ubiquitous computing for remote cardiac patient monitoring: a...

Hindawi Publishing CorporationInternational Journal of Telemedicine and ApplicationsVolume 2008 Article ID 459185 19 pagesdoi1011552008459185

Research ArticleUbiquitous Computing for Remote Cardiac PatientMonitoring A Survey

Sunil Kumar1 Kashyap Kambhatla1 2 Fei Hu3 Mark Lifson4 and Yang Xiao5

1 Department of Electrical and Computer Engineering San Diego State University San Diego CA 92182 USA2 Computational Science Research Center San Diego State University San Diego CA 92182 USA3 Department of Electrical and Computer Engineering The University of Alabama Tuscaloosa AL 35487 USA4 Department of Computer Engineering Rochester Institute of Technology Rochester NY 14623 USA5 Department of Computer Science The University of Alabama Tuscaloosa AL 35487 USA

Correspondence should be addressed to Sunil Kumar skumarmailsdsuedu

Received 11 February 2008 Accepted 22 April 2008

Recommended by Sajid Hussain

New wireless technologies such as wireless LAN and sensor networks for telecardiology purposes give new possibilities formonitoring vital parameters with wearable biomedical sensors and give patients the freedom to be mobile and still be undercontinuous monitoring and thereby better quality of patient care This paper will detail the architecture and quality-of-service(QoS) characteristics in integrated wireless telecardiology platforms It will also discuss the current promising hardwaresoftwareplatforms for wireless cardiac monitoring The design methodology and challenges are provided for realistic implementation

Copyright copy 2008 Sunil Kumar et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

1 INTRODUCTION

Ubiquitous cardiac monitoring can be defined as mobilecomputing medical sensor and communications technologiesfor monitoring cardiac patients This represents the evolutionof e-health systems from traditional desktop telemedicineplatforms to wireless and mobile configurations Ubiqui-tous cardiac monitoring is part of telemedicine research[1ndash134] Current and emerging developments in wirelesscommunications integrated with developments in pervasiveand wearable biomedical sensor technologies would have aradical impact on future health-care delivery systems Theywould provide a solution to the problems such as accessto care for large segments in the population continuinghealthcare cost inflation and uneven geographic distributionof quality Distribution of quality is improved by enhancingaccessibility to care for underserved populations containingcost inflation and improving quality through the continuouscare of patients

On the other hand we have the following requirementsfor the patient monitoring applications (i) periodic trans-mission of routine vital signs and transmission of alertingsignals when vital signs cross a threshold patients cross acertain boundary or device battery drops below a level (ii)

addressing many usability issues including user comfort andtrust by monitoring wireless and mobile networks includingthe use of wearable portable or mobile devices (iii)diversity of patients including those suffering from mentalillnesses is likely to make patient monitoring by wirelessnetworks a challenge because of possible paranoia related tohand-held or wearable wireless devices (iv) comprehensiveand high-speed access to wireless networks reliable andscalable wireless infrastructure secure and fast databasesand utilization of network intelligence and information (v)amount and the frequency of information that needs to betransmitted is another challenge Especially for the cardiacmonitoring systems we have the following few requirements(a) maintaining periodic transmissions of routine heart-beating signs and real-time transmission of alertalarm (b)creating wearable portable or mobile devices that providea user with comfort (c) accommodating the diversityamongst patients (iv) providing comprehensive and high-speed access to wireless networks reliable and scalable wire-less infrastructure secure and fast databases (d) utilizingnetwork intelligence and information for calculations (e)varying the amount and the frequency of information thatneeds to be transmitted is another challenge For examplesome patients require that certain vital signs be transmitted

2 International Journal of Telemedicine and Applications

every few minutes while for others continuous monitoringevery few seconds is necessary For all patients any majorchanges in the vital signs should be transmitted immediately

Continuous cardiac monitoring through wireless tech-nology can be used to follow up with patients that havesurvived cardiac arrest ventricular tachycardia or cardiacsyncope as well as for diagnostic purposes in patientswith diffuse arrhythmia As PDA devices are reasonablypriced and are becoming increasingly powerful telemedicinesystems using PDAs are a cost-effective solution in a range ofmedical applications and suitable for home care usage Somecurrently used patient operated ambulatory ECG recordingequipments such as holters and transtelephonic devicesare time consuming to setup and suffer from poor patientcompliance Patients undergoing acute myocardial infarctionand subsequent arrhythmia ending in ventricular fibrillationand sudden cardiac arrest will not be able to operate suchequipment For reliable monitoring it is necessary to developa completely automatic recording and analyzing unit whichcan detect cardiac abnormalities and automatically send dataand alarm(s) to a health provider or central alarm system Ithas been clearly documented that time is a critical factor inorder to perform early cardiopulmonary resuscitation (CPR)and early defibrillation and if the time to start CPR after acardiac arrest increases the chance of survival is reduced [4]

New wireless technology for telecardiology purposes givenew possibilities for monitoring vital parameters with wear-able biomedical sensors and give the patient the freedomto be mobile and still be under continuous monitoring andthereby better quality of patient care The implications andpotential of wearable cardiac monitoring technologies areparamount since they could (i) detect early signs of healthdeterioration (ii) notify health care providers in criticalsituations (iii) find correlations between lifestyle and health(iv) bring sports conditioning into a new dimension byproviding detailed information about physiological signalsunder various exercise conditions and (v) provide doctorswith multisourced real-time physiological data [1] Theywill therefore give the patient the freedom to be mobileand still be under continuous monitoring in differentenvironments such as both inside and outside homesoffices hospitals nursing homes and traveling Further-more context-awareness can enable personalized functionssuch as reminder services or medication support dependingon measured vital signs and individual disease patterns

In order to make wearable devices practical a seriesof technical legal and sociological obstacles should beovercome The major design requirements of the mobile unitare the following (1) portable and lightweight (2) powerautonomy of a few hours (3) user-friendly interface (4)collection and display of critical biosignals (5) very lowfailure rate and highly accurate alarm triggers especiallyif used for diagnostic purposes and (6) reliable real-timewireless data transmission any-time anywhere in any form

In this paper we will first introduce general require-ments of ubiquitous computing telecardiology platformsin Section 2 Section 3 will discuss existing systems Thearchitecture of heterogeneous wireless platforms is statedin Section 4 Quality-of-service (QoS) analysis in mobile

telecardiology systems is given in Section 5 The fourth-generation (4G) system is discussed in Section 6 FinallySection 7 provides the prospective of next-generation (xG)telecardiology systems

2 UBIQUITOUS COMPUTING FOR TELECARDIOLOGY

Ubiquitous computing also called pervasive computingis a concept for future computing environments where auser is surrounded by a large amount of small application-specific network-connected information appliances It ischaracterized by (i) physical and cognitive embedded sys-tems (ii) networking (iii) ubiquity (iv) context awarenessand (v) application specific devices (appliances) The costsfor integrating the necessary communication abilities areaffordable compared to the potential for cost savings andto the medical advantages (i) context-aware cognitive-embedded systems result in a better usability which isessential for the use in a home-monitoring scenario (thedevice is adapting itself to the user and not vice versa) (ii)patient mobility is maximized by physically embedding thedevices into wearable or implantable distributed systemsand (iii) networking compensates decentralization Thushigh performance services such as pattern recognition withneural networks can be provided anywhere to the mobiledevices

Problems emerge in ubiquitous computing in the follow-ing areas

(1) Embedded [39]

(a) both vital sensors and base station have to bewearable to ensure mobility and attention

(b) attention has to be paid to the body placementhuman movement weight size and otherconstraints

(c) reduce the power consumption relatively withthe increase in the performance of processorsmemories and other components

(2) Networking [40 41]

(a) providing ubiquitous access to central informa-tion services

(b) lower power consumption(c) ensuring high level of security(d) extensive interoperability features(e) integrated functionality such as service discov-

ery self-configuration encryption and authen-tication

(f) protection of privacy and communication secu-rity considering mobile Internet connections

(3) Context-awareness [42]

(a) personal identifications personalized healthmonitoring systems provide functions suchas reminder services or medication supportdepending on measured vital signs and individ-ual disease patterns The data therefore shouldtravel reliably to the remote nursephysician

Sunil Kumar et al 3

(b) time a very simple but important context usedfor the timing synchronization of distributedsensors

Wireless and mobile technologies are finding a role incardiac patient monitoring in several different environmentshomes hospitals and nursing homes However due to sev-eral limitations including unpredictable and spotty coverageof users by wireless networks the quality and reliability ofpatient monitoring have not been highly satisfactory

Wireless cardiac patient monitoring also raises severalissues (i) introduction of wireless technologies in patientmonitoring is very preliminary as patient monitoringrequirements and challenges in different environments havenot been identified (ii) unique capabilities of wirelessand mobile infrastructure for patient monitoring have notbeen utilized (iii) applications and solutions for patientmonitoring are limited to using a single type of wirelessnetwork thus restricting the access and coverage and (iv)introduction of wireless and mobile technologies in patientmonitoring is very fragmented and limited to few simplecases

For some patients certain vital signs need to be trans-mitted every few minutes while for others continuousmonitoring every few seconds is necessary For all patientsany major changes in the vital signs should be transmittedimmediately In wireless environment it could be betterto transmit differential changes since the last time or areference value to reduce the amount of information Thiswould also increase the chances of reception by others Anincreasing number of patients will be wearing portable ormobile devices that would have access to public or privatewireless networks To improve the quality and reliabilityof patient monitoring these devices could be designed tooperate in ad hoc wireless mode Also with a lack of coverageand variable fluctuating coverage by infrastructure-orientedwireless networks in some spots combined with patients inlocations not reachable by others an increased reliability ofmonitoring and higher chances of transmission of alert signalcan be achieved with the use of ad hoc wireless networks Dueto power and size requirements of these devices the range oftransmitted signal is likely to be small Further the range islikely to be affected both by the frequency of operation andthe nature of spectrum used (licensed versus unlicensed)For monitoring of patients who are not covered by aninfrastructure-oriented wireless networks the cooperationof others with wireless devices in an ad hoc configuration willbe utilized

Increasing life expectancy accompanied with decreasingdependency ratio in developed countries calls for newsolutions to support independent living of the elderlyUbiquitous computing technologies can be used to providethese solutions so that they naturally support the elderlyand their caregivers in their everyday environment Whiledesigning these solutions special attention should be paidon usersrsquo needs and abilities and on the way the solutions fitto the provisioning of the care Finally any solution shouldbe properly validated and tested in real environments with asufficient number of real users

Another concept called mobile health (m-health) has asimilar definition as the above system Current and emergingdevelopments in wireless communications integrated withdevelopments in pervasive and wearable technologies wouldhave a radical impact on future health-care delivery systemsA snapshot of recent developments in these areas and someof the challenges and future implementation issues fromthe m-health perspective are presented and addressed in[43] A comprehensive overview of some of these existingwireless telemedicine applications and research can be foundin recent publications in the area [44ndash47 118ndash134]

There are some limitations to existing wireless technolo-gies that mostly depend on general packet radio service(GPRS) technologies and on their deployment strategiesin health care Some of these issues can be summarizedas follows [48] (1) The lack of an existing flexible andintegrated ldquom-health-on-demandrdquo linkage of the differentmobile telecommunication options and standards for e-health services This lack of linkage and compatibility fortelemedical services exists due to the difficulty of achievingoperational compatibility between the telecommunicationservices terminals and devices standards and ldquom-healthprotocolsrdquo (2) The high cost of communication linksespecially between satellites and global mobile devicesand the limitation of existing wireless data rates especiallyfor the globally available 25G and third-generation (3G)services for some e-health services This is also combinedwith the availability of secure mobile Internet connectivityand information access especially for e-health systems (3)Health-care is a very complex industry that is difficult tochange Organizational changes are very often required forhealth-care institutions to benefit from e-health and m-health services (4) The short-term and long-term economicconsequences and working conditions for physicians andhealth-care experts using these technologies are not yet fullyunderstood or properly investigated (5) The methods ofpayment and reimbursement issues for e-health and m-health services are not yet fully developed and standardized(6) There is a lack of integration between existing e-healthservices and other information systems (eg referral andordering systems medical records etc) (7) The demonstra-tion projects so far have failed to show that m-health servicesresult in real savings and have cost effective potential

Mobile wireless technologies such as mobile computingwireless networks and global positioning systems (GPS)have been employed in several countries for emergency aswell as general health care [49 50] Though the systems showpromising research in using WLAN radios to transfer patientinformation to the hospital in real time analyzing signalinterference with other available Wi-Fi hotspots security ofmedical data transmission in areas devoid of Wi-Fi hotspotshas not been addressed significantly

