This conference paper presents the mid-term results of the two EUREKA projects “testEPS” and “Central System”. TestEPS addresses the certification of autonomous driving systems, while Central System focuses on infrastructure solutions for a connected vehicle system. Both integrate the same four technological fields: simulation and virtual testing, realworld testing, HD mapping, and communication, to realize their vision and to achieve their individual goals. The paper presents application use cases for each field as utilized in the respective project. Furthermore, the importance of collaboration between these two projects and respective technologies in advancing the state-of-the-art in autonomous and connected vehicle technologies is highlighted.

Wireless sensor networks are increasingly used for improving the operation of industrial machines and facilities. Such complex and distributed networks are composed of embedded devices. These devices are typically powered by batteries or energy harvesting, and can thus be classified as energy constrained devices. Especially, the embedded devices powered by energy harvesting rely on sufficient harvestable energy. The correct operation of the whole network may depend on the correct operation of a single device. Thus, relevant energy harvesting scenarios must be ideally covered by functional tests of such networks. To be able to emulate different energy harvesting scenarios in combination with the distributed character of such networks, we have developed a distributed testbed based on the robot operating system (ROS). This paper presents the architecture and describes relevant testing aspects for such devices. Furthermore, it introduces a use case for testing wireless sensor nodes supplied by energy harvesting and presents exemplary testing procedure results. Finally, it discusses the advantages of incorporating such testing procedures into a continuous integration process to verify the correct functionality of the embedded devices during development.

Wireless embedded devices are key elements of Internet-of-Things (IoT) and industrial IoT (IIoT) applications. The complexity of these devices as well as the number of connected devices to networks increase steadily. The high intricacy of the overall system makes it error-prone and vulnerable to attacks and leads to the need to test individual parts or even the whole system. Therefore, this paper presents the concept of a flexible and distributed testbed to evaluate correct behavior in various operation or attack scenarios. It is based on the Robot Operating System (ROS) as communication framework to ensure modularity and expandability. The testbed integrates RF-jamming and measurement devices to evaluate remote attack scenarios and interference issues. An energy harvesting emulation cell is used to evaluate different real-world energy harvesting scenarios. A climatic test chamber allows to investigate the influence of temperature and humidity conditions on the system-under-test. As a testbed application scenario, the automated evaluation of an energy harvesting wireless sensor network designed to instrument automotive engine test benches is presented.

In this work, the components that contribute to the effective end-to-end latency of unconfirmed LoRaWAN class A data transmission are identified and measurements of two typical real-world LoRaWAN scenarios with different types of backhaul connection to the network and application server, namely localhost and an intermediate UMTS cellular network are presented. The paper introduces the instrumentation for the analysis of end-to-end latency seen by the end-user application. For two specific network scenarios performance evaluations with regard to latency using different parametrization of spreading factor and payload size are carried out. The analysis shows that LoRaWAN may be applicable for selected Industrial IoT use cases where lower Spreading Factors (SF) are adequate, resulting in an achievable end-to-end delay of below 400 ms. For long distance transmission up to 15km requiring a high SF, the end-to-end latency is well above one second and far beyond real-time availability of sensor data.

A modular and scalable testbed for synchronized network-wide power consumption evaluation and analysis of synchronization and latency performance within industrial wireless sensor and actuator networks (IWSAN) is presented in this paper. Using a dedicated measurement hardware the highly dynamic power consumption of wireless embedded systems can be tracked over 5 decades from μW in low power sleep modes up to several hundreds of mW during RF transmission and full processor activity. Further, as IWSANs have high demands on synchronicity and low latency, our testbed allows automated measurements to evaluate synchronization accuracy and latency within the network with a time granularity of 125 ns and thus meets most industrial requirements. For this we use an Industrial RealTime Ethernet (RTE) network. Our combination of distributed ethernet-connected power measurement circuits with the RTE system allows a network-wide synchronized acquisition of the sensor nodes power consumption and supply voltage waveforms of all observed nodes. The wired RTE and Ethernet networks guarantee a scalable measurement setup and are not in conflict with the wireless devices under test. We demonstrate the usability of the proposed measurement setup by means of investigating two different heterogenous setups of real-world wireless networks. First we analyze the timing behavior of distributed standardized ZigBee nodes exclusively based on their power consumption measurements. And in contrary we present a proprietary industrial WSN dedicated to low power consumption and high sampling synchronicity of the individual nodes and evaluate their synchronization performance.

