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42
Recent and Emerging Topics in Wireless Industrial Communications: A Selection
, 2007
"... In this paper we discuss a selection of promising and interesting research areas in the design of protocols and systemsforwirelessindustrialcommunications.Wehaveselected topicsthathaveeitheremergedashottopicsintheindustrial communicationscommunityinthelastfewyears(likewireless sensornetworks),orwhi ..."
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Cited by 96 (1 self)
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In this paper we discuss a selection of promising and interesting research areas in the design of protocols and systemsforwirelessindustrialcommunications.Wehaveselected topicsthathaveeitheremergedashottopicsintheindustrial communicationscommunityinthelastfewyears(likewireless sensornetworks),orwhichcouldbeworthwhileresearchtopicsin thenextfewyears(forexamplecooperativediversitytechniques for error control, cognitive radio/opportunistic spectrum access for mitigation of external interferences).
A Comprehensive Analysis of the MAC Unreliability Problem in IEEE 802.15.4 Wireless Sensor Networks
"... Abstract – Wireless Sensor Networks (WSNs) represent a very promising solution in the field of wireless technologies for industrial applications. However, for a credible deployment of WSNs in an industrial environment, four main properties need to be fulfilled, i.e., energy efficiency, scalability, ..."
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Cited by 24 (5 self)
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Abstract – Wireless Sensor Networks (WSNs) represent a very promising solution in the field of wireless technologies for industrial applications. However, for a credible deployment of WSNs in an industrial environment, four main properties need to be fulfilled, i.e., energy efficiency, scalability, reliability, and timeliness. In this paper we focus on IEEE 802.15.4 WSNs and show that they can suffer from a serious unreliability problem. This problem arises whenever the power management mechanism is enabled for energy efficiency, and results in a very low packet delivery ratio, also when the number of sensor nodes in the network is very low (e.g., 5). We carried out an extensive analysis – based on both simulation and experiments on a real WSN – to investigate the fundamental reasons of this problem, and we found that it is caused by the contention-based MAC (Medium Access Control) protocol used for channel access and its default parameter values. We also found that, with a more appropriate MAC parameters setting, it is possible to mitigate the problem and achieve a delivery ratio up to 100%, at least in the scenarios considered in this paper. However, this improvement in communication reliability is achieved at the cost of an increased latency, which may not be acceptable for industrial applications with stringent timing requirements. In addition, in some cases this is possible only by choosing MAC parameter values formally not allowed by the standard.
A Generalized Markov Chain Model for Effective Analysis of Slotted IEEE 802.15.4
"... Abstract—A generalized analysis of the IEEE 802.15.4 medium access control (MAC) protocol in terms of reliability, delay and energy consumption is presented. The IEEE 802.15.4 exponential backoff process is modeled through a Markov chain taking into account retry limits, acknowledgements, and unsatu ..."
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Cited by 21 (5 self)
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Abstract—A generalized analysis of the IEEE 802.15.4 medium access control (MAC) protocol in terms of reliability, delay and energy consumption is presented. The IEEE 802.15.4 exponential backoff process is modeled through a Markov chain taking into account retry limits, acknowledgements, and unsaturated traffic. Simple and effective approximations of the reliability, delay and energy consumption under low traffic regime are proposed. It is demonstrated that the delay distribution of IEEE 802.15.4 depends mainly on MAC parameters and collision probability. In addition, the impact of MAC parameters on the performance metrics is analyzed. The analysis is more general and gives more accurate results than existing methods in the literature. Monte Carlo simulations confirm that the proposed approximations offer a satisfactory accuracy.
Improving the IEEE 802.15.4 Slotted CSMA/CA MAC for TimeCritical Events in Wireless Sensor Networks
- In Proc. of the 2nd Workshop on Real Time Networks (RTN
, 2006
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Performance analysis of IEEE 802.15.4 non Beacon-Enabled mode
- IEEE Trans. Veh. Technol
, 2009
"... Abstract—In this paper, an analytical model for the non beacon-enabled mode of the IEEE 802.15.4 medium ac-cess control (MAC) protocol is provided. A wireless sensor net-work (WSN) composed of nodes, which transmit data to a sink through direct links, is considered. Upon reception of a query from th ..."
