Kai-Di Chang,Jiann-Liang Chen,and Han-Chieh Chao

(1.Department of Electrical Engineering，National Taiwan University of Science and Technology，Taiwan，China; 2.Department of Computer Science and Information Engineering，Nation ILan University，Taiwan，China)

Prototype for Integrating Internet of Things and Emergency Service in an IP Multimedia Subsystem for Wireless Body Area Networks

Kai-Di Chang1,Jiann-Liang Chen1,and Han-Chieh Chao2

(1.Department of Electrical Engineering，National Taiwan University of Science and Technology，Taiwan，China; 2.Department of Computer Science and Information Engineering，Nation ILan University，Taiwan，China)

In recent years，the application of the Internet of Things(IoT)has become an emerging business.The most important concept of next⁃generation network for providing a common global IT platform is combining seamless networks and networked things，objects or sensors.Also，wireless body area networks(WBANs)are becoming mature with the widespread usage of the IoT.In order to support WBAN，the platform，scenario and emergency service are necessary due to the sensors in WBAN being related to wearer's life.The sensors on the body detect a lot of information about bioinformatics and medical signals，such as heartbeat and blood. Thus，the integration of IoT and network communication in daily life is important.However，there is not only a lack of common fabric for integrating IoT with current Internet and but also no emergency call process in the current network communication envi⁃ronment.To overcome such situations，the prototype of integrating IoT and emergency call process is discussed.A simulated boot⁃strap platform to provide the discussion of open challenges and solutions for deploying IoT in Internet and the emergency commu⁃nication system are analyzed by using a service of 3GPP IP multimedia subsystem.Finally，the prototype for supporting WBAN with emergence service is also addressed and the performance results are useful to service providers and network operators that they can estimate their migration to IoT by referring to this experience and experiment results.Furthermore，the queuing model used to achieve the performance of emergency service in IMS and the delay time of the proposed model is analyzed.

IoT;WBAN;radio frequency identification(RFID);emergency service;IP multimedia subsystem

1 Introduction

T he concept of Internet of Things(IoT)was intro⁃duced in 1999 with Auto⁃ID—the technology that underlies the electronic product code(EPC)sys⁃tem[1].The EPC system was designed to connect physical objects or devices via radio frequency identification (RFID)and a unique EPC code in the RFID tag.Researchers in Japan also proposed a UID solution that was an early IoT prototype[2].The IoT concept has expanded very quickly be⁃cause of new application demands and technological advances [3]-[5].IoT has been defined in different ways，according to different technologies and points of view.In[6]，Thiesse et al. propose solutions based on RFID or EPC.In[7]，Broll et al. propose the pervasive service interaction between things.In [8]，Vazquez et al.propose a solution that integrates smart ob⁃jects and mobile services.Most researchers focus on specific applications or functions[9];however，two areas of commonali⁃ty are security[10]，[11]and network OAM[12].The Future In⁃ ternet Assembly was founded by the European Commission to support fundamental and systematic innovation in the future In⁃ternet and IoT[13].

Although there has been much research on IoT，the architec⁃ture of future IoT has not yet been defined.Objects in IoT have unique identity and virtual personalities operating in smart spaces such as body area network or personal area network through using smart interfaces to connect or communicate with social，cyber and exchange user contexts.IoT technologies can promote the integration of material production with service management，i.e.，the integration of physical region，digital re⁃gion，and cyber region.IoT communication has been mainly supported by the evolution of information processing and ser⁃vices within the ICT industry.

With the popularization of the Internet and mobile communi⁃cations，IoT come to be regarded as the next wave of IT.The ITU has already stated that machine⁃to⁃machine and person⁃to⁃machine communications will be extended to a much wider range of devices embedded within the existing Internet.Thus，IoT will be an integral part of any future Internet.

Different types of IoT have already been accepted in many places，but further development of IoT depends greatly on the specification of new technologies，deeper social understanding of IoT⁃related issues，and stronger legal frameworks for IoT. Standards，reliability，and robustness are all important issues in IoT development，and a standardized architecture is the foundation for all IoT technologies.If there is no definite IoT architecture，it will be difficult to develop and integrate future applications and services.