Complete reliance on cellular architecture could provefutile in some locations where the cellular coverage iseither deteriorated significantly due to many factors or istotally unavailable as in rural areas In [51] excessive com-plex computations and frequently large data transmissionscould put serious restrictions on the energy utilization ofmobile phone Also significant interference alleviation of the


Bluetooth module with other networks such as Wi-Fi andpersonal area networks has not been addressed

Current 3G cellular and WLAN networks experiencesignal attenuationloss due to fading multiradio interferenceand multipath distortion Fading can be because of interfer-ence from other radio signals present in the same part ofthe spectrum as well as because of moving equipment Deadspots may occur within buildings due to signal attenuationby the construction material and metals creating a dead spotin its radio shadow Typical examples of dead spots includesubway train platforms indoor environments and under-ground areas The spontaneous loss of communications forno apparent reason is probably one of the most irritatingaspects of various wireless networks

Moreover subscribers experience higher call blocking indense areas known as hot spots such as downtown areasand amusement parks A costly solution is to install morebase stations or access points in such regions Alternativelymultihop relaying in ad hoc networks can be used toprovide communication in dead spot and hot spot regionswithout having to depend on an existing central controlleror an infrastructure Users in dead spot areas can maintainconnectivity with the base station (BS) by relaying theirmessages through other subscribers or by hopping to a userwho has a connection with the BS In hot spots a user canobtain a connection by hopping away from congested BSsto lightly loaded ones Relaying in cellular networks solvesthe coverage and high data rate problems reduces peakpower consumption and provides load balancing in denseand highly populated areas In fact due to these potentialbenefits there has recently been an interest in deploying thistechnique in 3G cellular systems as discussed below Effortsin developing heterogeneous networks by interconnectingthese technologies have opened up new areas of research

3 OVERVIEW OF EXISTING MOBILETELECARDIOLOGY SYSTEMS

In this section we provide an overview of technologies usedfor transmitting the vital physiological data from a cardiacpatient to a remote monitoring station

The European EPI-MEDICS project [24] uses an intelli-gent personal ECG monitor (PEM) for the early detection ofcardiac ischemia and arrhythmia The PEM records a 3-leadECG (DI DII and V2) derives the corresponding standard12-lead ECG using a patient specific transform [25] andstores the information in patientrsquos electronic health record(EHR) on a smart media card in the PEM device The PEMgenerates different levels of alarms based on the ECG andthe patientrsquos clinical history and forwards them with therecorded signals and the EHR to the health care providersby means of Bluetooth and GSMGPRS in store and forwardmode [26]

The fast development of mobile technologies includingincreased communication bandwidth and miniaturization ofmobile terminals has accelerated developments in the fieldof mobile telecardiology [2] Development of the efficientportable and body-worn devices and systems to measurephysiological parameters of cardiac patients (eg ECG

heart rate SpO2 and blood pressure) has been witnessingactive research lately A wireless PDA-based physiologicalmonitoring system for patients inside the hospital wasreported in [3] which transmits the acquired data to a centralmanagement unit by using the hospital WLAN

A system for out-of-hospital follow-up and monitoringof patients with chronic heart disease was discussed in[29] The patients belonged to one of four risk groupsarterial hypertension malignant arrhythmias heart failureand post-infarction rehabilitation They were provided withportable recording equipment and a cellular phone thatsupported ECG data transmission and wireless applicationprotocol (WAP) In order to avoid hospitalization for purelyhealth monitoring purpose researchers at the Universityof Karlsruhe are developing a remote personal healthmonitoring system by employing a platform consisting ofwearable smart sensors measuring vital signs and of a basestation communicating wirelessly with the sensors [30 31]A patient monitoring system using multihop ad hoc wirelessnetworks is presented in [32] in which vital signs from onepatient are forwarded to another patient and this could thenbe transferred to an access point within range

The patients with an artificial heart implant are dis-charged from the hospital after an appropriate stabilizationperiod A web-based database system for reliable intelligentcontinuous remote monitoring of such patients was devel-oped in [34] The system consists of a portabledesktopmonitoring terminal a database for continuous recordingof patient and device status and an ldquointelligent diagnosisalgorithm modulerdquo that noninvasively estimates blood pumpoutput

31 Using wearable sensors

Among commercial telemetry systems CardioNet is the firstprovider of mobile cardiac outpatient telemetry (MCOT)service in USA for continuous monitoring of patientrsquos ECGand heartbeat at home at work or traveling [14 15] It auto-matically detects and transmits (using cellular connection)abnormal heart rhythms to the CardioNet monitoring centerwhere certified cardiac technicians analyze the transmissionsand respond appropriately 247365 In a clinical studyCardioNet mobile cardiac outpatient telemetry detectedserious arrhythmias in 53 of patients who had beenpreviously monitored with Holter andor event recordingwhere no arrhythmia was detected Philips provides atelemetry system which consists of a portable TeleMoncompanion monitor and the IntelliVue Information Centerto offer an integrated surveillance and monitoring solutionfor ambulating patients who require vigilant oversight ofECG and SpO2 [16] The IntelliVue telemetry system usesa cellular network to provide reliable two-way communica-tions between transceivers and the Information Center Thesystem provides audible feedback from transceiver on SpO2spot checks and patient out of range The GMP WirelessMedicine Corp developed LifeSync wireless ECG system forbedside monitoring [17 18]

A wearable wireless biomedical sensor system has beendeveloped in [5] The patient wears a wireless ECG sensor

Sunil Kumar et al 5

which transmits ECG signals to a dedicated hand-held device(HDD) If an abnormal cardiac signal is encountered theHHD unit transmits (using 3G cellular phone) the recordedECG to a hospital with an alarm The system uses anerror correction protocol based on the TCPIP for reliabletransmission However the system prototype seems to be toolarge for routine use by outpatients

An innovative system named WEALTHY is presented in[6] where conducting and piezoresistive materials in form offiber and yarn are integrated in a garment and used as sensorand electrode elements for simultaneous recording of vitalsigns Microsoft Corporation has developed ldquoHealthGearrdquo areal-time wearable system consisting of a set of physiologicalsensors wirelessly connected via Bluetooth to a Bluetooth-enabled cell phone for monitoring and analyzing physio-logical signals [1] Some other wearable health monitoringdevices have been discussed in [7ndash12] The MobiHealthproject in Europe aims to provide continuous monitoringof patients outside the hospital environment by using a3G-enabled body area networks (BAN) [13] The majorissues considered in the MobiHealth project are securityavailability and reliability of communication resourcesand QoS guarantees for bandwidth delay and bit errorrate

A wireless and wearable ECG monitoring system wasproposed in [27] to detect the rare occurrences of cardiacarrhythmias and to follow up critical patients from theirhome It continuously measures and transmits the sampledECG signals to the patientrsquos PDA using a built-in RF-radiotransmitter The PDA automatically connects to a GPRSmobile network to transmit the data to health providerA real-time patient monitoring system that integrates vitalsigns sensors location sensors ad hoc networking electronicpatient records and web portal technology was designed anddeveloped in [28]

The design of a processor which samples signals fromsensors on the patient has been addressed in [37] The pro-cessor consists of a signal conditioning module a peripheralcontrol module a processor and memory module with amicrocontroller and a Bluetooth communication module InFinland a system with secure mobile healthcare services wastested in 2003 [38]

CodeBlue is a wireless infrastructure for emergencymedical care integrating low-power wireless vital sign sen-sors PDAs and PCs [19 20] Some of their researchinterests include the integration of medical sensors with low-power wireless networks wireless ad hoc routing protocolsand adaptive resource management The system is scalableand robust with respect to the number of simultaneousqueries data rates and transmitting sensors Some othercritical issues considered by CodeBlue are flexible devicediscovery and naming for sensors prioritization of patientdata security and fast and reliable tracking of rescuerand victim locations The AMON system is a wrist-wornmedical monitoring and alert system targeting high-riskcardiacrespiratory patients [21] The system includes con-tinuous collection and evaluation of multiple vital signsmedical emergency detection and GSMUMTS cellularconnection to a medical center

More recent advances in wearable medical sensors

A new system-on-a-chip radar sensor for next-generationwearable wireless interface applied to the human health-care and safeguard is presented in [135] The overall systemconsists of a radar sensor for detecting the heart andbreath rates and a low-power IEEE 802154 ZigBee radiointerface which provides a wireless data link with remotedata acquisition and control units Particularly the pulseradar exploits 31ndash106 GHz ultrawide band signals whichallow a significant reduction of the transceiver complexityand then of its power consumption Such a novel system-on-a-chip wireless wearable interface enables low-cost silicontechnologies for contactless measuring of the primary vitalsigns and extends the capability in terms of applications forthe emerging wireless body area networks

Reference [136] presents a compact planar antennadesigned for wireless sensors intended for healthcare appli-cations Antenna performance is investigated with regardsto various parameters governing the overall sensor opera-tion The study illustrates the importance of including fullsensor details in determining and analyzing the antennaperformance A globally optimized sensor antenna shows anincrease in antenna gain by 28 dB and 29 higher radiationefficiency in comparison to a conventional printed stripantenna The wearable sensor performance is demonstratedand effects on antenna radiated power efficiency andfront-to-back ratio of radiated energy are investigated bothnumerically and experimentally

Although it is suggested to use wearable medical devicesand sensors as the nodes of body sensor networks (BSN)could allow better long-term monitoring of health conditionthe protocol and criteria for validating these nodes in clinicalsettings are often overlooked By using the validation ofblood pressure (BP) measurement devices as an example[137] reveals the need for new standards for nodes of BSNand proposes essential considerations to it It is observedfrom a previous clinical survey and their theoretical analysisthat there are disagreements in existing standards on the vali-dation of conventional BP devices Moreover an experimentcarried out by their group on 85 subjects demonstrates theinappropriateness of using the existing protocols that aresetup for validating cuff-based BP devices to evaluate newcuff-less measurement techniques The results suggested thata third objective measure could be introduced to relate thevariant standards It is also proposed that different validationcriteria should be used for nodes of BSN that are developedbased on new measurement principles

Reference [138] analyzes the main challenges associatedwith noninvasive continuous wearable and long-termbreathing monitoring The characteristics of an acousticbreathing signal from a miniature sensor are studied in thepresence of sources of noise and interference artifacts thataffect the signal Based on these results an algorithm hasbeen devised to detect breathing It is possible to implementthe algorithm on a single integrated circuit making itsuitable for a miniature sensor device The algorithm is testedin the presence of noise sources on five subjects and shows an


average success rate of 913 (combined true positives andtrue negatives)

32 Using cell phones

Some researchers have used cellular phones to transmit thevital signs from the ambulance to the hospital either in store-and-forward mode [22] or in real-time mode [23]

A 3G universal mobile telecommunications system(UMTS) solution for the delivery of voice real-time videoECG signals and medical scans information from anambulance to a hospital is presented in [33] The quality-of-service constraints for different services are investigatedand feasibility of using UMTS technology is demonstratedHowever the QoS provisioning is provided within thepatientrsquos data only (ECGvideovoice) and not with otherservices in UMTS The number of lost packets is very highas the number of users approaches 30 The system has to beevaluated for reliability measurement at high transmissionrate requirements

Steady advances in wireless networking medical sensorsand interoperability software create exciting possibilitiesfor improving the way we provide emergency care TheAdvanced Health and Disaster Aid Network (AID-N) [35]being developed at Applied Physics Lab of Johns HopkinsUniversity explores and show cases of how these advances intechnology can be employed to assist victims and respondersin times of emergency The system in [28] covers a subset ofthe technologies in AID-N

A cost-effective portable teletrauma system that assistshealth-care centers in providing prehospital trauma careis developed and implemented in [36] The simultaneoustransmission of a patientrsquos video medical images andelectrocardiogram signals which is required throughout theprehospital procedure is demonstrated over commerciallyavailable 3G wireless cellular data service Physicians canremotely control the information sent from the patient sideThis allows a trauma specialist to be virtually present at theremote location and participate in prehospital care whichcan potentially reduce mortality and morbidity To alleviatethe limited and fluctuant bandwidth barriers of the wirelesscellular link the system adapts to network conditionsthrough media transformations data prioritization andapplication-level congestion control methods

