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To widen the control over a factory from purely wire based to the wireless domain, both secure and reliable communication infrastructure with real-time capabilities is needed. Based on wireless communication technologies , such infrastructures may be used to gain new flexibility within any step of a manufacturing process hence enabling the development of(More)
One typical approach to provide industrial automation networks with real-time guarantees is to plan a communication timeframe, which relies on synchronized clocks at all communication participants. This paper investigates how to reach such a clock synchronization accuracy in a wireless LAN, where commercially available chipsets dictate the implementation(More)
—Clock synchronization is one of the enabling technologies for real-time networking. This paper is motivated by the need for WLAN support of real-time factory automation networks. These networks need synchronized clocks for the typical time-slotted arbitration schemes. As this type of service is not yet available wireless LANs, this work investigates(More)
In distributed systems, clock synchronization performance is hampered by delays and jitter accumulated not only in the network, but also in the timestamping procedures of the devices being synchronized. This is particularly critical in software timestamp-based synchronization where both software- and hardware-related sources contribute to this behavior.(More)
—Between the wired and the wireless world a synchronization gap in terms of accuracy obviously exists due to the different possibilities of the technologies. This paper investigates means to access WLAN functionality in order to gain system-wide synchronization between access points and clients in order to establish a common notion of time in IEEE 802.11(More)
The clock servo is an essential constituent of distributed clock synchronization systems and a determining factor for the synchronization performance. This paper focuses on the clock servo design for better accuracy and precision in software-based clock synchronization over WLAN. The behaviour of the clock servo is analysed in this work and errors arising(More)
The usage of WLANs (Wireless Local Area Networks) for both office and non office (e.g. factory automation) applications is one of today's upcoming trends. However the usage of WLAN suffers from the problem that nowadays one cannot determine the exact position of standard compliant wireless nodes. This paper presents an approach for location based services(More)