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Abstract— The objectives of the study were to find ways to

enhance IPTV. The trend now is with context-aware

personalised services. The study first explained the basics of

IPTV, and then discussed the concerns and issues with current

implementations. Next definitions of contexts, identity, profiles,

roles and personalisation were introduced and the concept of

context-aware personalised IPTV was described. The

significance of the findings was discussed to conclude the study.

Index Terms—Context, Identity, IPTV, Personalization,

Profile, Privacy, Security.

I. INTRODUCTION

PTV is a Telecom initiative to provide broadcast

television to the consumer over IP networks as part of the

data, voice and video ―Triple Play‖ services. The

convergence is being driven by the incumbent operators who

find themselves in an increasingly difficult market. Their

mobile markets are reaching saturation limiting growth, with

revenues from fixed voice and data services dropping as they

face aggressive non-traditional competition from the cable

industry and MVNOs. In their bid to fight back, telecoms see

the delivery of broadcast video over their modern IP

networks as a critical strategic opportunity. They are

investing heavily in an attempt to capture more subscribers,

decrease churn and increase their revenues.

This study will first give a brief description of IPTV. And

then we will propose enhancements to IPTV such that it will

become a viable and attractive platform for broadcast

television, video on demand and other online content. The

study is conducted from an architectural and logical

perspective.

II. IPTV REVISITED

A. IPTV Basics

Video compression technologies like H.264 (MPEG-

Manuscript submitted July 31st, 2009.

Do van Thuan is with Linus AS; e-mail: t.do@ linus.no.

Paal Engelstad is with Telenor ASA; e-mail:

paal.engelstad@telenor.com

Boning Feng is with Oslo University College; e-mail:

boning.feng@iu.hio.no.

Tore Jønvik is with Oslo University College; e-mail:

tore.jonvik@iu.hio.no.

Do van Thanh is with Telenor ASA and the Norwegian University of

Science and Technology; e-mail: thanh-van.do@telenor.com.

Ivar Jørstad is with Ubisafe AS; e-mail: ivar@ubisafe.no.

Nicolay Bang is with Linus AS; e-mail: n.bang@linus.no.

4/AVC) and VC-1 allow the delivery of high quality video

over limited bandwidth links. There are a variety of access

technologies (xDSL, FTTx, WiMAX) available to provide

the last mile connectivity to the home. DRM technologies

have now matured to a point where they provide sufficient

protection to encourage content providers to give access to

their media for distribution over IP networks.

B. Multicast, unicast, and protocols

One of the major advantages of using IP networks as a

mechanism for delivering TV is the bi-directional nature of

the network. This provides the viewer previously unheard of

control over their viewing experience. As well as plain old

programmes, viewers can also enjoy other services such as

on-demand video.

In traditional broadcast networks content is unidirectional

―pushed‖ to the home and all programs are available at the

Set-Top Box (STB) often called the CPE (Customer Premise

Equipment) by the Telco’s. CA (Conditional Access)

determines whether or not the end user can actually view the

content, but it is all delivered to the STB. The control and

selection of the channel to be watched occurs within the STB

in response to requests from the user's remote. In IPTV

systems, two mechanisms are employed to deliver TV to the

home. The standard collection of broadcast channels are

delivered over multiple Multicast IP sessions (using Multiple

Program Transport Stream, MPTS) and VoD (Video on

Demand) is delivered over Unicast IP sessions (using Single

Program Transport Stream, SPTS).

A Multicast is transmitted throughout the network and

allows multiple viewers to join and receive the programming

carried in the Multicast. However, unlike standard TV

broadcast systems, in IPTV systems the selection of which

channel (or program) to be watched is not made in the home

on the STB but in the network itself. IPTV uses IGMP (IP

Group Membership Protocol) to request ―permission‖ to

leave the current Multicast and then to join the new one. It is

this protocol exchange and the response times in the network

that impact the channel change times in an IPTV network. As

these networks scale up, this presents a significant technical

challenge to those responsible for delivering IPTV services.

A Unicast effectively sets up a unique session between the

VoD server and the viewer with only that particular viewer

being allowed access to that Unicast. VoD systems normally

rely on RTSP to setup and control the session through the

network.