A multihop relaying scheme is used as overlay architec-ture for single-hop time division duplex (TDD) wideband-code division multiple access (W-CDMA) cellular networksin [52] A major challenge pertaining to the introduction ofthis technology into cellular networks is the design of anefficient slot assignment algorithm for relaying nodes Anheuristic slot assignment scheme namely delay-sensitive slotassignment (DSSA) is proposed in [53] DSSA is capableof fully utilizing a limited number of channels to enhancespatial reuse and reduce the end-to-end delay

A third-generation universal mobile telecommunicationssystem (UMTS) solution for the delivery of biomedicalinformation from an ambulance to a hospital is presentedin [115] The joint transmission of voice real-time videoelectrocardiogram signals and medical scans in a realistic

cellular multiuser simulation environment is consideredtaking into account the advantages and particularities ofUMTS technology for such transmission The accomplish-ment of quality-of-service constraints for different servicesis investigated and quantitative results were provided todemonstrate the feasibility of using UMTS technology foremergency care services on high-speed moving ambulancevehicles

The evaluation of the above technologies points to anumber of critical areas for future work The most seriousis the lack of reliable communication although results showthat this problem can be mitigated somewhat through redun-dant transmissions Reliable routing may not be requiredfor all medical data rather the system should allow eachquery to specify its reliability needs in terms of acceptableloss data rate or jitter Another area worth exploring isthe impact of bandwidth limitations and effective techniquesfor sharing bandwidth across patient sensors For exampleeach CodeBlue query could specify a data priority thatwould allow certain messages (eg an alert from a criticalpatient) to have higher priority than others in the presence ofradio congestion This approach can be combined with rate-limiting congestion control [14 25] to bound the bandwidthusage of patient sensors An important shortcoming of thecurrent CodeBlue prototype is its lack of security Integrationof private-key encryption [29] along with a public-keyprotocol for key distribution [22 38] should be investigatedThe privacy and security requirements for medical care arecomplex and differ depending on the scenario For exampleHIPAA privacy regulations need not be enforced during life-saving procedures Nevertheless integration of some formsof end-to-end security would be very helpful

4 USING HETEROGENEOUS (CELLULAR WLANAND AD HOC) NETWORKS

The advent of a myriad of wireless networking technolo-gies allows a mobile host today to be equipped withmultiple wireless interfaces that have access to differentwireless networks The present cellular network-based hybridschemes to handle host mobility are heavily dominatedby infrastructure-based schemes The vertical handoffs [6566] assuming the support of Mobile IP [67] have beenproposed to ensure continuous connectivity when themobile host roams between different wireless networksVarious interworking architectures [68ndash70 139 140] havealso been proposed to facilitate link-layer handoffs betweenthe WLAN and cellular networks Other approaches includeproviding a basic access network [71] or a communicationgateway [72] that the mobile host can access directlywithout being exposed to the heterogeneity of the backendnetwork infrastructure In [73] an end-to-end approach(without relying on the infrastructure support) is proposedto handle connection migration when the network addressof the mobile host changes during the lifetime of theconnection

The major drawbacks in handling host mobility in 3Gcellular-based heterogeneous networks are as follows

Sunil Kumar et al 7

(i) Reliance on infrastructure support Although severalapproaches have been proposed recently for achiev-ing host mobility without incurring the overheads inMobile IP [74ndash77] given the increasing heterogeneityof wireless access technologies the effectiveness ofthese approaches is greatly limited by the specificityto the networks they are designed for

(ii) Inability to leverage soft handoffs Even if soft handoffsare possible at the link layer in the absence ofany explicit support at a higher layer the migratedconnection experiences packet losses and suffers fromperformance degradation during the handoffs acrossheterogeneous networks Specifically although TCPmigration [78] achieves host mobility without relyingon the network support it performs a ldquohard handoffrdquoat the transport layer between the new and old TCPstates (ie transmission control blocks [79])

(iii) Lack of support for network-specific congestion controlschemes Despite the availability of network-specificcongestion control schemes no existing solutionsallow the mobile host to dynamically change them fora live connection when it migrates to a heterogeneousnetwork

(iv) No provision for resource aggregation When a mul-tihomed mobile host is within reach of more thanone network existing approaches do not allow it toleverage their resources simultaneously

An end-to-end scheme that enables a multihomedmobile host to seamlessly use the heterogeneous wirelessaccess technologies is recently proposed in [80] which allowshost mobility seamless vertical handoffs and effective band-width aggregation when the mobile host has simultaneousaccess to multiple networks

In 3G cellular networks mobile users experiencing poorchannel quality usually have low data-rate connections withthe base station A unified cellular and ad hoc network(UCAN) architecture for enhancing cell throughput whilemaintaining fairness is proposed in [54] In UCAN amobile client has both 3G cellular link and IEEE 80211-based peer-to-peer link The UCAN architecture improvesindividual userrsquos throughput by up to 310 and theaggregate throughput of the HDR downlink by up to 60Several companies such as GTRAN Wireless [55] are offeringintegrated cards that implement both IEEE 80211b and 3Gwireless interfaces Thus if routing protocols can be madeaware of both interfaces they can improve performancesignificantly by selecting the best interface(s) to deliverpackets to the mobile users

Deficiencies of mobile ad hoc networks include limitedwireless bandwidth efficiency low throughput large delaysand weak security Integrating it with a cellular network canimprove communication and security in ad hoc networks aswell as enrich the cellular services A cellular-aided mobilead hoc network (CAMA) architecture is proposed in [56]which provides throughput enhancements A CAMA agentin the cellular network manages the control information andthe routing and security information is exchanged between

mobile terminals (MTs) and the agent through cellular radiochannels A position-based routing protocol is developed inCAMA to make more accurate routing decisions CAMAinvolves high GPS cost and incurs delay when talking to theCAMA agent The integrated cellular and ad hoc relaying(iCAR) architecture addresses the congestion problem dueto unbalanced traffic in a cellular system and providesinteroperability for heterogeneous networks [57] A limitednumber of ad hoc relaying stations (ARS) and some increasein the signaling overhead (as well as hardware complexity)reduce the call blockingdropping probability in a congestedcell and the overall system A thorough performance studyof two such novel throughput enhancement architecturesiCAR and multihop cellular network (MCN) is carried outin [58] iCAR balances the traffic load and increases thenetwork throughput by relaying excess traffic from a hotcell to cooler cells through a multihop path over specialrouters called ad hoc relaying stations (ARS) However itrequires large number of relay stations due to small coverageand cellular channel shared between relay station and basestation MCN increases the network throughput by reducingthe data transmission power to half of the cell radiusthus increasing the spatial reuse of bandwidth These twoarchitectures thus benefit by combining the best of cellularand ad hoc systems

Directional antennas were used to enhance the spatialreuse in the ad hoc-cellular (A-Cell) architecture [59] In[60] the throughput performance of ad hoc GSM (A-GSM)scheme with respect to the number of dead spot locationsaverage dead spot size and mobile node population has beeninvestigated and compared to that of a 2G GSM systemArea coverage and capacity enhancement have also beeninvestigated in [61] where the multihop relaying increasesthe area coverage by 40 compared to the single-hop case

Correlated usage of mobile devices intensifies trafficbursts and introduces congestion in cellular networksldquoPARCelSrdquo which utilizes roaming mobile hosts to performroute relaying is discussed in [62] ldquoPARCelSrdquo performsoperations such as balancing traffic load avoiding trafficcongestion and reducing latency The disadvantages ofPARCelS are the need for high mobile station densitycomplexity and energy consumption

Another hybrid network model of cellular and ad hocnetworks called Sphinx is proposed in [63] which achieveshigher throughput and lower power consumption At thesame time Sphinx avoids the typical pitfalls of ad hoc net-works including unfair resource allocation and throughputdegradation due to mobility and traffic locality

Users in a hot cell typically experience a large delay Inmobile assisted data forwarding (MADF) scheme [64] anad hoc overlay network is added to the fixed cellular infras-tructure and special channels called ldquoforwarding channelsrdquoare used to connect users in a hot cell and its surroundingcold cells without going through the base station Theforwarding channel management in MADF is done bymobile units themselves A major advantage in MADF is thelow delay but the need for reserved cellular channels at therelay station (ie mobile unit) increases the computationalcomplexity


5 QOS REQUIREMENTS IN MOBILETELECARDIOLOGY APPLICATIONS

A comprehensive overview of various mobile telemedicinetechnologies as used in different settings is given in [81]Based on its delay tolerance the telemedicine data canbe classified as stream (eg ambient video and audio)conversational (videoconferencing) near real-time and notreal-time In medical environment different data trafficswith different classes of QoS requirements have to betransmitted simultaneously One of the critical issues to beinvestigated is how to optimize the network performanceto provide medical services with other multimedia servicessimultaneously

The telehealth data from different patients who may bewidely scattered will consist of various physiological param-eters text voice as well as video for diverse chronic diseasesThese data must coexist together as well as with othercommercial data such as voice video (streaming or real)multimedia and Internet QoS provisioning for the futureadvanced telehealth monitoring technologies and systemsis therefore a difficult proposition as the communicationinfrastructure must satisfy QoS requirements of differentclasses of applications In this section we analyze theresearch carried out in QoS provisioning in past telehealthmonitoring projects

The wide development of multimedia clinical applica-tions and the use of inter- and intrahospital communicationnetworks require a specific analysis to increase healthcare ser-vices efficiency A processing toolbox (QoSM3) for technicalevaluation of quality-of-service (QoS) traffic requirements innew healthcare services based on telemedicine is proposed in[116] This tool consists of the multimedia service definitionand the measurement and modeling processes which permitto analyze QoS requirements and to optimize applicationdesign regarding available network resources The proposedmethodology was tested to evaluate real-time and store-forward medical services

With the advent of the ldquonext-generation Internetrdquo andvarious related technologies important tradeoffs betweenemerging network capabilities and design-related applica-tion requirements for network-based distributed healthcaresystems are observed in [117] One of the aspects ofthese emerging network capabilities is quality of service(QoS) QoS guarantees are a necessary characteristic ofldquonext-generationrdquo networks which will have a profoundimpact on the deployment of advanced network-sensitivemedical applications Some of the underlying aspects ofQoS technologies and possible considerations in designingnetwork-based medical systems are discussed in [117] Onesuch system that attempts to solve some QoS problems aswell as provides a system for telehealth is called ldquoCardimonrdquoand will be overviewed in Section 7

QoS guarantees are a necessary characteristic of ldquonext-generationrdquo networks which will have a profound impacton the deployment of advanced network-sensitive medi-cal applications [82] A mobile telemedicine system wastested in three ambulances using commercial off-the-shelfequipment with data-management and physician interface

software [83] The main problems encountered by the aboveprototype were the instability in the commercial systemcomponents and unpredictable wireless connectivity andbandwidth resulting in inconsistent system performancewhich frustrates the physician The project in [84] tested apatient monitoring system and evaluated the network per-formance Although the 3G networks significantly performbetter than 25G they might not be adequate to supportthe bandwidth and delay requirements of the sophisticatedand demanding m-health services The teletrauma scenariorequires the transmission of patientrsquos vital signs togetherwith audiovideo signals in real-time from the scene of theaccident [85] High Plains Rural Health Network (HPRHN)based in Fort Morgan Colorado is an interactive video net-work for real-time monitoring and diagnosis of patients atthe sites of serious automobile accidents on the highways In[86] the notion of QoS for communication of telemedicinemultimedia data is presented for preorchestrated as well aslive videoconferences

The InfraVIDA telemedicine system allows remotelylocated health professionals to make telediagnosis and getsecond medical opinion from consultants [87] Applicationsget differentiated services (ie DiffServ QoS) from thenetwork (eg expedited forwarding assured forwarding)with associated parameters such as bandwidth delay jitterand packet loss A scalable and flexible QoS provisioningis discussed in [141] based on a bandwidth broker (BB)to automate admission control and router configurationThe BB allocates resources for each incoming flow basedon the requested QoS its service level agreement and theavailable resources The performance of a WCDMA cellularsystem supporting teleechography services is evaluated in[88] for two types of traffic with different source coding andQoS schemes A slow fading multipath Rayleigh channel isassumed in the paper

A load-balancing platform based on differentiation ofservices that improves the application-level QoS (such asclient response time priority) in a telecare application ispresented in [89] The platform allows the coexistence ofInternet services and distributed objects QoS parametersare associated to different service classes (premium goldbronze and best effort) Some of these telecare services (suchas signal processingconditioning alarm generation) needhigh performance and availability while some others needhigher priority (such as vital signals) When a client requestarrives the system knows what QoS parameters must beprovided depending on its service class

