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LEE et al. : FUNCTIONAL ARCHITECTURE FOR NGN-BASED PERSONALIZED IPTV SERVICES 331

Fig. 1. NGN architecture overview (illustration from [22]).

Fig. 2. Content value chain and IPTV domains. 1

Content Reconstitution : converting the content into aformat suitable for rendering on the end-user device(s).

Each role in the value chain has historically been bound toa type of stakeholder or technical component. Content Produc-tion, for example, is linked to production rms and to the pro-duction teams of TV stations.

2) Domain Model for IPTV Services: Fig. 2 shows the do-main and content value chains that are involved in the provi-sioning of IPTV services. Four domains of IPTV service provi-sioning are dened as follows [10], [11], [18]:

1Although considered as two separate entities, the Service Provider and theNetwork Provider may in fact be one organizational entity.

Content Provider : The entity that owns or is licensed tosell content or content assets.

Service Provider : A general reference to an operator thatprovides telecommunication services to customers andother users either on a tariff or contract basis. A serviceprovider can optionally operate a network. A serviceprovider can optionally be a customer of another serviceprovider.

Network Provider : The organization that maintains andoperates the network components required for IPTV func-

tionality. A network provider canoptionally also actas ser-vice provider.


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332 IEEE TRANSACTIONS ON BROADCASTING, VOL. 55, NO. 2, JUNE 2009

Fig. 3. NGN for supporting IPTV services.

End-user : The actual user of the products or services. Anend-user can optionally be a subscriber.

There are several reference points (RPs) between logical do-mains [12], [13], [18]:

RP 1: logical reference point between end-user and net-work provider (user to network RP).

RP 2: logical reference point between network providerand service provider (transport and control RP).

RP 3: logical reference point between service provider andcontent provider (content provider RP).

RP 4: logical reference point between end user and serviceprovider (service platform RP).

RP 5: logical reference point between network providerand content provider (out of scope).

RP 6: logical referencepoint between end-user andcontentprovider. A direct logical information ow may be set upfor rights management, protection, etc.

3) Several Types of IPTV Services: IPTV services are clas-sied as the follows [28]:

Broadcast type services (linear TV) : comprise a one-waytransmission of content from one point (the source) to twoor more points (the receivers), whereas the end-user hasno control over the content or timing of what he receives,apart from the ability to select a particular channel.

On-demand type service : is content prepared and deliv-ered by the content provider for retrieval, which is received

and stored by the service provider. If necessary, trans-coding can be performed to accommodate the storage de-vice characteristics. The end-user can then select and re-trieve such contents from this storage at any time, ac-cording to the constraints provided by the content protec-tion metadata.

Other type services : include advertising service, publicinterest service, tele-services, portal services, hosting ser-vices, IPTV interactive service, presence services, time-shifting and place-shifting service, session mobility ser-vice, supplementary content, etc.

C. Impact of NGN for IPTV Services

ITU-T has developed three IPTV architectures that enableservice providers to deliver IPTV services [18]:

Non-NGN IPTV functional Architecture (Non-NGNIPTV) : The Non-NGN IPTV architecture is based on ex-isting network components and protocols/interfaces. Thisapproach is a representation of typical existing networksproviding IPTV services.

NGN-based non-IMS IPTV Functional Architecture(NGN-Non-IMS IPTV) : The NGN Non-IMS IPTV ar-chitecture utilizes components of the NGN framework reference architecture as identied in [22] to support theprovision of IPTV services, in conjunction with otherNGN services if required.

NGN IMS-based IPTVFunctional Architecture (NGN-IMS-IPTV) : The NGN-IMS based IPTV architecture uti-lizes components of the NGN architecture including the

IMS component to support the provision of IPTV services,in conjunction with other IMS services if required. Keybenets of using this architecture are as follows [29]: Access-independent service delivery of a centralized

subscriber database Open interfaces to application servers Per-session dynamic QoS for an optimized QoE Multimedia communications supporting other services

(e.g., quad-play services).In this paper, we focus on IPTV services from the NGN per-

spective including IMS component. Specically, NGN can pro-vide enhanced capabilities for managing IP and broadband ser-

vices regardless of xed or wireless environment, which is cru-cial for support of xed mobile convergence (FMC) as shownin Fig. 3. NGN can facilitate the interworking with legacy net-works (e.g., IPv4/IPv6, mobile/wireless, broadcasting, PSTN,etc) and accommodate various kinds of end-user devices (e.g.,TV, personal computer (PC), phone, and wireless device in-cluding IPTV set-top box (STB)).

