15,212 research outputs found
BurstProbe: Debugging Time-Critical Data Delivery in Wireless Sensor Networks
In this paper we present BurstProbe, a new technique to accurately measure link burstiness in a wireless sensor network employed for time-critical data delivery. Measurement relies on shared probing slots that are embedded in the transmission schedule and used by nodes to assess link burstiness over time. The acquired link burstiness information can be stored in the node's flash memory and relied upon to diagnose transmission problems when missed deadlines occur. Thus, accurate diagnosis is achieved in a distributed manner and without the overhead of transmitting rich measurement data to a central collection point. For the purpose of evaluation we have implemented BurstProbe in the GinMAC WSN protocol and we are able to demonstrate it is an accurate tool to debug time-critical data delivery. In addition, we analyze the cost of implementingBurstProbe and investigate its effectiveness
Experiments Validating the Effectiveness of Multi-point Wireless Energy Transmission with Carrier Shift Diversity
This paper presents a method to seamlessly extend the coverage of energy
supply field for wireless sensor networks in order to free sensors from wires
and batteries, where the multi-point scheme is employed to overcome path-loss
attenuation, while the carrier shift diversity is introduced to mitigate the
effect of interference between multiple wave sources. As we focus on the energy
transmission part, sensor or communication schemes are out of scope of this
paper. To verify the effectiveness of the proposed wireless energy
transmission, this paper conducts indoor experiments in which we compare the
power distribution and the coverage performance of different energy
transmission schemes including conventional single-point, simple multi-point
and our proposed multi-point scheme. To easily observe the effect of the
standing-wave caused by multipath and interference between multiple wave
sources, 3D measurements are performed in an empty room. The results of our
experiments together with those of a simulation that assumes a similar antenna
setting in free space environment show that the coverage of single-point and
multi-point wireless energy transmission without carrier shift diversity are
limited by path-loss, standing-wave created by multipath and interference
between multiple wave sources. On the other hand, the proposed scheme can
overcome power attenuation due to the path-loss as well as the effect of
standing-wave created by multipath and interference between multiple wave
sources.Comment: This paper is submitted to IEICE IEICE Transactions on
Communications.
RFID Localisation For Internet Of Things Smart Homes: A Survey
The Internet of Things (IoT) enables numerous business opportunities in
fields as diverse as e-health, smart cities, smart homes, among many others.
The IoT incorporates multiple long-range, short-range, and personal area
wireless networks and technologies into the designs of IoT applications.
Localisation in indoor positioning systems plays an important role in the IoT.
Location Based IoT applications range from tracking objects and people in
real-time, assets management, agriculture, assisted monitoring technologies for
healthcare, and smart homes, to name a few. Radio Frequency based systems for
indoor positioning such as Radio Frequency Identification (RFID) is a key
enabler technology for the IoT due to its costeffective, high readability
rates, automatic identification and, importantly, its energy efficiency
characteristic. This paper reviews the state-of-the-art RFID technologies in
IoT Smart Homes applications. It presents several comparable studies of RFID
based projects in smart homes and discusses the applications, techniques,
algorithms, and challenges of adopting RFID technologies in IoT smart home
systems.Comment: 18 pages, 2 figures, 3 table
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