An IoT Aware Architecture For Smart Healthcare Systems

This is the author's version of an article that has been published in this journal. Changes were made to this version by the publisher prior to publication.The final version of record is available at ted functionalities and extend the range of applications[12], e.g. in the healthcare domain. To the best of authors’knowledge, only few attempts have been done to leverage thecombined use of UHF RFID and WSN technologies inhealthcare application scenarios. Furthermore, none of theavailable solutions realizes a seamless integration of differenttechnologies, according to the so-called Internet of Things(IoT) vision [13]. Basing on this concept, IoT devices will beremotely accessible though the Internet, thus allowing thedevelopment of innovative applications able to exploitpervasive collected data and leverage on the new controlpossibility offered by the IoT enabling solutions.In this work, a novel IoT-aware Smart Hospital System(SHS) is presented and discussed. It is able to guaranteeinnovative services for the automatic monitoring and trackingof patients, personnel, and biomedical devices within hospitalsand nursing institutes, by exploiting the potentialities offeredby the jointly use of different, yet complementary,technologies and standards, such as RFID, WSN, smartmobile, 6LoWPAN, and CoAP. Specifically, the designedSHS is able to collect, in real time, both environmentalconditions and patients’ physiological parameters via an ultralow-power Hybrid Sensing Network (HSN) composed of6LoWPAN nodes integrating UHF RFID Class-1 Generation2 (Gen2 hereafter) functionalities. In particular, two new kindsof WSN nodes are proposed. The former integrates an RFIDGen2 reader while the latter integrates an augmented RFIDGen2 tag in order to store sensor data and patient information.In this way, physiological parameters of patients can be easilyretrieved by RFID Gen2 readers scattered in the hospital anddelivered to a control center where an advanced monitoringapplication makes them easily accessible by both local andremote users via a Representational State Transfer (REST)web service. During normal operations, therefore, no WSNbased transmission is performed, thus reducing the nodepower consumption and limiting the impact on the networkcapacity. The designed system is also able to timely andreliably manage emergency situations. In fact, in this case, theWSN-based transmission is activated so as to promptly informthe nursing staff via Push Notifications on a customizedmobile application. Doctors can also connect their smartphoneto a portable UHF RFID reader and use the same mobileapplication to interact with patients’ nodes during dailymedical inspections.The paper is organized as follows. In Section II, the relatedwork is analyzed, whilst the architecture of the proposed SHSalong with involved hardware and software components areoutlined in Section III. Section IV discusses the adoptedRFID-WSN integration strategy and provides someexperimental results on RFID communication range andpower consumption. Details on the implemented architectureare given in Section V while a prototype implementation ofthe proposed SHS is described and validated in Section VI.Concluding remarks are drawn in Section VII.II. RELATED WORKRecent advances in micro-electromechanical systems(MEMS) have opened up great opportunities for theimplementation of smart environments. Especially in themedical field, several sensors to evaluate different types ofvital signs (i.e. heartbeat, body pressure and temperature,ECG, motion, etc.) have been developed, thus enabling thedesign of innovative services able to substantially improvecitizens' healthcare. In this field, among the several researchactivities already presented in the literature, those related onthe use of the UHF RFID technology are mainly focused ontracking patients in hospitals and nursing institutes. In [3],authors combine together wearable tags and ambient tags todevelop a fully-passive RFID system, named NIGHT-Care,for monitoring the state of disabled and elderly people duringthe night. Specifically, NIGHT-Care relies on an ambientintelligence platform which is capable to estimate sleepparameters, classify the human activity, and identify abnormalevents that require immediate assistance. In [4], RFIDLocator,a web-based application developed at the University ofFribourg (CH) in collaboration with Sun Microsystems, hasbeen proposed to improve the quality of hospital services.Passive RFID technology has been successfully used also in[5] for equipment localization in hospitals. As evident fromthe cited literature, since RFID tags can operate solely underthe reader coverage region, the use of UHF RFID technologyis limited to patient/devices monitoring and tracking in quitesmall environments.Another