Joint Optimization of Illumination and Communication for a Multi-Element VLC Architecture

Because of the ever increasing demand wireless data in the modern era, the Radio Frequency (RF) spectrum is becoming more congested. The remaining RF spectrum is being shrunk at a very heavy rate, and spectral management is becoming more difficult. Mobile data is estimated to grow more than 10 times between 2013 and 2019, and due to this explosion in data usage, mobile operators are having serious concerns focusing on public Wireless Fidelity (Wi-Fi) and other alternative technologies. Visible Light Communication (VLC) is a recent promising technology complementary to RF spectrum which operates at the visible light spectrum band (roughly 400 THz to 780 THz) and it has 10,000 times bigger size than radio waves (roughly 3 kHz to 300 GHz). Due to this tremendous potential, VLC has captured a lot of interest recently as there is already an extensive deployment of energy efficient Light Emitting Diodes (LEDs). The advancements in LED technology with fast nanosecond switching times is also very encouraging. In this work, we present hybrid RF/VLC architecture which is capable of providing simultaneous lighting and communication coverage in an indoor setting. The architecture consists of a multi-element hemispherical bulb design, where it is possible to transmit multiple data streams from the multi-element hemispherical bulb using LED modules. We present the detailed components of the architecture and make simulations considering various VLC transmitter configurations. Also, we devise an approach for an efficient bulb design mechanism to maintain both illumination and communication at a satisfactory rate, and analyze it in the case of two users in a room. The approach involves formulating an optimization problem and tackling the problem using a simple partitioning algorithm. The results indicate that good link quality and high spatial reuse can be maintained in a typical indoor communication setting

A Software-Defined Multi-Element VLC Architecture

In the modern era of radio frequency (RF) spectrum crunch, visible light communication (VLC) is a recent and promising alternative technology that operates at the visible light spectrum. Thanks to its unlicensed and large bandwidth, VLC can deliver high throughput, better energy efficiency, and low cost data communications. In this article, a hybrid RF/VLC architecture is considered that can simultaneously provide light- ing and communication coverage across a room. Considered architecture involves a novel multi-element hemispherical bulb design, which can transmit multiple data streams over light emitting diode (LED) modules. Simulations considering various VLC transmitter configurations and topologies show that good link quality and high spatial reuse can be maintained in typical indoor communication scenarios

Multi-Element Multi-Datastream Visible Light Communication Networks

Because of the exponentially increasing demand of wireless data, the Radio Frequency (RF) spectrum crunch is rising rapidly. The amount of available RF spectrum is being shrunk at a very heavy rate, and spectral management is becoming more difficult. Visible Light Communication (VLC) is a recent promising technology complementary to RF spectrum which operates at the visible light spectrum band (400 THz to 780 THz) and it has 10,000 times bigger bandwidth than radio waves (3 kHz to 300 GHz). Due to this tremendous potential, VLC has captured a lot of interest recently as there is already an extensive deployment of energy efficient Light Emitting Diodes (LEDs). The advancements in LED technology with fast nanosecond switching times is also very encouraging. One of the biggest advantages of VLC over other communication systems is that it can provide illumination and data communication simultaneously without needing any extra deployment. Although it is essential to provide data rate at a blazing speed to all the users nowadays, maintaining a satisfactory level in the distribution of lighting is also important. In this work, we present a multi-element multi-datastream (MEMD) VLC architecture capable of simultaneously providing lighting uniformity and communication coverage in an indoor setting. The architecture consists of a multi-element hemispherical bulb design, where it is possible to transmit multiple data streams from the bulb using multiple LED modules. We present the detailed components of the architecture and formulate joint optimization problems considering requirements for several scenarios. We formulate an optimization problem that jointly addresses the LED-user associations as well as the LEDs\u27 transmit powers to maximize the Signal-to-Interference plus Noise Ratio (SINR) while taking an acceptable illumination uniformity constraint into consideration. We propose a near-optimal solution using Geometric Programming (GP) to solve the optimization problem and compare the performance of this GP solution to low complexity heuristics. To further improve the performance, we propose a mirror employment approach to redirect the reflected LED beams on the wall to darker spots in the room floor. We compare the performance of our heuristic approaches to solve the proposed two-stage optimization problem and show that about threefold increase in average illumination and fourfold increase in average throughput can be achieved when the mirror placement is applied which is a significant performance improvement. Also, we explore the use case of our architecture to provide scalable communications to Internet-of-Things (IoT) devices, where we minimize the total consumed energy emitted by each LED. Because of the non-convexity of the problem, we propose a two-stage heuristic solution and illustrate the performance of our method via simulations

Optimal Multi-Element Vlc Bulb Design With Power And Lighting Quality Constraints