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Cited by 15 (3 self)
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Abstract—In this paper, an analytical model for the non beacon-enabled mode of the IEEE 802.15.4 medium ac-cess control (MAC) protocol is provided. A wireless sensor net-work (WSN) composed of nodes, which transmit data to a sink through direct links, is considered. Upon reception of a query from the sink, the nodes transmit their packets by using the carrier-sense multiple access with collision-avoidance algorithm defined by IEEE 802.15.4. Our mathematical model allows the evaluation of the statistical distribution of the traffic generated by the nodes. In particular, the probability that a node succeeds when accessing the channel, and that the final sink receives a packet coming from whatever node, is derived. The results show how the distribution of traffic changes when different loads are offered to the network. Moreover, the model allows the evaluation of the optimum size a packet should have so that the success probability for its transmission is maximized. The results are validated through simulations. The model differs from those previously published by other authors in the literature as it precisely follows the MAC procedure defined by the standard in the context of the WSN scenario described. Index Terms—Carrier-sense multiple access with collision avoidance (CSMA/CA), IEEE 802.15.4, medium access control (MAC), wireless sensor networks (WSNs). I.
A simulation based analysis of the impact of IEEE 802.15.4 MAC parameters on the performance under different traffic loads
- Journal Mobile Information Systems, Vol
, 2009
"... Abstract. IEEE 802.15.4, a MAC/PHY protocol for low power and low data rate wireless networks, is emerging as the popular choice for various monitoring and control applications. Depending on the application, the traffic load on an IEEE 802.15.4 network may vary over a wide range. The performance of ..."
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Cited by 6 (0 self)
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Abstract. IEEE 802.15.4, a MAC/PHY protocol for low power and low data rate wireless networks, is emerging as the popular choice for various monitoring and control applications. Depending on the application, the traffic load on an IEEE 802.15.4 network may vary over a wide range. The performance of the protocol, measured in terms of the packet loss probability and the packet latency, depends upon the prevailing traffic load among the nodes competing for channel access, the level of interference from the hidden nodes and the configuration of IEEE 802.15.4 MAC parameters. In this paper, we analyze via simulations the impact of different configurable MAC parameters on the performance of beaconless IEEE 802.15.4 networks under different traffic loads and under different levels of interference from the hidden nodes. Based on this analysis, we suggest the values of IEEE 802.15.4 MAC parameters that results in a good tradeoff between the packet loss probability and the packet latency under different conditions.
Improving Quality-of-Service in Wireless Sensor Networks by Mitigating “Hidden-Node Collisions”
, 2009
"... Wireless Sensor Networks (WSNs) emerge as underlying infrastructures for new classes of large-scale networked embedded systems. However, WSNs system designers must fulfill the Quality-of-Service (QoS) requirements imposed by the applications (and users). Very harsh and dynamic physical environments ..."
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Cited by 5 (0 self)
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Wireless Sensor Networks (WSNs) emerge as underlying infrastructures for new classes of large-scale networked embedded systems. However, WSNs system designers must fulfill the Quality-of-Service (QoS) requirements imposed by the applications (and users). Very harsh and dynamic physical environments and extremely limited energy/computing/memory/communication node resources are major obstacles for satisfying QoS metrics such as reliability, timeliness and system lifetime. The limited communication range of WSN nodes, link asymmetry and the characteristics of the physical environment lead to a major source of QoS degradation in WSNs – the “hidden node problem”. In wireless contention-based Medium Access Control (MAC) protocols, when two nodes that are not visible to each other transmit to a third node that is visible to the formers, there will be a collision – called hidden-node or blind collision. This problem greatly impacts network throughput, energy-efficiency and message transfer delays, and the problem dramatically increases with the number of nodes. This paper proposes H-NAMe, a very simple yet extremely efficient Hidden-Node Avoidance Mechanism for WSNs. H-NAMe relies on a grouping strategy that splits each cluster of a WSN into disjoint groups of non-hidden nodes that scales to multiple clusters via a cluster grouping strategy that guarantees no interference between overlapping clusters. Importantly, H-NAMe is instantiated in IEEE 802.15.4/ZigBee, which currently are the most widespread communication technologies for WSNs, with only minor
Towards IEEE 802.15.4e: A Study of Performance Aspects
, 2010
"... We discuss the applicability of IEEE 802.15.4 for application in industrial automation. Based on the specific requirements in this field, especially w.r.t. real-time operation, we analyzed the weaknesses of the standard protocol and proposed a novel MAC protocol that keeps the original PHY definiti ..."