Most of service providers consider IPTV as a key gate to thetriple-play service businesses (including voice, video, and dataservice) using rich contents; TV programs from broadcastingsources, On-demand video storage and user created video, etc.A combination of voice, data and video services over broadbandlinks and from a provider is seen as the ultimate goal of thebroadband revolution. Therefore, NGN adjustment with IPTVcharacteristics is a suitable way for supporting new emerging


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Fig. 4. IPTV architectural overview. 2 (illustration from [18]).

services over heterogeneous networking environment. We ex-pect that IPTV will have the principal role in accelerating bothdeployment and business of NGN.

III. FUNCTIONAL ARCHITECTURE FOR IPTV SERVICES

A. Overall Functional Architecture for IPTV

In this section, we introduce IPTV architectures based on[18]. To design functional architecture for IPTV, we consider theprincipal functional groups for IPTV. These functional groupsprovide a more detailed breakdown of the IPTV domains that

are discussed in Section II. The functional groups in the archi-tecture are derived by grouping related functions.Fig. 4 shows an overview of the IPTV functional architec-

ture. The following points give a description of each functionalgroup. The related functions in each functional group are furtherdecomposed as shown in Fig. 5.

End-User Functions : perform mediation between theend-user and the IPTV infrastructure.

Application Functions : enable the End-User Functions toselect and purchase or rent a content item.

Service Control Functions : provide the functions to re-quest and release network and service resources requiredto support the IPTV services.

Content Delivery Functions : receive content from theApplication Functions, store, process, and deliver it to the

End-User Functions using the capabilities of the Network Functions, under control of the Service Control Functions.

Network Functions : provide IP layer connectivity be-tween the IPTV service components and the End-Userfunctions.

Management Functions : perform overall system man-agement (i.e., operations, administration, maintenance andprovisioning (OAM&P)).

Content Provider Functions : provided by the entity thatowns or is licensed to provide content or content assets.

B. End-User Functions

1) IPTV Terminal Functions (ITF): The ITF are responsiblefor collecting control commands from the end-user, and inter-acting with the Application Functions to obtain service infor-mation (e.g., electronic program guide (EPG)), content licenses,andkeys for decryption. They interact with the Content DeliveryFunctions to receive the IPTV services. They also provide thecapability for content reception, decryption, and decoding.

2The rectangular blocks represent functional blocks in the IPTV architec-ture. The rounded rectangular areas represent the particular grouping of func-tions. The solid lines represent direct relationships between either Functions

or Functional Blocks. The dotted lines represent logical associations betweenEnd-User Functions and either Functions or Functional Blocks located outsidethe End-User Functions.


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Fig. 5. Detailed IPTV functional architecture (illustration from [18]).

Application Client Functions : exchange informationwith the Application Functions to support IPTV and otherinteractive applications. Service and application discovery & selection client

functional block On-demand client functional block Linear TV client functional block Other client functional blocks

Service and Content Protection (SCP) ClientFunctions : interact with SCP functions to provide serviceprotection and content protection and veries the usagerights and decrypts and optionally watermark the content. Content protection client functional block Service protection client functional block

Content Delivery Client Functions : receive and controlthe delivery of the content from the Content Delivery andStorage Functions. After receiving the content, the Con-tent Delivery Client Functions can optionally use the SCPClient Functions to decrypt and decode the content, andcan also optionally support playback control. Multicast content delivery client functional block Unicast content delivery client functional block Error recovery client functional block (option)

Control Client Functional Block : allows the ITF to ini-tiate service requests to IPTV Service Control Functional

Block, in order to prepare for the connection to the Con-tent Delivery Functions.


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2) Home Network Functions (HNF): The HNF provide theconnectivity between the external network and each IPTV ter-minal device. All data, content, and control trafc must passthrough the Home Network Functions in order to enter or exitthe end-users IPTV terminal device.

Delivery Network Gateway Functional Block : provides

IP connectivity between the externalnetwork andthe IPTVterminal device. It manages the IP connectivity, obtainsIP addresses and congurations for the HNF and IPTVterminal devices.

C. Application Functions

1) IPTV Application Functions (IAF): The IAF enable theIPTV Terminal Functions to select and purchase, if necessary,content.

Service and application discovery & selection functionalblock

Linear TV application functional block On-demand application functional block Other application functional blocks Application Prole Functional Block : stores the proles for

the IPTV applications. The proles can optionally include end-user setting, global setting (e.g., language preference), linearTV setting, video on demand (VoD) settings, personal videorecorder settings and IPTV service actions data, etc.

Content Preparation Functions : control the preparation andaggregation of the contents such as VoD programs, TV channelstreams, metadata, and EPG data, as received from the contentprovider functions.

Content management functional block Metadata processing functional block

Content processing control functional block Content pre-processing functional block Service & Content Protection (SCP) Functions : controls the

protection of the services and content. Content protection functional block for control of access

to contents Service protection functional block for authentication and

authorization of access to services Application Provisioning Functional Block : adds or with-

draws applications and manages the life-cycle of IPTVapplications.