IGMP and RTSP are control protocols that ―reside‖ in the

IPTV Revisited

Do van Thuan, Paal Engelstad, Boning Feng, Tore Jønvik, Do van Thanh, Ivar Jørstad and Nicolay

Bang, members of the Mobicome Project

I

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Control Plane. The digital video Transport Streams carried

within the Multi- or Uni-cast contain the media (in

compressed format) in the User Plane.

Unlike any other content type, video requires guaranteed

available bandwidth in a best effort network, and is

intolerant to network jitter and lost packets, is intolerant to

resends and out-of-sequence packets, and poor quality is

highly noticeable. All of these have an impact on the viewers

Quality of Experience (QoE). An experience that is equal to,

or better than, that on standard broadcast systems is a critical

success factor for IPTV systems. IP networks are ―best

effort‖ networks by nature. As a consequence they are prone

to jitter and packet loss and the allocation of guaranteed

bandwidth requires special control, protocols and the

effective application of network management policy.

C. Features and Requirements

Several factors during initial IPTV services introduction

will heavily influence customer perception and thereby

enable longer-term success:

Ease of installation and operation

Quality of experience for the viewer

Attractive content

Competitive and fair pricing

Due to the underlying complexity, the initial services

offered by most IPTV providers were merely a replacement

of the traditional broadcast television. Important initial

differentiators are sophisticated digital video recorder (DVR)

and time-shifting capabilities (the ability to stop, pause, and

rewind real-time programs) and a rich VoD portfolio.

Therefore it is essential for a sustainable IPTV business to

rapidly evolve the new offering toward an interactive

experience that clearly differentiates IPTV from those TV

offerings that subscribers can get and enjoy already. Alas,

much written about IPTV features such as video on demand,

being able to pause a film downstairs and watching the rest

of it upstairs on a different set, or searching for programmes

featuring a particular actor, are still vapourware.

The most important requirement to a successful IPTV

offering depends upon its successful integration with the

different services (data, voice, and mobility) into unique,

innovative applications. These include the ability to enjoy

entertainment not just on a TV but also on mobile devices

and at the same time to integrate communication services

with entertainment services to make the IPTV services more

interactive.

III. CURRENT IPTV STANDARDISATION OVERVIEW

A number of organisations are working on specifications

for IPTV. The IETF has defined the fundamental

mechanisms for support of IPTV such as the protocols for

the control of video streaming and of multicast flows. These

specifications have in turn been used by organisations such

as the Digital Video Broadcasting Project (DVB Project) in

the specification of IPTV systems. In addition to using the

basic mechanisms defined by the IETF, the DVB Project has

specified a protocol for service discovery and selection.

More recently ETSI TISPAN, Alliance for

Telecommunications Industry Solutions IPTV

Interoperability Forum (ATIS IIF), and the ITU-T Focus

Group on IPTV have begun work on IPTV, including the

integration of IPTV within NGN architectures. In addition,

mobile IPTV is being studied in the Open Mobile Alliance

(OMA) and 3GPP, and PacketCable and ITU-T Study Group

9 are studying IPTV for the cable networks.

A. Digital Video Broadcast

DVB specifications are published by ETSI. ETSI TR 102

033 describes an architectural framework for the delivery of

DVB services over IP-based networks and includes

descriptions of IPTV services. ETSI 102 034 specifies the

transport of MPEG-2-based DVB services over IP-based

networks and defines Real Time Streaming Protocol (RTSP)

profiles for Live Media Broadcast (LMB), Media Broadcast

with Trick Modes (MBwTM), and content on demand

(CoD).

B. IPTV and the Next-Generation Network

Two approaches to the integration of IPTV in NGN are

being studied. One is based on using IMS and the other uses

a dedicated IPTV subsystem without use of IMS session

control procedures. The IMS-based and non-IMS-based

approaches only differ in terms of the inclusion of the core

IMS session control functions in the IMS-based IPTV

solution. It is not yet clear whether the IPTV control and

IMS control functional entities are alternatives because the

detailed procedures have not yet been specified but in all

likelihood IPTV control procedures will be required in both

approaches. Thus, the IMS-based solution differs from the

non-IMS based solution with the addition of IMS session

control procedures. In both approaches common user profile

and charging functions can be utilised. In addition, in both

cases the NGN transport functions can be used, including

network attachment and resource and admission control

features, and NGN applications.