This work demonstrates a complete setup of a distributed LoRaWAN-based data-acquisition system where individual LoRa end-devices can be supervised by a remote debugging environment. We present the whole chain of data processing from an embedded Indoor Air Quality (IAQ) monitoring sensor in the field up to the data-storage and visualization for human end-users connected over the cloud. In particular, we focus on the development-process of the low-power sensor node itself, which plays a key role in every IoT scenario. The sensor node's hardware is realized with a low-cost resource-constrained microcontroller unit (MCU) which executes the sensor-application as well as the embedded LoRaWAN stack. We demonstrate the possibility of remote incircuit-debugging of the embedded wireless node's firmware during operation in the field. Together with the possibility to analyze the power consumption and the radio-frequency spectrum of the wireless node as well as undesired RF interferer the ability to remotely update and debug the MCU's firmware allows to optimize the sensor node for the specific usage scenario and the place of its final operation.

From wearables to smart appliances, the Internet of Things (IoT) is developing at a rapid pace. The challenge is to find the best fitting solution within a range of different technologies that all may be appropriate at the first sight to realize a specific embedded device. A single tool for measuring power consumption of various wireless technologies and low power modes helps to optimize the development process of modern IoT systems. In this paper, we present an accurate but still cost-effective measurement solution for tracking the highly dynamic power consumption of wireless embedded systems. We extended the conventional measurement of a single shunt resistor's voltage drop by using a dual shunt resistor stage with an automatic switch-over between two stages, which leads to a large dynamic measurement range from μA up to several hundreds mA. To demonstrate the usability of our simple-to-use power measurement system different use cases are presented. Using two independent current measurement channels allows to evaluate the timing relation of proprietary RF communication. Furthermore a forecast is given on the expected battery lifetime of a Wifi-based data acquisition system using measurement results of the presented tool.

From wearables to smart appliances in industrial areas, intelligent measurement techniques must be combined with smart communication technology. Many application areas require embedded, low-cost and cable-less sensor systems to perform distributed and real-time data acquisition or long-time maintenance-free standalone operation. Power consumption is a major concern since these systems are often operated by batteries or harvested energy. Beside the used sensor elements, the circuits supply voltage, the processing frequency of the microcontroller unit (MCU) and the wireless technology, the underlying software concept mainly determine the current consumption. In this paper, we present a simple-to-use measurement tool for tracking the highly dynamic power consumption of various wireless technologies used in embedded sensor systems. We extended the conventional measurement of a single shunt resistor's voltage drop by using a dual shunt resistor stage with an automatic switch-over between two stages, which leads to a large dynamic measurement range required for investigation of A-sleep modes up to high current peaks with several hundreds mA. Together with automated variation of operating conditions and MCU software parameters the development process of modern sensor systems can be optimized. To demonstrate the usability of the proposed development cycle measurement results of the analysis of a Wifi-based embedded data acquisition system are presented.

Deciding which communication technology is optimal for a given wireless sensor network (WSN) application depends on many factors and is not always unambiguous. Only a comparison when deploying the network in the target environment with real hardware can assure that the system behaves as expected. Both hard- and software design can benefit when a suitable testbed infrastructure specific for embedded wireless networks is used during the development phase. In this demo, we present a testbed infrastructure for embedded low-power wireless networks and the possible analysis of the node's power consumption and the network's behavior. The testbed is made up of a scalable setup of an Ethernet-based backbone of cost-effective distributed Linux Boards for basic remote programming, debugging and monitoring tasks as well as a dedicated high-performance power measurement system able to track the dynamic current consumption of sleeping ultra-low power sensor nodes in the μA-range up to several hundreds of mA of embedded Wifi-modules for high bandwidth applications.