D. Service Control Functions

IPTV Service Control Functional Block : provides the func-tions to handle service initiation, modication and terminationrequests, perform service access control, establish and maintainthe network and system resources required to support the IPTVservices requested by the ITF.

Provides registration, authentication and authorizationfunctions for the End-User Functions.

Processes requests from IAF and forwards them to theContent Delivery Functions in order that the Content De-livery Functions select the most appropriate Content De-livery & Storage Functions, for delivering content to theEnd-User Functions.

Requests the Content Delivery Functions or ApplicationFunctions to collect charging information.

Service User Prole Functional Block : used for storing ser-vice proles andgenerating responses to queries for service pro-les.

E. Content Delivery Functions

The Content Delivery Functions receive perform cache and

storage functionalities and deliver the content according to therequest from the End-User Functions. The content deliveryfunctions can optionally process the content.

Content Distribution & Location Control Functions(CD&LCF) : control the Content Delivery & Storage Functionsto optimize content distribution, selection and deliver contentto the ITF.

Distribution control functional block Location control functional block Content Delivery & Storage Functions (CD&SF) : store and

cache the content process it under the control of Content Prepa-ration Functions and distribute it among instances of ContentDelivery & Storage Functions based on the policy of ContentDistribution & Location Control Functions.

Content delivery control functional block Cache & storage functional block Distribution functional block Error recovery functional block (option) Content processing functional block Unicast delivery functional block Multicast delivery functional block

F. Network Functions

The Network Functions are shared across all services deliv-ered by IP to the End-User Functions. They provide the IP layer

connectivity in order to support IPTV services. Authentication & IP Allocation Functional Block : pro-

vides the functionality to authenticate the Delivery Net-work Gateway Functional Block, which connects to theNetwork Functions, as well as allocation of IP address tothe Delivery Network Gateway Functional Block and op-tionally to the IPTV Terminal Functions.

Resource Control Functional Block : provides control of the resources, which have been allocated for the deliveryof the IPTV services through the Access Network, Edgeand Core Transport Functions.

Access Network Functions : (1) aggregating and for-

warding the IPTV trafc sent by the End-User Functionsinto the edge of the core network and (2) forwarding theIPTV trafc from the edge of the core network towardsthe End-User Functions.

Edge Functions : forwarding the IPTV trafc aggregatedby the Access Network Functions towards the core net-work, and also to forward the IPTV trafc from the corenetwork to the End-User Functions.

Core Transport Functions : forwarding IPTV trafcthroughout the core network.

Multicast Transport Functions Multicastcontrol point functional block for the selection

of the individual multicast streams (McCPF) Multicast replication functional block for replicating

multicast stream (McRF)


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Unicast Transport Functions : the transport of unicastcontent streams from the Unicast Delivery FunctionalBlock to the End-User Functions.

G. Management Functions

The Management Functions handle overall system status

monitoring and conguration. This set of functions can option-ally be deployed in a centralized or a distributed manner.

Application management functional block Content delivery management functional block Service control management functional block End user device management functional block Transport management functional block

H. Content Provider Functions

The Content Provider Functionsprovide many different typesof sources to the Content Preparation Functions. The physicalinterfaces and content formats can optionally be different de-

pending on the type of the sources. It can optionally includefunctions for access control based on rating of the content.

Content Protection Metadata Sources : the usage rulesand rights for protected IPTV content.

Metadata Sources : an entity that provides contentprovider metadata associated with the IPTV content.

Content Sources : an entity that provides IPTV content.

I. Physical Conguration for Protocol Operation

According to decomposition of each functional group, Fig. 5shows detailed IPTV functional architecture. The IPTV archi-tecture needs to allow for IPTV network, service and applica-

tion components to exist at different physical and logical pointsin a network. The specied protocols are operating with align-ment of physical conguration and functional modules in IPTVarchitecture.

Content provider has content sources and service providerhas streaming server and transaction servers. Transactionservers of the service provider are composed of servers fordigital rights management (DRM), customer relationshipmanagement (CRM), billing, prole management, identitymanagement, web or IPTV portal, etc.

In network provider domain, IPTV functional elements canbe mapped into a physical network hierarchy specically for

linear TV. There are three types of network nodes [17], [18],[30]; Super Head End (SHE) the locations for acquisition

and aggregation of region-independent (national-level)linear/broadcast TV programming. SHEs are also thecentral points for on-demand content insertion.

Video Hub Ofce (VHO) the video distribution pointswithin a demographic market area. National content is re-ceived from each SHE. Local content is acquired and en-coded. Insertion of local content is also performed in theVHO. IPTV services are provided from the VHO via theaggregation/access network.

Video Serving Ofce (VSO) the VSO (typically a Cen-tral Ofce) hosts or connects all access systems for inter-connection to consumers. In addition, the VSO contains

Fig. 6. Functional mapping between IPTV and NGN architecture.

aggregation equipment to enable efcient and reliable in-terconnection to the VHO.