In the modern era of radio frequency (RF) spectrum crunch, visible light communication (VLC) offers a promising alternative. Thanks to its unlicensed and large bandwidth, VLC technology can deliver high throughput, energy efficient and low cost data communications. In this paper, we consider a VLC architecture with a novel multi-element hemispherical bulb, which can transmit multiple data streams over multiple LED boards. Simulations considering various VLC transmitter configurations and topologies show that good link quality and high spatial reuse can be maintained in typical indoor communication scenarios. We develop the characteristics of an optimum multi-element bulb design in terms of both illumination and communication under various constraints

MirrorVLC: Optimal Mirror Placement for Multi-Element VLC Networks

Visible Light Communication (VLC) is a rapidly growing technology which can supplement the current radio-frequency (RF) based wireless communication systems. VLC can play a huge part in solving the ever-increasing problem of spectrum scarcity because of the growing availability of Light Emitting Diodes (LEDs). One of the biggest advantages of VLC over other communication systems is that it can provide illumination and data communication simultaneously without needing any extra deployment. Although it is essential to provide data rate at a blazing speed to all the users nowadays, maintaining a satisfactory level in the distribution of lighting is also important. In this paper, we present a novel approach of using mirrors to enhance the illumination uniformity and throughput of an indoor multi-element VLC system architecture. In this approach, we improve the Signal-to-Interference plus Noise Ratio (SINR) of the system and overall illumination uniformity of the room by redirecting the reflected LED beams on the walls to darker spots with the use of mirrors. We formulate a joint optimization problem focusing on maximization of the SINR while maintaining a reasonable illumination uniformity across the room. We propose a two-stage solution of the optimization problem: design solution and communication solution. In the design optimization, we formulate an equivalent binary linear optimization to achieve the best illumination quality by optimizing the mirror placements and the LEDs\u27 transmit powers. In the communication problem, however, we aim to improve the throughput of the system using a fair utility metric based on maximizing the minimum user\u27s data rate. Due to non-convexity of the communication problem, we propose three different heuristic solutions and analyze their performance. We also show that about threefold increase in average illumination and fourfold increase in average throughput can be achieved when the mirror placement is applied which is a significant performance improvement

Optimization of SINR and Illumination Uniformity in Multi-LED Multi-Datastream VLC Networks

Visible Light Communication (VLC), which is a recent technology that operates at the visible light spectrum band, is a very propitious technology complementary to RF in the era of spectrum crisis. Because of the extensive deployment of energy efficient Light Emitting Diodes (LEDs) and the advancements in LED technology with fast nanosecond switching times, VLC has gained a lot of interest recently. In this paper, we consider a downlink VLC architecture which is capable of providing simultaneous lighting and communication coverage across an indoor setting. We design a multi-element hemispherical bulb which transmits multiple data streams from its LEDs to mobile receivers. The architecture employs a Line-of-Sight (LOS) alignment protocol to tackle the hand-off issue caused by the mobility of the receivers in the room. We formulate an optimization problem that jointly addresses the LED-user associations as well as the LEDs\u27 transmit powers in order to maximize the Signal-to-Interference plus Noise Ratio (SINR) while taking into consideration an acceptable illumination uniformity constraint across the room. We propose a near-optimal solution using Geometric Programming (GP) to solve the optimization problem, and compare the performance of this GP solution to low complexity heuristics

Resource Optimization in Visible Light Communication for Internet of Things

In the modern day, there is a serious spectrum crunch in the legacy radio frequency (RF) band, for which visible light communication (VLC) can be a promising option. VLC is a short-range wireless communication variant which uses the visible light spectrum. In this paper, we are using a VLC-based architecture for providing scalable communications to Internet-of-Things (IoT) devices where a multi-element hemispherical bulb is used that can transmit data streams from multiple light emitting diode (LED) boards. The essence of this architecture is that it uses a Line-of-Sight (LoS) alignment protocol that handles the handoff issue created by the movement of receivers inside a room. We start by proposing an optimization problem aiming to minimize the total consumed energy emitted by each LED taking into consideration the LEDs\u27 power budget, users\u27 perceived quality-of-service, LED-user associations, and illumination uniformity constraints. Then, because of the non-convexity of the problem, we propose to solve it in two stages: (1) We design an efficient algorithm for LED-user association for fixed LED powers, and (2) using the LED-user association, we find an approximate solution based on Taylor series to optimize the LEDs\u27 power. We devise a heuristic solution based on this approach. Finally, we illustrate the performance of our method via simulations

A Software-Defined Multi-Element Vlc Architecture

In the modern era of RF spectrum crunch, VLC is a recent and promising alternative technology that operates at the visible light spectrum. Thanks to its unlicensed and large bandwidth, VLC can deliver high throughput, better energy efficiency, and low-cost data communications. In this article, a hybrid RF/VLC architecture is considered that can simultaneously provide lighting and communication coverage across a room. The considered architecture involves a novel multi-element hemispherical bulb design, which can transmit multiple data streams over LED modules. Simulations considering various VLC transmitter configurations and topologies show that good link quality and high spatial reuse can be maintained in typical indoor communication scenarios