Experts around the world believe that new demands inproviding healthcare will require fundamental changes inthe structure of the network and communication [90] Itis almost impossible to separate the deployment of QoScapabilities from a thorough evaluation in the context ofan application (or class of applications) with the majorchallenge being their vast and highly variable requirementsSome compromises proposed in [91] are (i) evaluation ofpotential QoS mechanisms jointly in the context of physicalnetwork elements and a representative class of ldquonext-generationrdquo applications (ii) the development of mecha-nisms which end-users can access to participate directly

Sunil Kumar et al 9

in the negotiation between the network capabilities andapplication requirements In LAN-based networks and inthe concept of next-generation Internet there tends to berelatively few general approaches such as (i) shaping theaggregate traffic streams with simplistic regard for the needsof individual streams or (ii) having the capability to ensurespecific service characteristics for individual streams at theexpense of tremendous complexity for the user andorapplication to ensure the integrity of data streams

The wide deployment of multimedia clinical applicationsand the use of inter- and intrahospital communicationnetwork require a specific analysis to increase healthcare ser-vices efficiency A processing toolbox (QoSM3) for technicalevaluation of QoS traffic requirements in new healthcareservices based on telemedicine is proposed in [104] Themultimedia service definition and the measurement andmodeling processes permit to analyze QoS requirements andto optimize application design regarding available networkresources The proposed method has been tested to evaluatereal-time and store-forward medical services In order toextract the maximum benefit of telemedicine services it isessential to define a precise methodology to characterizethe QoS requirements for the transmitted information andthe management of the available network resources [105]Three important QoS evaluation metrics are (i) efficiency(ii) acceptability and (iii) usefulness In order to optimize theQoS in these telemedicine services it is crucial to study twoaspects [106ndash108] the nature of the transmitted biomed-ical information and the behavior of the communicationnetworks The variability of the resources (eg in mobileinfrastructures) and the heterogeneity of the connections(eg in the Internet) require to measure and to model theintercommunication networks [109ndash111]

When we study the traffic modeling to offer QoS itis essential to begin from source and network models thatcompose it to understand traffic dynamics and to use thatknowledge in the subsequent design Hence the teletrafficengineer role [112] would be the ldquofeedbackrdquo where themeasures inform about their behavior and the QoS criteriadefine their performance An extended criterion consistsof managing and adapting the information generated bythe applications (encoders transmission rates compressionratios etc) to the available networks resources Specificallyin healthcare environments it would allow improving thetelemedicine service QoS by looking for the optimum values[113 114]

Reducing the elapsed time between symptom onset andtreatment can be of great benefit to the patient while reduc-ing the health care costs [83] With mobile telemedicinevaluable prehospital transport time can be used to diagnoseand evaluate the patient en route

To alleviate the problems encountered in using mobilecommunications some enhancements proposed in [83] wereas follows

(i) Less reliance on commercial systems integration Thishelps in rapidly identifying and solving the problems

(ii) Creation of a hybrid connectivity architecture usingoverlapping wireless infrastructures Overlapping net-

work coverage provided by competing networkproviders enables (a) higher aggregate data through-put and (b) improved cell-to-cell connectivityCombining different types of wireless connectivityincluding both ldquoalways-onrdquo Internet-protocol-basedconnectivity and more traditional dial-up cellularcommunications the resulting smart communica-tions architecture allows to dynamically optimize theunderlying communications channels for bandwidthdelay throughput stability and cost

(iii) Bidirectional QoS control allows the receiving physi-cian to dynamically reprioritize the data transmissionto optimize bandwidth utilization and data through-put For example the receiving physician can alterthe frequency and quality of the images transmittedor may opt to turn on or off the waveform andnumerical vital signs information being sent bythe patient monitor Providing this level of controlalongside a dynamic graphical QoS display providesthe physician with the ability to direct QoS deliveredby the system in real time

A prerequisite for the successful deployment of m-healthservices for continuous monitoring of a patientrsquos vital signsis the QoS support (speed accuracy dependability of datadelivery and network availability user mobility and numberof concurrent users) by underlying wireless network(s) [92]as follows

(i) High delay variations (ie jitter) have major negativeinfluence on the system performance The delayvariations are contributed from the physical layermechanisms (eg due to 3G bearer (re)assignments)to the high-level protocol mechanisms (eg protocolrecovery from lower-level communication errors)Within the higher layers the jitter may be causedby the TCP retransmission mechanism together with(unnecessary) reduction of the sending rate dueto the noncongestion-based message loss Anotherpossible reason can be delays due to the unpredictableoverall-system events like resource problems or inter-mediary system (processing) delays Due to the highjitter the average end-to-end delay is much higherthan that expected

(ii) The 3G networks have asymmetric capacitythat is the downlink capacity is (much) higherthan the uplink However in telemedicine thepatientambulance transmits high quantities of datato the health providerhospital

(iii) Another problem observed is concerned with thebearer (re)assignment within the 3G network Datatransport always starts from the common bearer(which supports low bandwidth) and then graduallybased on the traffic volume the network assigns ahigher bearer (which supports higher bandwidth)The exact conditions under which the bearer assign-ment takes place depend on operator Bearer changes


were observed when the offered load was increasingbut random bearer changes were also observed whenthe offered load was stable This bearer changemechanismpolicy might cause problem (such asbuffer overflow and delay variations) for the m-health service when the service offers bursty traffic tothe transport system

(iv) The possibility to negotiate the QoS profiles thatldquoreserverdquo a particular dedicated bearer for trans-portation of m-health related data should beexplored If the bearer assignment mechanism isknown the service can be deployed such that itbenefits from the performance characteristics of theunderlying transport system Operators and manu-factures should consider this fact in order to allow fora better support of forthcoming m-health services

(v) Fulfillment of the reliability requirement is criticalto success of mobile wireless communications intelehealth applications However some services donot require 100 system reliability Moreover thereis a tradeoff between the systemrsquos reliability andthe performance The reliable service delivery isusually ensured by means of a TCP-based underlyingtransport service This reliable service delivery mayresult in system performance degradation that issignificant delay variation Therefore the use ofunreliable UDP-based underlying transport serviceshould be explored A study of accuracymdash(ie datacorruption probability) and dependabilitymdashrelated(ie transport system availability data loss probabil-ity) performance characteristics of the (UDP-based)transport system is an essential subject for futureresearch

(vi) Low power consumption is also an important issueto be considered in remote monitoring of mobilepatients For example the battery of the patientPDA will typically last only a few hours in a 3Gcommunication whereas 24 hours battery life isexpected

In [93] an in-depth analysis on the system bottleneckand scalability performance characteristics is presented TheQoS parameters for telemedicine constitute a set of user-specified tolerable degradations of multimedia presentationsthat may occur due to resource limitations These parameterscan be used to quantify the presentation process from theuserrsquos point-of-view and establish network resources require-ments to ensure the delivery of multimedia informationwith the desired quality Interstream synchronization couldbe used on applications which require that all data streamsmust be delivered prior to their deadlines [91] Anotherquality issue is the loss of telemedicine data due to limitedbuffer capacity at the client site Thus random network delaysand scheduling to ensure synchronization can lead to bufferoverflow However isochronous data such as video and audiocan tolerate some information loss without affecting theirplay-out quality Depending on the required quality a usercan quantify the acceptable data loss for each object

6 FOURTH GENERATION (4G) MOBILETELECARDIOLOGY

In this section we discuss the limitations of 3G wirelesstechnology in meeting some of the demands of efficientreal-time monitoring of cardiac patients We analyze the 3Gtechnology and also discuss the evolution and features of 4Gtechnology that will give a magnanimous boost to telehealthmonitoring applications

When the 3G systems scenario and capabilities evolved alot of research work was carried out to create next-generationtelemedicine systems using this technology One such effortwas carried out by the authors in [94] who proposed a test-bed based on a 3G cellular standard for the next-generationmobile telemedicine The 3G-based testbed (122 Kbps sim2 Mbps) had higher and wider transmission data ratesthan the 2G version (up to 96 Kbps) To demonstrate theusefulness of the testbed and the potential to improve theQoS for mobile medical applications a simple cardiologysystem was designed Because this testbed is based on 3GPPFDD mode standard its data traffic channel has five rates122 64 144 384 and 2084 Kbps to be selected accordingto the required medical service

There are multiple standards for 3G making it difficult toroam and interoperate across networks Therefore it cannotsupport the global mobility and service portability 3G isbased on primarily a wide-area concept It does not supporthybrid networks that utilize both wireless LAN (hot spot)concept and cell or base-station based wide area networkdesign 3G systems support a peak bandwidth of only a fewMbps Researchers have recently developed spectrally moreefficient modulation schemes that cannot be retrofitted into3G infrastructure We need all digital packet networks thatutilize IP in its fullest form with converged voice and datacapability

Research on fourth generation (4G) and beyond 4G(4G+) mobile communication systems is already under wayto achieve both high data rates and extended coverage ofthe geographical area [59 60 95ndash98] 4G is an initiativeby researchers from various universities and industry (egMotorola Qualcomm Nokia Ericsson Sun HP NTTDoCoMo) to move beyond the limitations and problems of3G to address future needs of a universal high-speed wirelessnetwork that will interface with wired backbone networkseamlessly [99] A comparison between features of the 3Gand 4G wireless networks is provided below

A number of spectrum allocation decisions spectrumstandardization decisions spectrum availability decisionstechnology innovations component development signalprocessing and switching enhancements and intervendorcooperation have to take place before the vision of 4G willmaterialize 3G experiencesmdashgood or bad technological orbusinessmdashwill be useful in guiding the industry in this effort

Providing mobile communication services based on newtechnology such as 4G technology involves more than simplyproposing and proving technologymdashit also requires field-testing of functions and performance standardization oftechnical specifications development of mobile terminalsand construction of network facilities A basic approach

Sunil Kumar et al 11

Table 1

Parameter 3G (including 25G sub 3G) 4G

Major requirementDriving architecture

Predominantly voice driven-datawas always add on

Converged data and voice over IP

Network architecture Wide area cell-basedHybrid-integration of wirelessLAN (Wi-Fi Bluetooth) andwide area

Speeds 384 Kbps to 2 Mbps 20 to 100 Mbps in mobile mode

Frequency bandDependent on country orcontinent (1800ndash2400 MHz)

2ndash8 GHz

Bandwidth 5ndash20 MHz 100 MHz (or more)

Switching design basis Circuit and packet All digital with packetized voice

Access technologies W-CDMA 1xRTT edge OFDM and MC-CDMA

Forward error correction Convolutional rate 12 13 Concatenated coding scheme

Component designOptimized antenna designmultiband adapters

Smarter antennas softwaremultiband and wideband radios

IPA number of air link protocolsincluding IP 50

All IP (IP60)

to the technical issues and system configuration involvedin achieving the capabilities and performance required ofthe 4G system based on the research at NTT DoCoMo isdescribed in [100]

The major design objectives of a 4G mobile com-munication system are (i) providing higher transmissionrates (approximately 100 Mbitss in an outdoor mobileenvironment and gigabit rates indoors) and larger capacity(both in terms of number of users and traffic volume)than IMT-2000 (ii) a transmission capacity (bandwidth)of at least 10 times that of IMT-2000 has to be achieved(iii) for achieving high throughput and high-level real-timecommunications it is necessary to achieve a low transferdelay time of 50 seconds (iv) seamless connection andhandoff between heterogeneous access systems (v) sincefuture services will all be based on IP networks efficienttransmission of IP packets over wireless connections is alsoa necessity and (vi) while increased capacity is also effectivein lowering the bit cost the cost per bit must be reduced tobetween 110 and 1100 of the current levels by reducing theinfrastructure equipment operation and construction costs

The major technical issues for the development ofa ubiquitous 4G mobile communication system are thefollowing

(1) High capacity and high-rate transmission IMT-2000achieves a transmission rate of 2 Mbps with a 5-MHzfrequency bandwidth Furthermore technology fortransmission at approximately 10 Mbps with thesame frequency bandwidth using multilevel adaptivemodulation and demodulation is under development[101] To achieve rates of 100 Mbps to 1 Gbps largerfrequency bandwidth and new transmission systemsare required that are suited to high-rate transmissionA radio access system that can transmit packetsefficiently with considering the importance of indoorarea coverage in the future allows the use of bothindoors and outdoors To obtain the broadband

frequencies for achieving high-rate transmission andmeet the expected large increase in data trafficdemand new frequency bands must be considered

