Everybody working together

Abstract

Wireless body area networks (WBANs) are rapidly growing in significance, partly due to their diverse and important applications. Perhaps the most important role they can play is in healthcare: from diagnosis, to monitoring and drug administration. Evidently, monitoring can save lives and a huge amount of research has been devoted to it but problems remain, especially in the context of sleep. The different nodes work cooperatively to improve patient monitoring during sleep As we will see below, sleeping patients are much more difficult to monitor reliably than patients who are awake, especially using WBANs. To address this, researchers from The Australian National University (ANU), and Australia's Information and Communications Technology Research Centre of Excellence (NICTA), have investigated various properties of WBAN channels to show that cooperative communication techniques can achieve a 20% performance improvement. WBANs represent the next generation of wireless personal area networks (WPANs). In this new generation, explained Samiya Shimly, one of the authors of the research, “miniaturised, intelligent, low power, invasive/non-invasive micro and nano technology sensor (and/or actuators) nodes are placed on, inside or around the human body for monitoring physiological signals.” Each WBAN then contains a hub which can connect to the internet or other relevant networks. Shimly told us that, while “WBAN offers a vast range of applications such as ubiquitous health care, military, sports, entertainment and many other areas, it is advanced healthcare that is the main focus of research.” The advantages of WBAN monitoring include patient quality of life – they can engage in their daily lives without being consigned indefinitely to hospital – as well as the ability to monitor several conditions at once. However, sleep still represents a problem, said Shimly, as “the sleeping body channel is a difficult channel to deal with: it is partially quasi-static in nature (not mobile, nor static), and it can be blocked for a long time due to changes in body posture, hence hindering reliability (when many patients can incur life-threatening risks during their sleep).” The work presented in this issue of Electronics Letters is the first to investigate the performance of sleeping body monitoring channels using different cooperative diversity techniques. The authors used cooperatively combined relayed links to improve significantly the reliability of monitoring a sleeping WBAN, which was not possible with single-hop communications. Expanding on this, Shimly explained that “two types of cooperative diversity techniques – 3-branch selection combining, and 3-branch switch-and-examine combining – are performed with two-hop relayed links, and then the results compared with single-hop communications.” This approach led to 7 dB and 20% performance improvement, in the cases of outage probability and outage duration, respectively. Significantly, she said, “the best-case outage probabilities estimated from single link and cooperatively combined links are not more than 10%, which indicates acceptable packet error rate within IEEE 802.15.6 standard requirements.” The improvements offered by the team's research mean that WBANs can be used to monitor patients continuously at home, in hospitals or in healthcare units. (Although, in the longer term, they also believe their prototype could be used for disaster response or emergency healthcare situations.) This will drastically improve the lives of patients in rehabilitation or those with disabilities. The associated devices are small and can activity in a number of situations However, the reliability of the monitoring process is just one part of the problem. The next steps the team are aiming to take are in patient mobility, security and reliability of data transfer, economy of power consumption and scalability. Shimly believes that if all of these aspects can be improved, then “WBAN technology will revolutionise the healthcare sector by enhancing health-care systems with the latest technological advancements leading to major life saving and reduction in healthcare costs.” She also expects that “WBANs wilI be pervasive across the society in many domains apart from healthcare, but it would be great to see WBANs fulfil their promise to save many lives, as well as delivering major improvements in quality of life.”