetitor’s encoder engine in Table 2. Our new
encoder achieved a 20% reduction in the bitrate ofcompressed video at the same encoding speed. It supports the 4:2:2 format, which is important for professional use, and it also has functionalities that are not
implemented in competitors’ encoder engines such as
automatic retry of encoding (described in section 5).

The H.264 encoder engine that we have developed
Vol. 9 No. 6 June 2011

Feature Articles

7. Conclusion
Our new software H.264 encoder engine achieves
fast encoding, high compression performance, and alower encoder operation cost, which are importantfeatures for reducing the cost of online video delivery

Masaki Kitahara

Research Engineer, Visual Media Communications Project, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees inindustrial and management engineering fromWaseda University, Tokyo, in 1999 and 2001,
respectively. Since joining NTT in 2001, he has
been engaged in the development of compression
and rendering algorithms for 3D video, video
compression algorithms, and software. He is amember of the Institute of Electronics, Information and Communication Engineers (IEICE).

services. It is therefore highly suitable for use in creating content for online video delivery services. Our
future work includes developing encoder applications
based on the software H.264 encoder engine andextending the technologies described here for use inother kinds of services.

Atsushi Shimizu

Senior Research Engineer, Visual Media Communications Project, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in electronic engineering from Nihon University,
Tokyo, in 1990 and 1992, respectively. Sincejoining NTT in 1992, he has been engaged invideo compression algorithm and softwaredevelopment. He is a member of IEICE, IIEEJ,
and the Institute of Image Information and Television Engineers.

Naoki Ono

Senior Research Engineer, Visual Media Communications Project, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in information engineering from Niigata University in
1989 and 1991, respectively. Since joining NTT
in 1991, he has been engaged in video compression algorithm and software development. He isa member of IEICE and the Institute of Image
Electronics Engineers of Japan (IIEEJ).



NTT Technical Review

Feature Articles: Services for Hikari Era: Terminal Component Technologies

Network Processing Technology
for Terminals Enabling
High-quality Services
Yukikuni Nishida† and Keiichi Koike
Abstract

This article describes the RENA-SoC, which is a network processor that provides basic functionalities
required for a home or SOHO (small office home office) network gateway in the fiber-to-the-home(FTTH) broadband era (RENA: routing engine for Next Generation Network access, SoC: system on achip). Network processing is performed by a packet processing engine, and the application processing
load is distributed over two microprocessors to provide the user with high-quality stable services.

1. Introduction
Managed networks such as the Next Generation
Network (NGN) can provide high-quality, secure
networking for triple-play services that provide voice
and video communications, video delivery, and Internet access. Personal computers (PCs) as well as televisions (TVs) and various sensors will be connected
to home networks, enabling operations such as TV
program reservation or remote monitoring of sensors.
Many other services are likely in the future even fromhome appliances such as refrigerators and microwave
ovens connected to the network.
The gateway is very important for connecting themanaged network with home networks and small
office home office (SOHO) networks, while also protecting the network and the access points for receiving various services. As shown in Fig. 1, the gateway
must provide many functions such as security, quality
control, and service enhancement, as well as the performance to process packets of Gigabit Ethernet signals.
The main functions of the gateway can be classified
into network functions and application functions.
Application functions must support voice over Internet protocol (VoIP), a basic service of managed net† NTT Cyber Space Laboratories
Yokosuka-shi, 239-0847 Japan

works, and may require the OSGi (Open Services
Gateway initiative) framework for managing application software, so that application software can be
added and deleted on demand. OSGi runs on the JavaVM (virtual machine), which avoids the need to take
into consideration differences in platforms, reduces
the need to develop application software for eachplatform (called bundled software in Java VM terminology), and makes development inexpensive. In thisway, users are expected to be able to get applications
at a reasonable cost.
At NTT Laboratories, we are promoting open innovation and have developed the OSGi Service Aggregation Platform (OSAP). This is a base technologythat extends OSGi, allowing bundled software fromservice providers for instance, software that lets theservice providers control home appliance, to be
downloaded and run on the gateway.
If microprocessor-intensive application software is
executed in a multitasking environment, the load on
the central processing unit (CPU) will increase andthe performance of packet processing, which is abasic gateway function, could decrease and lead tolonger packet delays. This could result in a decrease
in VoIP quality. To avoid this sort of quality of service(QoS) degradation, we designed an architecture that
distributes processing over three processing engines:-	a newly developed gigabit-per-second packet
processing engine,
NTT Technical Review

Feature Articles

Internet

Customer residence
Home/SOHO networks

CrackerPriority control,
shaping

Attacking packet

PC systems

Burst packets

AV systems
WAN
1 Gbit/s

OSAP

B

B

B

B

OSAP
center system

B

AV: audio-visual
B: software bundle
NAPT: network address port translstion

Telecommunication
systems

ControlB

Serviceadministration
OSGi
framework
JavaVMLAN

Routing
NAPT
Security
QoS
Firewall
VoIP
Etc.

B
Service provider

Gateway

Remote support
centerManaged network

Video content
providerOS

Home appliances

Sensor systems
OS: operating system
PC: personal computer
WAN: wide area network

Fig. 1. Home/SOHO networks.

-	a CPU for processing primary services such as
VoIP,-	a CPU for processing enhanced functions such as
OSGi bundles.
Gateways are also required to provide interfaces fordevices such as wireless local area network (LAN)cards and USB (universal serial bus) hard disk drives,and a LAN switch (LAN-SW) in order to connect
various pieces of network equipment. This can lead toa large number of components and result in increased
power consumption and cost, so to reduce power consumption and cost, we developed the RENA-SoC(RENA: routing engine for Next Generation Network
access [1], SoC: system on a chip), which is a network processor that incorporates a packet processing
engine, two CPUs, PCI (peripheral component interconnect) and USB interfaces, and a LAN-SW on asingle chip (Fig. 2).
2. Packet processing engine
The packet processing engine, which contributes
greatly to the packet processing performance of the
RENA-SoC, is composed of an IPsec block, an IP
Vol. 9 No. 6 June 2011

switch (IP-SW) block, a LAN switch (LAN-SW)
block, and a packet scheduler. The IPsec block handles packet encapsulation for virtual private network
communications, high-speed encryption, decryption,
and authentication, the IP-SW block handles packet
transmission as required for each connected party,
including firewall and NAPT (network address port
translation) functions, and the packet scheduler controls the QoS. These functional blocks are implemented in hardware, and they achieve processing
performance of 1 Gbit/s in each direction (uplink anddownlink). To confirm the performance of the packet
processing engine, we compared the throughput of an
off-the-shelf software-based router and a router
implemented using the RENA-SoC for various frame
lengths and NAPT table entry numbers. The results
are shown in Fig. 3. The software-based router
showed throughput dependent on the packet lengthand the number of simultaneous flows for NAPTs
since these affect the software load. However, the
RENA-SoC was not affected by these factors, andachieved 1-Gbit/s bidirectional packet processing.
This packet processing engine enables low-delay,
high-quality communications, even under high-loadFeature Articles

DDR2: double data rate 2
PHY: physical layer
RW: read/write operations
TDM: time division multiplexing

1 Gbit/s

CPU 0
PPC405400 MHzCPU 1
PPC405400 MHzUSB host
controller

TDM

Encryption
accelerator

PCI

DDR2 memory
controller

Processor local bus

128-bit x 2 way x 2 RW@133 MHz

WAN interface
Gigabit Ethernet

Packetengine2 Gbit/s
Inline IP sec

2 Gbit/s
IP-SW

5 Gbit/s
LAN-SW

PHY

DDR2-533
x32 bits

1 Gbit/s

LAN interface x 4
Gigabit Ethernet
Packet scheduler

Fig. 2. RENA-SoC block diagram.

Bidirectional throughput
1200

Router with RENA-SoC

No. of NAPTs: 1

1000
Throughput (Mbit/s)

No. of NAPTs: 1024
800
600

No. of NAPTs: 1

400
No. of NAPTs: 1024200
Off-the-shelf software router
0

0

200

400

600

800 1000 1200 1400 1600

Frame length (bytes)

Fig. 3. Packet transmission performance.

conditions of these sorts, by processing packets at the
maximum interface speed of 1-Gbit/s.


The packet processing engine can also support newservices through the following added functions.
-	Communication quality monitoring function(packet copy function)-	Packet processing support function (improves
the flexibility of hardware processing)
These functions are explained in detail below.
3. Communications quality
monitoring function
When packets are discarded along the communications path, which causes a QoS decrease in services
such as video delivery, it is necessary to detect whether the packets were discarded on the WAN (wide area
network) segment or LAN segment. Maintenancecosts can be reduced if the detection is not performed
by a dispatched worker but by a telemetering function. It is currently done by placing monitoring equipment on the home network segment and dispatchinga worker to the location to check the log information,
which involves a significant amount of labor. Thus,
there is demand for remote realtime monitoring of
NTT Technical Review

Feature Articles

Video delivery packets
Signaling packets

File download etc.
1 Gbit/s

RTP sequence number

When a packet does not
arrive, information before andafterward is stored and theremote center is notified asnecessary.
End(34567, 89012)
Detect(23456, 78901)
Period with nopacket arrivals
Start(12345, 67890)
Receive timestamp

RENA-SoC
Packet processing engine
CPU0

Packet identification

Signaling,transmission
control

Only video delivery packets
are identified among all
packets, copied, and sent
to CPU 1.

CPU 1
RTP
packetanalysis

RTP: Real-time transport Protocol

PC

Set-top box

Fig. 4. Quality management for video delivery packets.

communications quality in gateway equipment.
To improve transmission performance whensoftware is used to process packets, often only theheaders are read, which avoids the need to read andwrite entire packets. When packets are captured tomonitor quality, entire packets must usually be copied, separated from the packet transmission stream,and passed to the packet capture application. Continuous packet copying makes the processing load
heavy and can cause packet transmission performance to decrease significantly, so even if video
packets, for example, would have been transmitted
correctly, communications quality can be degradedand packet capturing may fail. This can result in
faults and errors being detected even when packets
could have been received normally.
For these reasons, we have implemented a packetcopy function in hardware that allows communications to continue while copied packets are processedby the CPU and allows realtime packet capturing toVol. 9 No. 6 June 2011

be done without decreasing communications quality.
Specifically, the packet processing engine identifies
packets to be captured and copies them as shown in
Fig. 4. Even with packets flowing at 1 Gbit/s, specific packets can be copied to the CPU without affecting the packets being transmitted. The CPU can capture specially selected packets, so quality monitoring
can be done without causing further packet loss. Figure 4 shows an example of a function that monitors
sequence numbers and timestamps of video delivery
packets. It also shows that information before andafter the event is saved if a sequence number is notcontinuous or if packets do not arrive for a period oftime. This information is reported to a remote center
when necessary, which ensures that the center is notified of decreases in service quality.
The above structures enable immediate remote
identification of where a network fault occurred froma remote location.

