Wireless networks present 'severe' energy inefficiencies

There are critical energy-efficiency challenges at the end-points of telecommunication infrastructures today with wireless networks, in particular, facing a more serious energy consumption problem, highlights a Bell Labs scientist.

In an interview with ZDNet Asia, Rod Alferness, chief scientist at Alcatel-Lucent's research arm Bell Labs, noted that access points account for a large part of overall energy utilization in today's communication networks. In fact, these end-points are where energy consumption issues are "particularly severe", he said.

While there are energy inefficiencies in both wired and wireless networks, Alferness said the problem is more serious for mobile networks due to the indiscriminate broadcasting of data waves. "In wireless, you are sending information everywhere so in some sense you are throwing away a lot of energy that doesn't get used," he said.

Solving green challenges in mobile networks is an important focus for Bell Labs. He noted that while wireless networks do not consume the largest amount of energy in telecommunication networks today, it will dominate in the future.

Demand for wireless networks is already "going through the roof" with the increasing number of applications that require high bandwidth such as videos, as well as growing data rates transmitted via 3G and Long Term Evolution connections, he said.

In contrast, fixed-line networks such as fiber optics tend to be more energy-efficient because data transmissions are "guided and can scale well", according to Alferness.

"You can transfer large amounts of information over a single fiber. And typically, as you aggregate data and put more information into [the pipes], the energy per bit is driven down," he said.

Overcoming wireless green challenge
Alferness believes that fiber optics, given their energy efficiencies, can be used to "feed" and support wireless networks in the future. With fiber-to-the-home already being implemented in countries such as Singapore, he noted that this infrastructure will increasingly be deployed to support data transmissions in backhaul base stations.

Backhaul offloading will also be necessary to handle higher data bit rates which users will want when moving to LTE and beyond, he added.

In future, Alferness added that more but smaller base stations--alongside femtocells--will be implemented to handle higher data transmission speeds and improve energy efficiencies.

He explained that while more base stations will be required in such deployments, these equipment will be simple to install and consume lower power.

Apart from handling backhaul wireless traffic, he added that these smaller base stations will provide greater bandwidth per user as they support fewer customers, which will also be beneficial to users.

Today, deployment of femtocells by telcos are generally not driven primarily by energy-efficiency considerations, said Alferness, noting that the goal for these players is to achieve savings in both capital and operational expenditure as well as improved performance for users.

Pushing wireless to the backhaul fiber network and deploying smaller base stations are not the only approaches to make networks greener, he said. Other methods the market should consider include powering off equipment when not needed, and making switching and routing equipment more energy efficient, he added.

He noted that all parts of the network need to be evaluated in efforts to improve energy consumption.

Bell Labs is the organizer of the Green Touch consortium, which was launched in January 2010 with the goal to increase energy efficiency in networks by 1,000 fold in five years, said Alferness. Group members aim to devise new architecture and technology to demonstrate the feasibility of achieving this goal, he added.