Why Li-Fi Can't Replace 5G and Wi-Fi?

Why Li-Fi Can’t Replace 5G and Wi-Fi?

We all know what Wi-Fi is, but what about Li-Fi? Despite the single-letter difference in their names, these are two completely different technologies.

Recently, the Institute of Electrical and Electronics Engineers (IEEE) officially standardized Li-Fi technology through the 802.11bb standard, including it as a form of optical wireless communication.

So, what exactly is Li-Fi technology? Will it replace Wi-Fi? Will we be using Li-Fi for internet access and phone calls in the future?

Why Li-Fi Can't Replace 5G and Wi-Fi?

Li-Fi: Using Visible Light Instead of Electromagnetic Waves

Li-Fi is not a particularly new concept. Over a decade ago, scholar Harald Haas in the field of mobile communications popularized Li-Fi in a TED talk titled “Wireless Data from Every Light Bulb.” Li-Fi stands for “Light Fidelity,” and it can be translated as internet access through light.

Conventional communication technologies like Wi-Fi and 5G rely on electromagnetic waves. These technologies often face the challenge of spectrum allocation, where specific frequency bands are designated for different purposes, such as 5G or Wi-Fi. This has led to spectrum scarcity, as seen with the competition for the 6GHz band between Wi-Fi 7 and 5G.

Li-Fi takes a different approach by utilizing visible light for data transmission. For example, a lit lightbulb can represent binary data (1 and 0) by toggling between on and off states. With specialized chips controlling the bulbs, Li-Fi can achieve rapid switching, potentially transmitting large amounts of data within seconds, all while being imperceptible to the human eye.

In the context of light, another familiar term is “flicker frequency,” which refers to the number of times a light source flickers per unit of time. For example, quality desk lamps marketed as eye-friendly often highlight their high flicker frequency. In China, qualified lighting products require a flicker frequency of 3125Hz, which equates to 3125 flashes per second. On the other hand, OLED screens, which initially faced criticism for their low flicker frequencies, have since improved, with some reaching 1920Hz.

Li-Fi offers several advantages. Firstly, it bypasses the congested electromagnetic spectrum, offering natural advantages in terms of communication resources. Secondly, visible light devices, such as LED bulbs, are already prevalent, and turning them into Li-Fi devices is cost-effective. Visible light sources are self-powered and do not require additional power sources like traditional base stations.

Furthermore, as LED technology advances, Li-Fi’s maximum achievable transmission rates in laboratory settings have continued to increase. In 2015, it was reported that real-time communication rates in visible light research in China reached 50Gbps.

Additionally, Li-Fi offers improved security, especially in enclosed spaces, as light signals do not easily refract or leak when obstructed.

Li-Fi’s Fatal Flaws

Despite its technical advantages, Li-Fi has several significant limitations that have hindered its widespread adoption. Firstly, Li-Fi is not conducive to bidirectional communication. In everyday communication technologies like wired broadband, 4G, and 5G, there is a clear concept of uplink and downlink, allowing for both data download and upload. While installing a signal transmitter on a lightbulb allows for data reception on mobile devices, enabling data transmission from the mobile device to the light source presents challenges. The use of infrared, as demonstrated in Harald Haas’s talk, could introduce speed limitations.

Secondly, Li-Fi is highly susceptible to interference. Light is easily blocked, whether by concrete buildings or atmospheric conditions like fog and rain. In contrast, electromagnetic-based technologies like Wi-Fi and cellular networks offer better penetration. Some might argue that optical fiber also uses light for data transmission with low interference. However, optical fiber relies on a physical medium to guide light internally, resulting in minimal signal loss. In wireless scenarios, combating various forms of interference is considerably more challenging.

Therefore, despite its technological potential, Li-Fi’s inherent limitations restrict its deployment in real-world scenarios.

Li-Fi as a Complement, Not a Replacement

People often hold high expectations for emerging technologies, and researchers and organizations promoting them contribute to the optimism. However, when a technology struggles to gain traction, it indicates that it faces current challenges and barriers to commercialization. Li-Fi is a fascinating technology that, under ideal conditions, can offer a novel experience.

However, at present, Li-Fi does not appear to have the potential to replace established communication technologies like Wi-Fi. Electromagnetic-based communication technologies have withstood decades of testing and have been highly successful in terms of user experience and commercialization. Li-Fi, while promising in its foundational technology, suffers from drawbacks such as poor interference resistance, making it challenging to achieve widespread adoption.

Nonetheless, Li-Fi can find useful niches in the short term. For instance, Li-Fi was employed in a venue hosting NBA games to provide internet access to fans. By standing under LED lights in the arena, fans could connect to the internet, relieving congestion from Wi-Fi and cellular networks. Additionally, in-store LED lighting with embedded Li-Fi technology, as experimented with by Philips in Carrefour supermarkets, may not provide internet access but can be used for indoor positioning, offering superior accuracy compared to GPS.

Recent trade shows like CES have also seen manufacturers showcasing Li-Fi desk lamps and lighting panels. While using these devices for internet access may not be as convenient as Wi-Fi currently, they serve a meaningful conceptual purpose. Their existence demonstrates that Li-Fi does have a place in specific applications.

In the foreseeable future, Li-Fi is more likely to serve as a supplementary technology alongside existing communication methods. Moreover, for the next-generation mobile communication technology, 6G, many experts anticipate it will encompass a variety of communication technologies, including electromagnetic waves, satellite positioning, and Li-Fi. In the 6G era, the untapped potential of Li-Fi may see further exploration.