498 research outputs found
Energy Efficient and Reliable Wireless Sensor Networks - An Extension to IEEE 802.15.4e
Collecting sensor data in industrial environments from up to some tenth of
battery powered sensor nodes with sampling rates up to 100Hz requires energy
aware protocols, which avoid collisions and long listening phases. The IEEE
802.15.4 standard focuses on energy aware wireless sensor networks (WSNs) and
the Task Group 4e has published an amendment to fulfill up to 100 sensor value
transmissions per second per sensor node (Low Latency Deterministic Network
(LLDN) mode) to satisfy demands of factory automation. To improve the
reliability of the data collection in the star topology of the LLDN mode, we
propose a relay strategy, which can be performed within the LLDN schedule.
Furthermore we propose an extension of the star topology to collect data from
two-hop sensor nodes. The proposed Retransmission Mode enables power savings in
the sensor node of more than 33%, while reducing the packet loss by up to 50%.
To reach this performance, an optimum spatial distribution is necessary, which
is discussed in detail
Impact of using CSS PHY and RTS/CTS Combined with Frame Concatenation in the IEEE 802.15.4 Non-beacon Enabled Mode Performance
This paper studies the performance improvement of the IEEE 802.15.4 non-beacon-enabled mode originated by the inclusion of the Request-To-Send/Clear-To-Send (RTS/CTS) handshake mechanism resulting in frame concatenation. Under IEEE 802.15.4 employing RTS/CTS, the backoff procedure is not repeated for each data frame sent but only for each RTS/CTS set. The maximum throughput and minimum delay performance are mathematically derived for both the Chirp Spread Spectrum and Direct Sequence Spread Spectrum Physical layers for the 2.4 GHz band. Results show that the utilization of RTS/CTS significantly enhances the performance of IEEE 802.15.4 applied to healthcare in terms of bandwidth efficiency.This work was supported by FCT/MCTES through
national funds and when applicable co-funded EU funds
under the project UIDB/50008/2020, COST CA20120
INTERACT, FundaciĂłn Carolina and Grupo Tordesillas
short stay grant in UC3M, SNF Scientific Exchange -
AISpectrum (project 205842), ORCIP (22141-
01/SAICT/2016) and TeamUp5G. TeamUp5G project has
received funding from the European Union’s Horizon 2020
research and innovation programme under the Marie
Skłodowska-Curie project number 813391.info:eu-repo/semantics/acceptedVersio
An Enhanced Reservation-Based MAC Protocol for IEEE 802.15.4 Networks
The IEEE 802.15.4 Medium Access Control (MAC) protocol is an enabling standard for wireless sensor networks. In order to support applications requiring dedicated bandwidth or bounded delay, it provides a reservation-based scheme named Guaranteed Time Slot (GTS). However, the GTS scheme presents some drawbacks, such as inefficient bandwidth utilization and support to a maximum of only seven devices. This paper presents eLPRT (enhanced Low Power Real Time), a new reservation-based MAC protocol that introduces several performance enhancing features in comparison to the GTS scheme. This MAC protocol builds on top of LPRT (Low Power Real Time) and includes various mechanisms designed to increase data transmission reliability against channel errors, improve bandwidth utilization and increase the number of supported devices. A motion capture system based on inertial and magnetic sensors has been used to validate the protocol. The effectiveness of the performance enhancements introduced by each of the new features is demonstrated through the provision of both simulation and experimental results
IEEE 802.15.4e: a Survey
Several studies have highlighted that the IEEE 802.15.4 standard presents a number of limitations such as low reliability, unbounded packet delays and no protection against interference/fading, that prevent its adoption in applications with stringent requirements in terms of reliability and latency. Recently, the IEEE has released the 802.15.4e amendment that introduces a number of enhancements/modifications to the MAC layer of the original standard in order to overcome such limitations. In this paper we provide a clear and structured overview of all the new 802.15.4e mechanisms. After a general introduction to the 802.15.4e standard, we describe the details of the main 802.15.4e MAC behavior modes, namely Time Slotted Channel Hopping (TSCH), Deterministic and Synchronous Multi-channel Extension (DSME), and Low Latency Deterministic Network (LLDN). For each of them, we provide a detailed description and highlight the main features and possible application domains. Also, we survey the current literature and summarize open research issues
Wireless sensor network for health monitoring
Wireless Sensor Network (WSN) is becoming a significant enabling technology for a wide variety of applications. Recent advances in WSN have facilitated the realization of pervasive health monitoring for both homecare and hospital environments. Current technological advances in sensors, power-efficient integrated circuits, and wireless communication have allowed the development of miniature, lightweight, low-cost, and smart physiological sensor nodes. These nodes are capable of sensing, processing, and communicating one or more vital signs. Furthermore, they can be used in wireless personal area networks (WPANs) or wireless body sensor networks (WBSNs) for health monitoring. Many studies were performed and/or are under way in order to develop flexible, reliable, secure, real-time, and power-efficient WBSNs suitable for healthcare applications. To efficiently control and monitor a patient’s status as well as to reduce the cost of power and maintenance, IEEE 802.15.4/ZigBee, a communication standard for low-power wireless communication, is developed as a new efficient technology in health monitoring systems. The main contribution of this dissertation is to provide a modeling, analysis, and design framework for WSN health monitoring systems. This dissertation describes the applications of wireless sensor networks in the healthcare area and discusses the related issues and challenges. The main goal of this study is to evaluate the acceptance of the current wireless standard for enabling WSNs for healthcare monitoring in real environment. Its focus is on IEEE 802.15.4/ZigBee protocols combined with hardware and software platforms. Especially, it focuses on Carrier Sense Multiple Access with Collision Avoidance mechanism (CSMA/CA) algorithms for reliable communication in multiple accessing networks. The performance analysis metrics are established through measured data and mathematical analysis.