Feature Articles

Twice NAT bidirectional throughput
600

Bidirectional throughput (Mbit/s)

500

Using packet processing support functions

400

300

200
Using software-only processing
100

0
0

200

400

600

800

1000

1200

1400

1600

Frame length (bytes)

Fig. 5. Performance of packet processing support functions.

4. Packet processing support functions
Packet processing engines are generally composed
mainly of hardware, so they have extremely high-performance packet processing; on the other hand, they
are inflexible in terms of support for new functions. If
the hardware cannot handle packets, even if it isbecause of a trivial modification to the packets, all of
the packets must be processed by software, whichcauses a dramatic degradation in performance. To
resolve this problem, the RENA-SoC implements
packet processing support functions that allow the
CPU to directly read and write packet data being processed by the packet processing engine. This allows
higher performance than is possible with softwareonly processing.
When packets are processed using only software,
the packet processing engine usually passes the entire
packet to the CPU, which performs software-based
network processing, and then passes the packet backto the packet processing engine. This uses up a lot ofprocessor resources for the packet processing. By
enabling the CPU to directly handle packets being
processed by the packet processing engine, we wereable to reduce the transfer times between the CPU
and packet engine and omit most of the network processing.
As an example, for the case of supporting twiceNAT (RFC 2663), in which IPv4 addresses of both
source and destination are rewritten, we comparedsoftware-only processing and the use of packet processing support functions (Fig. 5). For software-only
processing, the maximum possible transmission rate
was 90 Mbit/s; however, with packet processing support functions, we confirmed transmission speeds
over 500 Mbit/s.
5. Application protection
By opening up the system to OSGi bundles, as
described earlier, we enable various user applications
to be executed on the gateway. To prevent these applications from affecting the operation of basic services
such as VoIP, the RENA-SoC uses asymmetric multiprocessing, with an independent OS (operating system) operating on each CPU. Having two OSs running on the two CPUs increases the amount of memory required; however, even if, for example, CPU1
stops responding owing to an inadequately tested
OSGi bundle, CPU0 can reset only CPU1, which canrestart while CPU0 and the packet engine continue tooperate independently without being affected. This
makes system operation more stable and keeps primary services alive.
NTT Technical Review

Feature Articles

6. Summary
We have developed the RENA-SoC, which enables
the operation of high-performance systems throughits triple-processor architecture, consisting of a packet engine capable of 1-Gbit/s bidirectional packet
transmission with support for IPsec, firewalls, andquality control; a CPU for handling basic managednetwork services like VoIP; and a CPU for handlingenhanced applications such as OSGi bundles or qual-

Yukikuni Nishida

Senior Research Engineer, Promotion Project
1, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in electrical and computer engineering from Nagoya
Institute of Technology, Aichi, in 1992 and 1994,
respectively. He joined NTT LSI Laboratories,
Kanagawa, in 1994 and has been engaged inresearch on the design of low-power-consumption DSPs, automatic speech recognition systems, and network appliances. Since 2003, he has
been developing network processors performing
gigabit-per-second packet transmission for residential gateways. He is currently studying techniques for saving energy in home network equipment. He is a member of the Institute of Electronics, Information and Communication Engineers(IEICE).

Vol. 9 No. 6 June 2011

ity monitoring.
In the future we will continue research and development toward reducing the device’s power consumption and providing support for various services.
Reference[1]

Y. Nishida, K. Kawai, and K. Koike, “A 2Gb/s Network Processor
with a 24mW IPsec Offload for residential Gateways,” Proc. of
ISSCC 2010, Vol. 1, No. 1, pp. 280–281, San Francisco, CA, USA.

Keiichi Koike

Senior Research Engineer, Supervisor, Promotion Project 1, NTT Cyber Space Laboratories.
He received the B.E. and M.E. degrees in electronic engineering from Osaka University in1985 and 1987, respectively. Since joining NTT
LSI Laboratories in 1987, he has been engaged inresearch on the design of high-speed LSIs. He iscurrently researching an application-specific LSI
for gateway equipment. He is a member of
IEICE.



Regular Articles

Cabling Technologies Providing
More Optical Cabling Potential in
Multi-dwelling Unit Buildings
Hayato Minami†, Kensei Shiraishi, Tadashi Sasaki,
Kazutoshi Takamizawa, Tetsuhiro Numata, andOsamu Inoue
Abstract

For optical access services to multi-dwelling units (MDUs), we have developed compact optical
splitter modules that provide greater installation flexibility and indoor optical cabling that can beinstalled on the building’s exterior walls. They overcome problems encountered in providing opticalfiber cabling systems to MDUs and installing splitter modules in the limited space available in maindistributor-frame boxes as well as other difficulties caused by a lack of space in conduits or the absenceof conduits.

1. Introduction
In June 2010, the number of fiber-to-the-home(FTTH) contracts in Japan surpassed 18 million, heralding the age of ubiquitous optical fiber access.
However, since roughly 40% of all households inJapan live in multi-dwelling units (MDUs), such asapartment buildings and condominiums [1], there is
growing demand for more adaptable optical cabling
systems to provide fiber to households in these sortsof dwellings.
In contrast to FTTH cabling schemes for detachedhouses, which consist of a 4-branch optical splitter inthe central office and 8-branch splitter module parts(SPs) installed on the user side (supporting 32 subscribers), schemes for MDUs and office buildings use
32-branch SPs (or a cascade of one 4-branch SP followed by four 8-branch SPs). To date, thin low-friction indoor optical fiber [2] that enables more cables
to be installed in conduits and SPs that can beinstalled in the empty spaces scattered throughout

customer buildings (e.g., telephone conduits andmain distribution frame (MDF) boxes) [3] have beendeveloped and deployed to expand the range of available cabling systems. They have helped to reduce thenumber of MDU buildings unsuitable for optical fiber
cabling.
However, as indicated in Fig. 1, many mediumsized and large MDU buildings have a lack of empty
space available in existing MDF boxes etc., and themetallic nature of the hardware already installedmeans that the conventional SPs cannot be installedeasily, and many small MDUs have no conduits or
MDF boxes. These conditions make it difficult toprovide optical-fiber-based services to such buildings. To tackle these problems, we have developed (1)technologies for installing SPs in MDF boxes inmedium-sized MDU buildings, (2) cabling that canbe installed on the exterior walls of small MDU
buildings, and (3) technologies for installing SPs inlarge MDU buildings.

† NTT Access Network Service Systems Laboratories
Tsukuba-shi, 305-0805 JapanNTT Technical Review

Regular Articles

Small (up to 10 dwellings)

MDU size

Medium (10 to 50 dwellings)

Large (50 dwellings or more)

Image

Yes
Space
in
conduits
State of facilities

No

No conduitsor MDF boxes

Cabling with thin low-friction indoor optical fiber
Conduits exist, but there is no free space.

Large
SP FA

Space
in
MDF
boxes

No space in
MDF box

SP SC cord

SP 32 SCSP SC cord FL
MDF box has a little space.

Small
None
FA: field assembly
FL: flat
SC: common type of connector: Areas no applicable products exist

Fig. 1. Current state of hardware applications.

2. SP installation technologies for
medium-sized MDU buildings
Since the SP hardware needs to be small enough to
fit into the limited space available in existing MDF
boxes, we developed a range of smaller SPs that
includes both an ultra-compact SP that can beinstalled in very small MDF boxes and compact SPs
designed to provide better workability and allow
more flexible installation methods (Fig. 2). These aredescribed below.
2.1 Ultra-compact SP
For SP installation in very small spaces, we further
miniaturized the existing SP (called the SC cord FL(flat), shown in Fig. 1) [2]. An overview of the new
SP (SC cord S (small/stick)) is shown in Fig. 2. By
devising a way to fit the splitter section inside the casing, we reduced the space required for installation by
20%. We also developed multiple alignment members that can be fitted to individual cores, which protect the fiber core connections used for feeding thecord to subscriber residences.
2.2 Compact SPs
In dealing with the increasingly diverse cabling
Vol. 9 No. 6 June 2011

forms that result from cabling schemes in optical connection systems used for feeding single-core cable(single-drop optical fibers etc.), it is more efficient toassemble a cable sheath fixing connector (plug type)
and terminate it directly at the SP. Moreover, there isa growing need for more versatile attachment methods that do not rely on only ordinary screws, but alsoenable attachment to metal or plastic. Our new compact SPs (B and C types) are overviewed in Fig. 2. We
reduced the space required to maneuver the hardware
and install an SP by including input and output sockets and by eliminating the cord section. Unlike conventional equipment where the connectors are
secured with screws, these SPs use magnetic attachment to the SP and hinged SP mechanisms. The new
design enables much easier detachment and attachment and greatly simplifies the connection workrequired inside small MDF boxes.
3. External wall cabling technology forsmall MDUs
Some small condominiums do not have an MDF
box or conduits available for cabling subscribers
desiring optical fiber services. In this situation, acommercially available box is usually attached to theRegular Articles

MDF space

Large

SP nameConventional(FA type)

Very small
Compact SP(B type)Compact SP(C type)

Ultra-compact SP(SC cord S)

ImagesMounting images(2) Metal frame mounting(1) Vertical mounting on wood

Working with the hardware

Working with the hardware

Mounted in very small space

Fig. 2. Technologies for mounting SPs in MDF boxes in medium-sized MDUs.

exterior of the building and the SP is installed inside
it. Cabling enters the subscriber’s home via the balcony, but this means that work is performed wheneach individual residence applies for subscription,and negotiations with neighbors are required for permission to work on communal walls (Fig. 3(a)).
To address these problems, we have developed acompact box-type SP for attachment to building exteriors and indoor optical fiber bundles that eliminate
the need for repeated negotiations with neighbors
after the initial application for work.
An overview of the hardware is shown in Fig. 3(b).
We used the casing for two existing compact attachable boxes (PD and SS types) and it opens and closes
in the same way. We designed the units to be resistantto ultraviolet (UV) light and water in order to be suitable for external installation. The indoor optical fiber
bundle is a cable consisting of 8 UV-resistant indoor
optical fibers pre-twisted helically with suspension
members. When an optical fiber is fed into a subscriber residence, one of these optical fiber cores isselected and connected to the sheath grip connector(FA (field assembly) connector [3]) and then laid.
These systems can reduce the need for problematicnegotiations with neighbors about service connectionwork.


