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Simulation of the Data Transmission from the Aerobatic Plane

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This article deals with the optimization of data transmission from the fast-moving objects. Optimization is performed on the second layer of the RM OSI and uses multiple transmission channels. For simulation were created two cases using multiple transmission channels. These cases were compared with case of common wireless system with a single channel. Proposed cases reached better error rates and proved their usefulness. They are also independent on the transmission technology (due to implementation on the second layer of RM OSI), therefore are versatile. Streszczenie. W artykule opisano zagadnienie optymalizacji transmisji danych z szybko przemieszczających się obiektów, z wykorzystaniem drugiej warstwy RM OSI oraz transmisji wielokanałowej. Do symulacji opracowano dwa przypadki transmisji wielokanałowej, które porównano z działaniem wspólnego jednokanałowego systemu bezprzewodowego. Wyniki potwierdziły redukcję ilości błędów oraz niezależność badanych przypadków od metody transmisji, co świadczy o ich uniwersalności. (Symulacje transmisji danych z samolotu akrobacyjnego). Keywords: Wireless communication, simulation, Wi-Fi, high availability. Słowa kluczowe: komunikacja bezprzewodowa, symulacja, Wi-Fi, duża dostępność. Introduction The High Speed Mobile Communication project is focused on the design of the transmission system that would enable wireless transmission of the video and telemetric data from aerobatic plane during air show. Systems for transmission audio-visual data from fastmoving objects exist (Formula 1 or Red Bull Air Race), there, however, the machines move over a relatively welldefined route. Therefore, demanding on the radio part is not so high, it is just necessary to deploy properly the basic stations along the assumed trajectory and the connection is stable and good enough to transfer these data [1]. Nevertheless, this is not possible at aerobatic show because of unpredictable airplane trajectory. Presented so[...]

Methodology of the direct measurement of the switching latency

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The article provides a measurement methodology based on the related RFCs. It brings a solution of determining the switching latency on the physical layer using common measuring devices. As a proof of concept were done a number of the experimental measurements, including analysis of the results. Switching latency is an important performance parameter which participates in the decision-making whether to deploy the switch to low-latency environments. This is especially important in industrial networks for real-time systems involving smart grids. Determine the value of the switching latency is also an important step in the eventual deployment of the OpenFlow technology on this field. Streszczenie. Zaprezentowano metodę badania opóźnień w przełączaniu (switching latency) bazująca na RFC. Parametr ten jest bardzo ważny w sieciach przemysłowych łącznie z sieciami typu smart grid. (Metoda bezpośredniego pomiaru opóźnień przełączania w sieciach komputerowych) Keywords: switching latency, measurement methodology, OpenFlow, industrial networks, low-latency, Smart Grids. Słowa kluczowe: opóźienie przełączania, sieci komputerowe. Introduction Massive global usage of Ethernet as a transmission technology in local area networks has led to its use in other specialized sectors and exacting environments. These lowlatency environments lay great demands on the transmission time of critical messages interchanged between real-time systems. Critical fields of application are Ethernet networks in substation automation (SA). The standard IEC 61850 deals with these types of industrial networks. It defines that a network as a whole has to ensure the transmission delay less than 3 ms for GOOSE (Generic Object Oriented Substation Event) type messages. GOOSE messages contain information about incidents, as described in the IEC 61850-8-1 [1] or can carry sampled values from the IEC 61850-9-2 [2]. General requirements for the transmission delay of different traff[...]

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