The rapid development of IoT around the world has largely been led by governments，but industry has also initiated big⁃budget IoT projects even though the technologies and architec⁃ture of IoT are not yet mature.Lack of a clear architecture sty⁃mies the development of IoT，so it is very important figure out the future IoT architecture.

IoT is opening up the possibility for new Internet applica⁃tions，and next⁃generation networks(NGNs)will have a similar effect.All user requests for multimedia services and applica⁃tions can be fulfilled by deploying an IP multimedia subsystem (IMS)[14].IMS applications have grown quickly around the world，and IMS has become a key technology.The main IMS core network is a subsystem bounded with Universal Mobile Telecommunication System(UMTS)to provide end⁃to⁃end or core⁃to⁃end multimedia services.User equipment is supported so that it can be used in both fixed and mobile networks.There are two types of switching technology in UMTS network:circuit⁃switching，for voice transmission;and packet⁃switching，for data transmission.Improvement in the packet⁃switching do⁃main improves the migration of Internet and mobile communi⁃cations.

The specifications and standards of IMS are defined and dis⁃cussed in many international organizations，such as the 3rd generation partner project(3GPP)，telecommunications and in⁃ternet converged services and protocols for advanced network⁃ing(TISPAN)，ETST and ITU⁃T for ITU telecommunication standardization sector(ITU⁃T).The specifications provide a convergence goal for future Internet and service.IMS provides mobility，flexibility and scalability for services and applica⁃tions.In addition，with the important call session control func⁃tions(CSCFs)，the IMS core network has the capability of con⁃trolling sessions，delivering voice，data，video and message in fixed and mobile network.

Many elements deliver the signaling and control messages to achieve multimedia services and applications.These functions improve the efficiency of IMS.However，with smooth opera⁃tions in IMS，it is very difficult to avoid the emergency events in daily life.Emergency services are proposed to handle the emergencies.Furthermore，there are many objects for sensing different signal and information in IoT environment that in⁃cludes the various type of sensor in wireless body are network. The types of sensed message are extensive.Some of the mes⁃sage is highly related to the life of the wearer such as blood， heartbeats.Thus，a reliable message delivery transmission mechanism is necessary for emergency situations.In this re⁃search，the IP multimedia subsystem is selected as the fabric for supporting IoT.The emergency service in IMS is very suit⁃able for adapting to WBAN.The emergency signal can be sent through IMS emergency service when the sensors on the wear⁃er sense abnormal bioinformatics and medical signals.In order to analyze the prorogation delay of each element in IMS emer⁃gency service，the queuing model is used to achieve the goal and calculate the delay time.

The remainder of this paper is organized as follows.In sec⁃tion 2，we discuss the background of the Internet of Things，IP multimedia subsystem and emergency services.In section 3，we discuss the integrated prototype of IoT and emergency ser⁃vice model.In section 4，we discuss the deployment and perfor⁃mance analysis of the prototype.In section 5，we conclude and discuss future works are illustrated in last section.

2 Background

2.1 Internet of Things

IoT involves many technologies and includes research fields such as network architecture design，sensor and object identifi⁃cation，coding，data transmission，data processing，network planning and link/node discovery，etc.There are four key com⁃ponents of IoT:

1)Sensors with embedded intelligence.A sensor node in a tra⁃ditional wireless network was designed to sense data，and store and forward the result to a sink.In future IoT，the sen⁃sor node will have more intelligent algorithms，cognitive ca⁃pabilities.Thus，each sensor node will be an intelligent ob⁃ject rather than a simple sensor node.

2)Aggregators，such as hubs，for spokes.The moderate pro⁃cessing concept is included in the aggregators.It’s more powerful to handle messages in each place.

3)Ubiquitous network.Objects generate and communicate in⁃formation about environment or item status when queries triggered.The network connectivity is always on to achieve information communication and data exchanging.

4)Context⁃aware services.These enhance an object’s process⁃ing capability and facilitate decision⁃making between devic⁃es without human intervention.Thus，operations are per⁃formed automatically.

