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RFocus smart surface

Wallpaper-like surface could boost radio signals tenfold

Image credit: MIT CSAIL

Researchers from MIT’s Computer Science and AI Laboratory (CSAIL) have developed a “smart surface” which can be mounted on a wall to focus radio signals and improve their strength tenfold.

A radio’s signal strength is strongly related to its size; this means that increasingly miniaturised devices with limited space for antennas struggle to maintain reliable communication with other devices. This could prove a roadblock in the maturation of the IoT, as smaller devices suffer from poor signal.

A team of researchers from CSAIL has presented a system for improving radio signal [PDF], which does not use signal amplification or emit any power of its own.

Rather than using monolithic antennas, the system contains more than 3,000 tiny wireless antennas attached to a surface. These antennae - which can allow a signal to pass through or be reflected - are rearranged to maximise reception via an optimisation algorithm which relies on signal strength measurements from a receiver. 'RFocus' acts as a beam-forming controller, meaning that it is unnecessary to rely on radio transmitters and receiving devices to manage this activity (which is increasingly difficult to implement on miniaturised devices).

The researchers have created and tested a prototype of the RFocus surface. In an office environment, the prototype improves median signal strength almost tenfold and doubles the median channel capacity (the maximum rate at which information can reliably be transmitted).

“The core goal here was to explore whether we can use elements in the environment and arrange them to direct the signal in a way that we can actually control,” said Hari Balakrishnan, senior study author. “If you want to have wireless devices that transmit at the lowest possible power but give you a good signal, this seems to be one extremely promising way to do it.”

The surface consumes little power compared to conventional systems and it could be manufactured at a relatively low price (e.g. with a cost of just pennies per antenna). The team behind RFocus suggest that applications could include connecting hundreds of sensors monitoring the status of machinery or inventory in warehouses.

In order to bring it to market, the team will need to produce the surface at scale in a practical form, such as a thin wallpaper-like covering which requires no wiring. If widely adopted, the surface could provide stronger, longer-range connections for 5G and Wi-Fi, particularly for connected IoT devices too small to maintain a reliable wireless link.

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