Design guidelines for spatial modulation

A new class of low-complexity, yet energyefficient Multiple-Input Multiple-Output (MIMO) transmission techniques, namely the family of Spatial Modulation (SM) aided MIMOs (SM-MIMO) has emerged. These systems are capable of exploiting the spatial dimensions (i.e. the antenna indices) as an additional dimension invoked for transmitting information, apart from the traditional Amplitude and Phase Modulation (APM). SM is capable of efficiently operating in diverse MIMO configurations in the context of future communication systems. It constitutes a promising transmission candidate for large-scale MIMO design and for the indoor optical wireless communication whilst relying on a single-Radio Frequency (RF) chain. Moreover, SM may also be viewed as an entirely new hybrid modulation scheme, which is still in its infancy. This paper aims for providing a general survey of the SM design framework as well as of its intrinsic limits. In particular, we focus our attention on the associated transceiver design, on spatial constellation optimization, on link adaptation techniques, on distributed/ cooperative protocol design issues, and on their meritorious variants

Efficient frequency-domain channel equalisation methods for OFDM visible light communications

The authors present efficient frequency-domain channel estimation methods based on the intra-symbol frequency-domain averaging (ISFA), minimum mean squared error (MMSE) and weighted inter-frame averaging (WIFA) schemes for the orthogonal frequency division multiplexing (OFDM) visible light communications (VLC) system. OFDM-VLC with quadrature phase shift keying, 16- and 64-quadrature amplitude modulation mapping is experimentally demonstrated. Compared with the conventional least square channel estimation method, ISFA, MMSE and WIFA offer improved performance with MMSE offering the best performance in terms of the error vector magnitude but at the cost of high complexity. The authors show that the WIFA can improve the estimation accuracy of time-varying VLC optical channel

Spatial and wavelength division multiplexing for high-speed VLC systems: An overview

White light emitting diodes (LEDs) are becoming the primary source of illumination for the home and office environment. These LEDs can be intensity modulated to transmit high-speed data via an optical carrier. As a result, there is a paradigm shift in indoor wireless communication as the illumination infrastructure can be reused for data communications. It is widely expected that visible light communication (VLC) system will play a significant role in realizing the high-speed data communication envisaged for 5G connectivity. The goal of VLC systems is to provide a reliable and ubiquitous communication link that is an order of magnitude faster than current radio frequency (RF) links. In order to support the high data rates required for the current and future generations of communication systems, a number of techniques were explored for VLC by a number of research groups worldwide. This paper provides an overview of spatial and wavelength division multiplexing that has enabled multi-Gb/s transmission speeds in VLC using low bandwidth LEDs

Visible Light Communication (VLC)

Visible light communication (VLC) using light-emitting diodes (LEDs) or laser diodes (LDs) has been envisioned as one of the key enabling technologies for 6G and Internet of Things (IoT) systems, owing to its appealing advantages, including abundant and unregulated spectrum resources, no electromagnetic interference (EMI) radiation and high security. However, despite its many advantages, VLC faces several technical challenges, such as the limited bandwidth and severe nonlinearity of opto-electronic devices, link blockage and user mobility. Therefore, significant efforts are needed from the global VLC community to develop VLC technology further. This Special Issue, “Visible Light Communication (VLC)”, provides an opportunity for global researchers to share their new ideas and cutting-edge techniques to address the above-mentioned challenges. The 16 papers published in this Special Issue represent the fascinating progress of VLC in various contexts, including general indoor and underwater scenarios, and the emerging application of machine learning/artificial intelligence (ML/AI) techniques in VLC

Design and evaluation of optical laser diodes LD positioning arrangement and multiple input/ multiple output MIMO-OFDM systems

Optical communication system for the next generation of wireless communication systems are an exciting, unparalleled new technology. This paper presents a new visible light positioning algorithm system based on position by utilized neural network, which depending on directly measured received signal strength (RSS) information of 3D coordinates. This algorithm is called light positioning algorithm neural network (LPANN) which used 5 laser diodes LDs, each one consists of 5×5 LD chips. In addition, a novel multi Input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) based VLC systems generalized laser diodes (LD) modulation scheme as second part of this paper that is called Zero Forcing Equalizer Neural network ZFENN algorithm which based on 4 × 4 optical MIMO-VLC. It is accomplished by using LD index modulation and spatial multiplexing. Actual and imaginary parts of the complex time domain OFDM signals are therefore separated first and then, bipolar signals are transmitted through VLC channels by encoding sign-information in LD indexes. In addition, a novel receiver configuration is also suggested for flat frequency or limited channel scenarios. Based on the results of this analysis, the positioning accuracy have been improved, so this is lead to enhance data rate. While, by using the second part of the MIMO-OFDM system that leads to enhancing the SNR and BER more than 10-4, which are introduced to eliminate multi-user interference (MUI)