4. SP installation technologies for large MDUs
In cases where there are a large number of prospective users in a large MDU, it is more efficient tobatch-install 32-branch SPs rather than the cascadesof 4- and 8-branch SPs usually installed in small andmedium-sized MDUs. For large MDUs, in addition to
installations in the empty space in MDF boxes, there
is also demand for 19-inch rack-mounted SPs. Conventional 32-drop SP units are the same height as one
19-inch rack unit (1U), but taking into consideration
the space required for maneuvering the input andoutput cabling, each one needs 3U of free space.
Moreover, the installation of more than one conventional 32-drop SP (e.g., to handle 64 or more terminals) in a 19-inch rack requires the use of more than
3U. Therefore, it would be desirable to have morecompact hardware that can be installed in a standard
19-inch rack and can make better use of the space
available.
To ensure enough work space, we reconsidered thepitch between the usual connectors and chose to use
a modular scheme that enables the connector sections
to be moved horizontally in and out of the chassis.
Simply sliding the required section to insert a connector ensures the same level of workability as with the
NTT Technical Review

Regular Articles(a) Current technology (single-core cabling)
Commercial box usedbecause no externallymountable SP available.

201

202

203

204

101

102

103

104

- Cabling performed
upon application- Entry via
customer’s balcony

Example of single-drop optical cabling
Negotiations with neighbors required for each installation(b) Cabling with the new hardware
Multicore indoor optical fiber
Fiber coreTensionmemberSuspension
memberExternally mountable SP

Image

BranchesSize

4 or 8151 mm × 153 mm

201

202

101

102

203
103

204

External diameter: 12 mm

104

Feeding method
Initial work done in batches; less need for negotiations

Fig. 3. Comparison of conventional exterior cabling and the new system for small MDUs.

Structure comparison
325 mm

180 mmHalved in size

265 mm

180 mmConventional device

New device

Workability comparison
Max.: 33 mm
Stopper
Attachment
pitch: 33 mm

Conventional device

Range of movement
Slide

Better port number
display to prevent
connection mistakes

Movableconnector
sections

New device

Fig. 4. Comparison of conventional and new devices (for 32 SPs).

Vol. 9 No. 6 June 2011

Regular Articles

Conventional device

New device

3 rack spaces for 32 terminals

3 rack spaces for 64 terminals

Mounted in a 19inch rack

Mounting 32 SPs
into a 19-inchrack

32 SPs fits into 19-inch mounting bracket without tools.

16 screw attachments to fit 32 SPs into
the width of the 19-inch rack

Easy attachmentwith slots

Knurled screws
do not need tools
to tighten them.

Fig. 5. Comparison of 19-inch rack mounting procedures.

Small(up to 10 dwellings)

MDU size

Medium (10-50 dwellings)

Large (50 dwellings or more)

Image

Yes
Space inconduits

No conduits

Cabling with low-friction indoor optical fiber- Technologies for cabling in premises with a lack of conduit space- Technologies for cabling inside customer dwellings

No
State of facilities

Large
SP FA
No MDF box

Space in
MDF
boxes

SP SC cord

SP 32 SCSP SC cord FL

Cabinetinstallationinsmall spaces

Small
None

Cabinet technologies developed for new cabling development: Areas more thoroughly covered with these developments: Remaining issues

Fig. 6. Areas covered by the new developments and remaining issues.

NTT Technical Review

Regular Articles

conventional devices. We also designed a simple
19-inch rack installation method that does not require
the use of specialized tools, unlike the usual hardwarethat requires many screw attachments to add an
expansion SP.
An overview of the hardware is shown in Fig. 4.
The new device that we have developed (SP 32 SC-S
(slide/small)) fits in half the space required for theconventional device, so two of them, supporting 64
subscribers, can be installed in the 3U required to
install and work on one conventional unit supporting
32 subscribers.
We also developed a 19-inch mounting bracket for
the SP 32 19-inch rack installation (Fig. 5) to which
the unit is secured by simply sliding it into positionand securing with only two screws at the front. We
think that it could reduce work time by up to 80%. We
have also aimed for better workability by using
knurled screws for tool-free tightening by hand andkeyhole-type slot-in screw holes.

ability and expand the service provision coverage.
However, although the uptake of optical fiber services
such as FLET’S HIKARI continues at a phenomenalrate, it does not mean that 100% of services can beprovided to all subscribers. As shown in Fig. 6, further work is needed to expand services to areas notcovered by these new developments. With these newtechnologies as a base, we plan to continue working
to develop indoor cabling technologies that can beapplied to all MDUs as well as technologies thatstreamline the installation work required for opticalfiber access services.
References
[1]
[2]

[3]

5. Further plans
These new cabling technologies can improve work-

Vol. 9 No. 6 June 2011

Statistics Bureau, Ministry of Internal Affairs and Communications,“Housing and Land Survey 2003”.
S. Niwa, H. Minami, K. Takamizawa, Y. Takeshita, and T. Handa,“Development of New Optical Wiring Technology for Multi-dwelling
Unit Buildings,” NTT Technical Review, Vol. 7, No. 9, 2009.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2009
09le1.html
K. Takamizawa, H. Aoyama, O. Inoue, Y. Oda, S. Matsui, and H.
Minami, “Improving Cabling and Connection Workability in Multidwelling Units,” NTT Technical Journal, Vol. 20, No. 12, pp. 59–62,
2008 (in Japanese).
http://www.ntt.co.jp/journal/0812/files/jn200812059.pdf

Regular Articles

Hayato Minami

Kazutoshi Takamizawa

Kensei Shiraishi

Tetsuhiro Numata

Tadashi Sasaki

Osamu Inoue

Research Engineer, NTT Access Network Service Systems Laboratories.
He joined NTT in 2006. Since moving to NTT
Access Network Service Systems Laboratories in
2008, he has been engaged in the development ofsystems for optical wiring techniques for
MDUs.

Research Engineer, NTT Access Network Service Systems Laboratories.
He joined NTT in 2008. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs and optical fiber
drop cables.

Research Engineer, NTT Access Network Service Systems Laboratories.
He joined NTT in 1985. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs.



Senior Research Engineer, Supervisor, NTT
Access Network Service Systems Laboratories.
He joined NTT in 1987. Recently, he has been
engaged in the development of optical accessnetwork systems.

Senior Research Engineer, Supervisor, NTT
Access Network Service Systems Laboratories.
He joined NTT in 1990. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs.

Manager, NTT EAST-KANAGAWA CORPORATION.
He joined NTT in 1990. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs and optical fiber
drop cables. The work described in this article
was performed while he was a Senior ResearchEngineer in NTT Access Network Service Systems Laboratories. He moved to NTT EASTKANAGAWA CORPORATION in July 2010.

NTT Technical Review

Regular Articles

Lower-cost Cicada-resistant
Optical Fiber Drop Cable with
Better Workability
Kazuki Nakano†, Kensei Shiraishi, Yasuhiro Maehara,
Osamu Inoue, Atsushi Daido, Kazutoshi Takamizawa,and Tetsuhiro Numata
Abstract

We have developed a simpler type of cicada-resistant optical fiber drop cable that offers better
workability and is less expensive than the older one. It resulted from a rethink of the protective walls andsheath design.

1. Introduction
Increases in the number of contracts for fiber-tothe-home (FTTH) services mean increases in thenumber of optical cabling installations, which areleading to the emergence of various issues with optical fiber drop cables. Since identifying damage due tocicadas in 2001, NTT has studied measures to prevent
such damage. In 2007, cables with protective walls[1] were introduced to protect the optical fibers fromthis type of damage (Fig. 1). Although these cables
are effective in preventing cicada damage, their more
complicated structure means they are not as easy towork with as the conventional drop cables and they
are more expensive. To solve these problems, we havedeveloped a new low-cost optical fiber drop cable thatis effective in preventing cicada damage and has goodworkability [2].

Suspension member
Example of cicada damage
Ovipositor

TensionmemberNotch
Damage near notch

Optical core

Walls

2 mm
Generic optical drop fiber cableWall-type cicada-resistant
optical drop fiber cable

Fig. 1. Conventional cicada-resistant measures.

† NTT Access Network Service Systems Laboratories
Tsukuba-shi, 305-0808 JapanNTT Technical Review

Regular Articles

Current measures

Problems

Higher material cost
Cicada-resistant cable withprotective walls

More difficult sheath stripping(higher work cost)

Development concept
Cicada-resistant cable without protective walls

Fig. 2. Development concept.

2. Cicada damage and conventionalanti-cicada measures

Material properties

Hardness

The cicada (Cryptotympana facialis) that causes
the damage to drop cables is one of the larger speciesof cicada that inhabit Japan: it grows to a length of
6–7 cm. Preferring a warmer climate, the species canbe found in western Japan. During spawning, thefemale normally bores a hole in a branch of deadwood by stabbing the wood with her sharply pointed
ovipositor and then lays her eggs in the hole. Since
drop cables are similar in size and are erected at asimilar height to the branches that the cicadas prefer
for egg laying, they can easily be mistaken for abranch by cicadas. The conventional drop cables hada sheath made from soft materials, which let the
cicada gradually bore a hole into the cable and breakthe optical fiber. The cicadas tended to bore into thecable’s notch, which was intended to make it easier tostrip and expose the optical fiber core during installation work. To prevent cicadas from being attracted to
the notch, the notch was eliminated from the cable,
despite its usefulness. The hard protective walls oneither side of the optical core meant that the cicadas
were no longer able to bore deeply into the cable. The
introduction of this cable has reduced the amount ofdamage from cicadas.
3. New development concept
Although it was effective, the cable with protective
walls was more expensive to manufacture and harder
to work with when it needed to be stripped to expose
the core. The new development eliminates those protective walls while maintaining equally good cicadaVol. 9 No. 6 June 2011

Coefficient offriction
Tensilestrength
Tensileelongation
ratio

Tensilemodulus ofelasticity
Etc.

Cicada resistance
Penetration
depth

Correlative
analysisFig. 3. Considering material properties.

resistance characteristics (Fig. 2). Instead of walls
inside the cable, we have produced a simpler design
based on a harder sheath material that is more difficult
for cicadas to penetrate. This new cable is expected tohave lower costs and better workability.
4. Experiments
4.1 Method
Factors that give sheathing material its properties
include hardness, tensile strength, tensile modulus ofelasticity, tensile elongation ratio, and coefficient offriction. Since cicada resistance can be deduced fromthe ovipositor’s penetration depth, we made several
test cables with different properties to determine theright levels and combinations of these factors for
cicada resistance. For each sample, we determined
the relationship between the material properties andpenetration depth (Fig. 3) [3].
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To obtain data corresponding closely to actual conditions, we used live cicadas for our experiments. As
shown in Fig. 4, we constructed a large cage into
which we placed many cicadas captured outdoors.
These were allowed to spawn. To ensure that the
number of times cicadas laid eggs in each cable was
accurately recorded, the cicadas in the cage were
carefully observed and each spawning was counted.
After the experiment, the cables were cut up and thepenetration depths were measured radially from thesurface. Examples of cicada penetrations are shown

Cage

Test cable
CicadaFig. 4. Cicada cage experiment.

Reaches the fiber

Does not reach the fiber

Fig. 5. Penetration examples from the cage experiment.

