Mario Neugebauer

A new beacon order adaptation algorithm for IEEE 802.15.4 networks

The new IEEE 802.15.4 standard enables deployment of low-rate low-power personal area networks. It provides a mechanism for adaptation of the protocols duty cycle during runtime. In this paper we propose BOAA, a new algorithm for beacon order adaptation in IEEE 802.15.4 star-topology networks. By observing the communication frequency, the coordinator in such a network determines the required duty cycle and adapts the beacon interval accordingly. Investigations reveal that the algorithm enables power saving with a trade-off according to message delay

A traffic model for networked devices in the building automation

Traffic models play a decisive part in the performance evaluation and design of communications systems. However, the growing diversification of devices in large networks asks for automated generated traffic models. In this paper, we present a generic device model which is suited for automated generation in the domain of building automation. The traffic is deduced successive for common devices from measurements and simulations using classification of the devices by their traffic behaviour and automated parameterization of the device models

A new protocol for a low power sensor network

This paper proposes a simple protocol for low-power sensor networks with battery-operated sensing devices. The sensors are expected to become active only when certain events in the environment occur. Therefore, a scheme for the application and medium access cycles is developed which avoids common problems of energy loss due to idle actions. Subsequently, the protocol is evaluated according to sensor lifetime. In contrast to common performance analysis, the approach considers the application behavior as a main impact on the sensor lifetime. Capabilities to save energy are derived.

Duty cycle adaptation with respect to traffic

Energy is a scarce resource in wireless sensor networks. Usually, during the deployment phase an appropriate duty cycle has to be found to adjust the trade-off between energy consumption and transmission delay. In this paper an adaptation algorithm for the duty cycle adjustment during runtime of the sensor network is proposed. Thereby, the traffic originating from sensor nodes is monitored in the relay node. Subsequently, the relay node evaluates the traffic whether the duty cycle has to be changed. The algorithm is evaluated in static and dynamic scenarios. It reveals that it can adapt to changing traffic, depending on the parameterization of the adaptation. The proposed adaptation algorithm saves energy in applications with strong requirements according to energy consumption

Automated modeling and analysis of CSMA-type access schemes for building automation networks

During the design of large technical systems, the use of analytic and simulative models to test and dimension the system before implementation is of practical importance for an efficient and reliable design process. However, setting up the necessary models is time-consuming and therefore often too expensive in practice. Usually most information for modeling is already available in the design tool used to develop such extensive systems and only needs to be extracted for automatic model building. This paper presents an automated modeling approach from an existing design database using the example of a network analysis for building automation fieldbuses. The analysis is based on an analytical decomposition approach that enables fast estimation of performance measures for large-scale networks. The combination of fast analytical algorithms with automatic model generation allows network performance engineering with minimized effort for model generation and analysis.

EARLY DATA PROCESSING IN SMART ITEM ENVIRONMENTS USING MOBILE SERVICES

Abstract Smart Items are physical objects that are equipped with embedded computing units to enable close coupling of the real world to backend information systems. Such embedded computing units are called PEIDs (product embedded information devices). PEIDs can be RFID tags, sensor nodes, embedded PCs or similar devices. In this paper, we show how PEIDs can be used to support business decisions in the area of PLM (product lifecycle management) and discuss issues that arise from the restricted capabilities of devices and the large amounts of data to be handled. As current middleware systems are too inflexible to address these issues, we propose a new architecture based on mobile services. It effectively reduces the amounts of data to be transmitted by data processing close to the data source. Furthermore, it offers flexibility regarding to new data analysis requirements and heterogenous device capabilities.

Evaluation of Energy Costs for Single Hop vs. Multi Hop with Respect to Topology Parameters

Today, wireless technologies are increasingly deployed in industrial environments. Most available devices are plugged to a power source, but they achieve their real potential if they are used without any expensive cabling (e. g. for monitoring in remote locations). Furthermore, the question for an appropriate topology of the deployed network arises. Should the nodes directly transmit with higher power to the base station or instead use other nodes as relays, while transmitting at a lower power level? This can essentially impact the energy required for the data transmission. Especially if the wireless devices are battery driven, energy is a scarce resource in wireless sensor networks. In this paper the multi hop approach is compared to single hop according to energy consumption. Therefor, the network is parameterized with a local link rule in each sensor node, a global sensor density, the path loss and the size of the area with the deployed sensors. To model the radio wave propagation a varying path loss for the sensor connections is taken into account. Simulations reveal that only certain network and protocol configurations benefit from multi hop. Eventually, the results can be used to further parameterize the local link rule and to support the global selection of either multi hop or single hop in specific scenarios.

Automated modeling of LonWorks building automation networks

Developing building automation systems requires careful planning of the applications and the network topology. Editing a model with up to 32,000 nodes manually is very time-consuming. In this paper, an automated approach for modeling LonWorks networks is presented. As a basis the existing LNS network operating system which is suited for integration and management purposes is used. It contains all information implicitly. Therefore, certain data has to be extracted to generate an explicit model for performance evaluation. The approach requires no additional effort for the network developer to acquire a complete model of the LonWorks network. The model is used for accumulated arrival rate estimation and is a basis for later queuing analysis

Diagnosis and Consulting for Control Network Performance Engineering of CSMA-Based Networks

Network performance engineering can verify the design and dimensioning of large-scale control networks like CSMA-based building automation networks. It combines performance analysis with diagnosis methods to evaluate the network utilization and to detect design errors before installation and can therewith save the expenses of overdimensioning and redesign. This paper will develop a diagnosis model based on fault trees that is able to use the huge amount of performance analysis results to identify design errors and analyze their coherences. This enables not only a fast tracing back of fault causes and the derivation of solutions; it can also visualize the fault coherence to the user and help him to understand his design. Additional consulting tools implement best practice strategies, to support the user in parameterization.

Prediction of network load in building automation

Abstract The process of designing building automation networks is a very challenging task due to the inherent complexity. During the design process performance evaluation is essential for high reliability and cost efficiency. Therefore, no tool is available up to now, although in other fields of research sophisticated methods for analyzing the system performance exist. In this paper we introduce a method that comprehensively integrates the entire system to evaluate the performance fast and autonomous. By approximating the environment, automatically modelling the network components and analyzing the interrelations we achieve not only a specific load prediction, but also suggestions for optimization.