by Abdallah Khreishah, associate professor of electrical engineering and director of NJIT’s Optimized Networking Lab
The proliferation of mobile devices, ever-denser computer networks and the rise of the Internet of Things are changing core aspects of daily life, from commerce to communication, in profound ways. Biosensors that relay health information from patient to physician, energy management systems that monitor and regulate consumption and banking by cell phone are just a few examples.
But this steady stream of new applications, coupled with accelerating device speeds and capacity, is driving a seemingly insatiable demand for wireless bandwidth. Mobile devices have reached performance levels at which they are effectively “data starved,” since their ability to produce or consume data far exceeds the capabilities of the networks that feed them.

Electrical engineering professor Abdallah Khreishah with his graduate student, Sihua Shao, in NJIT's Optimized Networking Lab.
Visible light communications (VLC) or Li-Fi, which utilizes available indoor lights as information carriers, is emerging as an alternative, complementary technology to relieve pressure on the crowded radio frequency (RF) spectrum. The possibilities are exciting: VLC is unlicensed, has wide bandwidth, supports new levels of security due to the opacity of walls and can provide both lighting and data communications for little net increase in energy cost.
Here’s how it works: Data are delivered from overhead luminaires to receivers in the lighting field by turning the light signals generated by LEDs on and off fast enough that the photodetectors designed for information signal reception can decode the transmitted information imperceptibly to human eyes. Recent studies show data rates of up to 200 megabits per second per user can be achieved by each luminaire in a coverage area of less than 1 square meter.

Abdallah Kreishah, associate professor of electrical engineering, and his graduate student, Sihua Shao, demonstrate their Visible-Light-enhanced WiFi (Li+WiFi) technology.
But we must first resolve a few limitations, including the absence of uplinks. I developed a first practical hybrid RF-VLC system, which we’re adapting to user behavior. Our mission is to jointly optimize throughput and energy consumption, while ensuring security and seamless connectivity. Wish us luck!
Editor's note: This is a sponsored blog post from New Jersey Institute of Technology.
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