1.2

Penetration depth (mm)

4.2 Results
By testing various materials in the cicada cage
experiment, we determined that hardness and tensile
strength have an important effect on penetration
depth. Hardness is important in determining thematerial’s resistance to the concentrated external
force applied to the cable by the cicada ovipositor.
When considering a suitable hardness index for
cicada spawning, we chose durometer hardness type
D, which measures the repellent force of a needleshaped indenter, an analog of the cicada ovipositor.
As shown in Fig. 6, we found that the penetration
depths became smaller as we increased the material’s
hardness.
Tensile strength is an index that can describe thematerial’s toughness. We found that toughness, thematerial’s ability to resist fracture, also plays animportant role in preventing penetration by cicada
ovipositors. A material’s toughness is expressed as
the amount of energy required to break it, which iseffectively indicated by its tensile fracture strength.

Penetration depth (mm)in Fig. 5.

1.0* Ordinary drop cable
y=-1.1253x + 1.9553
R2 = 0.5102

0.8
0.6
0.4
0.2

0.0
0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
Hardness (relative)
1.2* Ordinary drop cable
1.0
y=-0.1116x + 0.6101
R2 = 0.0309
0.8
0.6
0.4
0.2
0.0
0.5

1.0

1.5
2.0
2.5
Tensile strength (relative)

3.0

Fig. 6. R elationships between material properties andpenetration depth.

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Tensile strength (relative)

3.0
2.5

Reached fiber
Did not reach fiber

Effective region

2.0
1.5
1.0
0.5
0.9

Ordinary drop cable
1.0

1.1

1.2 1.3 1.4 1.5
Hardness (relative)

1.6

1.7

1.8

Fig. 7. Relationship between hardness and tensile
strength for fiber-reaching and fiber-non-reaching
penetration depths.

Wall type

New type

Fig. 9. Appearance of the new cable type.

External diameter

Suspension member

Tension member

Optical core
Cable’s
shorter side
Walls
Notch

Cicada-resistant sheath
Wall type

New type

Fig. 8. Structure of the new cable type.

Although we were able to determine by experiment
the importance of these two factors, we were unable
to decisively determine effective ranges for them
individually. However, when we analyzed the relationship between hardness and tensile strength, wewere able to clarify an effective region (Fig. 7). We
found that the combination of hardness to prevent
penetration by the cicada ovipositor and toughness towithstand the repeated stabbing of the ovipositor was
effective against cicada attack.

Vol. 9 No. 6 June 2011

5. New cableThrough the process and experimentation describedabove, we were able to develop an optical fiber drop
cable using a sheath material resistant to cicada attack[4]. The cable structure and appearance are shown in
Figs. 8 and 9. The main characteristics of the new
cable are described below.
5.1 Basic structure
As in the conventional drop cables, the suspensionRegular Articles

1.2
Average

Penetration depth (mm)1.0

Average + 3σ

0.8Compared with ordinary
sheaths, the new type showedmuch smaller penetration
depths, i.e., better cicadaresistance characteristics.

0.6
0.4
0.2
0.0

Ordinary drop cable

New type

Fig. 10. Cicada-resistance characteristics of the new cable type.

Processing (stripping)
Wall type

New type

Notching

Sheathstripping

SheathremovalWallremovalEnd ofprocess

Make
notch

Sheathstripping

Sheathremoval

Make
notch

End ofprocessFig. 11. Simplified processing.

member and cable are incorporated as a single unit.
The suspension member is a 1.2-mm-diameter single
steel wire, as in the conventional cable, and we kept
its external diameter the same as the shorter side of
the rectangular cable. To make the cable compatible
with existing closures and sheath-holding connectors
etc., we retained the dimensions of existing drop
cables. We also included notches in the middle of thecable to enable easy sheath stripping.

5.3 Workability
In general, a harder sheath material means thatsheath stripping is more difficult. However, to maintain good workability with the harder sheath material
and ensure that the sheath is sufficiently cicada resistant, we optimized the notch shape and were able tocreate a cable that can be stripped in the normal manner.
6. Effects of this development

5.2 Cicada resistance
Since maintaining cicada resistance was the mostimportant consideration in this development, weverified the cable’s reliability in terms of cicada resistance. We found that the ends of cicada penetrations
into the cable were kept a satisfactory distance awayfrom the optical fiber core. A comparison of penetration depths with a generic non-cicada-resistant cableis shown in Fig. 10. It clearly shows that penetrationsin the new drop cable were much shallower.

This new cicada-resistant cable has two main
advantages. (1) Its simpler design eliminates the needfor protective walls and thus lowers both material andmanufacturing costs: it is more than 10% cheaper toproduce. (2) Workability has been improved byincluding cable notches that enable easier sheath
stripping to expose the optical fiber core; this meansthat technicians can use ordinary snips instead of
specialized notching tools to strip the sheath. It also
eliminates the wall-removal step (Fig. 11). Thisdevelopment produced a cable with the same
cicada-resistance characteristics as the conventional

NTT Technical Review

Regular Articles

cable type, but with a lower cost and better workability. It was first introduced in the fourth quarter offiscal 2009 by NTT EAST and NTT WEST.
References[1]

M. Kama, H. Aoyama, K. Nakayachi, and R. Tensaka, “Developmentof Protective Wall Type Optical Drop Cables for Cicadas Damage
Control,” NTT Technical Journal, Vol. 19, No. 6, pp. 61–63, 2007 (in

[2]

[3]
[4]

Japanese).
M. Arii, “Trends in Optical Access Technologies Supporting FTTH,”
NTT Technical Review, Vol. 8. No. 5, 2010.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2010
05sf5.pdf
K. Shiraishi, Y. Maehara, O. Inoue, and K. Takamizawa, “Development of Economical Cicada Resistant Optical Drop Cables,” Proc. of
the IEICE-CS Conference 2010, B-10-3, Sept. 2010 (in Japanese).
K. Shiraishi, Y. Maehara, O. Inoue, and K. Takamizawa, “Development of Economical Cicada Resistant Optical Drop Cables,” Proc. of
the 59th IWCS/IICIT, pp. 279–283, Providence, RI, USA, 2010.

Kazuki Nakano

Atsushi Daido

Kensei Shiraishi

Kazutoshi Takamizawa

Yasuhiro Maehara

Tetsuhiro Numata

Research Engineer, NTT Access Network Service Systems Laboratories.
He joined NTT in 2008. Recently, he has been
engaged in the development of optical fiber drop
cables.

Research Engineer, NTT Access Network Service Systems Laboratories.
He joined NTT in 2008. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs and optical fiber
drop cables.

Sub-manager, NTT-ME.
He joined NTT in 1995. Recently, he has been
engaged in the development of optical fiber drop
cables. The work described in this article was
performed while he was a Research Engineer in
NTT Access Network Service Systems Laboratories. He moved to NTT-ME in April 2010.

Senior Research Engineer, NTT Access Network Service Systems Laboratories.
He joined NTT in 1994. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs.

Senior Research Engineer, Supervisor, NTT
Access Network Service Systems Laboratories.
He joined NTT in 1987. Recently, he has been
engaged in the development of optical accessnetwork systems.

Senior Research Engineer, Supervisor, NTT
Access Network Service Systems Laboratories.
He joined NTT in 1990. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs.

Osamu Inoue

Manager, NTT EAST-KANAGAWA CORPORATION.
He joined NTT in 1990. Recently, he has been
engaged in the development of systems for optical wiring techniques for MDUs and optical fiber
drop cables. The work described in this article
was performed while he was a Senior ResearchEngineer in NTT Access Network Service Systems Laboratories. He moved to NTT EASTKANAGAWA CORPORATION in July 2010.

Vol. 9 No. 6 June 2011



Global Standardization Activities

Standardization Activities for
Cloud Computing
Hiroshi Sakai†
Abstract

This article describes standardization activities for cloud computing. Since cloud computing involves
a wide range of technical and business elements, the targets of cloud computing standardization are
diverse and many standards organizations are studying cloud computing focusing on their respective
areas of expertise. The study areas can be broadly classified into: (i) framework development, terminology definition, use cases, and requirements identification, (ii) cloud configuration management, and (iii)inter-cloud federation. Cloud computing standardization was started by industrial organizations, whichdevelop what are called forum standards. Since late 2009, de jure standards bodies, such as ITU-T and
ISO/IEC JTC1, and ICT-oriented standards bodies (ICT: information and communications technology),
such as IEEE (Institute of Electrical and Electronic Engineers) and IETF (Internet Engineering Task
Force), have also begun to study cloud computing standardization. In the USA and Europe, governmentaffiliated organizations are also discussing it.

1. Introduction
Cloud computing represents a form of computing
in which a user accesses networked-based information and communications technology (ICT) resources, such as servers, storage units and network devices,and services provided using those resources (cloudservices) via the network without worrying about
where the resources are actually located. It has been
rapidly taken up by the business community over thelast few years. This article describes standardization
activities for cloud computing.
2. Importance of standardizing cloud computing
One advantage of using a cloud service is that users
can use the service without owning their own ICT
resources. Instead, they pay only for the amount of
the service that they have actually used. The numberof users of cloud-based consumer services, such as
Amazon and Google, has been increasing rapidly inthe last few years. Cloud computing is steadily mak† NTT Information Sharing Platform Laboratories
Musashino-shi, 180-8585 Japan

ing its way into enterprises’ information systems andgovernment systems.
Technological evolution of cloud computing has
been so fast that cloud service providers have tried todifferentiate their services by using their own service
specifications. However, as cloud computing develops into widely used social infrastructures, serious
problems associated with users being locked into a
specific provider have arisen. Specifically, once anenterprise begins to use a specific provider’s service,
it finds it difficult to switch to another provider thatoffers more attractive service conditions and it faces
the risk of its business being interrupted if the provider goes out of business.
To enable users to continue to use cloud services
with confidence, activities for developing standards
that ensure interoperability and portability between
cloud services have been organized since around2009.
3. Targets of cloud computing standardization
Cloud computing is a conglomerate of a wide variety of technologies, from distributed processing tovirtualization. The types of service offered are also
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Global Standardization Activities

Studies on framework, terminology, use cases, and requirements
NIST
ITU-T

ISO/IEC JTC1

ETSI

KCSA

CCF

GICTF

Open Cloud Manifesto

SIENA

OGC

CBA

Cloud configuration management
Implementation
OASIS
OCC
technology

Users/
operators

Architecture

ITU-T

NIST
Management

SaaS APICloud
management
API

Other
cloudsSecurity

PaaS API
IaaS API

NIST

OGF

CSA

DMTF

ENISA
DMTF

SNIA

TM Forum

ATIS CSF

Coordination
among bodies
USbodies

OMG

GICTF
DMTF
ITU-T
IEEE

ITU-T

OpenStackGlobalbodiesIntercloud

OCC
ISO/IEC
JTC1

IEEE

Europeanbodies

KoreanbodiesJapanesebodies

OGC:
Open Government Cloud consortium
CBA:
Cloud Business Alliance
SIENA:
Standards and Interoperability for e-infrastructure Implementation initiative
KCSA:
Korea Cloud Service Association
ATIS CSF: Alliance for Telecommunications Industry Solutions Cloud Services Forum