In addition to the above four key components，there are three important characteristics of IoT:

1)Good cognitive capability and distributed sensing for input/ output modules

2)Robust transmission and stable bus for industry communica⁃tion

3)Smart process and programmable automation controller for

adapting to variable data sensing environments.

Ning and Wang[15]propose two IoT architectures:like man⁃kind neural system and social organization framework.

The like mankind neural system comprises M&DC，the brain respond s for objects management and centralized data center;spinal cord，there are distributed control nodes for con⁃trolling lowest level sensors;and a network of nerves，deploy IoT network and end⁃side sensors.

This IoT architecture transmits messages from low⁃level sen⁃sors to mid⁃level control nodes and top⁃level M&DC.It re⁃ceives，translates，and sends back message to sensors to con⁃trol the things/objects.The M&DC is a centralized data center. It is in charge of processing information，storing data，and its most important task is to manage the IoT network.

In Ning and Wang’s design，the social organization frame⁃work(SOF)plays three roles in IoT network.For national IoT，the SOF act as national management and data center which is called nM&DC.

For industry IoT，SOF acts as industry management and da⁃ta center called iM&DC.Finally，for regional IoT，SOF re⁃sponds to local management and data center called lM&DC. With different types of SOF IoT，each IoT has their different level policies，monitoring，security，and backup of important data.The“Like Mankind Neural System”can be regarded as a single IoT network，then the“Social Organization Framework”comprises many“Like Mankind Neural Systems，”such as multi⁃IoT networks.The main difference between LMNS and SOF is that each IoT network can exchange information with another IoT network.It is like a social network:one LMNS can share sensors with different LMNS.The behavior and status is similar to human conversation in society.However，there is no traffic analysis or model for IoT on internet in their research and they do not mention about their IoT operation management in the two IoT architectures.

2.2 IP Multimedia Subsystem

The detailed specifications of IP multimedia subsystems [16]were proposed by 3GPP.Many multimedia services voice call，data service and can be used smoothly based on the all⁃IP concept and technology.IMS supports the fixed and mobile de⁃vices by using Session Initiation Protocol，and can achieve seamless handover between heterogeneous networks.The con⁃cept can be extended to the whole network communication in⁃dustry.To enable users to use various multimedia services and multimedia content，the construction of NGN infrastructure is very important to operators.Finally，the operator can achieve the management of multimedia service and service control. Zhou and Chao proposed multimedia traffic security architec⁃ture[11].In this study，IMS is also an important architecture for future Internet.Moreover，Chen et al.discuss the impor⁃tance of IMS in IoT[17].In addition，the secured IMS environ⁃ment is also necessary[18]for emergency services.

Session control and resource allocation are managed by the cooperation of SIP servers and other physical network devices. In the IMS layer，the main components，called CSCFs，can pro⁃ cess the SIP message in the core network.The serving CSCF(S⁃CSCF)is the major component of IMS.The S⁃CSCF is respon⁃sible for call session control，handling the registration and au⁃thentication control.The proxy CSCF(P⁃CSCF)is the entry point of users to the IMS，which works as proxy and user agent. It is responsible for forwarding IMS registration message or oth⁃er IMS requests to IMS core.The interrogation CSCF(I⁃CSCF) communicates with other network operator，which provides routing query and hides the internal network topology between IMS realms.

Session initiation protocol(SIP)is an open standard pro⁃posed by IETF MMUSIC Working Group[19].SIP provides strong functions for session control in application layer such as session establishment，modification and terminate.The IMS network operators use IMS⁃SIP as the signaling protocol for providing voice and video multimedia service.

User equipment(UE)can access the IMS through different access networks with the flexibility and scalability of SIP.The signaling time to access IMS is different in different access net⁃works，such as GSM，WLAN and WiMAX.Thus，Wagle et al. compares the IMS access time between GSM and WLAN[16]. The results in[16]show that the GSM⁃IMS⁃GSM has longer ac⁃cess time than the WLAN⁃IMS⁃WLAN.The delay is affected by different bandwidth and network prorogation delay.Thus，in order to reduce delay，the messages and SIP signaling flow such as call setup，request and reply should be considered.Us⁃ers can have better quality with lower delay in IMS.Chang et al.proposed an advanced path⁃migration mechanism[20]for improving signaling efficiency in IMS.However，the research did not take into consideration emergency services.

