Visible light communication (VLC) is a promising technology that meets illumination and information transmission requirements in an indoor environment. Because light waves convey energy, a VLC link may exploit that fact for energy harvesting purposes. In this context, a single light emitting diode lamp located at a close distance over a tablet or laptop PC can potentially offer simultaneous lighting, Internet access, and battery recharging without cables. The present study introduces this threefold role of VLC systems by properly adapting some energy harvesting receiver architectures recently launched for usage in RF communications. The rate-energy trade-off for these architectures is revealed in order to maximize the efficiency of simultaneous energy and information reception, by elaborating on indicative numerical results. Furthermore, the performance in terms of the bit-error rate for pulse amplitude modulated signals is investigated. The results obtained offer some useful insights into the effective optical receiver implementation from the aspect of information theory.

The performance of a network consisting of several underwater sensors communicating with a terrestrial destination is studied for the first time in terms of the outage probability. In the scenario under consideration, $K$ sensors emit data to a decode-and-forward relay using underwater optical wireless communication links. The relay transfers the $N\text{th}$ best signal to the terrestrial destination by using a free-space optical link. Weak oceanic and atmospheric turbulence conditions are taken into account. Appropriate numerical results are provided in order to verify the derived analytical expression. The proposed setup is adequate to reliably transfer subaquatic data to large distances without expensive and complicated networking infrastructures.

The current work investigates the outage probability of a vertical diffused line-of-sight underwater optical wireless communication link where a fixed transmitter at the sea surface communicates with a receiver floated below sea level, which may be still but randomly placed at a given location or moving following the random waypoint model. In both considered scenarios, the channel gain follows a random distribution making the problem mathematically challenging. Novel mathematical expressions are derived for the channel gain statistics for either random placement and mobility effects. Afterward, the signal-to-noise ratio statistics are extracted, assuming indirect modulation/direct detection at the receiver. Hence, the outage probability and the average bit-error-rate for on–off keying are readily calculated. Finally, some relevant numerical results are depicted in a series of figures to highlight the overall performance.

Subcarrier free-space optical (FSO) systems using coherent recovery techniques at the receiver have acquired growing research interest in recent times. However, their optimal performance is diminished by the non-perfect synchronization of carrier frequency and phase, which is mainly due to phase noise problems. Moreover, turbulence and pointing error effects further deteriorate the overall performance. However, relay transmission schemes can extend the coverage distance and offer substantial improvements over fading conditions. In this respect, we consider a serially relayed network using decode-and-forward relays, and investigate its performance by means of average symbol error probability and mean outage duration. Turbulence is modeled by the recently unified M(alaga) distribution, which constitutes a very general statistical model that accurately describes the irradiance fluctuations from weak-to-strong turbulence conditions. Additionally, the presence of non-zero boresight pointing errors due to misalignment between the transmitter–receiver pair is considered, while the effect of phase noise is specified by a Tikhonov distribution. A comparison between single line-of-sight and serially relayed FSO configurations is provided as well. Novel approximated mathematical expressions are deduced, which are proved to be accurate enough over a wide range of turbulence strengths and signal-to-noise values. Finally, proper numerical results are presented and validated by Monte Carlo simulations.

Terrestrial free‐space optical (FSO) communication systems with subcarrier intensity modulation have experienced a particular research attention in the recent past. However, their performance strongly degrades in the presence of atmospheric turbulence, pointing errors, and phase noise impairments. In order to overcome these limitations, the authors consider a receiver diversity scheme of a typical subcarrier phase‐shift keying (PSK) system and investigate the performance by means of the average symbol error probability (ASEP). They assume a wide range of turbulence conditions, non‐zero boresight pointing errors, and phase noise strengths described through the gamma‐gamma, Beckmann, and Tikhonov distributions, respectively. Novel approximate ASEP expressions are derived for single‐input single‐output and single‐input multiple‐output (SIMO) configurations. Appropriate numerical results are depicted and validated by Monte Carlo simulations.