This dissertation evaluates the network performance of the IEEE 802.15.4 unslotted CSMA/CA mechanism for different parameter settings through analytical modeling and simulation. For this protocol, a Markov chain model is used to derive the analytical expression of normalized packet transmission, reliability, channel access delay, and energy consumption. This model is used to describe the stochastic behavior of random access and deterministic behavior of IEEE 802.15.4 CSMA/CA. By using it, the different aspects of health monitoring can be analyzed. The sound transmission of heart beat with other smaller data packet transmission is studied. The obtained theoretical analysis and simulation results can be used to estimate and design the high performance health monitoring systems
Performance enhancement of IEEE 802.15.4 by employing RTS/CTS and frame concatenation
IEEE 802.15.4 has been widely accepted as the de facto standard for wireless sensor networks (WSNs). However, as in their current solutions for medium access control (MAC) sub-layer protocols, channel efficiency has a margin for improvement, in this study, the authors evaluate the IEEE 802.15.4 MAC sub-layer performance by proposing to use the request-/clear-to-send (RTS/CTS) combined with frame concatenation and block acknowledgement (BACK) mechanism to optimise the channel use. The proposed solutions are studied in a distributed scenario with single-destination and single-rate frame aggregation. The throughput and delay performance is mathematically derived under channel environments without/with transmission errors for both the chirp spread spectrum and direct sequence spread spectrum physical layers for the 2.4 GHz Industrial, Scientific and Medical band. Simulation results successfully verify the authors’ proposed analytical model. For more than seven TX (aggregated frames) all the MAC sub-layer protocols employing RTS/CTS with frame concatenation (including sensor BACK MAC) allow for optimising channel use in WSNs, corresponding to 18–74% improvement in the maximum average throughput and minimum average delay, together with 3.3–14.1% decrease in energy consumption.info:eu-repo/semantics/publishedVersio
Innovative energy-efficient wireless sensor network applications and MAC sub-layer protocols employing RTS-CTS with packet concatenation
of energy-efficiency as well as the number of available applications. As a consequence there
are challenges that need to be tackled for the future generation of WSNs. The research work
from this Ph.D. thesis has involved the actual development of innovative WSN applications contributing
to different research projects. In the Smart-Clothing project contributions have been
given in the development of a Wireless Body Area Network (WBAN) to monitor the foetal movements
of a pregnant woman in the last four weeks of pregnancy. The creation of an automatic
wireless measurement system for remotely monitoring concrete structures was an contribution
for the INSYSM project. This was accomplished by using an IEEE 802.15.4 network enabling for
remotely monitoring the temperature and humidity within civil engineering structures. In the
framework of the PROENEGY-WSN project contributions have been given in the identification
the spectrum opportunities for Radio Frequency (RF) energy harvesting through power density
measurements from 350 MHz to 3 GHz. The design of the circuits to harvest RF energy
and the requirements needed for creating a WBAN with electromagnetic energy harvesting and
Cognitive Radio (CR) capabilities have also been addressed. A performance evaluation of the
state-of-the art of the hardware WSN platforms has also been addressed. This is explained by
the fact that, even by using optimized Medium Access Control (MAC) protocols, if the WSNs
platforms do not allow for minimizing the energy consumption in the idle and sleeping states,
energy efficiency and long network lifetime will not be achieved.
The research also involved the development of new innovative mechanisms that tries and solves
overhead, one of the fundamental reasons for the IEEE 802.15.4 standard MAC inefficiency. In
particular, this Ph.D. thesis proposes an IEEE 802.15.4 MAC layer performance enhancement by
employing RTS/CTS combined with packet concatenation. The results have shown that the use
of the RTS/CTS mechanism improves channel efficiency by decreasing the deferral time before
transmitting a data packet. In addition, the Sensor Block Acknowledgment MAC (SBACK-MAC)
protocol has been proposed that allows the aggregation of several acknowledgment responses
in one special Block Acknowledgment (BACK) Response packet. Two different solutions are
considered. The first one considers the SBACK-MAC protocol in the presence of BACK Request
(concatenation) while the second one considers the SBACK-MAC in the absence of BACK Request
(piggyback). The proposed solutions address a distributed scenario with single-destination and
single-rate frame aggregation. The throughput and delay performance is mathematically derived
under both ideal conditions (a channel environment with no transmission errors) and non
ideal conditions (a channel environment with transmission errors). An analytical model is proposed,
capable of taking into account the retransmission delays and the maximum number of
backoff stages. The simulation results successfully validate our analytical model. For more
than 7 TX (aggregated packets) all the MAC sub-layer protocols employing RTS/CTS with packet
concatenation allows for the optimization of channel use in WSNs, v8-48 % improvement in the
maximum average throughput and minimum average delay, and decrease energy consumption
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