The access network functions must be located between thevideo serving ofce (VSO) and end-user, the IP multicastreplication functions can also be optionally located in the VSO.Various access networks may provide passive optical network (PON), wireless, and Ethernet interfaces for delivery of IPTVcontent to the residential subscriber.

The end user comprises the IPTV terminal and delivery net-work gateway (DNG)/STB. DNG provides trafc managementand routing between the access network and the home network.

IV. NGN-B ASED IPTV ARCHITECTURE

A. Comparison of Functional Architecture Between IPTV and NGN

It is useful to relate the IPTV architecture to the generalNGN framework architecture and other networks to clarify thesimilarities and differences, as well as provide a reference forthe more detailed description of IPTV specic components.The NGN-based architecture means the IPTV architecture

in accordance with [22] for providing IPTV services. There-fore, functionalities for IPTV services have a correspondencerelationship with the NGN architecture. The NGN componentsdescribed in [22] were shown in Fig. 1.

Fig. 6 shows functional mapping between IPTV and NGN ar-chitectures according to the relationships between the functionsof these two architectures:

Application Functions may be included in ApplicationSupport Functions & Service Support Functions of NGN

Service Control Functions may be included in the ServiceControl Functions (i.e., IPTV service component) of NGN

Content DeliveryFunctionsmay interact with both ServiceStratum and Transport Stratum of NGN

Network Functions may be included in Transport Stratumof NGN


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Fig. 7. IPTV functional architecture in alignment with NGN 3 (illustration from [18]).

End-User Functions may be included in End-User Func-tions of NGN

Management Functions may be included in ManagementFunctions of NGN

Content Provider Functions may reside outside the NGN Content Delivery Functions may reside outside the NGN

in cases like a 3rd party service provider. Application Functions may reside outside the NGN in

cases like a 3rd party service provider. IPTV Service Control Functional Block corresponds to

NGN Service Control Functions. However, NGN ServiceControl Functions may include other functionalities.

B. Harmonized Architecture Between IPTV and NGN

Based on the functional mapping between NGN and IPTVfunctions (see Fig. 6), we show the IPTV functional architec-ture in alignment with NGN in Fig. 7. It presents the functionalarchitecture for NGN-based IPTV services.

The NGN-based IPTV architecture is based on the NGN ar-chitecture dened in [22] and uses the components and func-tions of the NGN. The non-NGN-based IPTV architecture doesnotnecessarily require these components and functionsandusesconventional and/or legacy network technologies for the de-livery of IPTV services. The main differences are the following:

3There are two NGN-based IPTV architectures; NGN-IMS-IPTV and NGN-non-IMS-IPTV. This diagram represents NGN-IMS-based IPTV architecture.

The NGN-based IPTV architecture uses NACF to providefunctions such as authentication and IP conguration.

The NGN-based IPTV architecture uses RACF to provideresource and admission control functions.

The NGN-based IPTV architecture uses Service ControlFunctions dened in [22] to provide service control func-tions.

The NGN-IMS-based IPTV architecture (see Fig. 7) usesCore IMS Functions such as IPTV Service Control FunctionalBlock and associated functions such as Service User ProleFunctional Block dened in [31] to provide service controlfunctions. The core IMS Functions offer a session control

mechanism, and provide functions for authentication and au-thorization of IPTV Terminal Functions based on user prole,as well as functions for the interaction with RACF for resourcereservation. The core IMS Functions also provide interactionbetween IPTV Terminal Functions, IPTV Application Func-tions and Content Delivery Functions. The core IMS Functionscan be used for Service Discovery. Functions such as chargingand roaming can also be supported by IMS mechanisms.

The NGN-non-IMS-based IPTV architecture uses ServiceControl Functions other than core IMS Functions to provideservice control functions.

The key advantages of NGN-based IPTV architecture areto realize personalized value-added services and use moreefciently network resources using tight integration with NGNfunctionalities such as NACF, RACF and IMS, etc.


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Fig. 8. Procedural ows for Linear TV and VoD services in NGN-IMS-IPTV architecture.

C. Procedural Flows for IPTV Services

This section provides detailed descriptions of the proceduralows for linear TV and VoD services in NGN-IMS-IPTV archi-tecture as shown in Fig. 8 [18].

First, the ITF acquire service parameters which include thecontent identier, logical uniform resource locator (URL),bandwidth, codec information for VoD, and a logical channelidentier for linear TV. Then, the ITF initiate a service requestto the core IMS functions. The core IMS functions optionallydetermine the location of the ITF, for example by querying theNACF.

