Implementation of wireless body area networks for healthcare systems

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Abstract

This work describes the implementation of a complete wireless body-area network (WBAN) system to deploy in medical environments. Issues related to hardware implementations, software and wireless protocol designs are addressed. In addition to reviewing and discussing the current attempts in wireless body area network technology, a WBAN system that has been designed for healthcare applications will be presented in detail herein. The wireless system in the WBAN uses medical bands to obtain physiological data from sensor nodes. The medical bands are selected to reduce the interference and thus increase the coexistence of sensor node devices with other network devices available at medical centers. The collected data is transferred to remote stations with a multi-hopping technique using the medical gateway wireless boards. The gateway nodes connect the sensor nodes to the local area network or the Internet. As such facilities are already available in medical centers; medical professions can access patients’ physiological signals anywhere in the medical center. The data can also be accessed outside the medical center as they will be made available online.

Introduction

As portable devices like cellular phones, pagers and MP3 players become popular; people start to carry such devices around their bodies. In 2001, Zimmerman [1] studied how such electronic devices operate on and near the human body. He used the term wireless personal area network (PAN). He characterized the human body and used it as a communication channel for intra-body communications. Later around 2001, the term PAN has been modified to body area network (BAN) to represent all the applications and communications on, in and near the body [2]. One of the most attractive applications to use BAN is in the medical environment to monitor physiological signals from patients.

Wireless body-area network (WBAN) is a special purpose wireless-sensor network that incorporates different networks and wireless devices to enable remote monitoring for various environments [3], [4]. One of the targeted applications of WBAN is in medical environments where conditions of a large number of patients are continuously being monitored in real-time. Wireless monitoring of physiological signals of a large number of patients is one of the current needs in order to deploy a complete wireless sensor network in healthcare system. Such an application presents some challenges in both software and hardware designs. Some of them are as follows: reliable communication by eliminating collisions of two sensor signals and interference from other external wireless devices, low-cost, low power consumption, and providing flexibility to the patients [5], [6]. A WBAN-based wireless medical sensor network system when implemented in medical centers has significant advantages over the traditional wired-based patient-data collection schemes by providing better rehabilitation and improved patient's quality of life. In addition a WBAN system has the potential to reduce the healthcare cost as well as the workload of medical professions, resulting in higher efficiency.

There is already a number of monitoring systems developed or being used in medical centers [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17]. The available medical monitoring systems are generally bulky and thus uncomfortable to be carried by patients. Most of the current effort has mainly been focused on the devices that are monitoring one or few physiological signals only. When multiple sensors are involved, wires are used to connect the sensors to a wearable wireless transmitter. Wired systems restrict patients’ mobility and comfort level, especially during sleep studies. Future implementation of medical monitoring necessitates the use of small, low-power sensor nodes with wireless capability [17], [18], [19].

Thus far there is no available standard for a wireless body-area network specifically targeting health care. Most popular wireless communication technologies and protocols proposed or used in medical monitoring systems are listed in Table 1. Existing monitoring systems use the short-range wireless systems such as ZigBee (IEEE 802.15.4) [9], [10], [11], WLANs [5], [8], GSM [12] and Bluetooth (IEEE 802.15.1) [13], [14], [15]. To make the power consumption and the size of the device low, short-range devices like Bluetooth and ZigBee are mostly used with sensors to collect medical data from a patient body. Especially WLAN technologies are avoided for low power sensor nodes because of their large size and power consumption used to provide longer ranges (i.e. 100 m). As these technologies may most probably be installed in medical environments due to other applications, medical gateway devices should be designed in a WBAN to interface with these wireless systems to provide a wireless link between the control unit and a mobile device (i.e. PALM) or between the control unit and Internet via a Wi–Fi link.