Fig. 1. Study areas for cloud computing standardization and major cloud computing standards bodies.

diverse: from infrastructure as a service (IaaS), in
which ICT resources are provided as a service, andplatform as a service (PaaS), in which database orother middleware programs are provided as a service,
to software as a service (SaaS), in which application
software, such as accounting programs and officesuits, are provided as a service.
The targets of cloud computing standardization are
so diverse that many standards organizations are
studying cloud computing focusing on their respective areas of expertise. The different study areas andmajor cloud computing standards bodies related toeach of them are shown in Fig. 1. Each body addresses issues that are so diverse that it is difficult to define
precisely what issues it covers. However, the study
Vol. 9 No. 6 June 2011

areas for cloud computing can be broadly classified
into the following three:(i)	Framework development, terminology definition, use cases, and requirements identification(ii) Cloud configuration management(iii) Inter-cloud federation.
3.1 S
 tudies on framework development, terminology definition, use cases, and requirements
identification
Since cloud computing involves a wide range oftechnical and business elements, it is crucial inadvancing standardization to sort out these elements
and define standard technical terms. A significant
contribution in these areas is being made by theGlobal Standardization Activities

National Institute of Standards and Technology(NIST), which first defined the now commonly used
terms IaaS and SaaS.
To identify what needs to be standardized for cloudcomputing, many organizations take an approach offirst discussing use cases and then sorting out requirements that need to be standardized. In addition to dejure standards bodies as the International Telecommunication Union, Telecommunication Standardization Sector (ITU-T) and International Organizationfor Standardization/International ElectrotechnicalCommission Joint Technical Committee 1 (ISO/IEC
JTC1), major regional and national standards bodies
in the USA, Europe, Korea, Japan, etc. are working
on these standardization issues.
3.2 Studies on cloud configuration management
In the area of configuration management of cloudsystems, many organizations are aiming to develop
specifications for a standard application programming interface (API), an interface through whichusers and operators manage cloud systems.
The Open Cloud Computing Interface Working
Group (OCCI-WG) of the Open Grid Forum (OGF)
has defined and released an API for managing IaaS.
The Open Cloud Standards Incubator (OCSI) of theDistributed Management Task Force (DMTF) has
also specified an IaaS management API.
The Storage Networking Industry Association(SNIA) has formulated the specifications of the
Cloud Data Management Interface (CDMI), which isan API for controlling storage units.
A non-standards organization is also active in thisarea. An open source community called OpenStack,which was established mainly by Rackspace andNASA in July 2010, makes the source code of its IaaS
management software open to the public.
All the cloud configuration management APIs now
under study are intended for IaaS. Few APIs are being
studied for PaaS or SaaS. This can be attributed to thegeneral recognition that PaaS and SaaS are in thecompetitive arena of business.
In addition, many organizations are studying reference architecture and security issues for cloud systems.
The Cloud Security Alliance (CSA) is defining thebest practice in thirteen areas, ranging from security
risks for cloud users and providers to governance andrisk management that need to be defined in introducing cloud computing, electronic disclosure of legal
evidence, compliance, and auditing.



3.3 Studies on inter-cloud federation
Studies on inter-cloud federation were started in thesecond half of 2009 so that multiple clouds can mutually give and take cloud resources to provide cloudservices stably even when individual cloud systems
become unable to provide service due to damage by amajor natural disaster or a serious failure, or when
their capacity is surpassed by the demand, or so thatusers can access two or more clouds seamlessly
through ID-based federation (ID: identification).
The Global Inter-Cloud Technology Forum(GICTF), which was established in Japan in July
2009, is one of the first bodies to address the issue ofinter-cloud federation. In June 2010, it issued a white
paper that documented use cases and functional
requirements for inter-cloud federation [1].
4. Current activities of major
cloud-related standards bodies
Cloud computing standardization was started byindustrial organizations, which develop what are
called forum standards. Since late 2009, de jure standards bodies, such as ITU-T and ISO/IEC JTC1, andICT-oriented standards bodies, such as IEEE (Institute of Electrical and Electronic Engineers) and IETF
(Internet Engineering Task Force), have also begun to
study it. In the USA and Europe, government-affiliated organizations are also discussing it. The activities of major forum standards bodies, ICT-oriented
standards bodies, de jure standards bodies, and government-affiliated bodies are described below.
4.1 Forum standards bodies
There are two groups of forum standards bodies
related to cloud computing. Those in the first group,
including DMTF, OGF, and SNIA, have been activein the field of grids and distributed processing management and have newly added cloud computing totheir agendas. The bodies in the second group, including OCC, CSA and GICTF, were newly founded toaddress cloud computing.
(1) DMTF (Distributed Management Task Force)
DMTF has defined the Open Virtualization Format(OVF), which is a standard virtual machine image
format. It established OCSI in April 2009 and isstudying standards that will allow interoperability
between cloud systems. The Cloud Management
Working Group (CMWG), in which VMware, Fujitsu, Oracle, and others are proposing a relevant API,was established in June 2010. DMTF issued a white
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Global Standardization Activities

paper on interoperability between cloud systems in
November 2009 and another on use cases of cloud
management and interactions in June 2010. Its Board
Members include VMware, Microsoft, IBM, Citrix,
Cisco, and Hitachi.
(2) OGF (Open Grid Forum)
OGF formed the OCCI-WG (WG: Working Group)in April 2009 and defined and released an API specification, OCCI [2], which makes possible lifecycle
management of virtual machines and workloads
through IaaS. OCCI is implemented in Europe’s
OpenNebula Project, etc. The main participants in
OCCI are Fujitsu, EMC, and Oracle.
(3)	SNIA (Storage Networking Industry Association)
SNIA established the Cloud Storage Technical
Working Group in April 2009 and released CDMI,
which is an interface specification for cloud storage
data management. In October 2009, it formed a subworking group called the Cloud Storage Initiative(CSI) to educate users and promote the cloud storage
market through the Cloud BUR SIG (Cloud Backup
and Recovery Special Interest Group) project. SNIA’s
membership includes EMC, IBM, Fujitsu, and Hitachi. Its Japan Chapter was established in 2010.
(4) OMG (Object Management Group)
OMG held a Cloud Standards Summit in July 2009and inaugurated Cloud Standards Coordination,
which is a round-table conference of cloud-related
standards bodies. Participants in the Coordination
currently include DMTF, OGF, SNIA, TM Forum(TeleManagement Forum), OASIS, OCC, CSA,ETSI, and NIST in addition to OMG.
(5)	OASIS (Organization for the Advancement ofStructured Information Standards)
OASIS established the Identity in the Cloud Technical Committee (IDCloud TC) in May 2010, surveyed existing ID management standards, and developed use cases of cloud ID management and guidelines on reducing vulnerability. It also developed
basic security standards, such as SAML (Security
Assertion Markup Language) and maintains liaison
with CSA and ITU-T. The main members are IBM,
Microsoft, and others.
(6) OCC (Open Cloud Consortium)
OCC is a nonprofit organization formed in January
2009 under the leadership of the University of Illinois
Vol. 9 No. 6 June 2011

at Chicago. It aims to develop benchmarks using acloud testbed and achieve interoperability between
cloud systems. Its Working Groups include OpenCloudTestbed, Project Matsu, which is a collaboration with NASA, and Open Science Data Cloud,which covers the scientific field. The main members
include NASA, Yahoo, Cisco, and Citrix.
(7) Open Cloud Manifesto
Open Cloud Manifesto is a nonprofit organization
established in March 2009 to promote the development of cloud environments that incorporate theuser’s perspective under the principle of open cloudcomputing. It published cloud use cases and requirements for standards as a white paper in August 2009.
The latest version of the white paper is version 4.0(V4) [3], which included for the first time the viewpoint of the service level agreement (SLA). The participants include IBM, VMware, Rackspace, AT&T,
and TM Forum. A Japanese translation of the white
paper is available [4].
(8) CSA (Cloud Security Alliance)
CSA is a nonprofit organization established in
March 2009 to study best practices in ensuring cloudsecurity and promote their use. It released guidelines
on cloud security in April 2009. The current version
is version 2.1 [5], which proposes best practices inthirteen fields, such as governance and compliance.
The main members are PGP, ISACA, ENISA, IPA,
IBM, and Microsoft. A distinctive feature of themembership is that it includes front runners in cloudcomputing, such as Google and Salesforce. A Japan
Chapter of CSA (NCSA) was inaugurated in June
2010.
(9) CCF (Cloud Computing Forum)
CCF is a Korean organization established in
December 2009 to develop cloud standards and promote their application to public organizations. Its
membership consists of 32 corporate members andmore than 60 experts. CCF comprises six Working
Groups, including Media Cloud, Storage Cloud, andMobile Cloud.
(10)	G ICTF (Global Inter-Cloud Technology
Forum)GICTF is a Japanese organization studying intercloud standard interfaces, etc. in order to enhance thereliability of clouds. As of March 2011, it has a membership of 74 corporate members and four organizations from industry, government, and academia. InGlobal Standardization Activities

June 2010, it released a white paper on use cases ofinter-cloud federation and functional requirements.
The main members include NTT, KDDI, NEC, Hitachi, Toshiba Solutions, IBM, and Oracle.
4.2 ICT-oriented standards bodies
Major standards bodies in the ICT field have also,
one after another, established study groups on cloudcomputing. These study groups are holding lively
discussions.
(1) IETF
IETF had been informally discussing cloud computing in a bar BOF (discussions over drinks in a bar;
BOF: birds of a feather) before November 2010
when, at IETF79, it agreed to establish the Cloud
OPS WG (WG on cloud computing and maintenance), which is discussing cloud resource management and monitoring, and Cloud-APS BOF (BOF on
cloud computing applications), which is mainly discussing matters related to applications. Since aroundthe end of 2010, it has been receiving drafts for surveys of the cloud industries and standards bodies,reference frameworks, logging, etc.
(2) IEEEIEEE formed the Cloud Computing Standards
Study Group (CCSSG) in March 2010. It announced
the launch of two new standards development projects in April 2011: P2301, Guide for Cloud Portability and Interoperability Profiles (CPIP) and P2302,
Standard for Intercloud Interoperability and Federation (SIIF).
(3) TM ForumIn December 2009, TM Forum established theEnterprise Cloud Buyers Council (ECBC) to resolve
issues (on standardization, security, performance,etc.) faced by enterprises when they host private
clouds and thereby to promote the use of cloud computing. In May 2010, it started the Cloud Services
Initiative, which aims to encourage cloud service
market growth. The main members of this initiative
are Microsoft, IBM, and AT&T.
4.3 De jure standards bodies
Since late 2009, major de jure standards bodies
have taken up cloud computing as part of their study
subjects. All these bodies are conducing a gap analysis based on the studies made by forum standards
bodies in order to identify the target areas where standardization by de jure standards bodies is desired.