2.3 Emergency Service

Emergency service in IMS consists of P⁃CSCF，S⁃CSCF，emergency⁃CSCF(E⁃CSCF)，location retrieval function(LRF) and UE.When UE triggers the emergency service，it first calls P⁃CSCF to decide whether the situation is emergent or not.If the event is truly an emergency，the P⁃CSCF forwards the event to E⁃CSCF in the same domain.Then，the E⁃CSCF can handle the event according to the message content and deter⁃mine the location of the user from the LRF.

If P⁃CSCF determines that this is not an emergency，the re⁃quest is forwarded to the home service proxy;then，the PSAP in home network processes the request.This architecture can handle emergency events effectively.Thus，this service makes the IMS much more reliable and secure to users.

The IMS emergency service in heterogeneous network envi⁃ronments is shown in Chen's research[21].It is the combina⁃tion of IMS core network，Internet and HSDPA data communi⁃cation by telecom operator，relay node and user.There are three⁃connection types for users to reach the IMS core:1)use the 3.5 G data communication service;2)relay by Bluetooth and cooperate with other user;3)use wired or Wi⁃Fi to reach IMS service.Users can use any service in any place at anytime with these heterogeneous networks.Also，the emergency service can be launched successfully.Chen et al.also pro⁃posed a cooperative IMS network[22]to extend the coverage of emergency service.

3 Integrated Prototype of IoT and Emergency Service Model

IoT is different from traditional wireless sensor networks and current Internet.The new concept should be considered in operations plane and strategy to satisfy the abovementioned four key components and three characteristics of IoT.The ar⁃chitecture and operation management of future internet IoT should be accommodating with IoT related workflow and tasks.

The architecture for network OAM depends on the network scale.For example，the IoT architecture and the work⁃process⁃ing model shall be centralized for small⁃scale system.Thus，the consumed resource can be reduced.In order to provide enough system capacity，the distributed model needs to be con⁃sidered if IoT is deployed in a large⁃scale network such as mul⁃tiple applications environment or ubiquitous system.

Unlike current Internet and mobile communications，IoT ar⁃chitecture for operation management should be flexible，com⁃promising and ubiquitous.Thus，each country or their industry can easily access a suitable IoT architecture or exclusive IoT architecture and communicate with other IoT networks.

3.1 IoT Operations

In order to achieve IoT operations management，the basic concept of IoT system architecture should be determined first. The layered architecture of IoT can be extended from WSN，and the extended architecture can be separated into three lay⁃ers.

Application layer⁃operators use the collected information to deploy their service and applications，such as intelligent traffic management，smart home[23]，[24]，smart gird，long⁃distance healthcare[25]environmental protection，mining monitoring，remote nursing，safety defense，and smart government.

Network Layer⁃there are data center，core network，network backbone，mobile phone networks，fixed telephone networks，broadcasting networks，and closed IP data networks for each carrier in this layer.All traffic is IP based and will be routed to the suitable destination in this layer.

Sensing Layer⁃the operators deploy RFID related devices such as sensor，tag，sensor gateway，smart terminal，and IoT gateway.Those objects in this layer handle the data cognition and information collection.

Thus，the operation management would focus on the func⁃tions in each layer.

3.2 IoT Business Operation Support Platform

Although there is no definitely specification for IoT，Qian et al.propose a Business Operation Support Platform(BOSP)for IoT management in business operation[26].The general archi⁃tecture of BOSP is shown in Qian’s design:

1)data interface.This interface receives IP packets over inter⁃connected heterogeneous networks for all IP⁃based net⁃works，such as broadcasting networks，fixed networks and mobile/wireless networks.It then forward packets to corre⁃sponding destinations.

2)application interface.This interface forwards data to applica⁃tion servers and provides specific functions to facilitate ap⁃plication systems.

