As Global Positioning System (GPS) cannot provide satisfying performance in indoor environments, indoor positioning technology, which utilizes indoor wireless signals instead of GPS signals, has grown rapidly in recent years. Meanwhile, visible light communication (VLC) using light devices such as light emitting diodes (LEDs) has been deemed to be a promising candidate in the heterogeneous wireless networks that may collaborate with radio frequencies (RF) wireless networks. In particular, light-fidelity has a great potential for deployment in future indoor environments because of its high throughput and security advantages. This paper provides a comprehensive study of a novel positioning technology based on visible white LED lights, which has attracted much attention from both academia and industry. The essential characteristics and principles of this system are deeply discussed, and relevant positioning algorithms and designs are classified and elaborated. This paper undertakes a thorough investigation into current LED-based indoor positioning systems and compares their performance through many aspects, such as test environment, accuracy, and cost. It presents indoor hybrid positioning systems among VLC and other systems (e.g., inertial sensors and RF systems). We also review and classify outdoor VLC positioning applications for the first time. Finally, this paper surveys major advances as well as open issues, challenges, and future research directions in VLC positioning systems.

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A Survey of Positioning Systems Using Visible LED Lights

Exploiting the increasingly wide use of Light-emitting Diode (LED) lighting, in this paper, we study the problem of using visible LED lights for accurate localization. The basic idea is to leverage the existing lighting infrastructure and apply trilateration to localize any devices with light sensing capability (e.g., a smartphone), using LED lamps as anchors. Through the design of Epsilon, we identify and tackle several technique challenges. In particular, we establish and experimentally verify the optical channel model for localization. We adopt BFSK and channel hopping to enable reliable location beaconing from multiple, uncoordinated light sources over the shared optical medium. We handle realistic situations towards robust localization, for example, we exploit user involvement to resolve the ambiguity in case of insufficient LED anchors. We have implemented the Epsilon system and evaluated it with a small scale hardware testbed as well as moderate-size simulations. Experimental results confirmed the effectiveness of Epsilon: the 90th percentile accuracies are 0.4m, 0.7m and 0.8m for three typical office environments. Even in the extreme situation with a single light, the 90th percentile accuracy is 1.1m. We believe that visible light based localization is promising to significantly improve the positioning accuracy, despite few open problems in practice.

/pdf/epsilon-a-visible-light-based-positioning-system-5bw22cjxcn.pdf

Epsilon: a visible light based positioning system

Indoor positioning systems (IPS) use sensors and communication technologies to locate objects in indoor environments. IPS are attracting scientific and enterprise interest because there is a big market opportunity for applying these technologies. There are many previous surveys on indoor positioning systems; however, most of them lack a solid classification scheme that would structurally map a wide field such as IPS, or omit several key technologies or have a limited perspective; finally, surveys rapidly become obsolete in an area as dynamic as IPS. The goal of this paper is to provide a technological perspective of indoor positioning systems, comprising a wide range of technologies and approaches. Further, we classify the existing approaches in a structure in order to guide the review and discussion of the different approaches. Finally, we present a comparison of indoor positioning approaches and present the evolution and trends that we foresee.

/pdf/evolution-of-indoor-positioning-technologies-a-survey-4wowbzt805.pdf

Evolution of Indoor Positioning Technologies: A Survey

Advances in visible light communication (VLC) technology and the ubiquity of illumination facility have led to a growing interest in VLC-based indoor positioning. Numerous techniques have been proposed to obtain better system performance. In this paper, we survey over 100 papers ranging from pioneering papers to the state-of-the-art in the field to present the positioning technology. Not only the light emitting diode technology, modulation method and types of receivers are compared but also a novel taxonomy method is proposed. In this paper, VLC-based indoor positioning systems (VLC-based-IPSs) are classified based on the methods used: 1) mathematical method; 2) sensor-assisted method; and 3) optimization method. Different from other survey works, we emphasize and analyze the accuracy of VLC-based-IPS in the experiment and simulation environments. Meanwhile, this paper illustrates challenges, countermeasures, and lessons learned.

