By Martynas Tovarovas, Wi-Fi NOW Staff Writer
Researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have developed a wallpaper-like ‘smart surface’ consisting of more than 3,000 low-cost antennas – an invention that could significantly boost Wi-Fi signals. The researchers have already demonstrated the system’s ability to enhance signal strength by nearly 10 times. Researchers also say their invention – dubbed RFocus – could be highly useful for IoT applications where devices tend to be a lot smaller.
Enhancing signal strength used to be a lot easier when devices were bigger: Simply install antennas on either the transmitter (Wi-Fi access points or cell towers) or the receiver (such as a phone or a laptop) and that’s all there was to it. Today the traditional scheme is proving harder and harder because typical devices – especially IoT devices for smart homes, sensors, or wearables – are getting smaller all the time. The end result is lowered signal strength.
CSAIL researchers are now attempting solve this problem by amplifying the environment itself rather than focusing on devices. What if it were possible to install thousands of small antennas into walls, perhaps transforming whole buildings into signal boosters? That’s the idea behind RFocus: A software-controlled smart surface that uses 3,200 miniature antennas to focus beams and automatically deliver the best signal reception possible.
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The platform relies on a beamforming scheme created by several antennas broadcasting the same signal at slightly different times. When constructive and destructive signal interference from the antenna array is managed correctly, the wall strengthens signals in specific directions. Think of RFocus as a gate keeper letting signals pass or reflecting them depending on where the signals are needed the most at any given moment, the researches say.
“Each antenna acts as a ‘pixel,’ which can be turned on or off. When on, it reflects incident radio. When off, it is effectively transparent and lets the signal through. By controlling which ones are on and which ones are off, we can control how the surface reflects the radio wave. For instance, we can turn it into a mirror/lens that focuses energy from the transmitter to the receiver. This way we can move beamforming functions from the endpoints to the environment,” says lead researcher and PhD student Venkat Arun.
The researchers claim that RFocus features the largest number of antennas ever assembled in forming a single communications link. The smart surface is designed to be easily applied in wallpaper-like sheets that could be incorporated into office spaces, factories, warehouses, or even in home environments, the researchers say.
RFocus is also a highly cost-effective as the antennas only costs a few cents each. Low costs are made possible due to the fact that antennas only manipulate how the signal is reflected as opposed to performing more complicated tasks. The researchers say they are not yet ready for commercialising the invention since it is still being tested as a prototype.
/Martynas.