Capacity bounds for dimmable visible light communications using PIN photodiodes with input-dependent Gaussian noise

Abstract

In this paper, we focus on a dimmable visible light communication (VLC) system using PIN photodiodes. In such a system, the main distortion is caused by additive Gaussian noise, however, with a noise variance depending on the current signal strength. Under the non-negativity, peak power and dimmable average power constraints, the lower and upper bounds on the channel capacity are derived, respectively. Specifically, the derivation of the lower bound is based on the fact that the entropy of the output is always larger than the entropy of the input, while the derivation of the upper bound relies on the dual expression of the channel capacity and the notion of capacity-achieving input distribution that escape to infinity. Numerical results show that the gap between the lower and upper bounds is very small in the VLC application zone.

Physical-Layer Security for Indoor Visible Light Communications: Secrecy Capacity Analysis

“…To obtain the optimal and robust beamforming, the authors in [25] also employed the TGN distribution for the input. Due to the constraints of the input signal in VLC, the uniform and TGN input distributions are generally not optimal [8], [10]. By using the variational method, an improved input distribution can be obtained [8], [10].…”

“…Due to the constraints of the input signal in VLC, the uniform and TGN input distributions are generally not optimal [8], [10]. By using the variational method, an improved input distribution can be obtained [8], [10]. By employing a discrete input distribution, the authors in [26] derived an upper bound on the secrecy capacity for the MISO VLC channels.…”

Fundamental Analysis for Visible Light Communication with Input‐Dependent Noise

“…According to Eq. (3), the conditional probability density function (PDF) of Y when given X ¼ x i can be written as [19] f…”

Indoor visible light communications: performance evaluation and optimization

“…However, owing to the stochastic behavior of photon emission in LED, the noise in VLC depends on the input signal [15]. Note that the channel capacity of VLC with the input-dependent noise is investigated in [16], and the mutual information for optical spatial modulation with the input-dependent noise is discussed in [17]. However, the link reliability of the VLC (such as bit error rate (BER)) with the input-dependent noise has not been studied.…”