Zigbee as a means to reduce the number of blind spot incidents of a truck

Every year in Europe, about 1500 people die in traffic because they are not noticed by the truck driver. This problem could be solved by developing a wireless communication system where the truck driver and the cyclist are informed about each others presence. In this paper a test setup is presented in which the position of the cyclist is determined and displayed on a screen when being in the neighborhood of a truck. The cyclist gets an indication about notification by the truck. Because of the fast changing network, the cyclist must be added quickly to the network and the position must be updated very fast. For this reason a Zigbee communication system is used. The position of the cyclist is displayed in zones around the truck. The setup is experimentally tested and it is demonstrated that the proposed setup leads to a reliable and fast method to reduce the number of blind spot incidents

Investigation of Visible Light Communication for Indoor Localization

Until today, the existing technological solutions for accurate indoor positioning do not have a sufficient accuracy and require expensive equipment to be practically useful. At the same time, there is the arrival of the Light Emitting Diode (LED) which provides a new form of lighting for different applications. Compared to other lighting technologies, LEDs have an additional interesting property, namely that the light can be modulated at high speed. This has led to a new technological challenge, namely the usage of the existing infrastructure of LED lighting in combination with a wireless link for data communication. Visible Light Communication (VLC) has a number of advantages compared to RF communication: the frequency band is not licensed and a number of orders wider, the data is better protected due to the local character, there are no EMC problems with other electronic equipment, ... In this PhD, we want to explore the unique properties of LEDs (especially the high modulation speeds and the local character of the light) for indoor positioning. Starting with the characterization of the LED, receiver and channel, we will gradually progress to the realization of a working proof-of-concept for indoor positioning. The solution should work without disturbing the original function of the LEDs, namely to illuminate the room according to the lighting standards (when required with possibility for dimming) when there is communication. For a robust solution, it is important to characterize all kinds of optical noise sources, which comes down to the definition of a good channel model. Another aspect of the PhD is the research of a multipoint (set of LED fixtures in the lighting infrastructure) to point (mobile) topology, as it is perfectly possible to receive the emitted light from different LEDs at the same time. An appropriate coding technique and a solution to determine the relative signal strength is essential for the technology to succeed. Therefore, the definition of a robust multiple access technology for a multipoint-to-point topology is required with light as a carrier of information. In many cases, the encoding is oriented towards the maximization of the data rate in point-to-point links. These technologies typically target applications for the establishment of a bi-directional high data rate link using VLC over short distances (typically a desk lamp to a computer, the headlights in an aircraft, ...). It is clear that for these applications, the optical interference (noise) and multiple access does not play an important role. However, we wish to develop a coding technique which is specifically designed for use in combination with a robust multiple access technology in a multi-point-to-point topology. The solution should not only be examined in a static environment but also the dynamic behavior (using soft handovers) might be critical for some application.nrpages: 168status: publishe

Combining Natural Human-Computer Interaction and Wireless Communication

In this paper we present how human-computer interaction can be improved by using wireless communication between devices. Devices that offer a natural user interaction, like the Microsoft Surface Table and tablet PCs, can work together to enhance the experience of an application. Users can use physical objects for a more natural way of handling the virtual world on one hand, and interact with other users wirelessly connected on the other. Physical objects, that interact with the surface table, have a tag attached to them, allowing us to identify them, and take the required action. The TCP/IP protocol was used to handle the wireless communication over the wireless network. A server and a client application were developed for the used devices. To get a wide range of targeted mobile devices, different frameworks for developing cross platform applications were analyzed

Influence of MAI in a CDMA VLP System

In this paper, we study a Visible Light Positioning (VLP) system using Code Division Multiple Access (CDMA). In order to facilitate implementation, the LEDs are transmitting data in a non-synchronized way to the receiver requiring no backbone network. The positioning algorithm uses the received optical power calculated from the auto- correlation peak value. Because of the asynchronous system Multiple Access Interference (MAI), random interference with the auto- correlation peak, will occur and cause position errors. Practical results show that a CDMA VLP system can have position errors smaller then 40 cm and not be influenced by synchronization problems due to MAI. The positioning error and synchronization aren't only determined by the MAI but also the receiver Field Of View (FOV) is an important parameter. Depending on the CDMA code, the LEDs still have 97% of the illumination functionality compared when there is no communication.status: publishe

