Beamsteering could cut mobile power consumption by 50 percent

Scientists at Rice University in Houston have come up with a method of directing mobile wireless signals that could lead to a dramatic 50 percent reduction in power consumption in devices such as smart phones, e-books and netbooks.

Researchers at the university have attempted to address the problem of the omni-directional signal which is emitted from wireless devices with a technique known as beamsteering. 

Beamsteering effectively limits “device energy efficiency but also poses a significant challenge toward the capacity of wireless networks through inter-link interference”.

Usually a mobile device will transmit a wireless signal in all directions which means that a large percentage used to transmit the signal is effectively wasted as it is not directed towards its intended target. 

Omni-directional signals can cause problems with interference in a world that is seeing the increasing proliferation of wireless devices.

In order to solve these problems Hang Yu, Lin Zhong and Ashutosh Sabharwal have developed software named BeamAdapt that offers a method which creates a single beam. It can then be directed specifically at its intended target by using a number of antennas.

The notion of creating a single beam to create a focused signal to achieve lower power consumption is not a new idea, it is in fact quite widespread within larger transmitting devices such as base stations.  However, problems have arisen with scaling the technology down to fit inside a mobile device.

“While beamsteering has been studied and deployed for base stations, access points, and even vehicles, it has never been examined for mobile devices due to its large form factor and power overhead,” the researchers said.

To create a single beam would require a number of antennas which would transmit a signal that would interfere with each other, and combine into one beam. To put it simply, think that scene in Ghostbusters. The problem with this in the past has been that to have a number of antennas will take up too much space on devices that are constantly seeking to be as discreet as possible.

However the engineers point out that this is no longer the case as sufficiently small antennas can be fitted inside devices such as an iPad.

“Beamsteering with four antennas can already fit on mobile devices such as Kindle and iPad and its circuit power overhead can be more than compensated by reduced transmit power.”

The other major problem for effective use in a mobile network is that of interference with other devices as the use of a four antenna system could easily drown out other users when transmiting to a node.

What Yu, Zhong and Sabharwal have done to remedy this is to develop the BeamAdapt software that ensures that all nearby network users have the same broadcast settings to enable the best transmission possible.

In the researcher’s paper, published by arXiv, the students show how this can lead to impressive and reliable results.

“The results show that averagely BeamAdapt can reduce client power consumption by 40 percent and 55 percent with two and four antennas respectively.”

Of course for the system to work would mean near universal take-up of the technology in mobile devices may be necessary, which would need serious backing from providers and manufacturers.