Specific activities to develop recommendations are
expected to start in 2011.
(1) ITU-T
In February 2010, ITU-T launched the Focus Groupon Cloud Computing, which is discussing the benefitsof clouds and target issues requiring standardizationfrom the telecommunication perspective. The Group
is currently developing six documents on topics suchas the cloud ecosystem, functional architecture, cloudsecurity, and utilization of networks in clouds. Afterwards, relevant Study Groups will develop recommendations for these issues.
(2) ISO/IEC JTC1
In its Sub Committee 38 (SC38) meeting held in
November 2009, ISO/IEC JTC1 established a Study
Group to study cloud computing. Its secretariat isprovided by the American National Standards Institute (ANSI). The Study Group is classifying cloudcomputing, sorting out terminology, and maintaining
liaison with other organizations. In Japan, SC38
Technical Committee was launched in February
2010. In addition, SC27 is studying requirements for
Information Security Management Systems(ISMSs).
(3)	ETSI (European Telecommunications Standards
Institute)
ETSI has established a Technical Committee on
grids and clouds. The TC Cloud has released a Technical Report (TR) on standards required in providing
cloud services.
4.4 Government-affiliated bodies
Government-affiliated bodies in the USA andEurope are active in cloud-related standardization.
Government systems constitute a large potential
cloud market. It is highly likely that the specifications
used by governmental organizations for procurement
will be adopted as de facto standards.
(1) NISTNIST is a technical department belonging to the
U.S. Department of Commerce. “The NIST Definition of Cloud Computing”, which was published in
October 2009, is referred to on various occasions.
NIST undertakes cloud standardization with five
WGs. One of them, Standards Acceleration to Jumpstart Adoption of Cloud Computing (SAJACC), isintended to promote the development of cloud standards based on actual examples and use cases. It
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Global Standardization Activities

discloses a number of different specifications andactual implementation examples on its portal. It also
discloses test results for the developed standard
specifications.
(2)	ENISA (European Network and Information
Security Agency)
In November 2009, ENISA, an EU agency, released
two documents: “Cloud Computing: Benefits, Risks
and Recommendations for Information Security”,
which deals with cloud security, risk, and assessment
and “Cloud Computing Information Assurance
Framework”, which is a framework for ensuring
security in cloud computing.
5. Future of cloud standardization
and NTT’s activities
While many organizations are discussing cloudstandardization, activities for consolidating their discussions are currently inadequate. Such activities arebeing undertaken only partially by Cloud Standards
Coordination. The key issue will be how well the dejure standards bodies that have begun full-scale studies of cloud computing can collaborate with forum
standards bodies.
Major front runners in cloud services, such as Amazon, Google, and Salesforce, are not participating in
the cloud standards organizations mentioned in thisarticle. There are not a few people who argue that it is
too early for cloud standardization because it may

impede technical innovation. It is unclear to what
extent the standards developed by the standards bodies will be adopted by the market. This trend should
be monitored carefully.
NTT believes that it is particularly important tostandardize the external interfaces of cloud systems if
we are to achieve interoperability and portability
between cloud services. Specifically, such interfaces
include interfaces for cloud users and those for cloud
application developers and inter-cloud interfaces toallow federated operation between clouds.
NTT is currently participating in GICTF as a board
member. NTT will make proposals to ITU-T and
NIST on the basis of the work undertaken by GICTF
on inter-cloud federation and other issues.
6. Conclusion
This article described standardization activities forcloud computing. NTT will promote the standardization of external interfaces of cloud systems, which
will enable interoperability and portability between
cloud services.
References
[1]
[2]
[3]
[4]
[5]

http://www.gictf.jp/doc/GICTF_Whitepaper_20100809.pdf
http://www.ogf.org/gf/docs/?archived
http://opencloudmanifesto.org/Cloud_Computing_Use_Cases_
Whitepaper-4_0.pdf
http://cloudusecases.org
https://cloudsecurityalliance.org/csaguide.pdf

Hiroshi Sakai

Senior Research Engineer, Supervisor, Information Sharing Platform SE Project, NTT Information Sharing Platform Laboratories.
He received the B.E. and M.E. degrees in electrical engineering from the University of Tokyoin 1991 and 1993, respectively. He joined NTT
Communication Switching Laboratories in 1993
and studied advanced intelligent networks andthe Next Generation Network (NGN). He is currently studying cloud computing including network virtualization and cloud federation. He is amember of the Institute of Electronics, Information and Communication Engineers.

Vol. 9 No. 6 June 2011



Practical Field Information about
Telecommunication Technologies

Fault Cases and Countermeasuresagainst Damage to Access System
Facilities Caused by Wildlife
Abstract

Wildlife that damages access system facility is classified into three groups (rodents, insects, and birds).
We have investigated the types of damage and have studied countermeasures. Such countermeasures willcontribute greatly to reducing maintenance costs and improving the reliability of access system facilities.
This article is the fifth in a bimonthly series on the theme of practical field information about telecommunication technologies. This month’s contribution is from the Access Engineering Group, Technical
Assistance and Support Center, Maintenance and Service Operations Department, Network Business
Headquarters.

1. Introduction
Most of the access system facilities maintained by
the NTT Group are exposed to the outside environment. This means that damage caused by rain, wind,lightning, and other natural phenomena can occur. In
addition, more than a little damage is caused by wildlife. In this article, we report on the various kinds ofdamage due to wildlife and countermeasures to maintain the reliability of access system facilities in Japan.
2. Fault cases
Access system facilities between a central officeand customer premises along with various kinds ofwildlife that cause damage are schematically illustrated in Fig. 1. Wildlife that causes damage to accesssystem facilities in Japan can be broadly classified
into (1) rodents (squirrels, flying squirrels, rats, etc.),(2) insects (moth larvae, cicadas, ants, etc.), and (3)birds (crows, woodpeckers, etc.). These kinds ofwildlife can be found throughout the country.
Most rodents are active all year (only a few hibernate), so the time when damage happens is not limited† NTT EAST
Ota-ku, 144-0053 Japanto a particular period. They mainly damage cables,
especially small-diameter ones.
The degree of damage and the time that damage
happens depends on the type and ecology of insects:
moth larvae damage cables in early summer (Juneand July) before they become chrysalises, and cicada
damage is caused specifically by adult females mainly from early summer to early fall (June to September).
Damage caused by birds mainly occurs during thebreeding season. In particular, crows can cause extensive damage in the period from March to June.
2.1 Rodents
Rodents have incisors on both upper and lower
jaws. These teeth continue to grow throughout theirlife, but rodents keep them to an appropriate length by
gnawing on objects. Rodents can be broadly classified into the Sciuridae family that includes squirrels
and flying squirrels and the Muridae family that
includes black rats and house mice. They chew on
telecommunication cables and connection closuresand damage copper wires inside metallic cables andfibers inside optical cables. Damage caused by members of the Sciuridae family frequently occurs along
aerial cable routes in mountainous areas and damage
caused by members of the Muridae family often
occurs in underground cable routes.
NTT Technical Review

Practical Field Information about Telecommunication Technologies

Rodents
Insects
Birds
Centipedes
and ants

Squirrels, flying
squirrels, and rats
Moth larvae
Woodpeckers

Moth larvae
Woodpeckers

CicadasBees (in conduit
openings)
Crows

Ants and bees

Remote terminalbox etc.
TermitesCentral office

Opticalfiber cable
Metallic cable

Dr

op

ca

Cable conduit

ble

Cockroaches
Underground cable

Fig. 1. Illustration of places in access system facilities that can be damaged by wildlife.

(b)

(a)

Connection closure

Fig. 2. Example of optical fiber cable damage (by a flying squirrel).

Optical fiber cable sheath

Incisor scars(upper)Incisor scars(lower)* This flying squirrel was
rescued after getting its
legs tangled up in the cable.

Fig. 3. Flying squirrel encounteredin an area in which damage
occurred.

Vol. 9 No. 6 June 2011

Fig. 4. D amage to an FFA closure(by a squirrel).

Fig. 5. Incisor scars left bysquirrel (upper and lower).

Practical Field Information about Telecommunication Technologies

An example of optical fiber cable damage (by aflying squirrel) is shown in Fig. 2, a flying squirrel
encountered in an area in which damage occurred isshown in Fig. 3, damage to a fiber free access (FFA)
closure (by a squirrel) is shown in Fig. 4, and asquirrel’s incisor scars (upper and lower) are shownin Fig. 5.
2.2 Insects
2.2.1 Moth larvae
Moth larvae burrow into trees and the ground andlive in holes. The larvae mistake telecommunication
cables for plants. As a result, they can damage thecable by chewing. An example of damage to an optical fiber cable (by a moth larva) is shown in Fig. 6.
2.2.2 Cicadas
Cicadas generally lay their eggs in dead trees,
avoiding living trees that might freeze over during thewinter. They may also try laying their eggs in a drop
cable by piercing the sheath with the ovipositor. Thisbehavior can damage an optical fiber inside the cable.
Cicada egg laying, cicada eggs, and damage to a drop
cable (by a cicada) are shown in Figs. 7–9.
2.2.3 Other insects
Other insects like ants and bees may invade connection closures or cable conduits through very small
gaps to build nests. This kind of activity can damage
facilities, and there are examples of centipedes invading outdoor access system equipment and getting
burned up by coming into contact with package terminals. Centipedes prefer tight spaces and can invade
equipment through small gaps such as cable entryways. A centipede found inside an outdoor remote
subscriber module is shown in Fig. 10.

Burrowing into cable

Moth larva

Fig. 6. Damage to an optical fiber cable (by a moth larva).

Drop cable

Tip of ovipositor

Fig. 7. Cicada egg laying.

Drop cable

Fig. 8. Cicada eggs.

Fig. 9. Damage to a drop cable (by a cicada).

Fig. 10. C entipede (charred body) found inside an outdoor
remote subscriber module.

NTT Technical Review

Practical Field Information about Telecommunication Technologies

2.3 Birds
2.3.1 CrowsIn the breeding season before summer, a pair ofcrows will build a nest by gathering slim, sturdy
materials like twigs or wires. During this time, thesecrows may use their beaks to bite around a drop
cable’s water-draining section (where the supporting
wire separates from the optical fiber section) anddamage the optical fiber inside the drop cable. An
example of damage to a drop cable (by a crow) isshown in Fig. 11.
2.3.2 Woodpeckers
Woodpeckers engage in drumming (knocking on atree trunk with their beaks) to prey upon insects or toassert territory or mating rights. They may also do
this on telecommunication cables, opening up holes
in the sheath and damaging copper wires. An example
of damage to a metallic cable (by a woodpecker) is
shown in Fig. 12.

Water-draining
sectionFig. 11. Damage to a drop cable (by a crow).