3)existing abilities entrance.This entrance makes carrier’s ex⁃isting abilities work directly.For example，the voice call ser⁃vice，video call，short messaging service，multimedia mes⁃saging service，location based service，conference service and some multimedia service can be used through existing abilities entrance.

4)existing BSS/OSS interface.This interface is used to visit billing/charging system such as CRM(customer relationship management)system，network management system，opera⁃tional data store and operation analysis system through carri⁃er’s ESB(enterprise service bus)to achieve accounting functions.Thus，the users used service and resource cost can be billed for business operation.

3.3 Queuing Time in Emergency Service

The emergency service mainly consists of elements in IMS. All the elements have different roles，such as P⁃CSCF，I⁃CSCF，S⁃CSCF and E⁃CSCF.The Poisson distribution is used to calculate the probability of service transfer and queue trans⁃action.Then，the delay cost in each queue is evaluated using a queuing model.Fig.1 shows the queuing model for emergency service.This is an M/M/1/∞/∞model.In the beginning，UEs have to wait in Q1.Then，they communicate with P⁃CSCF in or⁃der to connect to IMS.If the UE is in the front of the queue，it cannot enter the service queue.The P⁃CSCF first determines wither this is an emergency.If it is an emergency，the request is forwarded to Q5through Q2(I⁃CSCF).If not，the request is forwarded to Q3through Q2(S⁃CSCF)to be a normal service. Fig.2 shows the delay in different components.The delaymainly consists of DPq，DPs，DIq，DIs，DEq，DEs，DLq，DLs，DSq，DSs，DAqand DAs，the detailed explanations of notations are shown in ta⁃ble 1.

▲Figure 1.Queuing model for emergency service.

▲Figure 2.Emergency service call setup procedure.

All the requests are analyzed by using the standard M/M/1∞/∞queuing model.The arrival rates in the IMS core network are denotedλPP，λII，λSS，λAA，λEE，λLL。The service rates of ele⁃ments in the IMS core network are denotedμPP，μII，μSS，μAA，μEE，μLL.All the requests before entering the element have to wait until the element(P⁃CSCF，I⁃CSCF，S⁃CSCF，AS，E⁃CSCF，and LRF)is free to handle the request.

After establishing the link，the request is processed by P⁃CSCF，I⁃CSCF，S⁃CSCF，AS，E⁃CSCF，LRF.From(7)-(12)，the process time in each element can be achieved.

Before entering the P⁃CSCF，I⁃CSCF，S⁃CSCF，AS，E⁃CSCF and LRF，the average waiting requests can be obtained accord⁃ing to(13)-(18).

The average waiting number in P⁃CSCF，I⁃CSCF，S⁃CSCF，AS，E⁃CSCF and LRF is given by(19)-(24)

The overall delay can be calculated by the count waiting time of system in the queue and service time.Thus，DT1is the total delay in the normal situation.DT2is the total delay in an emergency situation.The total delay of IMS is given by(25)and(26):

▼Table 1.Delay notations

In order to achieve the arrival rate in different queue，the dif⁃ferent arrival rate is considered in Table 2 and Table 3.Table 2 shows the message arrival rate with Poisson distribution whenλ=50.Table 3 shows the service rate of system ele⁃ments with Poisson distribution whenλ=50.

The arrival rateλand service rateμin Table 2 and Table 3 are measured with Wireshark.These values can be used to esti⁃mate the delay time of system through the(1)-(26): The total delay in an emergency system is DT2=546.3 ms.

In this section，IoT Operations，IoT Business Operation Sup⁃port Platform and Queuing time in Emergency Service are dis⁃cussed.

4 Deployment and Performance Analysis

The proposed prototype system is shown in Fig.3，which is consists of WBAN，LAN，WAN，IoT domain and IMS domain. Then，the deployment evaluation，traffic analysis and emergen⁃cy signaling analysis are discussed.

