In this letter, we propose spatial diversity reception of non-line-of-sight (NLOS) ultraviolet (UV) communication in turbulent atmospheric channel. The turbulent atmospheric channel causes fluctuation in the received signal intensity of a UV system, resulting in power loss and subsequent performance degradation at the receiver. To mitigate this adverse effect, we present the spatial diversity reception in the form of dual-branch switch and stay combining (SSC) at the receiver. That is, one branch is only connected to the receiver at any instant using appropriate switching logic. The channels are assumed to be exponentially correlated in space, while irradiance fluctuation due to turbulence is modeled by a Gamma-Gamma distribution with parameters directly related to the attributes of the NLOS UV link. Analytic expressions for both the outage probability and the average symbol error probability are derived using the SSC diversity technique with the correlated receivers.

Ultraviolet (UV) wireless communication has recently received much attention only for outdoor applications. Due to inherent nature of UV transmission, we believe that UV can also be considered for efficient and low-cost indoor communications. In this article, we present a novel UV indoor communication with an in-depth description of design implementation, channel modeling, and performance analysis. We consider a discrete Poisson channel with transmit power constraints. While focusing mainly on the development of a UV-based indoor communication, an indoor UV channel model is first proposed. Based on this, physical characteristics of the UV indoor channel using on–off keying modulation are analyzed with direct detection in terms of bit error rate, channel dc gain, and delay spread. As the proposed UV indoor communication exhibits some limitations, we provide a brief discussion on design implementation and challenges. From the performance analysis, it is found that the proposed UV indoor communication can provide ubiquitous link connectivity in indoor applications, while keeping network structure and management simple.

To meet high data rate requirements of future wireless communication systems, there is a need for advanced communication technologies that could be used in combination with existing wireless RF technologies. Recently, optical wireless communication (OWC) has been extensively investigated as an attractive alternate technology to RF. OWC uses the optical carrier to convey data, with wavelengths ranging from ultraviolet (UV) to infrared (IR) to visible light. In the past years, there is a spike in interest over optical scattering communications (OSCs) employing UV wavelengths, thanks to the recent advances and rapid developments in deep UV light-emitting diodes (LEDs), laser diodes, and solar-blind UV filters and detectors. The unique atmospheric scattering and absorption properties of the deep UV band, which is solar-blind at the ground level, are the motivation for the recent development of the OSC systems. However, there is a clear gap in the existing literature that the OSC systems are yet to be systematically surveyed for their applicability to future wireless communications. In this context, this paper bridges the gap by providing the first contemporary and comprehensive survey on recent and new advancements in the OSCs, commonly known as UV communications. In summary, this survey is expected to provide a largely missing articulation between various aspects of UV communications. To be easy to follow, we commence our discourse by surveying the propagation concepts and historic evolution of UV communication systems. Next, we provide a detailed survey on UV channel modeling because accurate channel characterization is important for efficient system design and performance optimization of UV communication systems. We discuss various UV channel characterization efforts thus far made. Then, we present a classification to analyze current OSC system designs. Importantly, we survey recent advancements in the NLOS UV communication systems that include the application of artificial intelligence, artificial neural networks, game theory, orbital angular momentum, etc. Moreover, we conduct a comprehensive survey on recently documented UV-based indoor communication systems. Finally, we point out several key issues yet to be addressed and collate potentially interesting and challenging topics for future research. This survey is aptly featured by in-depth discussion and analysis of UV communication systems in various aspects, many of which, to the best of authors’ knowledge, are the first time presented in this field.

In recent years, optical wireless communication (OWC) is recognized as a propitious technology for indoor data communications. OWC offers reduced electromagnetic interference (EMI) in sensitive indoor communication environments such as hospitals and nursing homes, and has thus emerged as a good candidate for healthcare monitoring applications. In this paper, we investigate the use of infrared (IR) communication for multiple-patient biomedical data transmission. To transmit the multiple-patient data, we propose a novel periodic data transmission (PDT) scheme with real-time experimental demonstration. The transmit modules consist of IR light emitting diodes (LEDs) as the transmitter, and the receiver module comprises a narrow bandpass filter (BPF) followed by an IR photodiode (PD). Biomedical signals for the transmission include electrocardiography (ECG), blood pressure (BP), and body temperature. We consider the line-of-sight (LOS) data transmission with multiple transmitters corresponding to each patient and a single receiver where each patient is allowed to transmit the data periodically. Experiments are carried out to verify the effectiveness of the proposed system. The experimental results demonstrate that it achieves a bit error rate (BER) of better than 10-6, thus offering accurate health monitoring applications with negligible interference from multiple patients.