In this paper, we discuss the upcoming network stack LoRaWAN and its underlying modulation technology LoRa, which is an implementation of a LPWAN (Low Power Wide Area Network) and consider practical limitations that can occur when restricted Machine-to-Machine (M2M) data agreements for the connection of LoRa gateways to a cellular network are involved. We provide a theoretical estimate of the maximum possible communication range of a LoRa link depending on output power and spreading factor and illustrate a LoRa-transceiver's contrary behaviour of energy consumption and range versus the achievable data rate by means of current consumption and RF output power measurement results for different combinations of modulation parameters. Our analysis of the data overhead introduced by LoRa gateways identifies that the amount of generated backhaul network traffic can cause substantial costs for IoT service providers in case of cellular-connected gateways or limit the number of supported sensor nodes.

At least since the terms Internet of Things, Factories of the Future or Industrial Internet gave distinction to the modern world of communication, there is a special need for efficient test- and debug tools targeting research and development of embedded wireless sensor and actuator networks (WSAN) in industrial automation technology and other non-consumer application areas in adverse environments. Those networks usually have tighter requirements on dependability, synchronization, and real-time capability as compared applications in environmental monitoring or home automation. For WSAN research and development, testbeds are a valuable tool as they enable controlled and repeatable operation under conditions close to reality. The contribution of this Ph.D. dissertation is to design, implement and set up a test environment for embedded industrial wireless sensor actuator networks, with special focus on energy constrained network nodes. This testbed should offer an previously unattained level of insight in timing characteristics of the network and the energy behavior of a single node. It allows to make statements about limitations of the deployed WSAN technology, or to compare different WSAN solutions in an automated manner. The uniqueness of this testbed setup is due to a scalable, affordable and maintainable organization both in software as well as the structure of the used hardware components.

The idea of Internet of Things has grown into multiple dimensions, encompassing also the industrial world leading to initiatives like Factories of the Future (FoF) or Industrial Internet. Wireless Sensor and Actuator Networks (WSAN) play an important role in this professional domain. Their successful deployment in real-world applications calls for advanced testing and debugging effort in advance. This poster presents the architecture of TWECIS, a Testbed targeting the investigation of Wireless Energy Constrained Industrial Sensor and Actuator Networks. The proposed architecture tries to unite scalability, maintainability and a cost-saving design of the testbed infrastructure with the special requirements of research in industrial wireless network design.

The idea of Internet of Things has grown into multiple dimensions, encompassing also the industrial world leading to initiatives like Factories of the Future (FoF) or Industrial Internet. Wireless Sensor and Actuator Networks (WSAN) play an important role in this professional domain. Their successful deployment in real-world applications calls for advanced testing and debugging effort in advance. This poster presents the architecture of TWECIS, a Testbed targeting the investigation of Wireless Energy Constrained Industrial Sensor and Actuator Networks. The proposed architecture tries to unite scalability, maintainability and a cost-saving design of the testbed infrastructure with the special requirements of research in industrial wireless network design.

Wireless sensor networks (WSNs) are typically used to measure physical quantities of their environment at locations characterized by poor accessibility and lacking of wired infrastructure. To extend the operational time, energy harvesting systems (EHSs) support the power supply by transforming environmental energy into electrical energy. In the best case, a self-sufficient supply of the sensor node is possible. Information about the harvestable energy is necessary to design WSNs and EHSs properly. However, detailed information is often not available and special equipment is necessary to measure it. Therefore, this paper presents a simple method to estimate and track the harvestable power. The results can be used offline for design and simulations of nodes or networks, or online for work-load-distribution or energy aware network routing.

