Demonstration of 575-Mb/s downlink and 225-Mb/s uplink bi-directional SCM-WDM visible light communication using RGB LED and phosphor-based LED

Abstract

We propose and experimentally demonstrate a novel full-duplex bi-directional subcarrier multiplexing (SCM)-wavelength division multiplexing (WDM) visible light communication (VLC) system based on commercially available red-green-blue (RGB) light emitting diode (LED) and phosphor-based LED (P-LED) with 575-Mb/s downstream and 225-Mb/s upstream transmission, employing various modulation orders of quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM). For the downlink, red and green colors/wavelengths are assigned to carry useful information, while blue chip is just kept lighting to maintain the white color illumination, and for the uplink, the low-cost P-LED is implemented. In this demonstration, pre-equalization and post-equalization are also adopted to compensate the severe frequency response of LEDs. Using this scheme, 4-user downlink and 1-user uplink transmission can be achieved. Furthermore, it can support more users by adjusting the bandwidth of each sub-channel. Bit error rates (BERs) of all links are below pre-forward-error-correction (pre-FEC) threshold of 3.8x 10(-3) after 66-cm free-space delivery. The results show that this scheme has great potential in the practical VLC system.

A Carrierless Amplitude Phase (CAP) Modulation Format: Perspective and Prospect in Optical Transmission System

“…VLC using white LEDs offers many advantages for home area networking and next-generation short-range wireless access, such as worldwide availability, high security, immunity to radio frequency interference, and spatial reuse of the modulation bandwidth in adjacent communication cells [34]. High spectrally efficient modulation format like CAP can be a direct method to increase the capacity due to severe bandwidth limitation caused by LED in VLC system.…”

Design and realization of indoor VLC-Wi-Fi hybrid network

“…Establishing a bidirection VLC link is theoretically feasible [5,6] , but remains impractical owing to excessive energy consumption at the user terminal devices and discomfort to the users' eyes. Wi-Fi used as uplink is a potential scheme [7,8] , however, a co-channel transmission limits the throughput.…”

Multi-band carrier-less amplitude and phase modulation for bandlimited visible light communications systems

“…The BER is presented as a function of the energy-per-bit to noise power spectral density ratio (E b /N o ). The BER target is selected to be 10 -3 , which is slightly lower than the International Telecommunication Union's (ITU's) recommended error floor (3.8×10 -3 ) when using a forward error correction (FEC) with overhead of 7% [14]. Fig.…”