Next, for linear TV services, the core IMS functions forwardthe request to the Linear TV application with ITF location and

logical channel identier(s). The linear TV application passesthe ITF location and the logical channel identier(s) to the con-tent deliverycontrol function.Thecontent deliverycontrol func-tion determines the multicast addresses and which CD&SF usesto output the required channels and has multicast network pathsto the IPTV terminal based on the association between logicalchannel identiers and multicast addresses. It returns the corre-sponding multicast addresses to the linear TV application. Thelinear TV application returns the multicast network parametersto the core IMS.

For VoD services, the core IMS functions send a network re-source request to the RACF. The RACF performs network re-source reservation and sends the response to the core IMS func-tions. The core IMS functions send the service request with


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content identier, logical URL to the on-demand IPTV appli-cation functional block. The on-demand application functionalblock performs service authorization. The on-demand IPTV ap-plication functional block sends the request to the CD&LCF viacore IMS functions in order to select the CD&SF. The core IMSFunctions forward the request to the CD&LCF. The CD&LCF

selects a suitable CD&SF based on some criteria (e.g., the stateof the CD&SFsand the knowledge of distributed content amongthe CD&SF etc). The CD&LCF resolves the logical URL of content into the physical URL of an allocated CD&SF, and re-sponds the URL of selected CD&SF to on-demand applicationfunctional block via core IMS functions. The core IMS func-tions forward the response to the on-demand application func-tional block. The on-demand application functional block sendsthe content resource request to the selected CD&SF via coreIMS functions in order to allocate content resources. The coreIMS functions forward the content resource request to the se-lected CD&SF. The CD&SF performs content resource alloca-tion and sends the response to the core IMS functions. The coreIMS functions forward the response to the on-demand appli-cation functional block. The on-demand application functionalblock sends the service response to the core IMS functions.

After that, the core IMS functions send a network resourcerequest to the RACF. The RACF performs network resourceallocation andsends the response to the core IMS functions. Thecore IMS functions send the service response to the ITF.

Finally, for linear TV services, the ITF receivesa list of one ormore logical channels and their multicast addresses and main-tains this mapping for theduration of the multicastsession.Afterthat, the ITF initiate channel control request by initialing a mul-ticast join request and receives the multicast stream. When the

user exits the linear TV application (i.e., they stop watchingTV), the ITF will request the session be ended and will releaseany requested resources. For VoD services, the ITF connect tothe identied CD&SF to receive the content.

V. CHALLENGING ISSUES FOR NGN-B ASED IPTV SERVICES

A. Personalized IPTV Services

The challenge to a successful IPTV service lies not only inthe underlying transport networks but also in the need for ser-vice applications and their platforms to adapt to new business

models, and changing service trends and environments. IPTVservice is growing the number of service providers, users, andcontent, while enlarging its area of services at the same time.The potential of a growing quantity of IPTV services will re-sult in enormous expansion of options for users. Under thesecircumstances, spotting what the user may like or want to enjoybecomes a key factor for successful IPTV service. Moreover, thepersonalization of service allows providing more value addedservices, which will make the IPTV service worthwhile. TheIPTV services will adopt more Internet and telecommunicationcapabilities in step with the rapidly developing service environ-ment. New business modelswill require open, exible, andagileplatform such as Web or its more advance form, Web 2.0.

From the future trend in the end-users perspective, thevalue will be transferred from access service of traditional

Fig. 9. Personalized IPTV services using Web-based open platform.

telecom providers to content-based services such as IPTV. Thekey factor underpinning the success of all end-user-orientedservices lies in the degree of users awareness. Personalizedservices are identied as tailor-made to the users needs fordelivering appropriate content and services. These services areto improve the users experience and satisfaction. In addition, asdevices evolve, the real benets of IPTV using a multi-terminal(including multiple functions such as camera, video recorder,phone, TV, music player, etc) are in the merging of entertain-ment and communications, the integration of telephone featuresinto television experience, and the mobility of video servicesthat follow the user anywhere, anytime.

Accordingly, personalized IPTV services will permit forusers to access and consume what they want, when and wherethey want in a personalized way on local and/or remote personalstorage systems from both broadcast and online services. These

services are targeting and customizing content for individualusers based on the followings: user preferences, features of userdevices and/or access networks and natural environments suchas mood, location, time, etc.

Unlike the legacy Web world, where users were passive ob-servers of Web site content, the advanced web world such asWeb 2.0 is providing dynamicity and interactivity in near realtime to the users. The emphasis of Web 2.0 is not on creating re-tail community-type services of its own but on building an openplatform through which third-party application developers canaccess and launch their own services. The open platform gen-erates extra prots through extended management and the cre-

ation and deployment of value-added services while fully sup-porting new service requirements. Using interactive, collabora-tive and customizable features Web 2.0 can provide rich userexperiences/interfaces and new business opportunities for IPTVservices. From standards point of view, IMS-basedNGN will bea key platform for service control capabilities in IPTV.