DamageStainless steel

3. Countermeasures
3.1 Rodents
One method for preventing the problem introduced
above is to use high-strength-sheath cable that has aninternal stainless-steel layer. Another effective method for preventing partial cable damage is to use asquirrel-proof cover or squirrel-proof tape (both havea layer of stainless steel affixed to a PVC (polyvinyl
chloride) sheet). Connection closures can be protected by commercial protective covers. A high-strengthsheath cable, a squirrel-proof cover, squirrel-prooftape, an example of the construction of a squirrelproof cover and squirrel-proof tape, and a protective
cover for connection closures are shown in Figs.
13–17.
3.2 Insects
The countermeasures taken against moth larvae arebasically similar to those for rodents. Another effective method for preventing cable damage is to eliminate intrusion paths. It is effective to use commercial
anti-ivy products on the stay (Fig. 18), to remove ivy
entangled on the stay and elsewhere, and to cut down
trees in contact with cables to simply deny larvae apath to cables and other facilities. One countermeasure for protecting outdoor metallic cables against
cicadas is to change to type-G cables equipped with ametal band. For optical fiber drop cables, NTT Laboratories has tried various ideas such as removing the
V-notches on the surface of the cable’s sheath andincorporating an internal barrier. Consequently,
Vol. 9 No. 6 June 2011

Fig. 12. D amage to ametallic cable (bya woodpecker).

Stainless steel (band)

Fig. 14. Squirrel-proof cover.

Fig. 13. A ppearance ofhigh-strength
sheath cable.

Stainless steel (mesh)Fig. 15. S quirrel-proof
tape.

Squirrel-proof cover(straight section)

Squirrel-proof tape
(curved section)

Fig. 16. E xample of theconstruction ofsquirrel-proof
cover and tape.

Fig. 17. C ommercial
protective coverfor connection
closures.

Practical Field Information about Telecommunication Technologies

Drop cable

PVC protective coverIvy blocker

Ivy guard

Fig. 19. PVC protective cover for optical cable.

Fig. 18. Commercial anti-ivy products.

Laboratories adopts optical fiber drop cable with ahardened sheath material that prevents the cicada’s
ovipositor from penetrating the cable [1].
Damage caused by other insects that invade
facilities through small gaps can be prevented bysimply blocking the intrusion path. In the outdoor
equipment mentioned in this article, these gaps arelikely to be found at cable entryways or ventilation
holes. Cable entryways can be hermetically sealed
and a metal mesh can be attached over ventilation
holes.
3.3 Birds
An effective measure for preventing damage causedby crows is to wrap the most susceptible location—
the water-draining section where the supporting wire
separates from the optical fiber section—with a PVC
protective cover, as shown in Fig. 19.
Damage caused by woodpeckers can be prevented
by using a squirrel-proof cover and by installingsquirrel-proof tape in the straight and curved sections



of cable. It is also effective to use high-strengthsheath cable for aerial cables.
4. Conclusion
We reported on the various kinds of damage due towildlife and countermeasures to maintain the reliability of the access system facilities in Japan. Wildlife
may pose an ongoing risk to the operation of outdoor
facilities. Therefore, it is important to apply efficientcountermeasures. We would be pleased if the methods introduced here succeed in preventing wildlife
damage.
Reference[1]

K. Nakano, K. Shiraishi, Y. Maehara, O. Inoue, A. Daido, K. Takami­
zawa, and T. Numata, “Lower-cost Cicada-resistant Optical Drop
Cable with Better Workability,” NTT Technical Review, Vol. 9, No. 6,2011.
https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr2011
06ra2.html

NTT Technical Review

External Awards
Best Interactive Award
Winners: Kyosuke Nishida*1, Ryohei Banno*2, Ko Fujimura*1, andTakahide Hoshide*1*1	 NTT Cyber Solutions Laboratories*2 Hokkaido University

Date: Mar. 1, 2011
Organization: The 3rd Forum on Data Engineering and Information
Management
For “Tweet-Topic Classification on Twitter with Data Compression”.
Published as: K. Nishida, R. Banno, K. Fujimura, and T. Hoshide,“Tweet-Topic Classification on Twitter with Data Compression,” the3rd Forum on Data Engineering and Information Management(DEIM 2011), A1-6, Izu, Japan.
Young Engineer’s Award
Winner: Shin Kaneko, NTT Access Network Service Systems Laboratories
Date: Mar. 15, 2011
Organization: The Institute of Electronics, Information and Communication Engineers (IEICE)
For “Frequency-domain Optical CDM Employing Spectral M-ary
Modulation Based on Electrical-domain Spatial Code Spreading”
This paper proposes a novel transmitter configuration that flexibly

enhances the scalability for frequency-domain optical code-divisionmultiplexing (CDM) based on electrical-domain spatial code spreading. The transmitter employs dummy data input and pre-biasing circuits. The dummy data input to the transmitter means that the total
number of multiplexed binary data streams, comprising those that
actually accommodate users/services and the dummy streams,
remains constant. Pre-biasing circuits enable us to achieve high tolerance to multiple access interference by compensating for the non­linearity of the M-ary modulation and improve the receiver sensitivity. Owing to the dummy data input, none of the parameters for prebiasing must be changed regardless of the number of users/services.
Therefore, the proposed transmitter can flexibly enhance the scalability of optical CDM. The feasibility of the proposed transmitter isverified theoretically.
Published as: S. Kaneko, N. Miki, H. Kimura, and H. Hadama,“Frequency-domain Optical CDM Employing Spectral M-ary Modulation Based on Electrical-domain Spatial Code Spreading,” Technical Report of IEICE, OCS (B-10-47), Vol. 110, No. 176, pp. 37–40,
2010 (in Japanese).
For “Spectral Efficiency Improvement in Frequency-domain Optical CDM Based on Electrical-domain Spatial Code Spreading”
Published as: S. Kaneko, N. Miki, H. Kimura, and H. Hadama,“Spectral Efficiency Improvement in Frequency-domain Optical
CDM Based on Electrical-domain Spatial Code Spreading,” Technical Report of IEICE (B-10-45) No. 2, p. 232, 2010 (in Japanese).

Papers Published in Technical Journals andConference Proceedings
Heterostructure Growth of a Single-crystal Hexagonal AlN(0001) Layer on Cubic Diamond (111) Surface
K. Hirama, Y. Taniyasu, and M. Kasu
J. Appl. Phys. Vol. 108, No. 1, p. 013528, 2010.
We demonstrate heterostructure growth of a hexagonal AlN (0001)
layer on cubic diamond (111) surface and investigate the interface
structure in order to achieve AlN/diamond heterojunction devices.
From the initial growth, the single-crystal AlN (0001) layer grows on
the diamond (111) surface with an in-plane epitaxial relationship[1010]AlN//[110]diamond. A high-resolution transmission electron
microscope image shows an abrupt interface. Misfit dislocations are
distributed periodically at the heterointerface owing to the large lattice mismatch between AlN and diamond. Compared with the inplane epitaxial relationship [1120]AlN//[110]diamond, [1010]AlN//[110]diamond is energetically preferred because it has a higher bonddensity and, therefore, lower interfacial energy.

Extension of Secret Handshake Protocols with Multiple
Groups in Monotone Condition
Y. Kawai, S. Tanno, T. Kondo, K. Yoneyama, K. Ohta, and N.
Kunihiro
IEICE Trans. on Fundamentals of Electronics, Communications
and Computer Sciences, Vol. 93, No. 6, pp. 1122–1131, 2010.
The Secret Handshake protocol allows members of the same group
to authenticate each other secretly. That is, two members who belong
to the same group can learn that the counterpart is in the same group,
while non-members of the group cannot determine whether or not thecounterpart is a member of the group. Yamashita and Tanaka proposed Secret Handshake Scheme with Multiple Groups (SHSMG).
They extended a single group setting to a multi-group setting where
two members output “accept” if both members’ affiliations of themultiple groups are identical. In this paper, we first show a flaw in

NTT Technical Review

Papers Published in Technical Journals and Conference Proceedings

their SHSMG and construct a new secure SHSMG. Second, we introduce the new concept of the Secret Handshake scheme “monotone
condition Secret Handshake with Multiple Groups (mc-SHSMG)” inorder to extend the “accept” condition. In our new handshake protocol setting, members can authenticate each other in the monotone
condition (not only in the case where both members’ affiliations are
identical but also in the case where they are not identical). The communication costs and computational costs of our proposed mcSHSMG are lower than for the trivial construction of it.

Proxiable Designated Verifier Signature
M. Ushida, K. Ohta, Y. Kawai, and K. Yoneyama
Proc. of Security and Cryptography (SECRYPT) 2010, pp. 344–
353, Athens, Greece.
Designated Verifier Signature (DVS) guarantees that only a verifier designated by a signer can verify the validity of a signature. In
this paper, we propose a new variant of DVS: Proxiable Designated
Verifier Signature (PDVS), where the verifier can make a third party(i.e., the proxy) substitute for some of the verification process. In the
PDVS system, the verifier can reduce his computational cost by delegating some of the verification process without revealing the validity of the signature to the proxy. In all DVS systems, the validity of asignature means that a signature satisfies both of the following properties: (1) the signature is accepted by a decision algorithm and (2)the signature is confirmed to have been generated by the signer. In the
PDVS system, the verifier can make the proxy substitute for only thechecking of property (1). In the PDVS model, we divide the verifier’s
secret keys into two parts: one is a key for performing the decisionalgorithm, and the other is a key for generating a dummy signature,
which prevents a third party from being convinced of property (2).
We also define security requirements for PDVS and propose a PDVS
scheme that satisfies all of the security requirements that we define.

Transmission Characteristics of Chirp-managed Direct
Modulation over Hybrid Link of SMF and DSF
S. Usui, H. Iwashita, and T. Kubo
OptoeElectronics and Communications Conference (OECC)
2010, pp. 298–299, Sapporo, Japan.
A chirp-managed direct-modulated optical signal has a high tolerance for fiber dispersion. However, its tolerance for nonlinear effects
is not clear. We thus investigated its applicability to a hybrid link of
SMF and DSF without line amplifiers.

Diamond Semiconductor and Its Prospects for High RF
Power Devices
M. Kasu
Material stage, Technical Information Institute Co. Ltd., Vol. 10,
No. 7, pp. 58–61, 2010 (in Japanese).
The present status and prospects of diamond RF power devices arereviewed.

Cross-realm Password-based Server Aided Key Exchange
K. Yoneyama
WISA, KIISC, Lecture Notes in Computer Science, 2011, Vol.
6513, pp. 322–336, Jeju, Korea.
In this paper, we extend password-based server aided key exchangeVol. 9 No. 6 June 2011

(PSAKE) to the cross-realm setting which enables two clients in two
different realms with different passwords to exchange a session key
through their corresponding servers, i.e., there are two servers. We
cannot simply apply the previous security model of PSAKE to thecross-realm setting because there is a difference between the security
properties that can be captured in the previous setting and in the new
setting. Therefore, we define a new formal security model of crossrealm PSAKE. Our model captures all desirable security requirements, like resistance to leakage of ephemeral private keys, to keycompromise impersonation, and to undetectable on-line dictionary
attack. Furthermore, we propose a concrete construction of crossrealm PSAKE with the optimal number of rounds for a client that issecure in the sense of our model. Our scheme assumes no pre-established secure channels between different realms unlike previous
schemes, but just authenticated channels between different realms.

