Abstracts / 2010
Systemarchitektur intelligenter Sensorimplante
BMT 2010, 44. DGBMT Jahrestagung, Rostock, Oktober 2010
Kurzinfo: Intelligent implants are increasingly in focus of today’s researches. They are small devices with low power consumption. The size of the system is important for the acceptance by the patient and for an easy implantation. The low power consumption is important for the lifetime of the system. This paper presents system architecture for such an implant. It is developed, using discrete components.
ILA: Idle Listening Avoidance in Scheduled Wireless Sensor Networks
Proc. 8th International Conference on Wired / Wireless Internet Communications, (WWIC 2010), Berlin, Springer, LNCS 6074, 363 (2010)
Kurzinfo: There are applications that require a lifetime of several years from a sensor network and simultaneously need a guaranteed end-to-end delay. Obviously, these two parameters - lifetime and delay - contradict each other. In this work we present and evaluate a solution - Idle Listening Avoidance (ILA) - that copes with idle listening stemming from the delay between detecting that no message is transmitted and switching off the transceiver. ILA reduces idle listening from 50 to even more than 100 times, depending on the guaranteed end-to-end delays. As a result, it prolongs the lifetime by more than 50%. Moreover, the ideal solution, which requires a dedicated hardware, prolongs the lifetime by only 0.3% more than ILA, which can be applied on off-the-shelf sensor nodes.
Limiting End-to-End Delays in Long-Lasting Sensor Networks
8th ACM International Symposium on Mobility Management and Wireless Access (MobiWac 2010), Bodrum, October 17 - 21, 2010, Turkey
Kurzinfo: Many applications require a lifetime of several years from a sensor network while expecting low and guaranteed end-toend delays between sources and a sink. Obviously, these two parameters - lifetime and delay - contradict each other. In this work we present and evaluate a solution that limits the end-to-end delays and nevertheless achieves a long lifetime. We introduce a model for evaluation of delay and lifetime in multi-hop sensor networks. According to our model a network of off-the-shelf sensor nodes limits an end-to-end delay to 5 seconds and works for 8 months. However, if applications can tolerate the end-to-end delay of 20 seconds, the nodes prolong the lifetime to approx. 2 years. Our evaluation revealed that end-to-end delay affects the lifetime only to a certain limit. In our example this limit was 60 seconds, i.e. any delay change above 60 seconds does not influence the lifetime considerably.
On Efficient Clock Drift Prediction Means and Their Applicability to IEEE 802.15.4
Proc. 8th IEEE / IFIP International Conference on Embedded and Ubiquitous Computing (EUC-10)
Kurzinfo: Many applications require a lifetime of several years from a sensor network while expecting low and guaranteed end-toend delays between sources and a sink. Obviously, these two parameters - lifetime and delay - contradict each other. In this work we present and evaluate a solution that limits the end-to-end delays and nevertheless achieves a long lifetime. We introduce a model for evaluation of delay and lifetime in multi-hop sensor networks. According to our model a network of off-the-shelf sensor nodes limits an end-to-end delay to 5 seconds and works for 8 months. However, if applications can tolerate the end-to-end delay of 20 seconds, the nodes prolong the lifetime to approx. 2 years. Our evaluation revealed that end-to-end delay affects the lifetime only to a certain limit. In our example this limit was 60 seconds, i.e. any delay change above 60 seconds does not influence the lifetime considerably.
Evaluation and Optimisation of Robustness in the IEEE.802.15.4a Standard
ICUWB 2010, Sep. 2010, Nanjing China
Kurzinfo: In this paper, we introduce ways to improve robust transmissions using ultra-wideband impulse radio (UWB-IR) based on the standard IEEE 802.15.4a. These improvements target low-power, low-complexity transceivers used in environments with harsh multi path propagation and high noise levels, such as industrial control. These improvements include novel ways in receiver implementation to increase reception rates for low-power energy detection receivers that use slow sampling rates. We also introduce a modified preamble that significantly reduces packet loss caused by failed preamble synchronizations We evaluate our improvements by simulation and are able to reduce packet loss rates due to failed preamble synchronizations from 60% to nearly 0%. Our contributions to receiver implementation enable the receiver to achieve the same packet loss rate at a signal-to-noise ratio (SNR) 10 dB lower than traditional receiver designs.
Efficient synchronization method for IR-UWB 802.15.4a non-coherent energy detection receiver
IOTS 2010 - The 1st IEEE/ACM Internet of Things Symposium Hangzhou, PR China, December 18-20, 2010
Kurzinfo: Using UWB for wireless short range, low rate communication is attracting growing interest due to its low power consumption and very high bandwidth. Moreover, it is able to offer accurate localization in the range of few centimeters. Regarding these qualities, it is desirable to design an IR-UWB transceiver which consumes as little power as possible when it is applied for battery driven wireless sensors. For this reason a baseband design and performance of IR-UWB receiver based on the standard IEEE.802.15.4a was investigated in this paper with particular emphasis on energy efficient synchronization and preamble detection.
Automatic Gain Controlling in IR-UWB Communications Designed for Wireless Sensors
2010 IEEE International Conference on Ultra-Wideband (ICUWB 2010), Nanjing, September 20 - 23, 2010, PR China
Kurzinfo: Impulse Radio Ultra-Wideband (IR-UWB) communication system according to the standard IEEE.802.15.4a supporting non-coherent reception is discussed with the focus on the automatic gain controller (AGC). The performance of the transceiver is evaluated under noisy and common multipath channel environments. Simulation results confirm that a simple non-coherent, low power IR-UWB receiver can achieve the sensitivity of -70 dBm using a 6 bit analogue to digital converter with a sampling frequency of 62.4 MHz. It presents the maximum achievable performance from the system considered where integrating circuit and slower analogue to digital converter are contained. The sensitivity of the receiver can be further improved by using a higher resolution ADC where -100 dBm is still detected with the 12 bit ADC. The main components of the transceiver are explained with their functions.
Low Power Sensor Node Architecture
The17th IEEE International Conference on Electronics, Circuits, and Systems, ICECS 2010, 12th-15th December 2010, Athens, Greece
Kurzinfo: This paper presents a low power solution for sensor node processor architecture, where an asynchronous processor has been integrated with a number of peripherals in a quite unique fashion. The paper describes the most important architectural and design issues and presents the implementation results.
Adaptable Security in Wireless Sensor Networks by Using Reconfigurable ECC Hardware Coprocessors
29. September 2010: International Journal of Distributed Sensor Networks, Vol. 2010
Kurzinfo: Specific features of Wireless Sensor Networks (WSNs) like the open accessibility to nodes, or the easy observability of radio communications, lead to severe security challenges. The application of traditional security schemes on sensor nodes is limited due to the restricted computation capability, low-power availability, and the inherent low data rate. In order to avoid dependencies on a compromised level of security, a WSN node with a microcontroller and a Field Programmable Gate Array (FPGA) is used along this work to implement a state-of-the art solution based on ECC (Elliptic Curve Cryptography). In this paper it is described how the reconfiguration possibilities of the system can be used to adapt ECC parameters in order to increase or reduce the security level depending on the application scenario or the energy budget. Two setups have been created to compare the softwareand hardware-supported approaches. According to the results, the FPGA-based ECC implementation requires three orders of magnitude less energy, compared with a low power microcontroller implementation, even considering the power consumption overhead introduced by the hardware reconfiguration.