The IMS-based approach is most actively being pursued in

ETSI TISPAN but the architecture is currently under

discussion and has not yet been finalised so that work on

protocol mechanisms can begin. Therefore, there is a degree

of guesswork involved in envisioning the form that a

completely standardised IMS-based solution for IPTV will

finally take.

IV. PERSONALIZED SERVICES

A. Personalisation

IPTV technology promises to make more content

available, make it easier to access and make it portable

(while maintaining security). Personalisation for IPTV

means that the content can follow the user. It will adapt to

the user’s current device and network. Access rights are

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managed seamlessly between devices.

B. Preferences and Profiles

A profile is defined by a set of attributes, possibly

organized into abstract entities, whose values can be user-

defined or dynamically derived from user behaviour. A

profile is supposed to characterize user domain of interest

and all her specific features that help the application/service

to deliver the most relevant data in the right form at the right

place and the right moment.

C. Profiling

Profiling and personalisation technologies proposed so far

in the literature rely on explicit or implicit identification of

the user or the group profile to offer them a personalised

experience (like for content recommendation). However,

with the diversity of services offered by an IPTV

environment (EPG, VoD, IM, etc.), a single user or group

may need/want to define different identities and associated

profiles to use with the various services and circumstances

while preserving their privacy.

V. CONTEXT-AWARE ADAPTATION

Context-aware adaptation is to take into account ―context

data‖—such as the viewer's location, the local weather, the

time of day and records of their recent transactions—when

rendering an IPTV service.

Context data may also include information gleaned from

news reports. Storms, sporting events, holidays and transport

strikes, for example, can affect viewers' moods and

acceptance dispositions, and can be used to provide

guidelines to targeted advertising. ―Demographic mapping‖

features provide additional information about the products

viewers are most likely to buy based upon their location,

time of watching, and whether they are watching on a

television set or a mobile phone.

A viewer can supply her preferences to the system, and

depending on this set of preferences along with context

information, different services can be composed

automatically and presented to the viewer. This includes

direct enhancements supplements to the IPTV service, but

also other network service offerings that are made available

to the viewer.

VI. ISSUES AND OPPORTUNITIES

Despite of many of its advantages such as increased

interactivity, IPTV still raise concerns on privacy risks. With

the added capability of viewing other online content and

accessing Internet services, it is more urgent to IPTV service

providers to incorporate mechanisms into their delivery

platforms to preserve their customers’ privacy. In this

context, an integrated Privacy-enhancing Identity

Management (IDM) scheme would make accessing both

IPTV services and other Internet services more secure. IDM

would also facilitate the sharing of usage information

between service providers. Consequently, it is possible to

deliver personalised services that are secure and adaptive to

the context while preserving the viewer’s privacy.

VII. CHALLENGES

IPTV as much as its sibling voice service is basically a

service to an address. A subscriber is identified through an

address, a number, or a record in a directory in the operator

system. Novel methods to individually identify viewers in

front of the television set are therefore necessary for

personalised services such as tele-voting, survey, gaming,

etc.

Personalised service discovery and selection is a key

component for enabling ubiquitous mobile IPTV services.

The objective of personalised service discovery is to provide

subscribers the services that fit their personal preferences

and also are appropriate to the context. It should be

emphasized that the user preferences vary with their context.

The ETSI TISPAN is specifying the Service Discovery

Function (SDF) and Service Selection Function (SSF).

Maybe, the personalisation is partially considered in SDF

and SSF by considering the user behaviour patterns.

However, the recommended services to the users are not

context-aware. For instance, the users may not always prefer

services with the highest quality or the most popular channel

in a certain area. On the other hand, in ubiquitous

environment, the service discovery and selection should not

be constrained by the geographical area. This function

should find the services beyond the local domain by

considering the users changing preferences in new and

different places.