(2) Lower costs Using a higher frequency band to achievea higher transmission rate generally reduces the areaof the cell that a base station can cover Retainingthe original coverage area therefore requires morebase stations and this increases the network costIt is therefore necessary to expand the cell radiusby using higher performance radio transmissionand circuit technology such as improved modula-tiondemodulation techniques that can cope with alow signal-to-noise ratio adaptive array antennasand low-noise receivers To further reduce the systemconstruction and operating costs a study of diversi-fied entrance links that connect base stations to thebackbone network autonomous base station controltechnology and multihop radio connection technol-ogy employing simple relay stations is required

(3) Interconnection based on IP networking To enableinternational roaming a terminal that can be con-figured to work with multiple systems based onsoftware defined radio (SDR) technology [102] couldbe an effective way to cope with introductory periodsand differences in operating frequency bands amongdifferent countries and regions Furthermore futuremobile communication networks will be integratedwith heterogeneous access methods and variouskinds of cells with interconnection capabilities basedon IP networking Accordingly interconnection andhandover between such various access systems arerequired in addition to handover and roaming withinone mobile communication system

The system configuration for the 4G mobile com-munication system is as follows (i) IP-based connectionconfiguration 4G systems will be configured for connection


At homenursinghomehospice

At work

Sending alarms to nearestemergency rescue squad

Cardimon

Wired cum wirelessheterogeneous network

Mobile at leisuretime

On (business) trip

Cardiac surgeonexpert at theICUemergency station

Paramedic providing first aid

Application servers atlocal physician clinic Attending nursephysician802154

Figure 1 Ubiquitous monitoring of patients using xG networking

to IP networks considering efficient transmission of IPpackets coexistence with other access systems ease ofsystem introduction expandability and other such factorsIP networks can also connect with or accommodate wirelessaccess systems other than 4G systems (ii) Cell classificationand configuration according to the communication envi-ronment the 4G system has cells for outdoors indoorsand inside moving vehicles Outdoor cells cover a widearea unlike the hotspot areas of wireless LANs and allowhigh-rate packet transfer for fast-moving terminals Indoorareas are covered by indoor access point (APs) becausethe radio waves tofrom outdoor base stations suffer largeattenuation Indoor APs are designed not only to provide ahigh rate transfer and simple operation but also to competewith expected future wireless LANs [142 143] A multihopconnection which is effective in expanding the cell size isbeing investigated as a way to overcome dead spots caused byshadowing Data transmission via relay stations is expectedto allow communications even when the effects of limitedterminal transmitting power and radio wave propagationattenuation are large [103] (iii) Multimedia communica-tions conventional IP networks have provided mainly best-effort services but with real-time applications expectedto increase as multimedia communication diversifies theimportance of services that take into account QoS is alsoexpected to increase The 4G system configuration allows fora mechanism that guarantees the transmission rate to someextent and that prioritizes packet transfer by the packet typein cooperation with the IP network for QoS-aware packettransmission on a mobile radio link which is the bottleneck

7 NEXT-GENERATION (xG) TELECARDIOLOGYNETWORK ARCHITECTURE

Next-generation cardiac monitoringsystem provides ubiqui-tous monitoring to patients wherever and whenever neces-sary as shown in Figure 1 It consists of wearable and light-weight wireless biomedical sensors (for measuring 3 leadECG Spo2 heart beat and blood pressure) which constantlycommunicate to the monitor a unit about the size of amobile phone or PDA The monitor is battery poweredand equipped with signal processingconditioning modulememory and different wireless interfaces and radios Majorfeatures of xG system are the following

(i) The signal processing module carries out local anal-ysis of recorded physiological measurements andtransmits them based on the patient-specific moni-toring thresholds and response parameters such astiming and frequency of response as predeterminedby the health provider

(ii) When the monitor detects an abnormal or arrhyth-mic event it automatically transmits the ECG andother measurements to the health provider in real-time (with an alarm signal if required) as discussedbelow Or when a patient experiences symptom(s)heshe can transmit the physiological measurementssymptom(s) and activity data through a monitortouch-screen

(iii) The system is equipped with multiple radios andthe wireless interfaces for connectivity to different


wireless networks such as 3G cellular WLANWiMax and wireless ad hoc (for multihop relaying)This enables the system to connect to the best avail-able network depending on various QoS parameters

(iv) Location-based services using Global PositioningSystem (GPS) for positioning geographic informa-tion systems and location management functionsThis would enable the user to access nearby emer-gency services whenever required

(v) Generation of alarm signals when (a) abnormalmedical situation is detected (b) health providersends instructions to the patient or needs additionalinformation from the patient (c) when the system isunable to contact the health provider and send data(d) when the system is unable to detect signals frompatientrsquos sensors and (e) when the system is low onbattery

The cardiac patients in xG systems could be divided intothe following categories based on the severity of their healthconditions as detected by the system based on the thresholdsset by health provider The health provider while prescribingthe system to the patient assigns a particular class to thepatient This class is automatically changed by the transportprotocol in the system depending on the severity of the healthcondition as follows

(i) Class 0 (highest priority requiring real-time mon-itoring) Patients in emergency conditions like thepatients in the ambulances or in the followingmedical conditions

(a) ventricular fibrillation (VF) ventricular tachy-cardia (VT) with hemodynamic compromiseelectromechanical dissociation (cardiac stand-still) indicating risk of sudden cardiac deathrequiring medical assistance in less than 3minutes

(b) stable VT with no hemodynamic compromisebut still indicating very high risk of suddencardiac death requiring medical assistance in15ndash20 minutes

(c) AF with fall in BP and SpO2 indicates thatventricle is also beating fast which is life threat-ening Arrhythmias (such as short runs of VT)that precede and succeed a heart attack (iemyocardial infarction) and also precede suddencardiac death requiring medical assistance in 30minutes

(ii) Class 1 (requiring near real-time monitoring withinfew hours) The patients experience the followingabnormal rhythms such as atrial flutter paroxysmalatrial fibrillation fast supraventricular tachyarrhyth-mia sinus bradycardia like sick sinus syndrome ormobitz type 2 block

(iii) Class 2 (requiring periodic monitoring such as twicedaily)

(a) Patient with recurrent episodes of AF of morethan 10 minutes for 4-5 times in a day who isnot covered by anticoagulant like ldquocomudinrdquoHealth provider should be notified so thatheshe can be put on blood thinning drugldquocomudinrdquo to prevent development of highlymorbid and often mortal disease such as stroke

(b) Patient with recurrent and prolonged AF (fre-quency and duration) associated with fast ven-tricular rate (150ndash200) Health provider shouldbe notified for change in treatment to preventdevelopment of sudden cardiac death

(iv) Class 3 (requiring monitoring from time to time)

(a) Patients with heart failure who are at riskof SCD but are not candidates to get ICDimplantation Based on the monitoring resultssome of such patients may be triaged to get anICD despite not fulfilling the criteria

(b) Patients with syncope of unknown etiologydizziness lightheadedness palpitations

(c) Patients with obstructive sleep apnea to evalu-ate possible nocturnal arrhythmias

(d) Patients requiring arrhythmia evaluation foretiology of stroke or transient cerebral ischemiapossibly secondary to atrial fibrillation

The cardiac telehealth application has to coexist withother telemedicine emergency and consumer applicationson public wireless networks These applications have dif-ferent bandwidth (text audio video) reliability and delayrequirements Though the bandwidth utilized by cardiactelehealth data could be much less than many multimediaapplications reliable and low latency transmission of the datacould become challenging in many situations such as heavytraffic load and unavailability of reliable wireless link in deador hot spots

The unpredictable xG wireless network shown inFigure 2 could be a combination of wireless and wirednetworks The wireless networks are in turn a combination ofWLANs (like Wi-Fis of offices and other buildings) WiMAXnetworks 3G cellular and ad hoc wireless networks

As discussed earlier xG system has the capability toconnect to different networks simultaneously whereas theother routers including the edge routers shown in Figure 2may or may not have this capability The backbone network isalways chosen as the wired Internet The front-end networksare chosen by the system based on patientrsquos locationrequired telehealth service class and condition of availablenetworks The cardiac telehealth data could be sent in eithera single hop or multihop manner The multihop transfer ofmedical data is justified in cases of nonavailability of cellularconnection in some portions of a building due to fadingor interference from other networks The data is then sentthrough personal area networks or Wi-Fi networks availableand finally through the Internet or through a cellular base-station


Multimedia webapplications Remote Ethernet

database accessCellular users

Video contentservers

Unpredictable heterogeneouswirless network

Audiovideoapplications

Cardiac telehealthdata

Other hospitalinformation systems

Ambulance systemsemergencymedical paramedics

Wireless Ad-Hoc networkWLANWiMax

Figure 2 Unpredictable xG network over which the data has to be reliably sent to the remote health provider

xG system first senses for the available networks andtries to obtain information about their available bandwidthtraffic characteristics maximum delay and so forth Asshown in Figure 2 the patient can either connect to a Wi-Finetwork which could exist in a WiMax network or couldpick up an ad hoc network The data sent by the patientreaches the service provider through the Internet which isthe backend network or Wi-Fi or cellular network Anothercritical issue of the system is that when it is unable to connectto an intermediate network it immediately tracks a groupof closely available systems (through location-based services)to whom it can directly communicate selects the systemthat has the best connectivity in terms of network resourceslike available bandwidth traffic through the network andthen may send the data simultaneously through all ofthem This process requires tracking of neighboring systemsnegotiation for cognizance of the network parameters andselection of the best system to reduce the delay of datatransfer to the nearest emergency rescue squad

When xG system is unable to find any network fordata transmission it stores the data in its memory andtransmits it as soon as it can establish connection with anetwork When network connection is not available andthe signal processing module detects an abnormal medicalmeasurement the patient may be suitably alerted by thesystem to contact health provider or seek medical help bylocating nearby health facility with the help of GPS unit

8 CONCLUSIONS

This paper provides an overview of telecardiology systemsvia wireless and mobile technologies Especially we covered1GsimXG evolutions and their QoS requirements There aremany pitfalls encountered when creating a mobile telecardi-ology network Firstly the hardware itself must be wearable

and reliable as it will be worn for long periods of time invarious environments Secondly sensor communication toa base-station also worn on the body requires additionalresearch as the interference from multiple sensors does notscale linearly Thirdly the communication from base-stationto doctor must traverse multiple network types (3G WiFi4G Bluetooth etc) with different packet size requirementsand data loss parameters New protocols must be devised thatallow for transmission across all networks with a consistentquality of service because patients have differing severity ofhealth and sensors have different media to transmit (videosound text etc) the QoS can be different from patientto patient In this paper we addressed telehealth problemsalong with existing technologies mitigating these issues Thisincluded the advent of xG system which can operate across afew networks with some quality of service In sum there area wide variety of problems that must be overcome to makemobile telecardiology a reality

ACKNOWLEDGMENTS

The work is partially supported by the US National ScienceFoundation (NSF) under Grants no CNS-0716455 andno CNS-0716211 and Research Grants Committee (RGC)Award at The University of Alabama

REFERENCES

[1] N Oliver and F F Mangas ldquoHealthGear a real-time wearablesystem for monitoring and analyzing physiological signalsrdquoTech Rep MSR-TR-2005-182 Microsoft Corporation Red-mond Wass USA 2005

[2] C S Pattichis E Kyriacou S Voskarides M S PattichisR Istepanian and C N Schizas ldquoWireless telemedicinesystems an overviewrdquo IEEE Antennas and PropagationMagazine vol 44 no 2 pp 143ndash153 2002


[3] Y-H Lin I-C Jan P C-I Ko Y-Y Chen J-M Wong andG-J Jan ldquoA wireless PDA-based physiological monitoringsystem for patient transportrdquo IEEE Transactions on Informa-tion Technology in Biomedicine vol 8 no 4 pp 439ndash4472004

[4] T J Bunch R D White B J Gersh et al ldquoLong-termoutcomes of out-of-hospital cardiac arrest after successfulearly defibrillationrdquo New England Journal of Medicine vol348 no 26 pp 2626ndash2633 2003

[5] R Fensli E Gunnarson and O Hejlesen ldquoA wireless ECGsystem for continuous event recording and communicationto a clinical alarm stationrdquo in Proceedings of the 26th AnnualInternational Conference of the IEEE Engineering in Medicineand Biology Society (EMBS rsquo04) vol 1 pp 2208ndash2211 SanFrancisco Calif USA September 2004

[6] R Paradiso G Loriga and N Taccini ldquoA wearable healthcare system for vital signs monitoringrdquo in Proceedings ofthe 10th Mediterranean Conference on Medical and BiologicalEngineering and Computing (MEDICON rsquo04) Ischia ItalyAugust 2004