In this paper, we present a highly accurate but still cost-effective measurement solution for tracking the highly dynamic power consumption of wireless embedded systems. We extended the conventional measurement of a single shunt resistor's voltage drop by using a dual shunt resistor stage with an automatic switch-over between both stages, which leads to a large dynamic measurement range of 50 dB (1μA to 100 mA) with an average measurement error smaller than 1.2 %. Using two zero-drift current sense amplifiers for measuring the voltage drop over two different sized shunt resistors together with a 16 bit SAR ADC for each of both amplifiers leads to a far better thermal noise behaviour and a higher total measurement resolution compared to a single shunt solution, providing a minimum invasive measurement system with a maximum voltage drop of 100 mV. Using a state-of-the-art Ethernet connection allows our measurement system to forward the power samples with up to 250 kHz sampling rate to any remote networked computer.

Many applications in factory and process automation require robust wireless sensor networks (WSNs) for collecting sensor data with sampling and transmission rates up to 100 Hz from battery powered sensor nodes. To establish real-time communication in a star network topology, the LLDN mode of IEEE 802.15.4e amendment was released. We present a demonstration system which applies a recently introduced relaying method compatible to the LLDN mode, which uses dedicated relay nodes, thus increasing the reliability of the network while reducing the energy consumption of the sensor nodes. Furthermore, packet combining schemes on packets received erroneously from both, sensor node and relay node, are proposed, applied, and analyzed. Measurements with the demonstration system have shown that 96. 4% of these erroneous transmissions could be recovered correctly.

Wireless sensor and actuator networks (WSAN) for industrial applications usually have tighter requirements on dependability, synchronization, and real-time capability as compared applications in environmental monitoring or health care. For WSAN research and development, testbeds are a valuable tool as they enable controlled operation under conditions close to reality. In this contribution we present TWECIS, a testbed targeting the investigation of Wireless Energy Constrained Industrial Sensor and Actuator networks. We describe the concept, its architecture and the used hardware. Unique feature of TWECIS is the use of an industrial Real Time Ethernet system which offers the evaluation of the timing behavior of the nodes with a jitter below 100 ns. In addition TWECIS offers synchronized network-wide current measurements on all testbed nodes in a range from 1 μA to 100 mA for accurate power consumption profiling, remote and parallelized programming of nodes, remote in-circuit debugging, monitoring of UART output, and centralized storage of all captured data.

In industrial applications of wireless sensor networks (WSNs), synchronized sampling of data on each sensor node is often required. Thus, the wireless communication protocol needs to support accurate timing synchronization. If due to a high sampling rate also high data throughput is required, WSNs based on the IEEE 802.15.4 physical layer often do not provide sufficient data rate. Wireless communications based on the well-established IEEE 802.11 wireless local area network (WLAN) standard provides high data throughput but not an accurate timing synchronization unless the protocol stack is severely changed. We propose two low-complexity consensus-based synchronization algorithms for the hybrid WSN introduced, which are executable at limited embedded computing capacity, e.g., on an 8 bit microcontroller. A time division multiple access-based synchronization packet broadcasting with three-step-controlled or proportional-integral (PI)-controlled clock adjustment enables 1 kHz sensor sampling rate with a sampling jitter <;15 μs for the three-step-controlled synchronization algorithm and <;1 μs for the PI-controlled algorithm.

In industrial applications of wireless sensor networks (WSNs) synchronized sampling of data on each sensor node is often required. Thus the wireless communication protocol needs to support accurate timing synchronization. If due to a high sampling rate also high data throughput is required, WSNs based on the IEEE 802.15.4 physical layer often do not provide sufficient data rate. Wireless communication based on the well established IEEE 802.11 (WLAN) standard provides high data throughput but not an accurate timing synchronization unless the protocol stack is severely changed. We propose a hybrid WSN which uses WLAN for high rate data transmission combined with a proprietary wireless communication system operating on Sub-GHz short range devices for synchronization. A consensus-based synchronization algorithm is used to be independent from the number of WSN nodes and node failure. The proposed hybrid WSN performs a two-step synchronization algorithm which can easily be executed on an 8-bit microcontroller and achieves a sampling jitter smaller than 50 μs.