Evaluation of the Impact of the Topology and Hidden Nodes in the Performance of a ZigBee Network

Fernández-López, Helena; Macedo, Pedro; Afonso, José Roberto Rodrigues; Correia, José A.F.O.; Simoes, Ricardo

doi:10.1007/978-3-642-11528-8_18

Cited by 5 publications

(2 citation statements)

References 7 publications

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“…The ZigBee protocol has been successfully employed on several sensing applications in spite of the lack of quality-of-service (QoS) guarantees. Since it is based on carrier sense medium access (CSMA), it is susceptible to collisions even in lowtraffic scenarios [19]. Additionally, CSMA-based protocols are susceptible to the hidden-node problem, where some traffic being sent to a receiver may not be detected by another transmitter [6].…”

Section: Introductionmentioning

confidence: 99%

Towards the design of efficient nonbeacon-enabled ZigBee networks

et al. 2012

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a b s t r a c tThis paper presents experimental results of the communication performance evaluation of a prototype ZigBee-based patient monitoring system commissioned in an in-patient floor of a Portuguese hospital (HPG -Hospital Privado de Guimarães). Besides, it revisits relevant problems that affect the performance of nonbeacon-enabled ZigBee networks. Initially, the presence of hidden-nodes and the impact of sensor node mobility are discussed. It was observed, for instance, that the message delivery ratio in a star network consisting of six wireless electrocardiogram sensor devices may decrease from 100% when no hidden-nodes are present to 83.96% when half of the sensor devices are unable to detect the transmissions made by the other half. An additional aspect which affects the communication reliability is a deadlock condition that can occur if routers are unable to process incoming packets during the backoff part of the CSMA-CA mechanism. A simple approach to increase the message delivery ratio in this case is proposed and its effectiveness is verified. The discussion and results presented in this paper aim to contribute to the design of efficient networks, and are valid to other scenarios and environments rather than hospitals.

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Section: Introductionmentioning

confidence: 99%

Towards the design of efficient nonbeacon-enabled ZigBee networks

et al. 2012

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“…In [4] we have estimated, based on simulations, the performance of ZigBee WSNs designed for continuous vital signs monitoring. These networks were evaluated in terms of scalability considering different topologies.…”

Section: Introductionmentioning

confidence: 99%

Experimental Evaluation of IEEE 802.15.4/ZigBee for Multi-patient ECG Monitoring

Fernández-López

Correia

Simoes

et al. 2011

Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering

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IEEE 802.15.4/ZigBee wireless sensor networks (WSNs) are a promising alternative to cabled systems for patient monitoring in hospitals. Some areas where monitoring systems based on WSNs can be successfuly used are ambulatory, waiting and triage rooms, post-op, and emergency rooms. The low power and small size ZigBee devices have the ability to form selfconfiguring networks that can extend themselves through a hospital wing or floor. Using spatially distributed networks, it is possible to cover an extended area and serve several patients. However, the low data rate protocols provided by IEEE 802.15.4 poses several challenges, mainly because its protocols were primarily designed to operate in low traffic load scenarios but some vital signs sensors generate a large volume of data. This work presents an experimental evaluation of the performance of multi-hop ZigBee networks comprised of several nodes that carry the traffic of wearable electrocardiogram (ECG) sensors. The results indicate that star networks can relay 100% of the traffic generated by at least 12 ECG nodes. In tree topologies, the increase of the network traffic load reduces the performance but even these networks can reliably relay the traffic of a considerable number of ECG nodes.

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Evaluation of the Impact of the Topology and Hidden Nodes in the Performance of a ZigBee Network

Cited by 5 publications

References 7 publications

Towards the design of efficient nonbeacon-enabled ZigBee networks

Towards the design of efficient nonbeacon-enabled ZigBee networks

Experimental Evaluation of IEEE 802.15.4/ZigBee for Multi-patient ECG Monitoring

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