Thomas Herndl

A 2.4µW Wake-up Receiver for wireless sensor nodes with −71dBm sensitivity

This paper presents a complete ultra-low power receiver with direct down conversion architecture. It is designed as Wake-up Receiver for wireless sensor nodes. The 130nm CMOS chip includes envelope detector, low noise baseband amplifier, PGA, mixed-signal correlation unit and auxiliaries for stand-alone operation. At 868MHz, a receiver sensitivity of −71dBm is achieved with total power consumption of 2.4µW at 1.0V supply by means of baseband correlation over 7ms with 64 bit pattern, 99% detection probability and a false wake-up rate of 10−3/s.

A Bulk Acoustic Wave (BAW) Based Transceiver for an In-Tire-Pressure Monitoring Sensor Node

Attaching a tire pressure monitoring system (TPMS) on the inner liner of a tire allows sensing of important additional technical parameters, such as vehicle load or tire wearout. The maximum weight of the sensor is limited to 5 grams including package, power supply, and antenna. Robustness is required against extreme levels of acceleration. The node size is limited to about 1 cm3 to avoid high force-gradients due to device-deformation and finally, a long power supply lifetime must be achieved. In this paper a low-power FSK transceiver is presented. Exploiting BAW resonators the use of a bulky and shock-sensitive crystal and a PLL can be avoided. This makes the system more robust and radically reduces the start-up time to 2 ¿s from few ms as in state-of-the-art crystal oscillator based systems. The current consumption of the transceiver is 6 mA in transmit mode with a transmit output power of 1 dBm and 8 mA in receive mode with a sensitivity of -90 dBm at a data rate of 50 kBit/s and a bit error rate of 10-2. The transceiver ASIC and a microcontroller ASIC, a MEMS sensor, and a BAW die are arranged in a 3-D chip stack for best compactness, lowest volume, and highest robustness. The sensor node allows sensing of pressure, acceleration, supply voltage and temperature.

A robust wireless sensor node for in-tire-pressure monitoring

State-of-the-art tire pressure monitoring systems (TPMS) are wireless sensor nodes mounted on the rim. Attaching the node on the inner liner of a tire allows sensing of additional technical parameters, such as road condition, tire wearout, temperature, tire friction, side slip, wheel speed, and vehicle load. They may be used for improved tracking and engine control, feedback to the power train and car-to-car communication purposes.

Pawis: Towards a Power Aware System Architecture for a SoC/SiP Wireless Sensor and Actor Node Implementation

The goal of the PAWiS project is to develop both, efficient system architectures and the related design methodology for power aware wireless sensor and actor network nodes that allow for capturing inefficiencies in every aspect of the system. These aspects include all layers of the communication system, the targeted class of the application itself, the power supply and energy management, the digital processing unit and the sensor-actor interface. The proof of concept will be based on a prototype system that allows a future integration in a single SiP/SoC. The project is supported by Infineon Austria and started only recently, therefore the main focus of this paper is on the design approach. Copyright

Time-of-Flight 3D imaging for mixed-critical systems

Computer vision is becoming more and more important in the fields of consumer electronics, cyber-physical systems, and automotive technology. Recognizing and classifying ones environment reliably is imperative for safety-critical applications, as they are omnipresent, e.g., in the automotive or aviation domain. For this purpose, the Time-of-Flight imaging technology is suitable, which enables robust and cost-efficient three-dimensional sensing of the environment. However, the resource limitations of safety- and security-certified processor systems as well as complying to safety standards, poses a challenge for the development and integration of complex Time-of-Flight-based applications. Here we present a Time-of-Flight system approach that focuses in particular on the automotive domain. This Time-of-Flight imaging approach is based on an automotive processing platform that complies to safety and security standards. By employing state-of-the-art hardware/software and multi-core concepts, a robust Time-of-Flight system solution is introduced that can be used in a mixed-critical application context. In this work we demonstrate the feasible implementation of the proposed hardware/software architecture by means of a prototype for the automotive domain. Raw Time-of-Flight sensor data is taken and 3D data is calculated with up to 80 FPS without the usage of dedicated hardware accelerators. In a next step, safety-critical automotive applications (e.g., parking assistance) can exploit this 3D data in a mixed-critical environment respecting the needs of the ISO 26262.

