LiFi and Visible Light Communication by G.hn Technology


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Overview of Visible Light Communication (VLC) and LiFi

Visible light communication (VLC) is a data communications variant that uses visible light between 400 and 800 THz (780–375 nm). VLC is a subset of optical wireless communications technologies. Specially designed electronic devices generally containing a photodiode receive signals from light sources, although in some cases a cell phone camera or a digital camera will be sufficient. The image sensor used in these devices is in fact an array of photodiodes (pixels) and in some applications its use may be preferred over a single photodiode. Such a sensor may provide either multi-channel or a spatial awareness of multiple light sources. VLC can be used as a communications medium for ubiquitous computing because light-producing devices (such as indoor/outdoor lamps, TVs, traffic signs, commercial displays, and car headlights/taillights) are used everywhere.

Li-Fi (short for light fidelity) is a wireless communication technology that utilizes light to transmit data and position between devices. In technical terms, Li-Fi is a light communication system that is capable of transmitting data at high speeds over the visible light, ultraviolet, and infrared spectrums. In its present state, only LED lamps can be used for the transmission of visible light. In terms of its end-use, the technology is similar to Wi-Fi – the key technical difference being that Wi-Fi uses radio frequency to induce a voltage in an antenna to transmit data. Whereas Li-Fi uses the modulation of light intensity to transmit data. Li-Fi can theoretically transmit at speeds of up to 100 Gbit/s. Li-Fi’s ability to safely function in areas otherwise susceptible to electromagnetic interference (e.g. aircraft cabins, hospitals, military) is an advantage. The technology is being developed by several organizations across the globe.

Visible Light Communication (VLC) and LiFi Spectrum for G.hn Use

G.hn for VLC and LiFi

Xingtera’s G.hn is an optimal baseband solution for visible light communication and LiFi applications. This is because G.hn supports 200MHz baseband communication, with up to 2Gbps data rate in the PHY layer. G.hn naturally supports multi-node networks which can be easily implemented for VLC and LiFi as well. In addition, G.hn has employed AES-128 encryption to ensure the security of the domain. Therefore, by using G.hn as a baseband conversion between Ethernet and electrical signal, VLC or LiFi designs can take advantage of the maturity of G.hn modules, while focusing mainly on the optical part, thus saving design effort and reducing time to market. 

A typical solution diagram for using G.hn as the baseband processor for visible light communication or LiFi is shown below. 

Topology Diagram for G.hn Baseband + Visible Light Communication (VLC) / LiFi Solution

G.hn Features:

  • Compliant with ITU-T G.hn (Learn more about G.hn) standard (G.9960 and G.9961)
  • 2-200MHz SISO OFDM frequency range
  • Maximum PHY rate: 2000Mbps
  • 128-bit AES encryption
  • Plug-and-play with automatic domain master selection
  • Up to 8 nodes in a domain
  • 16 level QoS 
  • Low power consumption (Operational<2.3W / standby<1.3W)

G.hn Products for Visible Light Communication or LiFi Baseband

  • MOD957 G.hn module: 100MHz / 1Gbps for VLC/LiFi baseband applications 
  • MOD958 G.hn module: 200MHz / 2Gbps for VLC/LiFi baseband applications 

Learn more about Xingtera’s G.hn product line