A significant challenge is how easily to implement a

privacy control policy that reflects changes in the user’s

context –situation or environment. A simple example is when

a subscriber accessing IPTV services on the move returns

home. In addition, the meanings (semantics) of the contexts

can also be changed. It is crucial to have a policy system that

understands and interprets semantics of the contexts

correctly. Although the work will be carried out from the

privacy protection point of view, the approach can be used

for various context-aware applications and services.

Besides supporting personalised interaction, there must be

an identity architecture that would guarantee privacy through

pseudonyms. The architecture would cater for simplified

registration and sign-on to both subscribers and viewers who

have access to the IPTV services. We will also specify a

role-based access control to the user model. A combined

role-based and permission-based authorization programming

model will also be proposed in order to facilitate

development of new IPTV services.

VIII. CONTENT SECURITY

Although not the primary focus of this paper, content

security is a very important topic when discussing IPTV.

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Each IPTV solution vendor has a slightly different approach

to the content security requirement. Usually vendors will

partner with experts in this space to provide a complete

solution to the service provider and one which will be

acceptable to the content community.

Security issues can be considered from the perspective of:

Subscriber and viewer

Protection of the user’s rights and privacy issues

(identity and other information about the user)

Content provider

Content protection (rights management,

encryption)

Service provider

Securing the transport of content (key

management, encryption)

Ensuring that the IPTV and blended services are

available to authorized users only (user

authentication)

IX. SOME SERVICE SCENARIOS

A. Session Mobility

So if you're out of the house during the big World Cup

final game, you can tap into your Set-top Box from your

mobile phone, and then switch to the big screen--right where

you left off--when you get home.

B. Experience-sharing applications

An application combines television with audio-

conferencing so that a group of friends can watch a football

match ―together‖ from different locations.

C. Remote Control

Services enable customers to programme their digital-

video recorders remotely, either via the web or from a

mobile phone

D. Telephony and Television

It is the prospect of integrating your telephone with your

television, so that when you are watching a film and

someone calls you, the caller's name appears on the screen

and the film pauses automatically if you pick up the phone.

X. CONCLUSION

Television service providers are facing an imperative to

move from a broadcast delivery paradigm to an increasingly

personalised one. This is a perfect market opportunity for

IPTV.

Unfortunately, for the time being, the only advantage of

IPTV to the consumer remains the ―triple play‖ bundle

factor, that is buying phone, broadband and television

service together gives her a discount and a single bill, easier

than three separate ones. After all, video services, like voice

services, can be delivered over broadband pipes by other

companies too. At the moment, although real-time

multichannel television is too bandwidth-intensive to be

provided by third parties across the Internet, the situation

will be changed in the future. Besides, downloads of

individual television programmes and films are already

available from Amazon, Apple and others. As viewers move

away from traditional forms of television and towards a pick-

and-mix model, telecoms firms could find themselves in a

situation similar to that created by VoIP in the voice market:

their customers will be able to buy broadband Internet access

from one company and then choose from a host of Internet-

based firms for their video content.

Candidly, the way to make IPTV more compelling should

be through convergence and not only by proprietary

piecemeal context-aware personalisation services. This is of

course not a suggestion to completely abandon personalised

IPTV but rather a recommendation for a further integration

of IMS and IPTV services. All telecoms should support the

TISPAN effort on development of a flexible IPTV

architecture that can evolve to meet the needs of consumers,

content developers, and device designers.

This paper has discussed the key issues to implementing

IPTV personalised services. Future studies should address

business models to unlocking the considerable revenue

potential of personalised television, and enabling addressable

advertising, personalised EPGs, multi-channel HDTV,

viewer favourite lists and reviews, and other value-added

interactive services.

ACKNOWLEDGMENT

This research was partly funded by the Norwegian

Research Council under the Eureka programme.

REFERENCES

[1] A. Thawani, S. Gopalan, V. Sridhar, ―Context Aware Personalized Ad

Insertion in an Interactive TV Environment‖, Workshop on

Personalization in Future TV, (2004).

[2] J. Jabbar, T. Jeong, J. Hwang, and G. Park, ―Viewer Identification and

Authentication in IPTV using RFID Technique,‖ IEEE Transactions

on Consumer Electronics, Vol. 54, issue 1, February 2008.

[3] The Open IPTV Forum: Release 1 IPTV Solution Specifications

[4] ETSI TISPAN Specifications