The low-data rate IEEE 802.15.4 technology (ZigBee) has been the most popular short-range standard used recently in medical monitoring systems due to its low transmitter power [20], [21]. Systems using Zigbee wireless platform may however suffer from the strong interference by WLANs which share the same spectrum and transmit at a larger signal power [22]. Installing an interference free medical network in a hospital may thus be quite challenging since there exist a lot of other wireless systems and equipments using the 2.4 GHz band. The device technologies operating at the 2.4 GHz ISM band should thus deal with the interference and coexistence issues when they are located in the same environment [23]. As can be seen in Table 1, in addition to unlicensed ISM bands, there are medical bands such as MICS (Medical Implant Communication Service) and WMTS (Wireless Medical Telemetry Service) that are specifically regulated for medical monitoring by communication commissions around the world [24], [25], [26]. The recent short-range, low-data rate, ultra-wideband (UWB) technology is another attractive technology that could be used for body-area network applications because of its regulated low transmitter power [7].

In addition to review and discuss the current attempts in body-area network technology, a WBAN system that has been designed for healthcare applications will be presented in this paper.1 The proposed WBAN is a multi-hopping wireless medical network that uses the MICS band to obtain physiological data from sensors placed on or in the body and the WMTS band as an intermediate node for a longer wireless communication. The data is transferred to remote stations through the local area network or the Internet already available in medical centers as a part of their ICT (Information and communication technologies) infrastructure. Unlike the other medical sensor networks (they usually use 2.4 GHz ISM band); we use medical standards occupying the frequency bands that are mainly assigned to medical applications.

The paper is organized as follows. Section 2 describes an overview of WBANs for the medical environment. It gives the concept of WBAN applications with their important design features. Section 3 presents a complete WBAN implementation. Different medical scenarios are defined for a real implementation in hospital environment. This section also discusses the hardware implementation details for the proposed prototype system. The multi-access protocol used for multi-sensor and multi-patient scenario is also given here. Section 4 presents computer programs used for recording, monitoring and processing the medical data captured through the prototype system. An overall system performance evaluation as well as comparisons with the recent attempts of WBAN-based patient monitoring systems have been given in Section 5. And finally Section 6 concludes the paper.

Section snippets

Wireless body-area networks in medical environment

The application of WBAN in a medical environment may consist of wearable and implantable sensor nodes that sense biological information from the human body and transmit over a short distance wirelessly to a control device worn on the body or placed at an accessible location. The sensor electronics should be miniaturized, low-power and detect medical signals such as electrocardiogram (ECG), photoplethysmogram (PPG), electroencephalography (EEG), pulse rate, pressure, and temperature. The

A body-area network implementation for healthcare

Currently we are developing a complete wireless body-area network that is based on different frequencies in order to eliminate interference issues as well as to apply to different environments. We use MICS, WMTS and 433 ISM bands to detect signals from the sensors on the body. The goal in a WBAN application is to dedicate one sensor node to one physiological signal as described in Fig. 1(b) to eliminate placing wires on the patient body. However, there maybe some clinical applications that

Database, software programs and monitoring

In order to monitor data, several computer programs have been developed during this project. The necessary software programs have been identified in Fig. 2. The software called GATEWAY is developed at the monitoring PC to control the communication with the CCU to get readings from sensors and then forward them through the network/internet to an application on a remote PC (at a medical profession center). While performing this task, the GATEWAY also verifies the data integrity and schedules

Performance evaluation and discussion

One way to analyze the performance of a WBAN system is to measure the end-to-end delay during monitoring of patients. The end-to-end delay performance herein refers to the time taken for a packet to be transmitted from the sensor nodes to the monitoring computer. In order to evaluate the performance of the proposed WBAN, we have analysed the data received from an active patient (subject) when moving from a CCU towards other patients, as shown in Fig. 11. To observe the end-to-end delay of

Conclusions

In this paper we present a multi-hopping network for a WBAN system that can be used in medical environments for remote monitoring of physiological parameters. The system is different than the existing implemented ones in that we consider monitoring of physiological signals from many patients simultaneously to represent a real implementation in hospital environments. Issues related to a complete WBAN system to deploy in a medical center have been discussed. Portable and wireless gateway nodes

Acknowledgements

This work was supported in part by the Australian Research Council (ARC) under Discovery Projects Grant. I like to thank the following students Anthony Bott and Ng Peng Choong for their help in the developing boards. I also like to thank the anonymous reviewers for their comments and suggestions to strengthen the quality of the paper.

