Stefan Mahlknecht

An Ultra Low Power Wakeup Receiver for Wireless Sensor Nodes

An ultra-low power 2.4 GHz RF Wakeup Receiver is designed for wireless sensor networks nodes. The receiver demodulates On-Off Keying at 100 kbps. A 120 nm CMOS chip includes the analog front-end and consumes only 7.5 mu W from a single 1.5 V supply. The digital signal processing is implemented in an FPGA. The results of measures and simulations are evaluated for the use of this receiver in wireless sensor networks.

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.

On Architecture of Low Power Wireless Sensor Networks for Container Tracking and Monitoring Applications

Almost 90% of the world trade is accomplished with the help of containers using different means of transportation including ships and trains. The container trade faces a lot of challenges comprising of container tracking, real time monitoring and intrusion detection, real time theft reporting mechanism, and status reporting of shipment items. While in principle the above functionality can be provided by state of the art industrial monitoring systems, it does not provide the advantages in flexibility and cost of wireless sensor networks (WSNs). In combination with GSM and GPS/Galileo technologies, WSNs can result in a system capable of tracking and monitoring of containers in the real time. This paper discusses the problems faced by the container industry, how a wireless sensor network can help solving these problems, and the challenges ahead.

Throwing Objects -- A bio-inspired Approach for the Transportation of Parts

In this paper a new way of transporting parts in production systems is described. Based on the fact that in nature the highest speeds are reached at flight, a bio-inspired technical approach for the fast transportation of objects is derived. Objects shall be thrown by a throwing device and are caught again by a catching device. Such a transport approach requires besides proper working throwing and catching devices a high precision object detection mechanism. For object detection a 3D photonic mixer device (PMD) sensor is proposed. By assembling of this sensor on the catching device, it can detect the flying objects on their trajectories like a raptor which is hunting a prey. The technical feasibility of this concept is investigated and possible applications are described.

Energy Aware Distance Vector Routing Scheme for Data Centric Low Power Wireless Sensor Networks

This paper presents energy aware distance vector routing (EADV) protocol for ultra low power wireless sensor networks. EADV is based on a simple algorithmic approach to cater for low memory space and low energy available on sensor nodes. EADV assumes a data sink having unrestricted energy. It is inspired from a set of routing protocols including AODV, DSDV, and energy aware routing. The protocol consumes about 128 bytes of RAM. The beauty of EADV is in its computational and implementation simplicity and it keeps network lifetime as primary design parameter.

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

A partially decentralised forecast-based demand-side-management approach

This paper presents a demand-side management approach for private homes and small businesses based on wireless sensor/actor nodes controlling appliances, taking into account available local renewable energy resources like wind energy and photovoltaics. An approach for forecasting energy production by a local wind turbine is presented. Forecasts for such local renewable energy producers are preprocessed by a central energy management unit which generates abstract cost functions. The final decision making is then shifted to the sensor/actor nodes, and is based on these cost functions as well as the class of the appliance which is controlled. To this end, electrical appliances are classified appropriately.

WUR-MAC: Energy efficient Wakeup Receiver based MAC Protocol

Abstract This paper discusses WUR-MAC, a medium-access control (MAC) protocol suited for wireless nodes equipped with a Wakeup Receiver (WUR). Unlike other protocols, the WUR-MAC takes advantage of the WUR ultra-low power listening mode leaving it permanently active to wait for incoming requests. Due to the ultra low power nature of these radio receivers, energy consumption and latency can be optimized at the same time. Energy consumption of the combined physical and MAC layer of a WUR based design is compared to efficient schedule based low power MAC protocols using the same main underlying transceiver without a wakeup radio receiver. WUR-MAC is based on proven MAC concepts but avoids complicated algorithms that are needed to synchronize nodes in traditional WSNs. Simulation results show that with typically low traffic, the average power consumption of schedule-based MACs is significantly higher than by using WUR-MAC only in the case where very low power Wakeup Receivers (

Active single landmark based global localization of autonomous mobile robots

This paper presents landmark based global self-localization of autonomous mobile robots in a known but highly dynamic environment. The algorithm is based on range estimation to naturally occurring distinct features as it is not possible to modify the environment with special navigational aids. These features are sparse in our application domain and are frequently occluded by other robots. To enable the robot to estimate its absolute position with respect to a single landmark it is equipped with dead-reckoning sensors in addition to the stereo vision system mounted on a rotating head. The pivoted stereo vision system of the robot enables it to measure range and use bi/trilateration based methods as they require fewer landmarks compared to angle based triangulation. Further reduction of landmarks is achieved when robot orientation is estimated independently. Simulation results are presented which illustrate the performance of our algorithm.

Simple stereo vision system for real-time object recognition for an autonomous mobile robot

Intelligent sensors for mobile robots play an important role in many technical applications. In this paper, a real-time stereo object recognition system for a tiny mobile robot is presented, capable of detecting objects in real-time at a frame rate of up to 60frames/s. In order to get an all around view the stereo camera system is mounted on a pivoted head. We propose an object recognition algorithm that is optimized for the detection of well known objects on deeply embedded systems. The detection algorithm is based on a combination of edge and color detection and uses a fixed model for each object to be recognized. The stereo algorithm is a simple matching of two independently performed algorithms for each camera. Results of the ball recognition application show that its relative coordinates are found within <10ms