Li-Fi instead of Wi-Fi: Multipoint-to-multipoint optical data transmission for automation

Created December 15, 2017
Applications and Research

Left, Mobile robots handling logistics in a warehouse could communicate over Li-Fi hotspots.

Developers at the Fraunhofer IPMS, Dresden, Germany, are convinced that Li-Fi technology, the use of light to exchange large amounts of data, will soon become serious competition to the Wi-Fi networks currently used in industrial environments. In addition to allowing different users to simultaneously use an access point, the IPMS-developed optical transmission technology also enables each user to communicate with several access points.

Therefore, say its developers, Li-Fi is no longer limited to stationary applications. The Fraunhofer IPMS specialists first presented this multipoint-to-multipoint-capable technology to the professional public for the first time at the 2017 SPS IPC Drives expo in Nuremberg, at the end of November, 2017.

In the age of smart production, more and more users rely on wireless data transfer between devices used in logistics, industrial manufacturing or machine maintenance. However, those radio solutions (Wi-Fi), which have proven themselves in the consumer sector, quickly reach their limits in highly automated production environments.

Fast and interference-free
Wi-Fi networks are susceptible to interference because other wireless methods, such as Bluetooth applications, partially transmit in the same frequency ranges, causing multiple channel assignments and overlapping frequency usages. They are slow as the increased number of users and larger volumes of data to be transferred decelerate both the data rate as well as communication cycle times. Wi-Fi networks are also susceptible to abuse, as it is relatively easy for skilled hackers to crack even encrypted networks.

The Fraunhofer IPMS optical data transmission (Light Fidelity or Li-Fi) performs far better here in every respect. The “Li-Fi-Hotspot” transceiver system uses the spectrum of light, available free of regulations worldwide, thereby eliminating any interference from radio-based systems. Net-Bandwidths of up to one gigabit per second are much faster than current Wi-Fi wireless solutions. And, even in closed rooms, every Li-Fi network offers security against hacker attacks.

However, optical data transmission also has a systemic vulnerability: the visual axis between transmitter and receiver must remain unobstructed, a significant shortcoming, especially in mobile applications. In order not to be limited to stationary application scenarios when using Li-Fi technology, Fraunhofer IPMS specialists work on so-called multipoint-to-multipoint solutions.

Uninterrupted data exchange
“Our communication modules allow multiple users to act simultaneously in the same spot,” said Dr. Alexander Noack, Project Manager at Fraunhofer IPMS. “At the same time, each user can switch between different, overlapping access points along a production line. Provided the adequate coverage, we are in a position to guarantee mobile users a free viewing axis at all times to accommodate uninterrupted data exchange – faster, more stable, and more secure than possible with radio-based infrastructures.”

The Fraunhofer IPMS driverless transmit / receive modules combine an optical transceiver and a protocol controller with a Gigabit-Ethernet interface and can be easily combined with standard industrial systems. In order to let customers personally test the benefits of Fraunhofer IPMS Li-Fi technology for a wide variety of applications, the Dresden-based research institute provides its clients with Customer Evaluation Kits.


This article was written
by Matthew Peach

Matthew Peach is a freelance technology journalist specialising in photonics and communications. He has previously worked for several business-to-business publishers, editing a range of high-tech magazines and websites.