Is wireless communication using light the future of the Internet?

The technology is 100 times faster than WiFi and more secure with enhanced privacy

Dr Md Jahid Hasan

October 29, 2022, 3:05 p.m.

Last modification: October 29, 2022, 3:10 p.m.

Dr Md Jahid Hasan. Sketch: TBS

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Dr Md Jahid Hasan. Sketch: TBS

In the not-too-distant future, lights installed in your home will act as wireless antennas, allowing you to connect multiple devices to the Internet. You will be able to stream on YouTube while standing near the bulbs.

Light-based wireless connectivity has gained great potential in many wireless communication technologies.

On record, the first demonstration of visible light communication (VLC) was made by Alexander Graham Bell, when the photophone was invented to transmit modulated voice signals using sunlight over a few meters distance.

However, with the invention of infrared (IR) light-emitting diodes (LEDs) in 1962, the use of invisible light for remote control became widespread.

It is undoubtedly one of the most successful applications of Optical Wireless Communication (OWC) technology to date. In recent decades, several researchers have also considered using white LEDs. As such, Harald Haas of the University of Edinburgh coined the term “light fidelity” (LiFi) to define light-based indoor communication as an alternative to “wireless fidelity” (WiFi).

How OWC Works

Similar to any conventional wireless communication system, the OWC system has three parts: transmitter (Tx), propagation channel and receiver (Rx).

At Tx, the bits of information to be transmitted are first converted into an electrical signal and then introduced into an optical source using a control circuit after modulation.

At the Rx, the propagated optical signals are collected by a photodetector and the resulting photocurrent is converted into a voltage signal by an amplifier before being sampled.

Finally, the original transmitted bits are recovered after demodulation of the signal. Typically, two-way light-based access in indoor scenarios uses the visible and infrared spectra for uplink and downlink communications, respectively.

Internet of the future

Due to the availability of unregulated spectrum and high-speed light connectivity, LiFi is considered one of the most efficient candidates for future 6G networks.

In particular, the lights generally do not pass through opaque walls, which improves privacy and security while allowing frequency reuse. In addition, compared to traditional Wi-Fi, LiFi can provide 100 times faster Internet access.

Thus, PureLiFi, a LiFi startup, has designed a Gigabit LiFi system transmitting data at speeds of up to 1 Gbps, while laboratory studies have demonstrated theoretical speeds of up to 224 Gbps. On the other hand, Oledcomm, a French technology company, has developed an IR-based bi-directional Gigabit chip that can be embedded in mobile and wearable devices.

In addition to LiFi, optical wireless communication (OWC) technology is particularly preferred in environments where radio frequencies are prohibited, such as military confinements.

A common misconception is that this technology is only suitable for indoor communication. However, laser diodes could be used for point-to-point communication in long-distance transmission systems, for example in free space and under water.

Due to higher bandwidth efficiency, lower power consumption and smaller antenna size, OWC has recently gained popularity in inter- and intra-satellite communications, vehicle communications to vehicle and outdoor wireless access.

Recently, Oledcomm has been working on a project to replace network cables inside satellites with optical wireless networks, which would save crucial weight and space for satellites. The most interesting applications include drone-to-drone communication, farm monitoring, smart homes, trains and subway stations.

Research Opportunities

Although the LiFi industry is booming, there are also several limiting factors. For example, they include user mobility, obstacles in indoor scenarios, fog, clouds and dust for outdoor applications, etc.

Additionally, multiple users may need to transfer their data at the same time, which would require appropriate modulation and multiple access techniques. Increasing the reliability of the communication system is another interesting area of ​​research.

In Bangladesh, the AIUB (American International University Bangladesh) has already started funding research into the next generation of LiFi. AIUB researchers, in particular, are working on innovative modulation and multiple access approaches for LiFi use cases. The long-term goal is to design and develop experimental testbeds for LiFi in Bangladesh for the first time.

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