set of related work proposes the use of WSNtechnology to implement solutions able to meet the specificrequirements of pervasive healthcare applications. In [1], aWSN providing patient localization, tracking, and monitoringservices within nursing institutes is presented. The localizationand tracking engine rely on the received signal strengthindicator (RSSI) and particle filters while bi-axialaccelerometers are used to classify the movements of patients.In [14], a wireless localization network able to track thelocation of patients in indoor environments and also tomonitor their physical status is presented. A location-awareWSN to track patients using a ranging algorithm based onenvironment and mobility adaptive filter (REMA) is proposedin [15]. A quite complete project providing patients’monitoring and tracking is WSN4QoL [16]. Specifically,WSN4QoL relies on a three-tier system architecture, where, atthe lowest tier, a Bluetooth-enabled wireless body areanetwork (WBAN) connects sensor nodes to a local collectorwhich, in turn, sends measurements reports towards a gatewaythrough a IEEE 802.15.4-based ZigBee network. Finally, thegateway performs local computation and forward data to thepublic IP network towards the professional caregivers for realtime analysis. In [17], the 6LoWPAN standard and smartmobile communication techniques are combined to monitorthe health condition of patients and provide several effectivehealthcare services. More in detail, the proposed solutionmakes use of WSN devices to measure photoplethysmogram(PPG) signals and deliver them to a server through theInternet. An Android device is used to provide a mobilehealthcare service by means of a customized application.Unlike the UHF RFID technology, the use of WSN allows theCopyright (c) 2015 IEEE. Personal use is permitted. For any other purposes, permission must be obtained from the IEEE by emailing pubs-permissions@ieee.org.

This is the author's version of an article that has been published in this journal. Changes were made to this version by the publisher prior to publication.The final version of record is available at ts to be monitored in a more efficient manner at the costof complex algorithms required for their precise tracking. Thecombined use of the UHF RFID and WSN technologies, onthe contrary, could bring considerable benefits, thus pavingthe way for the development of innovative, smart services.A first example combining UHF RFID and WSNtechnologies is presented in [18] where a wireless localizationsystem for monitoring child position in theme park isimplemented by equipping WSN nodes with UHF-RFIDreader capabilities. The localization problem is also addressedin [19], where a grid of UHF RFID tags is used to enhance thelocalization accuracy of standard RSSI-based WSNalgorithms. In [20], authors propose the integration of WSNnodes and UHF RFID readers for the development of a smartwarehouse management system.To the best of authors’ knowledge, only few attempts havebeen done to leverage the combined use of UHF RFID andWSN technologies in healthcare scenarios. In [21], RFID,WSN, and GSM are exploited together to track patients inhospitals and monitor their physiological parameters. A smartsystem using active UHF RFID, WSN, and GSM for real-timesupervision of patients is presented and discussed in [22]. Aninteresting attempt that aims to combine and integrate, atphysical layer, heterogeneous technologies, adopt the RESTfulparadigm and Push Notifications, and manage alert events in asmart hospital is reported in our prior work [23]. More indepth, it describes a smart system based on UHF RFID andZigBee-based WSN solutions for the automatic monitoringand tracking of patients within hospitals. It is able to collect, inreal time, both patients’ physiological parameters andenvironmental conditions, and, in case of emergency, topromptly inform the nursing staff via a software applicationspecifically designed for smartphones and tablets. In order toaddress the shared goal to design a seamless framework easilydeployable in a variety of scenarios, the use of a WSN basedon the Constrained Application Protocol (CoAP) forconnecting and monitoring medical sensors is advocated [24].The CoAP adoption in healthcare scenarios represents animportant aspect since some CoAP built-in features, such asresource observation (particular useful for real-timemonitoring of patients’ vital signs) and discovery, enable adynamic environment where the available resources areautomatically discovered and configured.III. SYSTEM ARCHITECTURE OVERVIEWThis work aims at designing and implementing an IoTaware Smart Hospital System (SHS) having, as mainpeculiarity, the capability to readily combine different, yetcomplementary, technologies enabling novel functionalities.Basically, the system we envision should be able to collect, inreal time, both environmental conditions and patients’physiological parameters and deliver them to a control center.At this point, an advanced monitoring application shouldanalyze the received data and send alert messages in case ofemergency. The conceived SHS has been put into effectaccording to the architecture illustrated in Fig. 1. As shown, itis composed of three main parts: (1) the RFID-enhancedFig. 