PERSONALCASTING

Personalization on Datacasting

Roberto D. Amaral

, Francisco Cercas

and Carlos Gonçalves

ISCTE-IUL, Av. das Forças Armadas, 1649-026 Lisboa, Portugal

ISCTE-IUL and Instituto de Telecomunicações (IT), Av. das Forças Armadas, 1649-026 Lisboa, Portugal

Keywords: Digital Terrestrial Television, Personalization, Datacasting.

Abstract: Digital Terrestrial Television (DTT) allows the simultaneous transmission of different digital contents with

the video signal, i.e. datacasting. This become possible due to coding and compression technologies used to

process the signal, not previously available with analogue technology. This subject created the discussion

about the digital dividend, which addresses the best way to use the spectrum, so as to improve its efficiency.

This article presents the concept of Personalcasting applied to data, which is sent simultaneously by DTT to

the entire coverage area, while directing contents to specific users. This provides a better use of the DTT

spectrum, due to high data volume that will be used with datacasting.

1 INTRODUCTION

Bove, in 1985, introduced the concept of

Personalcasting, “Personalization on Broadcasting”,

which was revolutionary at the time, for it provided

convergence of TV with computer data, allowing a

VCR recorded program to be put into words with the

support of information provided by the closed

caption. However, the advent of Digital Terrestrial

Television, using Advanced Television Systems

Committee (ATSC), Digital Video Broadcasting -

Terrestrial (DVB-T) or Integrated Service Digital

Broadcasting - Terrestrial (ISDB-T) standards,

allowed the possibility of data broadcasting, which

in some countries due to regulatory matters, contains

a connection of up to 14 Mbps (Montez & Becker,

2006) and, consequently, created a discussion about

the “digital dividend”, which deals with the

optimization of the spectrum. Thus, broadcasters

will be able to apply a variety of services and

multimedia to their systems, which will

simultaneously be available to television viewers. A

considerable amount of information may be

available, which implies the need to use selective

technologies that allow the user to receive contents

and services of his interest. To materialize this, a

new concept of Personalcasting “Personalization on

data broadcasting” is proposed, which deals with

sending information through a DTT data channel to

a specific user or group of users. The proposed

model addresses the personalization of content in the

three levels of connectivity with TV broadcasting

(Lemos et. al., 2004), and the interaction occurs

even without the need for a return channel. This

system is very flexible and it may have high impact

due to the fact that television has high penetration

and numerous applications that can be performed.

The article structure is as follows: section 2

presents key topics related to DTT datacasting;

section 3 defines the proposed model of

Personalcasting, which is materialized with an

example to quantify the system and its many

potential applications. Finally, section 4 presents the

main conclusions.

2 DATACASTING

We usually refer to a data broadcasting system when

it distributes data from one point to many others.

With the generalization of digital formats, including

digital animation and others behind simple audio and

video, many broadcasters are now defining

“datacasting” due to the inclusion of, these

aggregated formats to the spectrum previously

meant for broadcast (Jones et. al., 2007). Therefore

datacasting can provide substantial advantages to

292

D. Amaral R., Cercas F. and Gonçalves C. (2009).

PERSONALCASTING - Personalization on Datacasting.

In Proceedings of the International Conference on Knowledge Management and Information Sharing, pages 292-295

DOI: 10.5220/0002303402920295

 SciTePress

Figure 1: Proposed system.

complement, substitute or even to bring digital

technologies where there were no infrastructures.

For example, datacasting can provide broadband

internet distribution to some populated areas,

reaching millions of people with low cost.

However, datacasting is restricted by regulatory

matters directly related to the standard used. Below

is an example of the data rate that can be used in the

three most usual standards of DTT on a 6 MHz band

(Wu, 1999).

Table 1: DTT Standards data rate.

DTT Standards Data Rate

Specifications : Mod.=64QAM(8VSB, OFDM)

FEC=3/4 IG=1/16 BW= 6Mhz

ATSC 19,4 Mbps

DVB-T 19,6 Mbps

ISDB-T 19,3 Mbps

These data rates are shared between different

sources of video, audio and data, with datacasting, in

countries where it is allowed by regulation, and it

can be broadcasted simultaneously using SDTV for

programming, up to 15 Mbps (table 2) of data on a 6

MHz channel (Montez & Becker, 2006). However,

these calues can changeaccording to modulation

specifications, video compression and signal to noise

conditions.

Table 2: Average bit rate using Mpeg-2 on a 6 MHz

channel.

HDTV

at 1080p

HDTV

at 720p

SDTV

at 480i

Datacasting

(Mbps)

18Mbps 13Mbps 4Mbps

Scenario 1 1 0 0 1,3

Scenario 2 0 1 0 6,3

Scenario 3 0 0 1 15,3

Scenario 4 0 1 1 2,3

According to the configuration used on the

encoder and multiplexer, different quality of service

can be available as shown in table 2.