4.1 IoT Deployment Evaluation

In the current environment，the main consideration of de⁃ploying IoT network is connecting low⁃layer objects to the In⁃ternet.Also，there are lack of specifications and standards for IoT.The business operation model or platform is not shown inthe current Internet.In order to evaluate IoT deployment，we construct a bootstrap platform and map it with Ning and Wang’s Like Mankind Neural System[15]and combined with wireless sensor body network，the OPNet network modeler is taken by this research.Finally，the environment for integrating IoT and IMS for WBSN are proposed as an environment.

▼Table 2.The inter arrival rate of different message(λ=50)

▼Table 3.The service rate of each function(λ=50)

4.2 IoT Traffic Analysis

In this simulation，each object sends a 1024 bit packet per second，which stores sensed information，to the coordinator in this IoT bootstrap platform.Then the coordinator handles these messages and feeds back to each object.We measure number of hops，traffic to coordinator，router and object，and finally the average end⁃to⁃end delay.

The number of hops for data transmission is shown in Fig.4. In this scenario，most objects send their data to the coordinator via one hop.However，some data is delivered via more than two hops.The reason for this is the native limitation of IoT rout⁃er and the distance from object to coordinator.This causes the information to be delivered through other objects.

▲Figure 3.Overview of proposed prototype system.

▲Figure 4.Data transmission hops.

The traffic in bootstrap platform is drawn in Fig.5.The IoTcoordinator receives most data from objects.The IoT router for⁃wards data from objects to the coordinator and vice versa.

The average end⁃to⁃end delay is given in Fig.6.In the be⁃ginning，the delay is quite small;however，traffic increases and delay rises violently.The reason is that the queue length in each router and coordinator is fixed.Finally，the delay increas⁃es with the continually incoming traffic.

4.3 Emergency Signaling Analysis

In this paper，the call setup time of emergency service is dis⁃cussed and analyzed.The main signaling of emergency call is shown in Fig.2[27].It includes three phases that can be sepa⁃rated by T1and T2.T1begins from UE dials emergency number such as 911 to lunch emergency service.The P⁃CSCF is re⁃sponsible for delivering messages from UE to IMS.This con⁃firms that the request is an emergency.If the location of an emergency event was not clear，the emergency CSCF triggers the LRF to obtain location of the UE.Then，the emergency ser⁃vice starts with the detailed event，message，and location. Thus，the different phase of emergency service is obtained from the following definition.T1is the time from INVITE mes⁃sage to call setup procedures.T2is the time for the call setup procedure to be completed.Finally，the total delay time of an emergency call can be calculated from the relationship be⁃ tween T1and T2:D=T2⁃T1.

▲Figure 5.Traffic in components’MAC layer.

In an emergency，users make an emergency call in a short time，and the request needs to be made as soon as possible. The result of emergency service and proposed queuing model is shown in Fig.4.From the simulation result in Fig.7，the call setup time in normal system and emergency service are compared.Then，the call arrival rate is increased to 10，20，30，40 and 50.The results show the call setup delay in a normal system increases when the arrival rate is higher than 30.All the call setup time in emergency service is lower than the nor⁃mal system.Thus，the emergency can provide lower delay and process the emergency call in a short time.

5 Conclusion

In this paper，the prototype of IoT bootstrap platform for sup⁃porting WBAN in the network modeler is evaluated.The cur⁃rent Internet is insufficient to maintain the operation quality when constructing and deploying the IoT networks from traffic analysis results.In our opinion，3GPP IP multimedia subsys⁃tem can be a fabric and a suitable core network for integrating IoT mobile communication network，Internet[17].Further⁃more，the emergency service in IMS is discussed.The detailed signaling and application of emergency elements are analyzed with queuing model.Then the network scenario and element are considered to calculate the call setup delay and compare the simulation result in both a normal IMS system and IMS with emergency service.From the results，the call setup time with different arrival rate in emergency service is always lower than normal system.Thus，the emergency service can be used to establish emergency calls，deliver emergency messages，and make it useful in emergencies.The goal of this research is to reduce the call setup time and improve the performance of the emergency service.Finally，for obtaining better，more suitablesupport for WBAN，the tighter integration of IoT and emergen⁃cy service through 3GPP IMS would be evaluated in our future work.

Acknowledgements

This research was partly funded by Ministry of Science and Technology of R.O.C.under grants no.NSC 101⁃2221⁃E⁃197⁃008⁃MY3.