[7] T Martin E Jovanov and D Raskovic ldquoIssues in wearablecomputing for medical monitoring applications a case studyof a wearable ECG monitoring devicerdquo in Proceedings ofthe 4th International Symposium on Wearable Computers(ISWC rsquo00) pp 43ndash49 Atlanta Ga USA October 2000

[8] P-T Cheng L-M Tsai L-W Lu and D-L Yang ldquoThedesign of PDA-based biomedical data processing and analysisfor intelligent wearable health monitoring systemsrdquo inProceedings of the 4th International Conference on Computerand Information Technology (CIT rsquo04) pp 879ndash884 WuhanChina September 2004

[9] S Park and S Jayaraman ldquoEnhancing the quality of lifethrough wearable technologyrdquo IEEE Engineering in Medicineand Biology Magazine vol 22 no 3 pp 41ndash48 2003

[10] Foster-Miller ldquoFoster-miller receives additional $3 millionfrom DOD for electro-textile health-monitoring vest devel-opmentrdquo httpwwwfoster-millercom

[11] E Jovanov A Milenkovic C Otto and P C de GroenldquoA wireless body area network of intelligent motion sensorsfor computer assisted physical rehabilitationrdquo Journal ofNeuroEngineering and Rehabilitation vol 2 article 6 pp 1ndash10 2005

[12] D Husemann C Narayanaswami and M Nidd ldquoPersonalmobile hubrdquo in Proceedings of the 8th International Sympo-sium on Wearable Computers (ISWC rsquo04) vol 1 pp 85ndash91Arlington Va USA October-November 2004

[13] D Konstantas A V Halteren R Bults et al ldquoMobile patientmonitoring the mobihealth systemrdquo in Proceedinggs of theInternational Conference on Medical and Care Compunetics(ICMCC rsquo04) Hague The Netherlands June 2004

[14] httpwwwcardionetcommediapdfMCOTRothmapdf[15] httpwwwcardionetcom[16] httpwwwmedicalphilipscommainproductspatient

monitoringproductstelemetry[17] httpwwwwirelessecgcom[18] httpcommunitynursingspectrumcomMagazineArticles

articlecfmAID=12390[19] D Malan T Fulford-Jones M Welsh and S Moulton

ldquoCodeblue an ad hoc sensor network infrastructure foremergency medical carerdquo in Proceedings of the InternationalWorkshop on Wearable and Implantable Body Sensor Networks(BSN rsquo04) London UK April 2004

[20] K Lorincz D J Malan T R F Fulford-Jones et alldquoSensor networks for emergency response challenges and

opportunitiesrdquo IEEE Pervasive Computing vol 3 no 4 pp16ndash23 2004

[21] U Anliker J A Ward P Lukowicz et al ldquoAMON a wearablemultiparameter medical monitoring and alert systemrdquo IEEETransactions on Information Technology in Biomedicine vol8 no 4 pp 415ndash427 2004

[22] P Giovas D Papadoyannis D Thomakos et al ldquoTrans-mission of electrocardiograms from a moving ambulancerdquoJournal of Telemedicine and Telecare vol 4 supplement 1 pp5ndash7 1998

[23] S Pavlopoulos E Kyriacou A Berler S Dembeyiotis and DKoutsouris ldquoA novel emergency telemedicine system basedon wireless communication technologymdashAMBULANCErdquoIEEE Transactions on Information Technology in Biomedicinevol 2 no 4 pp 261ndash267 1998

[24] P Rubel F Gouaux J Fayn et al ldquoTowards intelligentand mobile systems for early detection and interpretationof cardiological syndromesrdquo in Proceedings of the AnnualConference on Computers in Cardiology vol 28 pp 193ndash196Rotterdam The Netherlands September 2001

[25] H Atoui J Fayn and P Rubel ldquoA neural network approachfor patient-specific 12-lead ECG synthesis in patient mon-itoring environmentsrdquo in Proceedings of the Annual Con-ference on Computers in Cardiology vol 31 pp 161ndash164Chicago Ill USA September 2004

[26] F Gouaux L Simon-Chautemps J Fayn et al ldquoAmbientintelligence and pervasive systems for the monitoring ofcitizens at cardiac risk new solutions from the EPI-MEDICSprojectrdquo in Proceedings of the Annual Conference on Comput-ers in Cardiology vol 29 pp 289ndash292 Memphis Tenn USASeptember 2002

[27] R Fensli E Gunnarson and T Gundersen ldquoA wearableECG-recording system for continuous arrhythmia monitor-ing in a wireless tele-home-care situationrdquo in Proceedingsof the 18th IEEE Symposium on Computer-Based MedicalSystems pp 407ndash412 Dublin Ireland June 2005

[28] T Gao D Greenspan M Welsh R R Juang and AAlm ldquoVital signs monitoring and patient tracking overa wireless networkrdquo in Proceedings of the 27th AnnualInternational Conference of the IEEE Engineering in Medicineand Biology Society (EMBS rsquo05) pp 102ndash105 ShanghaiChina September 2005

[29] C H Salvador M P Carrasco M A G de Mingo et alldquoAirmed-cardio a GSM and internet services-based systemfor out-of-hospital follow-up of cardiac patientsrdquo IEEETransactions on Information Technology in Biomedicine vol9 no 1 pp 73ndash85 2005

[30] ldquoITIV Uni Karlsruhe Personal Health Monitoring Systemrdquohttpwwwphmonde

[31] C Kunze U Grossmann W Stork and K D Muller-Glaser ldquoApplication of ubiquitous computing in personalhealth monitoring systemsrdquo in Proceedings of the 36th AnnualCongress of the German Society for Biomedical Technology(DGBMT rsquo02) pp 360ndash362 Karlsruhe Germany September2002

[32] U Varshney ldquoUsing wireless networks for enhanced mon-itoring of patientsrdquo in Proceedings of the 10th AmericasConference on Information Systems (AMCIS rsquo04) pp 1ndash7New York NY USA August 2004

[33] J R Gallego A Hernandez-Solana M Canales J LafuenteA Valdovinos and J Fernandez-Navajas ldquoPerformanceanalysis of multiplexed medical data transmission for mobileemergency care over the UMTS channelrdquo IEEE Transactions


on Information Technology in Biomedicine vol 9 no 1 pp13ndash22 2005

[34] J Choi J W Park J Chung and B G Min ldquoAn intelligentremote monitoring system for artificial heartrdquo IEEE Transac-tions on Information Technology in Biomedicine vol 9 no 4pp 564ndash573 2005

[35] ldquoAID-N Advanced Health and Disaster Aid Network down-loadable fromrdquo httpwwwsentillacompdfSentilla CaseStudy-AID-Npdf

[36] Y Chu and A Ganz ldquoA mobile teletrauma system using 3Gnetworksrdquo IEEE Transactions on Information Technology inBiomedicine vol 8 no 4 pp 456ndash462 2004

[37] M F A Rasid and B Woodward ldquoBluetooth telemedicineprocessor for multichannel biomedical signal transmissionvia mobile cellular networksrdquo IEEE Transactions on Informa-tion Technology in Biomedicine vol 9 no 1 pp 35ndash43 2005

[38] P Jelekainen ldquoGSM-PKI solution enabling secure mobilecommunicationsrdquo International Journal of Medical Informat-ics vol 73 no 3 pp 317ndash320 2004

[39] F Gemperle C Kasabach J Stivoric M Bauer and RMartin ldquoDesign for wearabilityrdquo in Proceedings of the 2ndInternational Symposium on Wearable Computers (ISWC rsquo98)pp 116ndash122 IEEE Computer Society Press Pittsburgh PaUSA October 1998

[40] Bluetooth Special Interest Group (SIG) httpwwwbluetoothorg

[41] M Jakobsson and S Wetzel ldquoSecurity weaknesses in blue-toothrdquo in Proceedings of the Cryptographersrsquo Track at RSAConference (CT-RSA rsquo01) vol 2020 of Lecture Notes inComputer Science pp 176ndash191 Springer San FranciscoCalif USA April 2001

[42] G Chen and D Kotz ldquoA survey of context aware mobilecomputing researchrdquo Tech Rep TR2000-381 Departmentof Computer Science Dartmouth College Hanover Canada2000

[43] R S H Istepanian E Jovanov and Y T Zhang ldquoGuesteditorial introduction to the special section on M-healthbeyond seamless mobility and global wireless health-careconnectivityrdquo IEEE Transactions on Information Technology inBiomedicine vol 8 no 4 pp 405ndash413 2004

[44] R S H Istepanian and S Laxminaryan ldquoUNWIRED thenext generation of wireless and internetable telemedicinesystems-editorial paperrdquo IEEE Transactions on InformationTechnology in Biomedicine vol 4 pp 189ndash194 2000

[45] G Fasol ldquoWireless telemedicine technology trends May2004 Available fromrdquo httpeurotechnologycominfofasolzurich552004pdf

[46] T F Budinger ldquoBiomonitoring with wireless communica-tionsrdquo Annual Review of Biomedical Engineering vol 5 pp383ndash412 2003

[47] R S H Istepanian and H Wang ldquoTelemedicine in UKrdquoin European Telemedicine Glossary of Concepts StandardsTechnologies and Users L Beolchi Ed pp 1159ndash1165European CommissionmdashInformation Society Directorate-General Brussels Belgium 5th edition 2003

[48] R S H Istepanian and J Lacal ldquoM-health systems futuredirectionsrdquo in Proceedings of the 25th Annual InternationalConference of the IEEE Engineering in Medicine and BiologySociety (EMBS rsquo03) pp 17ndash21 Cancun Mexico September2003

[49] J Geier ldquoSaving lives with roving LANsrdquo NetworkWorld February 2001 httpwirelessitworldcom4246NWW0205bgsidepfindexhtml

[50] H Jan ten Duis and C van der Werken ldquoTrauma care systemsin The Netherlandsrdquo Injury vol 34 no 9 pp 722ndash727 2003


[52] M Al-Riyami A M Safwat and H S Hassanein ldquoChannelassignment in multi-hop TDD W-CDMA cellular networksrdquoin Proceedings of IEEE International Conference on Communi-cations (ICC rsquo05) vol 3 pp 1428ndash1432 Seoul South KoreaMay 2005

[53] A Safwat ldquoA-cell a novel multi-hop architecture for 4Gand 4G+ wireless networksrdquo in Proceedings of the 58th IEEEVehicular Technology Conference (VTC rsquo03) vol 5 pp 2931ndash2935 Orlando Fla USA October 2003

[54] H Luo R Ramjee P Sinha L Li and S Lu ldquoUCANa unified cellular and ad-hoc network architecturerdquo inProceedings of the 9th Annual International Conference onMobile Computing and Networking (MobiCom rsquo03) pp 353ndash367 San Diego Calif USA September 2003

[55] GTRAN Dual-Mode 80211CDMA Wireless Modem httpwwwgtranwirelesscomnewseventspressreleases 20020422htm

[56] B Bhargava X Wu Y Lu and W Wang ldquoIntegratingheterogeneous wireless technologies a cellular aided mobilead hoc network (CAMA)rdquo Mobile Networks and Applicationsvol 9 no 4 pp 393ndash408 2004

[57] H Wu C Qiao S De and O Tonguz ldquoIntegrated cellularand ad hoc relaying systems iCARrdquo IEEE Journal on SelectedAreas in Communications vol 19 no 10 pp 2105ndash21152001

[58] B S Manoj C D Frank and C S R Murthy ldquoPerformanceevaluation of throughput enhancement architectures fornext generation wireless systemsrdquo ACM SIGMOBILE MobileComputing and Communications Review vol 6 no 4 pp 77ndash90 2002

[59] A M Safwat ldquoACA channel assignment in ad hoc 4G andbeyond wireless networks with directional antennasrdquo in Pro-ceedings of IEEE International Conference on Communications(ICC rsquo04) vol 6 pp 3143ndash3147 Paris France June 2004

[60] G N Aggelou and R Tafazolli ldquoOn the relaying capabilityof next-generation GSM cellular networksrdquo IEEE PersonalCommunications vol 8 no 1 pp 40ndash47 2001

[61] A Fujiwara S Takeda H Yoshino and T Otsu ldquoAreacoverage and capacity enhancement by multihop connectionof CDMA cellular networkrdquo in Proceedings of the 56th IEEEVehicular Technology Conference (VTC rsquo02) vol 4 pp 2371ndash2374 Vancouver Canada September 2002