Performance analysis and optimization of the combined-contour labeling algorithm for real-time applications

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A Survey on Multiple Access Visible Light Positioning

© 2016 IEEE. Due to the ubiquitous presence of smart mobile devices, the search for an enabling technology for indoor positioning has accelerated. Different systems have been designed for applications like asset tracking, guiding and other Location Based Services (LBS). Depending on the application, the solutions use RF-, InfraRed or ultrasound technologies as communication system between the mobile nodes and the reference points. The biggest challenge with the different technologies is the rough indoor environment leading to an insufficient accuracy, combined with a high installation cost. In recent years, Visible Light Communication (VLC) has received a lot of attention as a new wireless means of communicating. The local character of the light and the dense deployment of light fixture make VLC a candidate to bring a solution for indoor positioning. This paper gives an overview of the current research results on Visible Light Positioning (VLP) systems classified according to the multiple access technology used. The advantages and disadvantages of the different VLP topologies are addressed in this work.status: publishe

Optical CDMA Codes for an Indoor Localization System using VLC

© 2014 IEEE. This paper describes the use of optical Code Division Multiple Access (CDMA) codes for an indoor localization system using Visible Light Communication. VLC uses Intensity Modulation and Direct Detection (IM/DD) so the CDMA codes can be used as baseband signals which makes the driving electronics less complex. In order to keep the installation cost low, a backbone network between the LEDs is not present. This makes it an asynchronous CDMA system where the cross- correlation is random and can in some cases introduces large distance errors. There are two groups of Optical CDMA codes namely uni- and bi- polar. When bipolar codes are used, the receiver should be equipped with an appropriated High Pass Filter (HPF). The results show that there is no large difference in cross- correlation between the codes but bipolar codes can reduce the distance error and so the position error even when there is static surrounding light like e.g. sunlight.status: publishe

Combining Natural Human-Computer Interaction and Wireless Communication

In this paper we present how human-computer interaction can be improved by using wireless communication between devices. Devices that offer a natural user interaction, like the Microsoft Surface Table and tablet PCs, can work together to enhance the experience of an application. Users can use physical objects for a more natural way of handling the virtual world on one hand, and interact with other users wirelessly connected on the other. Physical objects, that interact with the surface table, have a tag attached to them, allowing us to identify them, and take the required action. The TCP/IP protocol was used to handle the wireless communication over the wireless network. A server and a client application were developed for the used devices. To get a wide range of targeted mobile devices, different frameworks for developing cross platform applications were analyzed.status: publishe

Design of a Visible Light Communication Transmitter for the Evaluation of a Wide Range of Modulation Techniques

In this paper, we describe the development of a dedicated transmitter to be used in Visible Light Communication applications. The transmitter has a high power efficiency, so the communication functionality does not lead to significant power consumption. For this reason, a Trans-Conductance Amplifier (TCA) was designed making use of a class AB amplifier. The final design has an electrical bandwidth from 20 kHz until 25 MHz and is able to power LEDs with a driving current up to 700 mA. Results show that the bandwidth of the driver electronics is much larger than the bandwidth of the commonly used power LEDs that are designed for illumination purposes. Because the transmitter has the ability to implement different modulation techniques, as well digital as analogues in nature, it can be used in a wide range of applications depending on the needs of data rate and bandwidth. © 2013 IEEE.status: publishe

A Test Bench for a VLP System using CDMA as Multiple Access Technology

In this paper, we present a test bench for a Visible Light Positioning (VLP) system using Code Division Multiple Access (CDMA). A VLP system should be easy and low cost to install in existing infrastructures meaning there is no backbone network between the LEDs. CDMA can therefor be used as multiple access technology, with the challenging observation that the LEDs are transmitting data in a non-synchronized way to the receiver. Because the VLP system uses the received optical power for the positioning algorithm, Multiple Access Interference (MAI) can introduce errors. For the evaluation of the influence of MAI a test bench was developed where different CDMA codes are used in a VLP system. From practical measurements it is demonstrated that our approach leads to position errors smaller then 20 cm making the system suitable for indoor Location Based Services (LBS).status: publishe