We expect that a new service platform, which combinesweb-based open structure using Web and IMS-based NGN asshown in the Fig. 9, will provide Personalized IPTV Servicesas one of new business models for service providers/network providers. The illustrated service platform creates new businessfor IPTV services with new features. The web-based IPTV isa platform that allows an organization to integrate its businessinformation, applications, and services into a web-based IPTVportal beneting from easy navigation and access.


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Fig. 10. Example of functional architecture for Web-based open IPTV platform.

Fig. 11. Service examples of personalized IPTV using intelligent multimedia, Web and personalized networking technologies.

B. Web-Based Open Platform for IPTV Services

For the emerging personalized IPTV services, we provide anexample of functional architecture for web-based open IPTVplatform in NGN as shown in Fig. 10. The illustrated IPTV ar-chitecture consists of the following functional components:

Contents : The contents are classied into digital broad-casting, online content and stored content in digital videodiscs (DVDs) and hard disk drives (HDDs), etc. The con-tent domain requires functionality, which receives videocontent from producers and other sources. Afterward,

these contents are encoded and stored in an acquisitiondatabase for VoD, etc.

Head-end : The head-end domain requires a function-ality which receives video streams in different formats.These video streams in different formats are then refor-matted and encapsulated for transmission with appropriateQoS indications to the network through content prepara-tion. This makes them ready for delivery to end-usersusingservice delivery management. In addition, to support per-sonalized IPTV services, web-based service operation andpersonalization functions are very critical.


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Network : The IMS-based NGN of the network domaincan support transport functions, and service and transportcontrol functions. Specically, it supports delivery capa-bilities, such as multicast, which is necessary for the reli-able and timely distribution of IPTV data streams from theservice nodes to the end-user. Moreover, the core and ac-

cess network of NGN cover the optical distribution back-bone network for high capacity and the various digital sub-scriber line access multiplexers (DSLAMs).

End-user : The device of the end-user performs func-tional processing through web-based client, service usagemonitoring, and content decoder. The functional pro-cessing includes setting up the connection and QoS withthe service node, decoding the video streams, channelchange functionality, user display control and connectionsto user appliances such as a standard denition television(SDTV) or a high denition television (HDTV) monitorusing Web. The end-user also has a network interfacewhich terminates the IPTV trafc at the home network.

C. Service Examples of Personalized IPTV

In order to provide personalized IPTV services using pro-posed web-based open IPTV platform, intelligent multimedia,Web and personalized networking technologies should betightly interacted with several functions which are illustrated inFig. 10. In particular emerging Web technologies which includeontology, semantic, mash-up, and community functions, etccan be key enablers of personalized IPTV services. Here weintroduce service examples of personalized IPTV from the

viewpoint of customer (e.g., smart client) as an end user asshown in Fig. 11 [32], [33].

The personal IPTV broadcast services provide a customerwith a wayto advertisepersonal contents so that other customerscan access such contents. These services make the IPTV cus-tomer into a content provider. The service provider is respon-sible for relaying session information between the broadcastingcustomer and the receiving customers, possibly assuming someaccess control functions so as to ensure that a given customer isentitled to broadcast his/her personal contents.

The development and provisioning of IPTV services throughthe use of portal sites will increase. Portal services are branded

aggregation of products and services designed to satisfy a largemajority of customers needs, such as VoD, shopping, banking,communication, entertainment and other interactive serviceswith a portal menu. The portal services can target customersby broadcasting commercials, advertisements and interactiveresponsible advertising. Portal services may provide walledgarden access and/or direct Internet access.

The IPTV portal services basically operate in a similarmanner to a web service on the Internet and take advantageof the TV screen in the same way as data broadcasts in digitalbroadcasting, and control functions related to IPTV services.These services support hyperlink functions for linking to otherparts of the same portal site or to other portal sites.

Consequently, Web-based open IPTV can provide commu-nity-based content navigation/ranking, personalized content

creation and customized content provisioning with collectiveintelligence to customers.

VI. CONCLUSION

In this paper, we reviewed the basic concept and architecture

models of IPTV in relation with NGN. We explained the im-pact of NGN on IPTV services emphasizing that NGN can pro-vide IPTV services more efciently through managed IP andconvergence broadband capabilities. Then, we have analyzedIPTV architecture developed by ITU-T and provided functionalarchitecture for NGN-based IPTV services according to func-tional mapping between IPTV and NGN functions. For this, weshowed the detailed functional architecture and relevant opera-tions with functional blocks and presented the harmonized ar-chitecture between IPTV and NGN for NGN-based IPTV ser-vices. As a conclusion, taking into consideration all this andthe emergence of advanced user requirements, we introduced apersonalized IPTV service concept combining Web-based openplatform with NGN environment and illustrated functional ar-chitecture for Web-based personalized IPTV services and ser-vice examples.

