Aim: This work presents detailed experimental performance results from tests executed in the hospital environment for Health Monitoring for All (HM4All), a remote vital signs monitoring system based on a ZigBee Ò (ZigBee Alliance, San Ramon, CA) body sensor network (BSN). Materials and Methods: Tests involved the use of six electrocardiogram (ECG) sensors operating in two different modes: the ECG mode involved the transmission of ECG waveform data and heart rate (HR) values to the ZigBee coordinator, whereas the HR mode included only the transmission of HR values. In the absence of hidden nodes, a non-beacon-enabled star network composed of sensing devices working on ECG mode kept the delivery ratio (DR) at 100%. Results: When the network topology was changed to a 2-hop tree, the performance degraded slightly, resulting in an average DR of 98.56%. Although these performance outcomes may seem satisfactory, further investigation demonstrated that individual sensing devices went through transitory periods with low DR. Other tests have shown that ZigBee BSNs are highly susceptible to collisions owing to hidden nodes. Nevertheless, these tests have also shown that these networks can achieve high reliability if the amount of traffic is kept low. Contrary to what is typically shown in scientific articles and in manufacturers' documentation, the test outcomes presented in this article include temporal graphs of the DR achieved by each wireless sensor device. Conclusions: The test procedure and the approach used to represent its outcomes, which allow the identification of undesirable transitory periods of low reliability due to contention between devices, constitute the main contribution of this work.
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.
Low power consumption and small footprint make 802.15.4/ZigBee based devices well suited for personal healthcare applications, representing a promising alternative to patient monitoring under important scenarios such as emergency, postop, continuous care, and chronic diseases. However, their use in a healthcare facility to monitor several mobile patients poses several difficulties, mainly because this protocol was primarily designed to operate in low data rate scenarios. This paper presents simulation results used to evaluate important quality of service (QoS) markers and, ultimately, estimate the maximum number of sensors that could integrate a wireless vital signs monitoring system. Results show that the system is able to carry the signals from 30 ECG sensors with delivery ratio higher than 99% in the considered scenario, provided that an adequate number of retransmissions are allowed.
Low power consumption and small footprint make ZigBee based devices well suited for personal healthcare applications, being a promising alternative to general care patient monitoring. However, their use in a health care facility to monitor several mobile patients poses several difficulties, mainly because this protocol was primarily designed to operate in low data rate scenarios. This paper introduces HM4AII, a remote vital signs monitoring system, and presents a prototype system being deployed in a hospital internment floor. Its architecture, original network topology, software applications and wireless sensors are described.they must be powered by batteries. On the other hand, the reliance on these systems depends on the satisfaction of quality of service (QoS) requirements, such as sustainable throughput, small delay and high reliability. The main difficulty arises from the fact that some sensors must be sampled quite often, generating a large amount of data and, consequently, requiring the network to operate under high load, which is not common in typical WSN scenarios. Therefore, a careful network design is required, as will be further discussed, to assure that QoS requirements are achieved.The usage of standard-based communication technologies with healthcare oriented profiles can offer several benefits, such as: • Standard protocol stacks implementations are reliable and can considerably reduce development costs. • Standard-based radios and integrated communication modules are cheaper than customized solutions. • Medical sensors from a variety of manufacturers can coexist and exchange information.In this paper, we introduce HM4All (Health Monitor for All), a prototype vital signs monitoring system that will be deployed in an internment floor of a private hospital in Portugal. HM4All is based on WSN technologies and standard based protocols, and was designed to allow remote monitoring of ECG (electrocardiography), Sp02 (oxygen saturation in the blood), and skin temperature. Out-patients recovering at home can also be monitored by specialized healthcare providers in the hospital. Additionally, we have developed the infrastructure necessary to monitor patients anywhere using a personal digital assistant (PDA).The paper is organized as follows. In the next section, we present a short discussion about the IEEE 802.15.4 and ZigBee protocols. In Section III, we introduce the overall system architecture and the network topology adopted. Section IV presents the prototype system being deployed, including the specific topology, and the wireless sensors and software applications developed for this work. In Section V, we discuss some results already achieved. In the next section, we present the related work and, finally, in the last section, the conclusions are presented. AND ZIG BEE PROTOCOLS HM4AII WSN is based on the 802. 15.4 [4] and ZigBee [5] protocols, which provide the network infrastructure required for WSN applications. The 802.15.4 standard was developed by the IEEE, and defines the physical (PHY) and me...
Low power and small footprint IEEE 802.15.4/ZigBee based devices are a promising alternative to 802.11a/b/g and proprietary protocols for non-critical patient monitoring under important scenarios such as post-op and emergency rooms. However, their use in a healthcare facility to monitor several mobile patients poses several difficulties, mainly because these protocols were primarily designed to operate in low traffic load scenarios. This work presents simulation results used to evaluate the performance of an IEEE 802.15.4/ Zig-Bee based wireless sensors network (WSN) in a vital signs monitoring scenario, for both star and tree based network topologies. The scalability problem in nonbeacon enabled networks is addressed to quantify the degradation in quality of service (QoS) markers when the number of sensor nodes increase. Additionally, the impact of hidden nodes is assessed for the star topology. Results indicate that, to achieve a delivery ratio (DR) higher than 99%, the number of electrocardiogram (ECG) nodes in a star network must not exceed 35. However, considering a tree topology, the maximum number of nodes must be reduced to 18 to maintain the same DR. The network performance is severely impacted by hidden nodes. For instance, in the absence of hidden nodes, a star network consisting of 32 ECG nodes presents a DR higher than 99%; however, if the percentage of hidden nodes is increased to 5%, it drops to 94%. If the same percentage of hidden nodes is maintained, it is necessary to reduce the number of nodes to 13 to reestablish a 99% DR.
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.
Wireless medical systems are comprised of four stages, namely the medical device, the data transport, the data collection and the data evaluation stages. Whereas the performance of the first stage is highly regulated, the others are not. This paper concentrates on the data transport stage and argues that it is necessary to establish standardized tests to be used by medical device manufacturers to provide comparable results concerning the communication performance of the wireless networks used to transport medical data. Besides, it suggests test parameters and procedures to be used to produce comparable communication performance results.
Wireless sensor networks can help healthcare providers enhance patient monitoring and communication capabilities. This paper describes the present state of the development of a vital signal monitoring network applied to the hospital environment. The proposed network is based on non-obstructive sensors able to communicate through a low power wireless sensor network based on the ZigBee protocol. This network enables continuous patient monitoring, creating entirely new mechanisms for providing healthcare under a plethora of cases (e.g. post-op, continuous care, and chronic diseases). The main advantages of this system include increased patient mobility, faster detection of potential problems, real-time feedback to caregivers and patients, and faster response to emergency situations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
334 Leonard St
Brooklyn, NY 11211
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.