3 PERSONALCASTING

Personalization on datacasting, has the objective of

sending personalized content to a particular user or

group of users, required by the user or an agent,

searching for direct communication with the

spectator. Unlike the personalization of

programming, addressed by many authors

(Maybury et al., 2002) (Bove, 1985),

Personalcasting in this proposal deals with the

personalization of content sent through the data

source. This concept is not limited to models used

PERSONALCASTING - Personalization on Datacasting

293

by users in order to have direct access to

broadcasting TV. It focuses on demonstrating the

interactive and personalization content, and there is

no need for a return channel with the broadcasting

concessionaire.

Figure 1 shows the diagram of the

Personalcasting model proposed, which is divided in

four categories:

• User: Spectator using a mobile or stationary

device.

• Society: Government bodies, advertising

agencies, businesses, groups of people,

professional corporations, etc. It will be

responsible for user-broadcaster interaction, but

not in real-time.

• Broadcasting TV: TV broadcaster with the right

to provide the digital signal.

• Telecoms: Telecommunication service

concessionaire companies. They will be

responsible for real-time connection between the

user and the TV broadcaster.

In Personalcasting, all data will be transmitted

simultaneously to the population, but only the

hardware containing a given key will be able to

access its corresponding user contents. This “key”

can be programmed in a language such as Java, NCL

or Lua, or incorporated to the middleware using the

MAC address or a Global Position System (GPS).

The different stages shown in Figure 1 can be

summarized as follows:

1. The user searches a particular information

2. The request for that information is performed

according to the existing technological

availability:

a. Without a return channel – The request is

previously performed by subscription to a

service or by database registration.

Example: Registration at websites, stores

or public services.

b. Intermittent communication - The request

is made with limited data access and is

only made available when necessary.

Example: GPRS, SMS, phone line, etc.

c. Permannent communication – The request

is made through broadband, however, it

can be received through Broadcasting or

even through another broadband existing

service. Example: ADSL, WIMAX, 3G,

etc.

3. Analysis of the required content

4. Content search

5. Compacting of information to be sent

6. User identification

7. Transmission to the user

8. Reception of broadcast signal

9. User identification

10. Storage of personalized content

11. Notification when the user receives the desired

content

12. Visualization of the content

The nature and quantity of different personalized

contents that can be quantified to a specific

audience, depends on the available bandwidth used

by the video signal and the bit rate that can be

allocated for the transfer of data. Table 3 shows an

example of how contents can be delivered according

to the scenarios proposed in Table 2, using specific

bit rates.

Table 3: Quantity of different personalized contents.

0,1 Kbps 0,5 Kbps 1 Kbps 5 Kbps

Scenario 1

153.000 30.600 15.300 3.060

Scenario 2

63.000 12.600 6.300 1.260

Scenario 3

23.000 4.600 2.300 460

Scenario 4

13.000 2.600 1.300 260

These values show that we can have a

considerable amount of content that can be delivered

to users with this system. The maximum

personalized content, i.e. individualized, may be

difficult to reach in cities with large populations due

to bandwidth constrainsts. However, this can be an

interesting solution for other geographical areas and

it can be costumized by interest groups such as

families or others.

A large variety of social and commercial

applications can be made available. Below is a list

containing a few examples of such applications:

• Personalized notifications

• Pre-scheduled service reminders

• Service subscriptions

• Pre-scheduled contents

• Personalized publicity

• Residence personalized contents

• T-learning

• T-Banking

• T-commerce

• Chat (through SMS or broadband)

• Digital Signage distribution

• Emergency Information distribution

A great advantage of this service is that many of

its applications do not require a return channel to the

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DTT concessionaire, the interactivity exists

regardless to the levels. The number os services

providing more personalized content increase as

more bandwidth is made available for this

datacasting service.

Since this is a relatively new concept, there are a

number of topics requiring research and

development, such as user identification methods,

data encryption for security, appropriate graphical

interface for the user, content creation and content

adaptability, among others.

4 CONCLUSIONS

In this paper we have presented the concept of

Personalcasting, which can be a great opportunity

for DTT, following the migration from analog TV.

The proposed system allows the access to

personalized digital content for normal TV users or

groups of users in a given geographical area. These

contents can serve as the basis for the sustainability

of the band connection, providing a better use of the

spectrum available to TV broadcasts.

REFERENCES

Jones G., Layer D., Osenkowsky T., Williams E., 2007,

NAB Engineering Handbook, Hardcover, 10

edition

Maybury, M., Greiff W., Boykin, S., Ponte, J., Mchenry,

C., Ferro, L., 2004, Personalcasting: Tailored

Broadcast News, In User Modeling and User-Adapted

Interaction, Kluwer Academic Publishers Hingham,

MA, USA.

Bove, V.M., 1985. Personalcasting: Interactive Local

Augmentation of Television Programming. Master's

thesis, MIT, 2

edition

Montez, C., Becker, V., 2006, TV Digital Interativa:

conceitos, desafios e perspectivas para o Brasil., Ed.

UFSC, Florianópolis, 2

edition

Wu, Y., 1999. Performance comparison of ATSC 8-VSB

and DVB-T COFDM transmission systems for digital

television terrestrial broadcasting, In ICCE

International Conference on Consumer Electronics,

Los Angeles

Lemos G., Fernandes, J., Silveira G., 2004, Introdução à

Televisão Digital Interativa: Arquitetura, Protocolos,

Padrões e Práticas. In Congresso da Sociedade

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