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Cited by 4 (0 self)
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We discuss the applicability of IEEE 802.15.4 for application in industrial automation. Based on the specific requirements in this field, especially w.r.t. real-time operation, we analyzed the weaknesses of the standard protocol and proposed a novel MAC protocol that keeps the original PHY definition in order to work using available IEEE 802.15.4 chipsets. In earlier work, we analytically derived the worst case latency for using the improved protocol version in typical industrial setups. We now also implemented this protocol version in a simulation environment in order to show the typical behavior in the network taking into account typical channel conditions. We performed extensive simulation experiments that show the limitations of the standard protocol and that demonstrate the capabilities of the new protocol in a selected automation scenario. Our protocol variant is going to become the forthcoming IEEE 802.15.4e standard.
On the Development of a Test-Bed Application for the ART-WiSe Architecture
- WiP Session of the 18th Euromicro Conference on Real-Time Systems (ECRTS’06
, 2006
"... The ART-WiSe (Architecture for Real-Time communications in Wireless Sensor Networks) framework aims at the design of new communication architectures and mechanisms for time-sensitive Wireless Sensor Networks (WSNs). We adopted a two-tiered architecture where an overlay Wireless Local Area Network (T ..."
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Cited by 4 (4 self)
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The ART-WiSe (Architecture for Real-Time communications in Wireless Sensor Networks) framework aims at the design of new communication architectures and mechanisms for time-sensitive Wireless Sensor Networks (WSNs). We adopted a two-tiered architecture where an overlay Wireless Local Area Network (Tier 2) serves as a backbone for a WSN (Tier 1), relying on existing standard communication protocols and commercial-off-the-shell (COTS) technologies – IEEE 802.15.4/ZigBee for Tier 1 and IEEE 802.11 for Tier 2. In this line, a test-bed application is being developed for assessing, validating and demonstrating the ART-WiSe architecture. A pursuit-evasion application was chosen since it fulfils a number of requirements, namely it is feasible and appealing and imposes some stress to the architecture in terms of timeliness. To develop the test-bed based on the previously referred technologies, an implementation
The MAC unreliability problem in IEEE 802.15.4 wireless sensor networks
- in Proc. of the 12 th ACM-IEEE International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWIM 2009
, 2009
"... In recent years, the number of sensor network deployments for real-life applications has rapidly increased and it is expected to expand even more in the near future. Actually, for a credible deployment in a real environment three properties need to be fulfilled, i.e., energy efficiency, scalability ..."
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Cited by 3 (1 self)
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In recent years, the number of sensor network deployments for real-life applications has rapidly increased and it is expected to expand even more in the near future. Actually, for a credible deployment in a real environment three properties need to be fulfilled, i.e., energy efficiency, scalability and reliability. In this paper we focus on IEEE 802.15.4 sensor networks and show that they can suffer from a serious MAC unreliability problem, also in an ideal environment where transmission errors never occur. This problem arises whenever power management is enabled – for improving the energy efficiency – and results in a very low delivery ratio, even when the number of nodes in the network is very low (e.g., 5). We carried out an extensive analysis, based on simulations and real measurements, to investigate the ultimate reasons of this problem. We found that it is caused by the default MAC parameter setting suggested by the 802.15.4 standard. We also found that, with a more appropriate parameter setting, it is possible to achieve the desired level of reliability (as well as a better energy efficiency). However, in some scenarios this is possible only by choosing parameter values formally not allowed by the standard. Categories and Subject Descriptors