Mehmet Rasit Yuce received the M.S. degree in Electrical and Computer Engineering from the University of Florida, Gainesville, Florida in 2001, and the Ph.D. degree in Electrical and Computer Engineering from North Carolina State University (NCSU), Raleigh, NC in December 2004. Currently he holds senior lecturer position in the School of Electrical Engineering and Computer Science, University of Newcastle, New South Wales, Australia.

Between August 2001 and October 2004, he has served as a

References (44)

  • N. Golmie et al.

    Performance analysis of low rate wireless technologies for medical applications

    Computer Communications

    (2005)
  • Carta

    Design and implementation of advanced systems in a flexible-stretchable technology for biomedical applications

    Sensors and Actuators A

    (2009)
  • T.G. Zimmerman

    Personal Area networks: near-field intrabody communication

    IBM Systems Journal

    (1996)
  • K.V. Dam et al.

    From PAN to BAN: why body area networks?

  • E. Jovanov et al.

    A wireless body area network of intelligent motion sensors for computer assisted physical rehabilitation

    Journal of Neuro Engineering and Rehabilitation

    (2005)
  • WBAN standard group. http://www.ieee802.org/15/pub/TG6.html, March,...
  • A. Soomro et al.

    Opportunities and challenges in using WPAN and WLAN technologies in medical environments

    IEEE Communications Magazine

    (2007)
  • M.R. Yuce et al.

    Implementation of body area networks based on MICS/WMTS medical bands for healthcare systems

  • C.K. Ho et al.

    Low data rate ultra wideband ECG monitoring system

  • Fischer, R., et al., SMART: scalable medical alert and response technology....
  • T. Gao et al.

    Vital signs monitoring and patient tracking over a wireless network

  • C.A. Otto et al.

    WBAN-based system for health monitoring at home

  • C.H. Chan et al.

    A hybrid body sensor network for continuous and long-term measurement of arterial blood pressure

  • U. Anliker

    AMON: a werable multiparameter medical monitoring and alert system

    IEEE Transactions on Information Technology in Biomedicine

    (2004)
  • C.M. Jong et al.

    Hardware design & compression issues in compact Bluetooth enabled wireless telecardiology system

  • M.F.A. Rasid et al.

    Bluetooth telemedicine processor for multichannel biomedical signal transmission via mobile cellular networks

    IEEE Transactions on Information Technology in Biomedicine

    (2005)
  • J. Proulx et al.

    Development and evaluation of a Bluetooth EKG monitoring system

  • M.R. Yuce et al.

    Monitoring of physiological parameters from multiple patients using wireless sensor network

    Journal of Medical Systems

    (2008)
  • C. Park et al.

    An ultra-wearable, wireless, low power ECG monitoring system

  • Wireless ECG patch by IMEC. http://www2.imec.be/,...
  • EEG sensor by Icap. http://www.icaptech.com/,...
  • N.F. Timmons et al.

    Analysis of the performance of IEEE 802. 15. 4 for medical sensor body area networking

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    Mehmet Rasit Yuce received the M.S. degree in Electrical and Computer Engineering from the University of Florida, Gainesville, Florida in 2001, and the Ph.D. degree in Electrical and Computer Engineering from North Carolina State University (NCSU), Raleigh, NC in December 2004. Currently he holds senior lecturer position in the School of Electrical Engineering and Computer Science, University of Newcastle, New South Wales, Australia.

    Between August 2001 and October 2004, he has served as a research assistant with the Department of Electrical and Computer Engineering at NCSU, Raleigh, NC. He was a post-doctoral researcher in the Electrical Engineering Department at the University of California at Santa Cruz in 2005. His research interests include wireless implantable telemetry, wireless body area network (WBAN), analog/digital mixed signal VLSI for wireless, biomedical, and RF applications. Dr. Yuce has published about 50 technical articles and received a NASA group achievement award in 2007 for developing an SOI transceiver. He is a senior member of IEEE.

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