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OKI Develops Bandwidth Allocation Control Technology for Next-generation Optical Access Systems

Combines efficient, effective bandwidth provision with energy savings

TOKYO, October 2, 2012 -- OKI (TOKYO: 6703) has recently developed Bandwidth Allocation Control Technology to enable OLT(*1) drive control for next-generation optical access systems. This technology controls the number of OLT drive units(*2) in response to traffic conditions and ensures efficient bandwidth allocation by varying the number of OLT drive units. In addition to dramatically increasing OLT bandwidth efficiency, the technology allows OLTs to sleep when traffic is low, cutting power consumption by a projected 30% on average.

In terms of subscriber access systems (PON systems(*3)), the rapid introduction of FTTH(*4) has been assisted by the spread of GE-PON(*5). Based on continuing growth in communications traffic, 10 Gbps PON systems (10G-EPON(*6)) are currently being developed to expand the bandwidth of FTTH communications. However, higher communication speeds increase power consumption. Projections for higher energy consumption by communication devices have prompted a search for ways to cut power consumption.

To resolve such issues, OKI has worked since 2009 as part of the "Research and development of wide area optical access networks" project commissioned by the National Institute of Information and Communications Technology (NICT). OKI has also sought to develop virtual PONs that would permit flexible configuration of connections between an OLT of central office and user ONUs,(*7) thereby ensuring an immediate and practical application of the research technology.

"OKI developed its OLT drive control technology as part of this research program. The Bandwidth Allocation Control Technology developed by OKI is technology that will advance OLT drive control technologies, allowing OLT drive control units to vary the number of operating OLT drive units and thereby responding to bandwidth shortages by adjusting upper bandwidth limits in response to bandwidth volume fluctuations generated by user demand," says Takeshi Kamijoh, General Manager of Research and Development Center at OKI. "Varying the numbers of OLT drive units will result in significantly more efficient use of bandwidth. Verification testing has shown the system can cut bandwidth shortages by roughly one-fifth and power consumption by roughly 30%."

OKI will strive to commercialize this technology, including efforts to extend the technology to multi-channel bandwidth control and deployment to software defined networks (SDN(*8)).

The research leading to this technology was presented on September 18 at the ECOC 2012 (European Conference and Exhibition on Optical Communication), held from September 16 to 20 in Amsterdam, The Netherlands.

Overview of Bandwidth Allocation Control Technology for OLT control drive

"OLT control drive" refers to control that switches OLTs on/off and varies the number of ONU connections to suit the overall traffic handled by the central office. The technology monitors total bandwidth demand from downstream ONUs and data volumes sent from upstream; it does this by configuring a virtual PON configured as a logical star using optical switches or multi-wavelength routing for connections between OLTs and ONUs. Under conditions of light traffic, a single OLT is driven and connected to all accommodated ONUs, with control commensurate with user demand for high or low data rates. Under heavy traffic conditions, all OLTs are driven, and the control incorporates ONU group allocation to allow large-capacity communication in response to user demand. (See Figure 1.) Since average equipment operating rates are lower than with conventional full utilization, the technology is expected to reduce power consumption by roughly 30%.

Figure 1: Overview of OLT control drive

Bandwidth Allocation Control Technology allocates bandwidth efficiently in response to bandwidth demand by calculating excesses/shortfalls in response to the bandwidth demanded by users and switching the number of OLT drive units. Other control techniques include varying the upper limit bandwidth when summing bandwidth demand in light of past fluctuations in bandwidth demand. The system is capable of reducing bandwidth shortages by approximately one-fifth (see Figure 2) and offers practical bandwidth usage levels.

Figure 2: Allocation results by bandwidth allocation control technology


  • *1 :OLT (Optical Line Terminal)

    A terminal device that forms part of a PON system.

  • *2 :Number of OLT drive units

    OLT drive control is achieved by switching the OLT MAC (Media Access Control) function on or off. The number of OLT drive units is equal to the number of MAC functions.

  • *3 :PON (Passive Optical Network) system

    Optical access systems currently in wide use to create networks in which the central office and user devices are connected without active devices.

  • *4 :FTTH (Fiber To The Home)

    Optical communications (optical access) service based on optical fiber running to residences. GE-PON is the format currently deployed in Japan.

  • *5 :GE-PON (Gigabit Ethernet Passive Optical Network)

    1 Gbps PON system based on Ethernet frames; standardized in IEEE 802.3 and widely deployed across Japan.

  • *6 :10G-EPON (10 Gigabit Ethernet Passive Optical Network)

    10 Gbps PON system based on Ethernet frames; standardized in IEEE 802.3 and currently being developed by a number of companies.

  • *7 :ONU (Optical Network Unit)

    A PON user end device.

  • *8 :SDN (Software Defined Network)

    Technologies enabling software-defined networks, based on the OpenFlow core technology; under study for creating virtual core networks.

About OKI Electric Industry (OKI)

Founded in 1881, OKI Electric Industry is Japan's leading telecommunications manufacturer. Headquartered in Tokyo, Japan, OKI provides top-quality products, technologies, and solutions to customers through its info-telecom systems and printer operations. Its various business divisions function synergistically to bring to market exciting new products and technologies that meet a wide range of customer needs in various sectors. Visit OKI's global website at http://www.oki.com/.

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  • * Information in the press releases is current on the date of the press announcement, but is subject to change without prior notice.

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