1. Overview of the Smart Hospital System (SHS) architecture.wireless sensor network, named Hybrid Sensing Network(HSN) hereafter, (2) the IoT Smart Gateway, and (3) the userinterfaces for data visualization and management.The HSN consists of an integrated RFID-WSN 6LoWPANnetwork composed of four typologies: (1) 6LowPAN BorderRouters (6LBR), (2) 6LowPAN Routers (6LR), (3) 6LowPANRouter Readers (6LRR), and (4) 6LowPAN Host Tag (HT).According to the 6LoWPAN standard, the 6LBR is in chargeof connecting the network to the Internet by translating6LowPAN packets into IPv6 packets and vice-versa, while the6LR provides forwarding and routing capabilities. Referring tothe proposed RFID-WSN integrated system, the 6LRR isdefined as a 6LR node interfaced with an RFID Gen2 readerwhile HT identifies a typical 6LowPAN Host (i.e. a nodewithout routing and forwarding capabilities) interfaced with anRFID Gen2 tag. More details about HSN nodes with RFIDGen2 capabilities are provided in Section IV.At a finer level of detail, the proposed SHS assumes thatseveral 6LR are deployed in the hospital to collect data fromthe environment, such as temperature, pressure, and ambientlight conditions. In addition to the sensing capabilities, themain function of 6LRR nodes, instead, is to track patients,nursing staff, and biomedical devices labeled with RFID Gen2tags. In particular, we envision patients wearing a HT nodewhich is capable to detect important physiological parameters,such as heartbeat and movement/motion. Sensed data areperiodically logged on the user memory of the RFID Gen2 tag,thus allowing 6LRR nodes deployed in the environment toretrieve and deliver them to the IoT Smart Gateway. This lastone is connected, on the one hand, directly with the HSN and,on the other hand, with the Internet through a Local AreaNetwork (LAN). Therefore, in the proposed architecture, theCopyright (c) 2015 IEEE. Personal use is permitted. For any other purposes, permission must be obtained from the IEEE by emailing pubs-permissions@ieee.org.

This is the author's version of an article that has been published in this journal. Changes were made to this version by the publisher prior to publication.The final version of record is available at y plays the role of 6LBR, enabling the communicationbetween WSN nodes and remote users. A MonitoringApplication (MA) running on the gateway analyzes thereceived data and store them into the database (Control DB inFig. 1). To make the collected data easily accessible by bothlocal and remote users, the REST Web-based paradigm hasbeen adopted. Specifically, a Web-based graphical interfaceallows network operators to manage environmental parametersof sensor and actuator nodes. The same interface allowsdoctors with specific privileges to access both real time andhistorical patient data. Such information can also be managedremotely by the medical staff through a customized mobilesoftware application. Furthermore, doctors can be equippedwith a smartphone connected to a portable RFID Gen2 readerand running a customized application, named Medical App.Through this App, during the daily medical inspections inhospital, doctors can interact directly with the HT node wornby the patient and check his/her physiological parameters byreading the most recent information stored into the usermemory of the RFID Gen2 tag or historical information storedinto the Control DB. The Medical App allows doctors also toupdate the memory content with important information toremind (e.g. the last visit, changes of patient therapy, healthexaminations, etc.). As clarified in the next section, the RFIDGen2 technology not only provides standardized EPCglobalidentification and tracking of both patients and nursing staffwearing the HT node, but also enables quasi-zero-powerread/write memory operations.By exploiting the RFID-WSN integration, the developedSHS architecture is also able to timely manage emergencysituations. Indeed, only in case of critical events, such aspatient falls or heartbeat irregularities, the HT node resorts toits long-range, high-power, reliable IEEE 802.15.4 r

smart mobile technologies are leading this evolutionary trend. In the wake of this tendency, this paper proposes a novel, IoT-aware, smart architecture for automatic monitoring and tracking of patients, personnel, and biomedical devices within hospitals and nursing institutes. Staying true to the IoT vision, we propose