TOKYO--(BUSINESS WIRE)--Nippon Telegraph and Telephone Corporation (NTT, Chiyoda-ku, Tokyo, CEO:
Hiroo Unoura), Hitachi, Ltd. (Hitachi, Chiyoda-ku, Tokyo, President &
CEO: Toshiaki Higashihara), Oki Electric Industry Co., Ltd. (OKI,
Minato-ku, Tokyo, President Shinya Kamagami), Keio University (Keio,
Minato-ku, Tokyo, President Professor Atsushi Seike), KDDI Research,
Inc. (KDDI Research, Fujimino-shi, Saitama, president, CEO: Yasuyuki
Nakajima) and Furukawa Electric Co., Ltd. (Furukawa Electric,
Chiyoda-ku, Tokyo, President: Keiichi Kobayashi) have jointly challenged
the advanced future network for 2030 and beyond by conducting innovative
studies on “Elastic Lambda Aggregation Network (EλAN)”.
EλAN sets
an adaptive modulation OFDM transmission system, which leads to the
significant improvement of optical frequency utilization efficiency,
into the access (subscriber’s home-central office)-metro (central
office-central office) network that directly connects the subscriber’s
home and the metro central offices via fibers and WSSs. Therefore, EλAN
provides flexible assignment of the transmission speed and optical
frequency bandwidth to support diversified services with different types
of traffic, such as internet, enterprise line, and mobile services.
We
demonstrated the reliability of EλAN through a prototype testbed network
which utilizes optical path provisioning and switching technologies. The
demonstration successfully showed, for the first time, that the service
accommodated in the failed office was automatically re-connected within
10 sec to another office some 10km away with the same transmission speed
as before the failure. The project accomplishments will be presented at
an international conference on optical communications, iPOP2017 (The
13th International Conference on IP + Optical Network 2017:
Kawasaki-city, Kanagawa, Japan: June 1-2, 2017).
This research and development project was contracted with the National Institute of Information and Communications Technology (NICT) of Japan under a research contract titled “Research and development of elastic lambda aggregation network.”
[Background]
Along with the wider penetration of FTTH (Fiber
to the Home) services, efficient operation of a large number of network
sets is essential in recent optical access networks. Moreover, the
future access network must support, in addition to conventional FTTH
service, multiple access services, such as mobile, high-definition video
and IoT (Internet of Things) services.
Until now, multiple access
services have been provided using distinctly different network
infrastructures to meet the disparate service requirements. However, to
provide them more efficiently, all services should coexist on the same
service-adaptive network that can flexibly meet individual service
requirements. If multiple access services share an optical fiber
network, high reliability is essential so that the network can keep
providing services by autonomous reconfiguration of the network
resources remaining after a disaster. Furthermore, high optical
frequency utilization efficiency (transmission rate per unit of optical
frequency) should also be provided to accommodate a large number of
services and subscribers.
From this background, as advanced
research studies targeting beyond 2030, the six institutions (NTT,
Hitachi, OKI, Keio, KDDI Research, and Furukawa Electric) have been
researching EλAN, a service adaptive access-metro network that provides
multiple services with high reliability and high optical frequency
utilization efficiency.
[Elastic lambda Aggregation Network (EλAN)]
In conventional
access networks, the central office equipment (OLT) is located at access
central offices close to subscribers’ homes. EλAN, on the other hand,
transfers the OLT to a metro central office that aggregates the traffic
of metro networks. Moreover, EλAN improves the reliability of
access-metro networking, which will need to accommodate a huge number of
subscribers, by using WSSs to switch optical paths flexibly. This
innovative architecture offers lower end-to-end latency and power
consumption, since Optical-Electrical-Optical (O-E-O) conversion in the
access central office is not needed.
EλAN employs a digital
coherent OFDM system with adaptive modulation, a technique that can
realize dramatically high optical frequency utilization efficiency and
large-scale flexible service allocation by using the elastic control of
transmission speed and optical frequency bandwidth. In addition, EλAN
applies the world’s first dynamic bandwidth allocation algorithm in
OLTs. This makes it possible for the users to share the additional bits
in a fair manner regardless of optical distribution network (ODN)
conditions.
[Future Outlook]
We will work to enhance the maturity and
the reliability of basic technologies for EλAN, and will carry out
further development activities.