[62] J Zhou and Y Yang ldquoParcels pervasive ad-hoc relaying forcellular systemsrdquo in Proceedings of the 1st Annual Mediter-ranean Ad Hoc Networking Workshop (Med-Hoc-Net rsquo02)Sardegna Italy September 2002

[63] H-Y Hsieh and R Sivakumar ldquoA hybrid network model forcellular wireless packet data networksrdquo in Proceedings of IEEEGlobal Telecommunications Conference (GLOBECOM rsquo02)vol 1 pp 961ndash966 Taipei Taiwan November 2002

[64] X Wu S-H G Chan and B Mukherjee ldquoMADF a novelapproach to add an ad-hoc overlay on a fixed cellular infras-tructurerdquo in Proceedings of IEEE Wireless Communicationsand Networking Conference (WCNC rsquo00) vol 2 pp 549ndash554Chicago Ill USA September 2000

[65] M Stemm and R H Katz ldquoVertical handoffs in wirelessoverlay networksrdquo Mobile Networks and Applications vol 3no 4 pp 335ndash350 1998


[66] K Pahlavan P Krishnamurthy A Hatami et al ldquoHandoffin hybrid mobile data networksrdquo IEEE Personal Communica-tions vol 7 no 2 pp 34ndash47 2000

[67] C Perkins ldquoMobile IPrdquo IEEE Communications Magazine vol40 no 5 pp 66ndash82 2002

[68] ETSI BRAN HIPERLAN2 ldquoRequirements and architecturefor internetworking between HIPERLAN2 and 3rd genera-tion cellular systemsrdquo TR 101 957 V111 August 2001

[69] A K Salkintzis C Fors and R Pazhyannur ldquoWlAN-GPRSintegration for next-generation mobile data networksrdquo IEEEWireless Communications vol 9 no 5 pp 112ndash124 2002

[70] M Buddhikot G Chandranmenon S Han Y W Lee SMiller and L Salgarelli ldquoIntegration of 80211 and third-generation wireless data networksrdquo in Proceedings of the22nd Annual Joint Conference on the IEEE Computer andCommunications Societies (INFOCOM rsquo03) vol 1 pp 503ndash512 San Francisco Calif USA March-April 2003

[71] G Wu M Mizuno and P J M Havinga ldquoMIRAI archi-tecture for heterogeneous networkrdquo IEEE CommunicationsMagazine vol 40 no 2 pp 126ndash134 2002

[72] W Kellerer H-J Vogel and K-E Steinberg ldquoA communi-cation gateway for infrastructure-independent 4G wirelessaccessrdquo IEEE Communications Magazine vol 40 no 3 pp126ndash131 2002

[73] A Snoeren and H Balakrishnan ldquoAn end-to-end approachto host mobilityrdquo in Proceedings of the 6th Annual Inter-national Conference on Mobile Computing and Networking(MobiCom rsquo00) pp 155ndash166 Boston Mass USA August2000

[74] K Chen and C Wu ldquoInternet working between HIPER-LAN2 and UMTSrdquo Wireless Personal Communications vol26 no 2-3 pp 179ndash202 2003


[76] David Crowe ldquoArticles WiFi and cellular a marriage madein heaven wireless telecom 2nd quarter 2003 Avail-able fromrdquo httpwwwcnp-wirelesscomArticleArchiveWireless20Telecom2003Q2-Cellular-WiFihtml

[77] M Inoue K Mahmud H Murakami M Hasegawa and HMorikawa ldquoIntegration of heterogeneous wireless networksusing MIRAI architecture 3rd ETRI-CRL joint conferenceKorea November 2002rdquo

[78] C Guo Z Guo Q Zhang and W Zhu ldquoA seamless andproactive end-to-end mobility solution for roaming acrossheterogeneous wireless networksrdquo IEEE Journal on SelectedAreas in Communications vol 22 no 5 pp 834ndash848 2004

[79] J Postel ldquoTransmission control protocolrdquo Tech Rep IETFRFC 793 Information Sciences Institute University ofSouthern California Marina del Rey Calif USA September1981

[80] H-Y Hsieh K-H Kim and R Sivakumar ldquoAn end-to-end approach for transparent mobility across heterogeneouswireless networksrdquo Mobile Networks and Applications vol 9no 4 pp 363ndash378 2004

[81] H S Ng M L Sim C M Tan and C C Wong ldquoWire-less technologies for telemedicinerdquo BT Technology JournalSpringer Netherlands vol 24 no 2 pp 130ndash137 2006

[82] Y L Liang and S McClellan ldquoIssues and techniques innetwork-based distributed healthcare quality of service andbandwidthrdquo in Proceedings of the 4th World Conferenceon Integrated Design and Process Technology (IDPT rsquo99)Kusadasi Turkey July 1999

[83] J Cullen W Gaasch D Gagliano J Goins and R Gunawar-dane ldquoWireless mobile telemedicine en-route transmissionwith dynamic quality-of-service managementrdquo Tech RepUniversity of Maryland School of Medicine Baltimore MdUSA 2001

[84] K Wac R Bults A van Halteren D Konstantas and VNicola ldquoMeasurements based performance evaluation of 3Gwireless networks supporting M-health servicesrdquo in Multi-media Computing and Networking vol 5680 of Proceedings ofSPIE pp 176ndash187 San Jose Calif USA January 2005

[85] A Alonso ldquoDetailed description of trial scenariosrdquo Mobi-Health Deliverable 13 February 2003

[86] A Bhargava M F Khan and A Gharoof ldquoQoS managementin multimedia networking for telemedicine applicationsrdquoin Proceedings of IEEE Workshop on Software Technologiesfor Future Embedded Systems (WSTFES rsquo03) pp 39ndash42Hakodate Japan May 2003

[87] A L Lage J S B Martins J Oliveira and W Cunha ldquoAquality of service framework for tele-medicine applicationsrdquoin Proceedings of the Joint Conference of the 10th BrazilianSymposium on Multimedia and the Web and the 2nd LatinAmerican Web Congress (WebMedia amp LA-Web rsquo04) pp 18ndash20 Ribeirao Preto Brazil October 2004

[88] W Yao R S H Istepaniad A Z Salem H Zisimopoulosand P Gossee ldquoThroughput performance of a WCDMAsystem supporting tele-echography servicesrdquo in Proceedingsof the 4th Annual IEEE Conference on Information TechnologyApplications in Biomedicine pp 310ndash313 Birmingham UKApril 2003

[89] A Serra D Gaiti G Barroso and J Boudy ldquoA load-balancing distributed platform based on differentiated ser-vices for a telecare applicationrdquo in Proceedings of IEEEInternational Conference on Control Applications vol 1 pp69ndash74 Taipei Taiwan September 2004

[90] B Tulu S Chatterjee and S Laxminarayan ldquoA taxon-omy of telemedicine efforts with respect to applicationsinfrastructure delivery tools type of setting and purposerdquoin Proceedings of the 38th Annual Hawaii InternationalConference on System Sciences (HICSS rsquo05) p 147 Big IslandHawaii USA January 2005

[91] R Steinmetz ldquoHuman perception of jitter and mediasynchronizationrdquo IEEE Journal on Selected Areas in Commu-nications vol 14 no 1 pp 61ndash72 1996

[92] J Korhonen O Aalto A Gurtov and H LaamanenldquoMeasured performance of GSM HSCSD and GPRSrdquo in Pro-ceedings of IEEE International Conference on Communications(ICC rsquo01) vol 5 pp 1330ndash1334 Helsinki Finland June2001

[93] K E Wac and R G A Bults Performance evaluation of atransport system supporting the MobiHealth BANip methodol-ogy and assessment MS thesis University of Twente TwenteThe Netherlands 2004

[94] S G Miaou and C Y Huang ldquoA next-generation mobiletelemedicine testbed based on 3G cellular standardrdquo inProceedings of the Annual Conference on Computers in Car-diology vol 28 pp 683ndash686 Rotterdam The NetherlandsSeptember 2001

[95] A M Safwat ldquoA-cell a novel architecture for 4G and4G+ wireless networksrdquo in Wireless Communication Systemsand Networks pp 53ndash69 Kluwer Academic PublishersDordrecht The Netherlands 2005

[96] A M Safwat ldquoOn CAC DCA and scheduling in TDD multi-hop 4G wireless networksrdquo in Proceedings of the 23rd IEEE


International Performance Computing and CommunicationsConference (IPCCC rsquo04) pp 541ndash546 Phoenix Ariz USAApril 2004

[97] A Bria F Gessler O Queseth et al ldquo4th-generation wirelessinfrastructures scenarios and research challengesrdquo IEEEPersonal Communications vol 8 no 6 pp 25ndash31 2001

[98] T J Harrold and A R Nix ldquoIntelligent relaying for futurepersonal communication systemsrdquo in Proceedings of IEEColloquium on Capacity and Range Enhancement Techniquesfor Third Generation Mobile Communications and Beyond pp62ndash66 London UK February 2000

[99] httpwwwmobileinfocom3G4GVisionampTechnologieshtm

[100] httpwwwnttdocomocomservicesimodeindexhtml[101] K Uehara K Araki and M Umehira ldquoTrends in research

and development of software defined radiordquo NTT TechnicalReview vol 1 no 4 pp 10ndash14 2003

[102] A Fujiwara S Takeda H Yoshino T Otsu and Y YamaoldquoSystem capacity expansion effect of multi-hop access in abroadband CDMA cellular systemrdquo IEICE Transaction B volJ85-B no 12 pp 2073ndash2079 2002

[103] T Yamashita H Kayama L Chen D Kitazawa M Motegiand N Umeda ldquoWireless QoS control technologiesrdquo NTTTechnical Review vol 2 no 9 pp 32ndash39 2004

[104] I Martinez and J Garcıa ldquoSM3mdashquality of service (QoS)evaluation tool for telemedicine-based new healthcare ser-vicesrdquo in Proceedings of the 2nd International Conference onComputational Bioengineering (ICCB rsquo05) H Rodrigues MCerrolaza M Doblare J Ambrosio and M Viceconti EdsLisbon Portugal September 2005

[105] R Holle and G Zahlmann ldquoEvaluation of telemedicalservicesrdquo IEEE Transactions on Information Technology inBiomedicine vol 3 no 2 pp 84ndash91 1999

[106] M Maheu P Whitten and A Allen E-Health Telehealth andTelemedicine Guide to Start-up amp Success Jossey-Bass SanFrancisco Calif USA 2001

[107] W C Hardey QoS Measurement and Evaluation of Telecom-munications Quality of Service John Wiley amp Sons New YorkNY USA 2002

[108] R Chodoreck ldquoQoS measurement and evaluation oftelecommunications quality of service [Book Review]rdquo IEEECommunications Magazine vol 40 no 2 pp 30ndash32 2002

[109] K Zielinsky ldquoKrakow centre of telemedicinemdashdevelopingthe platform for regional telemedical networksrdquo in Proceed-ings of the International Conference on E-Health in CommonEurope Krakow Poland June 2003

[110] D Caramella S Giordano R DellrsquoOsso and C PetrildquoAn advanced IP based telemedicine trial supporting QoSfor multimedia teleconsultingrdquo in Proceeding of the 18thInternational EuroPACS Conference (EuroPACS rsquo00) pp 239ndash245 Gratz Austria September 2000

[111] W R McDermott J L Tri M P Mitchell et al ldquoOpti-mization of wide-area ATM and local-area ethernetFDDInetwork configurations for high-speed telemedicine commu-nications employing NASArsquos ACTSrdquo IEEE Network vol 13no 4 pp 30ndash38 1999

[112] P E Wirth ldquoThe role of teletraffic modeling in the new com-munications paradigmsrdquo IEEE Communications Magazinevol 35 no 8 pp 86ndash92 1997

[113] J-F Huard I Inoue A A Lazar and H YamanakaldquoMeeting QoS guarantees by end-to-end QoS monitoringand adaptationrdquo in Proceedings of the 5th IEEE InternationalSymposium on High Performance Distributed Computing pp348ndash355 Syracuse NY USA August 1996

[114] I Martınez J Salvador J Fernandez-Navajas and J GarcıaldquoTraffic requirements evaluation for a telemedicine networkrdquoin Proceedings of the 1st International Congress on Compu-tational Bioengineering (ICCB rsquo03) pp 389ndash394 ZaragozaSpain September 2003