We believe that the web-based open IPTV platform is a chal-lenging architectural issue.Personalized IPTV services will be akey solution for value-added services over NGN, and the emer-gence of Web 2.0 will provide an open platform and a new busi-ness model for IPTV services in the near future.

ACKNOWLEDGMENT

The authors are grateful to Dr. Daniel Genin from NationalInstitute of Standards and Technology (NIST) for reviewing andproviding many helpful comments which have improved thequality of this paper.

REFERENCES

[1] General Overview of NGN, ITU-T Recommendation Y.2001, Dec.2004.

[2] Draft Recommendation Y.iptv-req, Requirements for the Support of IPTV Services, ITU-T TD 139 (IPTV-GSI), Sep. 2008, consented asY.1901 .

[3] A. Takahashi, D. Hands, and V. Barriac, Standardization activities inthe ITU for a QoE assessment of IPTV, IEEE Communications Mag-azine , vol. 46, no. 2, pp. 7884, Feb. 2008.

[4] ITU-T SG 13 Website [Online]. Available: http://www.itu.int/ITU-T/ studygroups/com13/index.asp

[5] The Draft Recommendation Y.NGN-R2-Reqts, Requirements andCapabilities for ITU-T NGN Release 2, ITU-T TD 262 (NGN-GSI),Sep. 2008, work in progress .

[6] FG IPTV Deliverables [Online]. Available: http://www.itu.int/publ/T-PROC-IPTVFG-2008/en

[7] ITU-T IPTV-GSI Website [Online]. Available: http://www.itu.int/ ITU-T/gsi/iptv/

[8] NGN Functional Architecture , ETSI ES 282001V2.0.0, TISPAN,Mar.2008.

[9] IMS-Based IPTV Stage 3 Specication , ETSI TS 183 063 V2.1.0,TISPAN, Jun. 2008.

[10] IPTV architecture requirements, ATIS-IPTV Interoperability Forum ,Apr. 2006, ATIS-0800002.

[11] IPTV architecture roadmap, ATIS-IPTV Interoperability Forum ,

Aug. 2006, ATIS-0800003.[12] IPTV high level architecture, ATIS-IPTV In teroperability Forum ,Mar. 2007, ATIS-0800007.


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[13] Open IPTV ForumFunctional ArchitectureV 1.1, Open IPTVForum, Jan. 2008.

[14] IP Multimedia Subsystem (IMS); Stage 2, 3GPP TS 23.228 V8.7.0,tech. spec, Dec. 2008.

[15] E. Mikoczy, D. Sivchenko, B. Xu, and J. I. Moreno, IPTV servicesover IMS: Architecture and standardization, IEEE Communications Magazine , vol. 46, no. 5, pp. 128135, May 2008.

[16] I. Mas, V. Berggren, R. Jana, J. Murray, and C. W. Rice, IMS-TV:

An IMS-based architecture for interactive, personalized IPTV, IEEE Communications Magazine , vol. 46, no. 11, pp. 156163, Nov. 2008.[17] S. V. Vasudevan, X. Liu, and K. Kollmansberger, IPTV architectures

for cable system: An evolutionary approach, IEEE Communications Magazine , vol. 46, no. 5, pp. 102109, May 2008.

[18] IPTV Functional Architecture , ITU-T Recommendation Y.1910, Sep.2008.

[19] J. Lyu, S. Pyo, J. Lim, M. Kim, S. Lim, and S. Kim, Design of openAPIs for personalized IPTV service, in Proc. the 9th InternationalConference on Advance Communication Technology , Feb. 2007, vol.1, pp. 305310.

[20] M. Hofmanand L. R. Beaumont, Open pluggable edge services,an ar-chitecture for networked content services, IEEE Internet Computing ,vol. 11, pp. 6773, Jan. 2007.

[21] S. Kim and S. Y. Lee, Web technology and standardization for Web2.0 based IPTV service, in Proc. the 10th International Conferenceon Advance Communication Technology , February 2008, vol. 3, pp.17511754.

[22] Functional Requirements and Architecture of the NGN, ITU-T Rec-ommendation Y.2012, Sep. 2006.

[23] NGN Release 1 Scope, ITU-T Recommendation Y.2000SerSup1,Jul. 2006.

[24] NGN Release 1 Requirements, ITU-T Recommendation Y.2201,Apr. 2007.

[25] General Principlesand General Reference Model for NextGenerationNetworks, ITU-T Recommendation Y.2011, Oct. 2004.

[26] Network Attachment Control Functions in Next Generation Net-works, ITU-T Recommendation Y.2014, Jan. 2008.

[27] Resource and Admission Control Functions in Next Generation Net-works, ITU-T Recommendation Y.2111, Sep. 2006.

[28] FG-IPTV Deliverable: IPTV Service Scenarios, ITU-T TD 3 (IPTV-GSI), Jan. 2008, work in progress.