A power management unit for ultra-low power wireless sensor networks

Wireless sensor networks become more and more attractive due to their ongoing miniaturization and decreasing costs. One of the major challenges concerning the design is the power consumption of the wireless sensor node. Low power consumption is mandatory to guarantee a long lifetime if a battery is used as a power source or to allow the use of an energy harvester. In this work a multi-stage power management for a wireless sensor node is presented. Energy-efficient power management is achieved by employing several state machines controlling different power domains which can be turned on and off separately depending on the operating mode of the wireless sensor node. A test chip has been produced in an Infineon 130nm CMOS process. The presented wireless sensor node consumes 240 nA in power down mode, most of which is leakage current. In different deep-sleep modes it consumes between 750 nA and 1.5 µA.

Real-time wireless communication in automotive applications

Wireless communication in a car has several advantages, given that demanded safety and real-time requirements are fulfilled. This paper presents a wireless MAC protocol designed for the needs of automotive and industrial applications. The proposed MAC protocol provides special support for network traffic prioritization in order to guarantee worst-case message delays for a set of high-prioritized nodes. The performance is further analyzed with a network simulator and compared with the IEEE 802.15.4 standard CSMA/CA protocol.

A bulk acoustic wave(BAW)-based sensor node for automotive wireless sensor networks

SummaryThe following paper presents a 2.1 GHz transceiver, which makes use of BAW resonators to replace the external quartz crystal and the external band select filter. It has been fabricated in a 130 nm CMOS process and has a power consumption of 5 mA. To derive the specifications for the transceiver the requirements of a TPMS have been taken into consideration.ZusammenfassungDer folgende Artikel stellt einen 2,1-GHz-Transceiver vor, der anstelle einer externen Quarzreferenz und eines externen Hochfrequenzfilters BAW-Resonatoren einsetzt. Der Chip wurde in einem 130-nm-CMOS-Prozess gefertigt und hat einen Stromverbrauch von 5 mA. Um die Spezifikationen abzuleiten, wurden die Anforderungen an ein TPMS (Reifendrucküberwachungssystem) betrachtet.

High performance Time-of-Flight and color sensor fusion with image-guided depth super resolution

In recent years, depth sensing systems have gained popularity and have begun to appear on the consumer market. Of these systems, PMD-based Time-of-Flight cameras are the smallest available and will soon be integrated into mobile devices such as smart phones and tablets. Like all other available depth sensing systems, PMD-based Time-of-Flight cameras do not produce perfect depth data. Because of the sensors characteristics, the data is noisy and the resolution is limited. Fast movements cause motion artifacts, which are undefined depth values due to corrupted measurements. Combining the data of a Time-of-Flight and a color camera can compensate these flaws and vastly improve depth image quality.This work uses color edge information as a guide so the depth image is upscaled with resolution gain and lossless noise reduction. A novel depth upscaling method is introduced, combining the creation of high quality depth data with fast execution. A high end smart phone development board, a color, and a Time-of-Flight camera are used to create a sensor fusion prototype. The complete processing pipeline is efficiently implemented on the graphics processing unit in order to maximize performance. The prototype proves the feasibility of our proposed fusion method on mobile devices. The result is a system capable of fusing color and depth data at interactive frame rates. When there is depth information available for every color pixel, new possibilities in computer vision, augmented reality and computational photography arise. The evaluation shows, our sensor fusion solution provides depth images with upscaled resolution, increased sharpness, less noise, less motion artifacts, and achieves high frame rates at the same time; thus significantly outperforms state-of-the-art solutions. Index Terms-Time-of-Flight, 3D sensing, sensor fusion, GPGPU, image processing.

A secure miniaturized wireless sensor node for a smart home demonstrator

Recently, the technology of wireless sensor networks (WSNs) experiences a growing use in home automation or advanced industry infrastructure applications. Despite a strong interest of industries in this technology, key issues like miniaturization and security of WSN nodes has not been solved yet. State-of-the-art WSN nodes do not provide credible security nor satisfying configurability and miniaturized implementations. This publication deals with these limitations and presents a WSN node that provides security, configurability, and a miniaturized design. To show the sensor node feasibility, the WSN node is implemented within a smart home demonstrator. Additionally, a miniaturized pre-study WSN node design is presented using the novel embedded wafer level ball grid array (eWLB) packaging technology. Furthermore, an eWLB based WSN node design is proposed that further miniaturize the presented WSN node.