[115] P R Liu M Q-H Meng F F L Tong X J Chen and PX Liu ldquoA 3G based network solution to the telehealthcarerobotic system 6th World Congress on Intelligent Controland Automation WCICA 2006 Vol 1rdquo IEEE Transactions onInformation Technology in Biomedicine pp 381ndash385

[116] I Martinez and J Garcia ldquoSM3-quality of service (QoS) eval-uation tool for telemedicine-based new healthcare servicesrdquoin Proceedings of the 2nd IEEE International Conference onComputational Bioengineering Lisbon Portugal September2005

[117] F Hu Y Wang and H Wu ldquoMobile telemedicine sensornetworks with lowenergy data query and network lifetimeconsiderationsrdquo IEEE Transactions on Mobile Computing vol5 no 5 pp 404ndash417 2006

[118] Y Xiao and H Chen Eds Mobile Telemedicine A Computingand Networking Perspective Auerbach Boca Raton Fla USA2007

[119] F Hu L Celentano and Y Xiao ldquoError-resistant RFID-assisted wireless sensor networks for cardiac tele-healthcarerdquo to appear in Wireless Communications andMobile Computing Published Online 28 February 2008httpwww3intersciencewileycomjournal117923052abstractCRETRY=1ampSRETRY=0

[120] J Chen K Cao Y Sun Y Xiao and X Su ldquoContinuous druginfusion for diabetes therapy a closed-loop control systemdesignrdquo EURASIP Journal on Wireless Communications andNetworking vol 2008 Article ID 495185 10 pages 2008

[121] D Takahashi Y Xiao F Hu J Chen and Y SunldquoTemperature-aware routing for telemedicine applications inembedded biomedical sensor networksrdquo EURASIP Journalon Wireless Communications and Networking vol 2008Article ID 572636 11 pages 2008

[122] D Takahashi Y Xiao F Hu and M Lewis ldquoA survey ofinsulin-dependent diabetesmdashpart I therapies and devicesrdquoInternational Journal of Telemedicine and Applications vol2008 Article ID 639019 15 pages 2008

[123] F Hu M Jiang L Celentano and Y Xiao ldquoRobust medicalad hoc sensor networks (MASN) with wavelet-based ECGdata miningrdquo to appear in Ad Hoc Networks

[124] F Hu M Jiang and Y Xiao ldquoLow-cost wireless sensor net-works for remote cardiac patients monitoring applicationsrdquoWireless Communications and Mobile Computing vol 8 no4 pp 513ndash529

[125] Y Xiao X Shen B Sun and L Cai ldquoSecurity and privacyin RFID and applications in telemedicinerdquo IEEE Communi-cations Magazine vol 44 no 4 pp 64ndash72 2006

[126] D Takahashi Y Xiao and F Hu ldquoLTRT least total-route temperature routing for embedded biomedical sensornetworksrdquo in Proceedings of the 50th Annual IEEE GlobalTelecommunications Conference (GLOBECOM rsquo07) pp 641ndash645 Washington DC USA November 2007

[127] Y Xiao D Takahashi and F Hu ldquoTelemedicine usage andpotentialsrdquo in Proceedings of IEEE Wireless Communicationsand Networking Conference (WCNC rsquo07) pp 2738ndash2742Kowloon Hong Kong March 2007

[128] F Hu S Kumar and Y Xiao ldquoTowards a secure RFID sensor based tele-cardiology systemrdquo in Proceedings of the4th Annual IEEE Consumer Communications and Networking


Conference (CCNC rsquo07) pp 732ndash736 Las Vegas Nev USAJanuary 2007

[129] Y Xiao and F Hu ldquoWireless telemedicine and M-heathrdquo inProceedings of the 4th Annual IEEE Consumer Communica-tions and Networking Conference (CCNC rsquo07) pp 727ndash731Las Vegas Nev USA January 2007

[130] Q Alexander Y Xiao and F Hu ldquoTelemedicine for pervasivehealthcarerdquo in Mobile Telemedicine A Computing and Net-working Perspective Auerbach Boca Raton Fla USA 2008

[131] L Biggers Y Xiao and F Hu ldquoConventional telemedicinewireless telemedicine sensor networks and case studiesrdquo inMobile Telemedicine A Computing and Networking Perspec-tive Auerbach Boca Raton Fla USA 2008

[132] F Hu M Lewis and Y Xiao ldquoAutomated blood glucosemanagement techniques through micro-sensorsrdquo in MobileTelemedicine A Computing and Networking Perspective Auer-bach Boca Raton Fla USA 2008

[133] D Takahashi Y Xiao and F Hu ldquoA survey of securityin telemedicine with wireless sensor networksrdquo in MobileTelemedicine A Computing and Networking Perspective Auer-bach Boca Raton Fla USA 2008

[134] F Hu L Celentano and Y Xiao ldquoMobile secure tele-cardiology based on wireless and sensor networksrdquo in MobileTelemedicine A Computing and Networking Perspective Auer-bach Boca Raton Fla USA 2008

[135] D Zito D Pepe B Neri D De Rossi and A LanataldquoWearable system-on-a-chip pulse radar sensors for thehealth care system overviewrdquo in Proceedings of the 21st Inter-national Conference on Advanced Information Networking andApplications Workshops (AINAW rsquo07) pp 766ndash769 NiagaraFalls Canada May 2007

[136] A Alomainy Y Hao and F Pasveer ldquoNumerical andexperimental evaluation of a compact sensor antenna forhealthcare devicesrdquo IEEE Transactions on Biomedical Circuitsand Systems vol 1 no 4 pp 242ndash249 2007

[137] Y-T Zhang X Y Xiang and C C Y Poon ldquoThe evaluationof nodes of body sensor networks wearable blood pres-sure measuring devicesrdquo in Proceedings of the InternationalWorkshop on Wearable and Implantable Body Sensor Networks(BSN rsquo06) pp 158ndash161 Cambridge Mass USA April 2006

[138] P Corbishley and E Rodrıguez-Villegas ldquoBreathing detec-tion towards a miniaturized wearable battery-operatedmonitoring systemrdquo IEEE Transactions on Biomedical Engi-neering vol 55 no 1 pp 196ndash204 2008

[139] Y Xiao Y Pan and K K Leung ldquoSpecial issue mobilitypaging and quality of service management for future wirelessnetworksrdquo Wireless Communications and Mobile Computingvol 5 no 7 pp 709ndash711 2005

[140] Y Xiao K K Leung Y Pan and X Du ldquoArchitecturemobility management and quality of service for integrated3G and WLAN networksrdquo Wireless Communications andMobile Computing vol 5 no 7 pp 805ndash823 2005

[141] P Chimento ldquoQbone Signaling Design TeammdashReportrdquo2002

[142] Y Xiao ldquoIEEE 80211n enhancements for higher throughputin wireless LANsrdquo IEEE Wireless Communications vol 12 no6 pp 82ndash91 2005

[143] Y Xiao ldquoEfficient MAC strategies for the IEEE 80211n wire-less LANsrdquo Wireless Communications and Mobile Computingvol 6 no 4 pp 453ndash466 2006

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2010

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



every few minutes while for others continuous monitoringevery few seconds is necessary For all patients any majorchanges in the vital signs should be transmitted immediately

Continuous cardiac monitoring through wireless tech-nology can be used to follow up with patients that havesurvived cardiac arrest ventricular tachycardia or cardiacsyncope as well as for diagnostic purposes in patientswith diffuse arrhythmia As PDA devices are reasonablypriced and are becoming increasingly powerful telemedicinesystems using PDAs are a cost-effective solution in a range ofmedical applications and suitable for home care usage Somecurrently used patient operated ambulatory ECG recordingequipments such as holters and transtelephonic devicesare time consuming to setup and suffer from poor patientcompliance Patients undergoing acute myocardial infarctionand subsequent arrhythmia ending in ventricular fibrillationand sudden cardiac arrest will not be able to operate suchequipment For reliable monitoring it is necessary to developa completely automatic recording and analyzing unit whichcan detect cardiac abnormalities and automatically send dataand alarm(s) to a health provider or central alarm system Ithas been clearly documented that time is a critical factor inorder to perform early cardiopulmonary resuscitation (CPR)and early defibrillation and if the time to start CPR after acardiac arrest increases the chance of survival is reduced [4]

New wireless technology for telecardiology purposes givenew possibilities for monitoring vital parameters with wear-able biomedical sensors and give the patient the freedomto be mobile and still be under continuous monitoring andthereby better quality of patient care The implications andpotential of wearable cardiac monitoring technologies areparamount since they could (i) detect early signs of healthdeterioration (ii) notify health care providers in criticalsituations (iii) find correlations between lifestyle and health(iv) bring sports conditioning into a new dimension byproviding detailed information about physiological signalsunder various exercise conditions and (v) provide doctorswith multisourced real-time physiological data [1] Theywill therefore give the patient the freedom to be mobileand still be under continuous monitoring in differentenvironments such as both inside and outside homesoffices hospitals nursing homes and traveling Further-more context-awareness can enable personalized functionssuch as reminder services or medication support dependingon measured vital signs and individual disease patterns

In order to make wearable devices practical a seriesof technical legal and sociological obstacles should beovercome The major design requirements of the mobile unitare the following (1) portable and lightweight (2) powerautonomy of a few hours (3) user-friendly interface (4)collection and display of critical biosignals (5) very lowfailure rate and highly accurate alarm triggers especiallyif used for diagnostic purposes and (6) reliable real-timewireless data transmission any-time anywhere in any form

In this paper we will first introduce general require-ments of ubiquitous computing telecardiology platformsin Section 2 Section 3 will discuss existing systems Thearchitecture of heterogeneous wireless platforms is statedin Section 4 Quality-of-service (QoS) analysis in mobile

telecardiology systems is given in Section 5 The fourth-generation (4G) system is discussed in Section 6 FinallySection 7 provides the prospective of next-generation (xG)telecardiology systems

2 UBIQUITOUS COMPUTING FOR TELECARDIOLOGY

Ubiquitous computing also called pervasive computingis a concept for future computing environments where auser is surrounded by a large amount of small application-specific network-connected information appliances It ischaracterized by (i) physical and cognitive embedded sys-tems (ii) networking (iii) ubiquity (iv) context awarenessand (v) application specific devices (appliances) The costsfor integrating the necessary communication abilities areaffordable compared to the potential for cost savings andto the medical advantages (i) context-aware cognitive-embedded systems result in a better usability which isessential for the use in a home-monitoring scenario (thedevice is adapting itself to the user and not vice versa) (ii)patient mobility is maximized by physically embedding thedevices into wearable or implantable distributed systemsand (iii) networking compensates decentralization Thushigh performance services such as pattern recognition withneural networks can be provided anywhere to the mobiledevices

Problems emerge in ubiquitous computing in the follow-ing areas

(1) Embedded [39]

(a) both vital sensors and base station have to bewearable to ensure mobility and attention

(b) attention has to be paid to the body placementhuman movement weight size and otherconstraints

(c) reduce the power consumption relatively withthe increase in the performance of processorsmemories and other components

(2) Networking [40 41]

(a) providing ubiquitous access to central informa-tion services

(b) lower power consumption(c) ensuring high level of security(d) extensive interoperability features(e) integrated functionality such as service discov-

ery self-configuration encryption and authen-tication

(f) protection of privacy and communication secu-rity considering mobile Internet connections

(3) Context-awareness [42]

(a) personal identifications personalized healthmonitoring systems provide functions suchas reminder services or medication supportdepending on measured vital signs and individ-ual disease patterns The data therefore shouldtravel reliably to the remote nursephysician

Sunil Kumar et al 3
























Sunil Kumar et al 5

























Sunil Kumar et al 7
























Sunil Kumar et al 9




























Table 1








2ndash8 GHz








All IP (IP60)











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Sunil Kumar et al 3
























Sunil Kumar et al 5

























Sunil Kumar et al 7
























Sunil Kumar et al 9




























Table 1








2ndash8 GHz








All IP (IP60)











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation























Sunil Kumar et al 5

























Sunil Kumar et al 7
























Sunil Kumar et al 9




























Table 1








2ndash8 GHz








All IP (IP60)











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation























Sunil Kumar et al 7
























Sunil Kumar et al 9




























Table 1








2ndash8 GHz








All IP (IP60)











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation




















Sunil Kumar et al 9




























Table 1








2ndash8 GHz








All IP (IP60)











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation























Table 1








2ndash8 GHz








All IP (IP60)











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











At work


Cardimon



On (business) trip













































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











































8 CONCLUSIONS



ACKNOWLEDGMENTS


REFERENCES

























































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation































































































































































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









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