Communication nowadays is possible with radio, acoustic, infrared, ultra-violet waves and even visible light signals. Each of these technologies has its own advantages and drawbacks.
Nevertheless, as heavy bandwidth users in an increasingly-connected world, we will once again underscore the contribution of WiFi–this little over two-decade-old, ubiquitous wireless technology–on World WiFi Day, celebrated annually on June 20.
Economic value
WiFi technology contributed more than US$2 trillion to the global economy in 2018, according to the Wi-Fi Alliance. The number is forecast to increase to US$3.2 trillion by 2023.
Based on the Institute of Electrical and Electronics Engineers (IEEE) wireless communication standard 802.11, the technology has consistently improved with each generation introducing faster speeds and lower latency.
Yet, no amount of bandwidth will ever be enough. Especially, since most of us are still working from home and may continue doing so.
A 1:1 video call, for instance, typically requires 600kbps (down) for high quality video and 1.2 Mbps (down) for HD video, according to Zoom Video Communications, Inc.
WiFi 6
The majority of devices shipping today, based upon the 802.11ac standard, are identified as WiFi 5. The latest generation of WiFi 6 devices, based on the 802.11ax standard, are more efficient. In 2018, there were 169 million global public hotspots, according to the Wi-Fi Alliance.
By 2023, the number is expected to touch 628 million. Of those public Wi-Fi hotspots, 11 per cent are forecast to be WiFi 6 enabled. Speeds will also improve. WiFi users in 2023 may experience WiFi speeds of up to 92 Mbps–triple the average speed of a WiFi connection in 2018 at 30 Mbps, notes the Wi-Fi Alliance.
but 5G is faster
Currently, though, 5G offers faster average download speeds than Wifi in seven out of eight leading 5G countries, according to a May 6 report by market research firm Opensignal Ltd.
The report does not suggest that cellular connectivity will replace Wifi anytime soon. However, with rising speeds and additional spectrum capacity, smartphone users will see a faster service in most situations if they switch off Wifi and use their regular mobile connection.
WiFi 6, 5G are complementary
These two technologies co-exist and work better together to support different use cases, according to a Cisco report this March. With improvements in speed, latency, and higher density of connected devices, WiFi 6 is ideal for indoor enterprise networks, the report says.
On the other hand, 5G is yet to fully roll out but the early businesses cases–including fixed wireless (broadband backhaul), connected cars, drones and smart cities–make it the preferred method for outdoor networks.
LiFi: Internet from LED bulbs
Unlike WiFi that uses radio waves, Light fidelity or LiFi exploits light waves. The term was coined by Prof. Harald Haas, founder and chief scientist of pureLiFi, and also a professor of mobile communications at Edinburgh University.
LiFi is a category of Optical Wireless Communications (OWC), which includes infrared and ultra-violet communications as well as visible light. However, it is unique in that the same light energy used for illumination may also be used for communication.
LiFi comprises multiple light bulbs to form a wireless network. When an electrical current is applied to a LED light bulb, a stream of light (photons) is emitted from the bulb. As explained on the pureLiFi website, LED bulbs are semiconductor devices, which means that the brightness of the light flowing through them can be changed at extremely high speeds.
Hence, one can transmit a signal by modulating the light at different rates. The signal can then be received by a detector which interprets the changes in light intensity (the signal) as data. The intensity modulation cannot be seen by the human eye.
The communication, thus, is as seamless as other radio systems, allowing the users to be connected where there is Li-Fi enabled light, according to information on the pureLiFi website. Using this technique, data can be transmitted from an LED light bulb at high speeds.
Wipro Lighting, a unit of Wipro’s consumer care business based in India, began offering this technology to domestic customers in partnership with PureLifi Scotland in 2019.
LiFi can find applications wherever there is an LED light. LiFi, according to the Wipro Lighting website, offers opportunities for connectivity within hospitals and electromagnetic interference (EMI) sensitive environments–internet connectivity is limited in hospitals and prohibited inside an operation theatre, as WiFi emits electromagnetic signals that can interfere with medical equipment.
LiFi can replace WiFi in educational facilities, and used with IoT (Internet of Things) for smart cities, Wipro Lighting further notes.
The company explains that LED lights on streets, buildings and vehicles would provide a framework that will enable communication coupled with public LiFi spots. Moreover, Li-Fi can be more secure that WiFi since the signals can be restricted to a defined communication area.
Aqua-Fi, or Underwater WiFi
Researchers from the King Abdullah University of Science and Technology (KAUST), under the leadership of first author Basem Shihada, have built an underwater wireless system, Aqua-Fi, that supports internet services such as sending multimedia messages using either LEDs or lasers, according to an 11 June press statement.
LEDs provide a low-energy option for short-distance communication. Lasers are more efficient. They can carry data further but need more power. “The Aqua-Fi prototype used green LEDs or a 520-nanometer laser to send data from a small, simple computer to a light detector connected to another computer,” the researchers explained in the press release.
Essentially, LEDs and lasers are optical transmitters. They comprise an electrical interface, a data encoder or modulator, a laser, and an optical interface. The digital data, thus, can be transmitted from an LED source to a transmitter through an electrical signal.
According to the press release, the technology works thus. In the case of the Aqua-Fi prototype, the first computer converted the photos and videos into a series of 1s and 0s. These were, then, converted into light beams that flickered at very high speeds.
The light detector in the prototype sensed this variation, and converted the light beams back into 1s and 0s. The second computer converted these binaries back into the original footage.
Image courtesy of KAUST: Xavier Pita
The researchers said they tested the system by simultaneously uploading and downloading multimedia between computers set a few meters apart in static water.
They recorded a maximum data transfer speed of 2.11 megabytes per second and an average delay of 1.00 millisecond for a round trip. “This is the first time anyone has used the internet underwater completely wirelessly,” Shihada said in the press statement.
That said, Aqua-Fi will not be available until the researchers overcome obstacles like improving the link quality and the transmission range with faster electronic components, Shihada acknowledged in the press statement.
The light beam, according to the researchers, must also remain perfectly aligned with the receiver in moving waters. The team is considering a spherical receiver that can capture light from all angles to address this situation.
Binding it all with Zigbee, Z-Wave
Of course, if you want to set up a hub to control your devices, you may choose Z-Wave and Zigbee. Both consume lesser power than WiFi and unlike WiFi, the connection becomes stronger as more devices are added.
The reason: Both Z-Wave and Zigbee are mesh networks in which all nodes are interconnected and collaborate to route data efficiently.