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[22]C.Y.Chen，K.D.Chang，H.C.Chao，and J.L.Chen，“Extending emergency services coverage in cooperative IMS networks，”International Journal of Au⁃tonomous and Adaptive Communications Systems(IJAACS)，vol.5，no.4，pp. 417-434，2012.

[23]Y.W.Ma，C.F.Lai，C.C.Hu，M.C.Chen，and Y.M.Huang，“RFID⁃based seamless multimedia services for smart homes，”International Journal of Inter⁃net Protocol Technology，vol.4，no.4，pp.232-239，2009.

[24]Y.Wang，and K.Li，“Topology mining of sensor networks for smart home envi⁃ronments，”International Journal of Ad Hoc and Ubiquitous Computing，vol.7，no.3，pp.163-173，2011.

[25]Y.M.Huang，M.Y.Hsieh，H.C.Chao，S.H.Hung，and J.H.Park，“Perva⁃sive，secure access to a hierarchical sensor⁃based healthcare monitoring archi⁃tecture in wireless heterogeneous networks，”IEEE Journal on Selected Areas inCommunications，vol.27，pp.400-411，2009.doi:10.1109/ JSAC.2009.090505.

[26]X.C.Qian and J.D.Zhang，“Study on the structure of‘Internet of Things (IOT)’business operation support platform，”in Proceedings of 2010 12th IEEE International Conference on Communication Technology(ICCT)，Nan⁃jing，China，Nov.2010，pp.1068-1071.

[27]3rd Generation Partnership Project;Technical Specification Group Services and System Aspects;Feasibility Study on Voice Call Continuity Support for Emergen⁃cy Calls(Release 9)，Technical Report 3G TR 23.826 version 9.0.0(2009⁃03)，2009.

Biographiesphies

Jiann⁃Liang Chen(lchen@mail.ntust.edu.tw)received his PhD degree in electrical engineering from National Taiwan University，in 1989.Since August 1997，he has worked in the Department of Computer Science and Information Engineering，Na⁃tional Dong Hwa University.He is currently a professor and vice dean of Science and Engineering College at that university.He is also a full professor in the Depart⁃ment of Electrical Engineering，National Taiwan University of Science and Technol⁃ogy.His current research interests include cellular mobility management，digital home network，telematics applications，cloud computing，and RFID middleware de⁃sign.He is an IEEE Senior Member and UK BCS fellow.He has published more than 150 papers in journals and conferences proceedings and also holds several pat⁃ents.

Han⁃Chieh Chao(hcc@niu.edu.tw)received his MS and PhD degrees in Electrical Engineering from Purdue University in 1989 and 1993.He is a jointly appointed professor in the Department of Electronic Engineering and Institute of Computer Sci⁃ence and Information Engineering，National Ilan University，Taiwan.He also holds a joint professorship in the Department of Electrical Engineering，National Dong Hwa University，Taiwan.His research interests include high⁃speed networks，wire⁃less networks，and IPv6 based networks and applications.He is an IEEE senior member and fellow of the IET and BCS.

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2014⁃04⁃03Kai⁃Di Chang(kedy@ieee.org)received his BS degree in electrical engineering from National Dong Hwa University，Taiwan，in 2007.He received his MS degree from the Institute of C0omputer Science and Information Engineering，National I⁃Lan University，Taiwan.He is currently pursuing his PhD degree in electrical engi⁃neering at National Taiwan University of Science and Technology.He is a student member of IEEE.His research interests include cloud computing，IP multimedia subsystems，Internet of Things，and network security.He is also a researcher at United Daily News Digital Taiwan，where his primary role is to research and devel⁃op ICT technologies according to his research interests.His professional certifica⁃tions include IRCA Information Security Management Systems(ISMS)Auditor/ Lead Auditor(ISO 27001:2005)，2009;Cisco Certified Academy Instructor(CCAI) for CCNA Security(CCNAS)，2010;and BS 10012 Personal Information Manage⁃ment System Lead Auditor(TLATPI0109)，2013.