Monday, March 26, 2012

GreenTouch Achieves Major Gains in Energy Efficiency for Optical Access

The GreenTouch Consortium, a global research initiative dedicated to dramatically improving network energy efficiency, introduced a major breakthrough for optical access -- Bit-Interleaved Passive Optical Network (Bi-PON) technology. GreenTouch estimates Bi-PON ultimately could deliver power reduction of 30 times over current technologies while improving performance and reducing cost.

In a webcast, researchers from Alcatel-Lucent's Bell Labs, France's INRIA research lab and France Telecom Orange, described how the bit interleaving passive optical network (BIPON) leverages a new protocol that cuts energy consumption in time division multiplexing (TDM) PON optical network units (ONUs) by a factor of 10 compared to today’s protocols. The key observation is that 99% of data is unnecessarily processed in ONUs today. By modifying the protocol, an order of magnitude improvement in ONU performance can be attained.

The bit interleaving protocol reduces energy consumption in the ONU by reducing clock speed requirements, data processing requirements, voltage requirements, and memory requirements. The bits are spaced in time to match the clock rate. The bit interleaving protocol frame structure includes a header and a payload section. The header contains a synchronization code word and a unique identifier for each ONU on the PON. The header also contains information that allows the ONU to know where its payload bits are — at what offset and bit rate they are being sent in the payload section.

The consortium members said Bi-PON represents the next major leap in passive optical network (PON) technologies. It is expected to be a necessity as electronic processing will increase with future 40GPON systems.

“With this demonstration, GreenTouch again shows why it is one of the most ambitious collaborative environments in sustainable network technologies,�? said Gee Rittenhouse, GreenTouch chairman. “We are committed to reducing energy consumption across all ICT networks and Bi-PON is a huge and critical step in helping us achieve that goal. The impact is clear and wide-ranging including wireless backhaul and fiber to the home. Implementing Bi-PON over current technologies will have the energy savings equivalent to the carbon impact of permanently taking all the cars in a city like San Francisco off the road. We are making great progress toward our goal and are planning to make advances like this across all of our 25 research projects that are currently underway.�?

  • In February 2011, the GreenTouch Consortium demonstrated a Large-Scale Antenna System proof of concept with the potential for tremendous energy savings thanks to its novel wireless transmission techniques. Such an antenna array, consisting of dozens of individual units, would transmit only one percent of the energy transmitted by a single antenna, for the same quality of service. Instead of broadcasting signals throughout the entire coverage area as other antenna systems typically do, the Large-Scale Antenna System utilizes knowledge of the propagation channels to transmit concentrated beams of information selectively to many users at once. The greater the number of antenna elements deployed, the higher the concentration of the beams and, therefore, the lower the power that any antenna needs to send a given amount of information.

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