Li-Fi Research and Development Centre platform designs

UP-VLC transmitter driver chip

UP-VLC transmitter driver chip
Figure 2: The fabricated transmitter driver chip
UP-VLC driver chip layout
Figure 1: The driver chip layout

A custom-designed transmitter driver chip, implemented in an Austria Micro Systems 0.18 µm CMOS process. The chip consists of 4 independent digital-to-analogue converters (DACs), each capable of directly driving an individual light emitting diode (LED) and having its own 8-bit LVDS digital data interface. The chip also comes with an internal buffer/de-serializer to support ganging/MIMO operation. A serial LVDS interface is provided for chip configuration. An n-channel metal-oxide semiconductor (NMOS) transistor based circuitry is used to realize the driver functionality due to the better carrier mobility and lower area requirement compared with p-channel MOS (pMOS) transistors. Each driver can sink an LED drive current of up to 255 mA, and is designed to operate at a bandwidth of up to 250 MHz.

UP-VLC receiver chip

UP-VLC receiver chip
Figure 3: The fabricated receiver chip

A custom-designed receiver chip, implemented in a 0.18 µm CMOS process and featuring nine individually-addressable avalanche photo diode (APD) receivers. Each photo diode (PD) can be operated as a regular PIN diode or in avalanche mode. The maximum reverse bias necessary for the avalanche mode is 12 V, which is significantly lower than other APD technologies. The measured receiver sensitivity is around 2.5 A/W – so comparable to standard off-the-shelf APDs. Each PD is paired with an on-chip shunt-feedback transimpedance amplifier (TIA). As a result, the overall configuration is able to support up to nine individual receiver channels operating at up to 250 MHz of analogue bandwidth.

Li-Fi front-end platform

Li-Fi Front-End Platform. A custom designed platform on a single PCB
Figure 4: A first generation prototype board

A custom designed platform on a single PCB, able to support a range of Li-Fi analogue front-end components and to form the basis of Li-Fi demonstration systems and tranceivers. The board features an FPGA chip, Ethernet connectivity, an analogue-to-digital converter (ADC), a digital-to-analogue converter (DAC), and expansion connectors. It includes a custom designed digital signal processing (DSP) chip developed in the course of the University of Edinburgh ‘PASTA2’ project, as well as a transmitter driver chip developed in the ‘UP-VLC’ programme. The platform supports communication speeds in the range from several hundred Megabit per second, up to a Gigabit per second.

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For more information on the Li-Fi R&D Centre technology platforms, please contact us.


Other technology platforms from partners

The following Li-Fi technology platforms are currently available from Li-Fi R&D Centre partners.

pureLiFi Li-1st

Technology platforms: pureLiFi's LiFi-1st productThe Li-1st provides the first major opportunity for customers to rapidly develop and test VLC applications for cost-effective, high-speed data communication solutions that utilize commercial light emitting diode (LED) infrastructures. The product offers full duplex communication with a capacity of 5Mbps in both the downlink and uplink over a range of up to three metres, while simultaneously providing ample desk space illumination.

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pureLiFi Li-Fire platform

The Li-Fire platform will enable the world’s first ubiquitous high-speed wireless network solution using VLC. Li-Fire technology will deliver data densities substantially greater than state-of-the-art Wi-Fi solutions and its inherent security properties will eliminate unwanted external network intrusion. In addition, the merger of illumination with wireless communications will provide a measurable reduction in both infrastructure complexity and energy consumption.

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