Visible light communications: increasing data rates with polarization division multiplexing

Abstract

In this Letter, we propose a new configuration for visible light communication systems, which results in doubling of the data rate due to the use of polarization division multiplexing. As light-emitting diodes are unpolarized incoherent light sources, we isolate both the perpendicular s and parallel p modes for independent modulation. For the first time, to the best of our knowledge, we show that it is possible to transmit and successfully recover two separate orthogonal frequency division multiplexing (OFDM) signals on each polarization (pol-OFDM). Furthermore, we compare the performance of the pol-OFDM system with the transmission of a single conventional OFDM signal without a polarizer over the same physical link. We show that similar bit error rates can be achieved while obtaining ∼ 45 % improvement in both the data rate and spectral efficiency due to polarization multiplexing.

EVM Loss: A Loss Function for Training Neural Networks in Communication Systems

“…The neural network is designed to be trained on sequences of received QPSK symbols after transmission over a visible light link using SEFDM with a given bandwidth compression factor, or OFDM where α = 1. The VLC link is characterized in [17] with a bandwidth of >50 MHz. We set our signal bandwidth to be 1 MHz to ensure a flat-band response since this paper is not about improving data rates.…”

A SIMO Hybrid Visible-Light Communication System for Optical IoT

“…s(t) generated in MATLAB, is uploaded to the arbitrary waveform generator (AWG-Teledyne test tools T3AWG3252 with a sampling frequency of 1 GS/s) the output of which is used for intensity modulation of the LED via the bias-T (BT-A11). We have used a commercially available red LED with a peak wavelength λr of 630 nm (Vishay VLMS1500-GS08) with its power-current-voltage characteristics described in [6]. The LED was biased at a bias current Ib of 90 mA with the transmit output power Pt of ~3.3 mW [6].…”

“…We have used a commercially available red LED with a peak wavelength λr of 630 nm (Vishay VLMS1500-GS08) with its power-current-voltage characteristics described in [6]. The LED was biased at a bias current Ib of 90 mA with the transmit output power Pt of ~3.3 mW [6]. Table I shows the key parameters adopted in this work.…”

“…OWC utilizing the visible light spectrum (i.e., ~370-780, nm), known as visible light communications (VLC) with a useable bandwidth B of ~ 400 THz, which is 10,000 times wider than RF [4,5], uses lightemitting diodes (LEDs) luminaries and photodetectors (PDs) to simultaneously provide data communications, illumination, localization, and sensing in mostly indoor environments [4]. VLC systems with data rates Rb within the range of 100 Mb/s to 15.7 Gb/s using polarization division multiplexing [6] and orthogonal frequency division multiplexing (OFDM) with adaptive bit loading technique [7 -9], respectively have been reported in the literature.…”

Polarization Differential Visible Light Communication: Theory and Experimental Evaluation

“…Researchers demonstrated an optimized pre-equalization circuit [ 12 ] and proposed an asymmetric 3 × 2 multi-input multi-output (MIMO) system for PDM [ 13 ]. Recent studies have applied PDM in conjunction with Orthogonal Frequency Division Multiplexing (OFDM), achieving a 45% increase in data rate and spectral efficiency [ 14 ]. Related work demonstrated a setup consisting of red/green/blue laser diodes reaching 40 Gbit/s using PDM OFDM signals [ 15 ].…”