Circulator-free Reflection-type Tunable Optical Dispersion
Compensator Using Cascaded Arrayed-waveguide Gratings
Y. Ikuma, T. Mizuno, H. Takahashi, and H. Tsuda
Optical Communication (ECOC) 2010, Vol. We. 8. E. 7, pp. 1–3,
Torino, Italy.
A tunable optical dispersion compensator that uses cascaded
arrayed-waveguide gratings and an integrated phase shifter is reported. It has a reflective configuration but does not require a circulator.
The dispersion is successfully controlled from +142 to +1148 ps/
nm.

Observation of n-type Conduction in Arsenic-doped CVD
Diamond
M. Kasu
Proc. of Int. Symp. on Compound Semicond 2010, Vol. 1, No. 1,
p. 1, Takamatsu, Japan, 2010.
We achieved n-type diamond by using arsenic doping.

Increase of Hole Concentration of H-terminated Diamondand Its Application to FET
K. Michal and M. Kasu
Proc. of Int. Symp. on Compound Semicond 2010, Vol. 1, No. 1,
p. 1, Takamatsu, Japan, 2010.
We improved H-terminated diamond FET by NO2 adsorption.

Indifferentiable Security Reconsidered: Role of Scheduling
K. Yoneyama
Proc. of ISC’2010, Lecture Notes in Computer Science, No. 6531,
pp. 430–444, Florida, CA, USA.
In this paper, the substitutability of the indifferentiability framework with non-sequential scheduling is examined by reformulating
the framework through applying the Task-PIOA framework, which
provides non-sequential activation with oblivious task sequences.
First, the indifferentiability framework with non-sequential scheduling is shown to be able to retain the substitutability. Next, thisframework is shown to be closely related to the reducibility of systems. Finally, two modelings with sequential scheduling and nonsequential scheduling, respectively, are shown to be mutually inde-Papers Published in Technical Journals and Conference Proceedings

pendent. Thus, the importance of scheduling in the indifferentiability
framework is clarified.

Hierarchical ID-based Authenticated Key Exchange Resilient to Ephemeral Key Leakage
A. Fujioka, K. Suzuki, and K. Yoneyama
Proc. of IWSEC 2010, Lecture Notes in Computer Science, No.
6434, pp. 164–180, Kobe, Japan.
In real applications of (public key-based) cryptosystems, hierarchical structures are often used to distribute the workload by delegating key generation. However, there have been few previous studies
about such a hierarchical structure in the ID-based authenticated key
exchange (AKE) scenario. In this paper, we introduce the first hierarchical ID-based AKE that is resilient to ephemeral secret key leakage.
We provide a formal security model for hierarchical ID-based AKE.
Our model is based on eCK security to guarantee resistance to leakage of ephemeral secret keys. We also propose an eCK-secure hierarchical ID-based AKE protocol based on a hierarchical ID-based
encryption.

Universally Composable NBAC-based Fair Voucher
Exchange for Mobile Environments
K. Yoneyama, M. Terada, S. Hongo, and K. Ohta
Proc. of IWSEC 2010, Lecture Notes in Computer Science, No.
6434, pp. 42–59, Kobe, Japan.
Fair exchange is an important tool to achieve “fairness” of electronic commerce. Several previous schemes satisfy universally composable security which provides the property of security preservation
over complex networks like the Internet. In recent years, as thedemand for electronic commerce has increased, fair exchange forelectronic vouchers (e.g., electronic tickets and money) to obtain
services or contents has been in the spotlight. The definition of fairness for electronic vouchers is different from that for general electronic items (e.g., duplicated use of exchanged electronic vouchers by
one user should be prevented). However, although there are universally composable schemes for electronic items, there have been noprevious studies for electronic vouchers. In this paper, we introduce
a universally composable definition of fair voucher exchange that
represents ideal functionality for fair voucher exchange. Also, we
prove the equivalence between our universally composable definition
and the conventional definition for electronic vouchers. Thus, ourformulation of the ideal functionality is justified. Finally, we propose
a new fair voucher exchange scheme from non-blocking atomic commitment as a black-box, which satisfies our security definition and isadequate for mobile environments. Because general building blocks
are instantiated with known practical ones, our scheme can also bepractical because it is implemented without a trusted third party inusual executions.

Enhancement and Stabilization of Hole Concentration of
Hydrogen-terminated Diamond Surface Using Ozone
Adsorbates
M. Kubovic and M. Kasu
Jpn. J. Appl. Phys. Vol. 49, No. 110208, 2010.
The p-type conductivity of H-terminated diamond surface can belinked to adsorption of a specific gas species on the surface. O3, NO2,
NO, and SO2 were identified as adsorbates that induce holes on Hterminated diamond surface. Among them, exposure to O3 increases

hole concentration the most. The increased concentration remains
high even after exposure to the gas has stopped, indicating that ozone
is the most stable adsorbent. X-ray photospectroscopy spectra of O3adsorbed H-terminated diamond surface show partial oxidation of thesurface and upward band bending and are very similar to those ofNO2-exposed diamond surfaces.

Arsenic-doped n-type Diamond Grown by Microwaveassisted Plasma Chemical Vapor Deposition
M. Kasu and M. Kubovic
Jpn. J. Appl. Phys. Vol. 49, No. 110209, 2010.
We grew n-type arsenic (As)-doped single-crystal diamond layers
using tertiarybutylarsine as an As source. The n-type conduction of
the As-doped layers was confirmed both in Hall measurements andfrom the current–voltage characteristics of the diodes. In the Asdoped layers, electron concentration increased with As concentrationin the layers. The ionization energy of the As donor decreased from
1.6 to 0.7 eV as As concentration increased from 1×1017 to 9×1019
cm-3. A diamond p–n junction diode with an n-type As-doped layer
exhibited a rectification ratio of ~1000 at ±10 V at room temperature.

Structure of Rat Ultrasonic Vocalizations and Its [sic] Relevance to Behavior
N. Takahashi, M. Kashino, and N. Hironaka
PLoS ONE, Vol. 5, No. 11, pp. e14115–14122, 2010.
Rats are known to emit ultrasonic vocalizations (USVs). These
USVs have been hypothesized to hold biological meaning, and therelationship between USVs and behavior has been extensively studied. However, most of these studies looked at specific conditions,such as fear-inducing situations and sexual encounters. In the present
experiment, the USVs of pairs of rats in ordinary housing conditions
were recorded and their features were examined. Three clusters of
USVs in the 25-, 40-, and 60-kHz ranges were detected, whichroughly corresponded to fighting, feeding, and moving, respectively.
We analyzed sequential combinations of two or more clusters using astate transition model. The results revealed a more specific correspondence between the USVs and behaviors, suggesting that rat USV
may work as a type of communication tool.

NTT Communication Science Laboratories at TRECVID
2010 Content-based Copy Detection
R. Mukai, T. Kurozumi, K. Hiramatsu, T. Kawanishi, H. Nagano,and K. Kashino
Proc of TRECVID 2010, NIST, Vol. 1, No. 1, pp. 340–349, Gaithersburg, MD, USA.
In this paper, we describe our approaches that were tested in the
TRECVID 2010 Content-Based Copy Detection (CBCD) task. We
introduce a method consisting of a feature degeneration and sparsefeature selection process for video detection tasks, which is highlyrobust as regards video signal distortion. For audio detection tasks,
we adopt a method based on spectral partitioning to cope with additive interfering sounds. Both methods are key techniques for our
Robust Media Search (RMS) technology, which has already been
deployed for various commercial services. Evaluation results show
the effectiveness of our methods.

NTT Technical Review

Papers Published in Technical Journals and Conference Proceedings

Diamond/nitride Semiconductor Heterostructure: Growthand Properties
K. Hirama, Y. Taniyasu, and M. Kasu
Journal of the Surface Science Society of Japan, Vol. 31, No. 12,
pp. 657–666, 2010 (in Japanese).
Diamond/III-V nitride semiconductor heterostructure appears
promising not only for high-efficiency deep-UV light emitting diodes(LEDs) but also for high output power field-effect transistors (FETs).
However, diamond has a diamond crystal structure, while III-V
nitride semiconductors have a wurtzite crystal structure. Due to thedifference in the crystal structures, single-crystal III-V nitride growth
on diamond substrate has been difficult. In this study, we obtained
single-crystal aluminum nitride (AlN) (0001) layers on diamondsubstrates by using the (111) diamond surface orientation and preventing the formation of the interface layer. We revealed the heteroepitaxial growth mechanism and proposed a model of the atomic
arrangement at the diamond/AlN heterointerface. Furthermore, we
demonstrated a p-type diamond/n-type AlN heterojunction diode andsuccessfully observed band-edge emission from diamond. In addition, an AlGaN/GaN heterostructure with a two-dimensional electrongas (2DEG) was grown on diamond (111) by using the single-crystal
AlN buffer layer.

Fabrication of p-n Junction Diamond Diodes with n-type
Arsenic-doped Diamond
M. Kasu and M. Kubovic
MRS Meeting, the Materials Research Society (MRS), Vol. 1, No.
1, p. 1, Boston, MA, USA, 2010.
We achieved n-type diamond doped with arsenic and fabricatedp-n junction diodes.

Vol. 9 No. 6 June 2011

Effect of NO2 and Its Related Molecules on Increasing Hole
Concentration in Hydrogen-terminated Diamond
M. Kasu and M. Kubovic
MRS Meeting, the Materials Research Society (MRS), Vol. 1, No.
1, p. 1, Boston, MA, USA, 2010.
We investigated the increase in hole concentration caused bymolecular adsorption.

Strongly Secure Two-pass Attribute-based Authenticated
Key Exchange
Kazuki Yoneyama
Proc. of Pairing, Lecture Notes in Computer Science, 2010, Vol.
6487/2010, pp. 147–166, Yamanaka-onsen, Japan.
In this paper, we present a two-party attribute-based authenticated
key exchange scheme that is secure in a stronger security model thanthe previous models. Our strong security model is a natural extensionof the eCK model, which is for PKI-based authenticated key
exchange, into the attribute-based setting. We prove the security of
our scheme under the gap Bilinear Diffie-Hellman assumption.
Moreover, while the previous scheme needs a three-pass interaction
between parties, our scheme needs only a two-pass interaction. In apractical sense, we can use any string as an attribute in our scheme
because the setup algorithm of our scheme does not depend on thenumber of attribute candidates (i.e., the setup algorithm outputs constant-size parameters).

