Flight: A Flexible Light Communications network architecture for indoor environments

Recent experimental works have demonstrated the feasibility of the visible light based vehicular communications (VVLC) in intelligent transportation systems (ITS). However, in many respects, this technology is in its infancy and requires further research efforts in several areas. This work presents a flexible network architecture named flexible light (Flight), which is designed for VLC to tackle existing mobility challenges in the network environment. Flight proposes a low-latency handover system that decreases the handover delays to a few tens and hundreds of milliseconds. By means of experiments, we emulate and evaluate indoor mobile network scenarios using only VLC technology

FDLA: A Novel Frequency Diversity and Link Aggregation Solution for Handover in an Indoor Vehicular VLC Network

VLC (VLC) has been introduced as a complementary wireless technology that can be widely used in industrial indoor environments where automated guided vehicles aim to ease and accelerate logistics. Despite its advantages, there is one significant drawback of using an indoor () network that is there is a high handover outage duration. In line-of-sight VLC links, such handovers are frequently due to mobility, shadowing, and obstacles. In this paper, we propose a frequency diversity and link aggregation solution, which is a novel technique in Data link layer to tackle handover challenge in indoor networks. We have developed a small-scale prototype and experimentally evaluated its performance for a variety of scenarios and compared the results with other handover techniques. We also assessed the configuration options in more detail, in particular focusing on different network traffic types and various address resolution protocol intervals. The measurement results demonstrate the advantages of our approach for low-outage duration handovers in. The proposed idea is able to decrease the handover outage duration in a two-dimensional network to about 0.2 s, which is considerably lower compared to previous solutions

A Flexible Transport Layer Protocol Architecture for Handover in a Vehicular VLC Network

Recent research works have focused on the feasibility of using the multipath-transmission control protocol (MPTCP) in order to optimize network throughput and latency. In this work, we propose a novel architecture using MPTCP for a vehicular visible light communications (VLC) network to improve the performance in terms of network outage duration and throughout. Two relevant MPTCP schedulers and an MPTCP tool are selected to analyze VLC performance during the handover. The results show that the proposed system offers low-outage duration handover of 24 ms and high data throughput of 125 Mbps using "Redundant"and "Default"schedulers, respectively

Analyzing Interface Bonding Schemes for VLC with Mobility and Shadowing

Node mobility and shadowing are the most common reasons requiring a handover in vehicular visible light communications (VVLC). In order to provide seamless mobility during the handover, it is required to decrease the network outage duration. This paper aims to improve the outage duration in handover caused by mobility and shadow for VLC networks. We analyze interface bonding schemes using two different primary interface reselection methods. The results show that using "failure"interface selection method instead of "always"method reduces the VLC handover outage duration by 62% and 44% in bonding schemes for transmission control protocol (TCP) and user datagram protocol (UDP) network traffic, respectively

Surface reconstruction of illuminated objects via photometric stereo

Ein Verfahren dient zur Oberflächenrekonstruktion, wobei mindestens ein Objekt (O) von mehreren voneinander beabstandeten Leuchten (a-d) gleichzeitig beleuchtet wird, eine fotografische Sequenz mit mehreren Einzelbildern (EBr-EBr+n) des mindestens einen Objekts (O) aufgenommen wird und mindestens eine sichtbare Objektoberfläche (OS1, OS2) des Objekts (O) mittels fotometrischer Stereoanalyse rekonstruiert wird, wobei das von den Leuchten (a-c; a-d) abgestrahlte Licht (La-Ld) mit unterschiedlichen Modulationsfrequenzen (fa-fc; fa-fd) moduliert wird, die von dem Objekt (O) reflektierten Lichtanteile der jeweiligen Leuchten (a-d) anhand ihrer Modulationsfrequenzen (fa-fd) erkannt und jeweiligen Teilbildern (TBa-TBd) zugeordnet werden und die Teilbilder (TBa-TBd) als Eingangsbilder für die fotometrische Stereoanalyse verwendet werden. Eine Vorrichtung (S1, S2) ist zur Durchführung des Verfahrens nach einem der vorhergehenden Ansprüche eingerichtet. Die Erfindung ist insbesondere anwendbar zur Raumüberwachung von Innen- und/oder Außenräumen und/oder zur Objekterkennung, insbesondere im Zusammenhang mit einer Allgemeinbeleuchtung

Method for automatically controlling at least one device of a building by means of a building management system and building management system

The invention relates to a method for automatically controlling at least one device (18) of a building (10) by means of a building management system (12), wherein in a learning phase (LP) at least one user (B, B1, B2, B3, B4) of the building ( 10) is identified on the basis of at least one detected first user characteristic (C1), at least one control input (SE), which is made by the at least one user (B, B1, B2, B3, B4) for controlling the at least one device (18) , is detected while the at least one identified user (B, B1, B2, B3, B4) is in the building (10) and in dependence on the at least one detected control input (SE) of the at least one identified user (B, B1 , B2, B3, B4) the building management system (12) determines control rules (R1) associated with the at least one identified user (B, B1, B2, B3, B4) and according to which the at least one device (18) of the building ( 10) autom in a second phase (AP) of the building management system (12), while the at least one user (B, B1, B2, B3, B4) is located in the building (10)