[29] Cisco, The evolving IPTV Service Architecture, White Paper, C11-409311-00, May 2007.

[30] S. Han, S. Lisle, and G. Nehib, IPTV transport architecture alterna-tives and economic considerations, IEEE Communications Magazine ,vol. 46, no. 2, pp. 7077, Feb. 2008.

[31] IMS for Next Generation Networks ITU-T Recommendation Y.2021,Sep. 2006.

[32] Supplement on IPTV Service Use Cases, ITU-T Y.1900-series, May2008.

[33] Revised Draft Recommendation H.IPTV-MAP, Multimedia Applica-tionPlatformsand EndSystems for IPTV,ITU-T TD 198(IPTV-GSI),Nov. 2008, work in progress.

Gyu Myoung Lee (M02) received B.S. degree inelectronic and electrical engineering from Hong Ik University, Seoul, Korea, in 1999 and M.S., andPh.D. degree in school of engineering from Infor-mation Communications University (ICU), Daejeon,Korea, in 2000 and 2007, respectively.

He is currently with Institut TELECOM SudParisas a research fellow, specializing in IPTV networksand standards development. Since 2007 he has beenworking as a research professor in ICU, Korea and asan invited researcher in Electronics and Telecommu-

nications Research Institute, Korea. He worked as a guest researcher in NationalInstituteof Standardsand Technology, USA, in 2007 andas a visiting researcherin the University of Melbourne, Australia,in 2002. His research interestsincludeubiquitous networking and IPTV services for NGN, IPv6 protocols, and trafcengineering including optical switching technologies.

Dr. Lee has activelyparticipated in standardization meetings includingITU-TSG 13, IPTV-GSI, and IETF. He received several Best Paper Awards in interna-tional and domestic conferences and served as a reviewer of IEEE journal andinternational conferences.

Chae Sub Lee received the B.Sc. (Eng.) and M.Sc(Eng.) degree from Kon-Kuk University in elec-tronics engineering, Seoul, Korea in 1983 and in1985, respectively.

He has been working in the telecoms standardiza-tion eld for over 20 years. He has been actively in-volved in regional standards in ASTAP, APT, TTAand CJK in the area of network standards. He has

been involved in ITU-T standards development forthe ISDN, GII, IP-based networks and NGN. He wasmainly involved in Study Group XVIII (currently SG

13) as a rapporteur on Architecture and Interworking areas. He is a chairmanof ITU-T SG 13 on future networks including mobile and NGN. He has beenserved as one of Vice-Chairman of ITU-T IPTV Focus Group since July 2006.He shared his role as a Chairman of NGN Focus Group from June 2004 tillNovember 2005. After a career of twenty years with KT as a senior researchingengineer, he has been an invited researching staff to ETRI.

Woo Seop Rhee (M01) received B.S. degree incomputer science from Hong Ik University, Seoul,Korea, in 1983 and M.S., and Ph.D. degree in 1995and 2003, respectively, in computer science fromChungnam National University, Daejeon, Korea.

From 1983 to 2005, he was with the Electronicsand Telecommunication Research Institute (ETRI).He involved in development of TDX switchingsystem, HANbit ACE ATM switching system andOptical access system as a project leader.

In 2005, Dr. Rhee joined Hanbat National Univer-sity, Daejeon, Korea and is currently assistant professor of Multimedia engi-neering department. His research interests are concerned with broadband net-work architecture, quality of service in Internet and mobility management withmulticast. He is an active member of ITU-T SG 13 as Editor and member of KICS in Korea and IEEE.

Jun Kyun Choi (SMXX) received the B.Sc. (Eng.)from Seoul National University in electronics engi-neering, Seoul, Korea in 1982, and M.Sc (Eng.) andPh.D. degree in 1985 and 1988, respectively, in elec-tronics engineering fromKorea AdvancedInstitute of Science and Technology (KAIST).

From June 1986 until December 1997, he waswith the Electronics and Telecommunication Re-search Institute (ETRI). In January 1998, he joinedthe Information and Communications University(ICU), Daejeon, Korea as a Professor. He is a

Senior Member of IEEE, the executive member of The Institute of ElectronicsEngineers of Korea (IEEK), Editor Board of Member of Korea InformationProcessing Society (KIPS), Life member of Korea Institute of CommunicationScience (KICS). His research interests are concerned with broadband network architecture and technologies particular emphasis on performance and protocolproblems. Secondary interests include the international standard activities onbroadband network architecture and protocol with mobility support.

Dr. Choi is an active member of ITU-T SG 13 as a Rapporteur or Editor fromJanuary 1993 on theATM, MPLS, andNGN issues. He hadalso submittedmorethan 30 drafts on IETF during last few years.

Documents

Functional Architecture for NGN-Based