Indoor Positioning Systems Based on Visible Light Communication: State of the Art

While visible light communication (VLC) has become the candidate for the wireless technology of the 21st century due to its inherent advantages, VLC based positioning also has a great chance of becoming the standard approach to positioning. Within the last few years, many studies on VLC based positioning have been published, but there are not many survey works in this field. In this paper, an in-depth survey of VLC based positioning systems is provided. More than 100 papers ranging from pioneering papers to the state-of-the-art in the field were collected and classified based on the positioning algorithms, the types of receivers, and the multiplexing techniques. In addition, current issues and research trends in VLC based positioning are discussed.

https://www.mdpi.com/1424-8220/16/5/678/pdf

An in-Depth Survey of Visible Light Communication Based Positioning Systems.

Indoor positioning has become an attractive research topic within the past two decades. However, no satisfying solution has been found with consideration of both accuracy and system complexity. Recently, research on visible light communications (VLC) offer new opportunities in realizing accurate indoor positioning with relatively simple system configuration. An indoor positioning system based on VLC technology is introduced, with no synchronization requirement on the transmitters. Simulation results show that, with over 95% confidence, the target receiver can be located with an accuracy of 5.9 cm, assuming indirect sunlight exposure and proper installation of light-emitting diode bulbs.

https://www.spiedigitallibrary.org/journals/Optical-Engineering/volume-53/issue-4/045105/Asynchronous-indoor-positioning-system-based-on-visible-light-communications/10.1117/1.OE.53.4.045105.pdf

Asynchronous indoor positioning system based on visible light communications

An LED based 2-D indoor localization system is proposed. For evaluation purpose we also present computer simulations results that show for a normal room size, we can locate a target to within centimeters.

A 2-D indoor localization system based on visible light LED

Indoor positioning based on visible light communication (VLC) technology has become a very popular research topic
recently. This paper provides an overview of different VLC based indoor positioning techniques and their performance.
Three schemes of location estimation together with their mechanisms are introduced. We then present a detailed
comparison on their performances in terms of accuracy, space dimension and complexity. We further discuss a couple of
factors that would affect the performance of each of these positioning systems, including multipath reflections and
synchronization. Finally, conclusions and future prospects of research are addressed.

Comparison of VLC-based indoor positioning techniques

This paper introduces an indoor positioning system based on visible light communication technology with three-dimensional positioning capability. Light-emitting diodes are employed as transmitters, with photodiodes as receivers to obtain the received signal strength (RSS) information. Based on the trilateration technique, the proposed algorithm is able to calculate horizontal coordinates of the receiver with RSS information, after which the height of the receiver is estimated. The system does not require other measurements such as time-of-arrival or angle-of-arrival, thus system design and costs are simplified and minimized. Basic framed slotted ALOHA is applied as the channel access method to enable asynchronous transmissions. In addition, Kalman and particle filters are used in order to realize target tracking. Results show that both filters help to increase the positioning accuracy and the particle filter exhibits a better performance than the Kalman filter, with a higher computational complexity.

Three-dimensional light positioning algorithm with filtering techniques for indoor environments

Because of the importance of calculating an accurate impulse response of an indoor optical wireless room environment that includes sufficient orders of multipath reflections from reflecting surfaces of the room, several different algorithms exist to solve the problem of calculating impulse responses accurately and in a reasonable amount of computing time. Deterministic approaches that divide the reflecting surfaces into small elements give the best accuracy but they require high computing time. Modified Monte Carlo methods provide a very fast approach of calculating impulse responses but the calculated impulse responses contain variance or, in other words, they are not as temporally smooth when compared to deterministic approaches. In this paper, we have taken a combined approach where we calculate the contribution of first reflections to the total impulse response by a deterministic method, and then the contributions of second and rest of the reflections to the total impulse response are calculated by the Modified Monte Carlo method. This carries the advantage of both of these approaches. Moreover, the algorithm can be easily implemented for parallel computation similar to the Modified Monte Carlo method to utilize the full power of modern multicore computer processors.

Weizhi Zhang

Papers

Asynchronous indoor positioning system based on visible light communications

A 2-D indoor localization system based on visible light LED

Comparison of VLC-based indoor positioning techniques

Three-dimensional light positioning algorithm with filtering techniques for indoor environments

Combined deterministic and modified monte carlo method for calculating impulse responses of indoor optical wireless channels