Отчет мсэ-r bt. 2140-1 (05/2009)



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2.2 Mobile services

2.2.1 Sound


Mobile sound service consists of traditional Audio programs. The small devices and low price are requested. One important problem is Long battery lives.

Compared to stationary reception of broadcasting, the portable broadcast receiver is introducing this new user requirement, which can only be met, if the broadcasting link system allows for low power consumption of the receiving handheld terminals.

This has been taken into account through different means in some of the standards/specifications, which have already been elaborated on a regional/national basis.

2.2.2 Mobile TV


Mobile TV services consist of traditional TV programs or TV-like programs. TV type of services presented to mobile handheld devices with small screens is predicted to be designed different from content offered to large screen receiving terminals in a stationary broadcasting environment.

Instead of users watching a two-hour movie on the smaller screen of a handheld terminal, a more typical usage scenario would be to watch news flashes, sports features, music videos, weather forecasts, stock exchange reports and other such content, which is suitable for “ad hoc” consumption during smaller time slots.


2.2.3 Enhanced mobile TV


Online TV shopping, chat, gaming and quiz plus voting are examples of functionalities, which may be introduced as enhancements to the mobile TV to allow a true interactive mobile broadcasting experience.

2.2.3.1 The Electronic Service Guide (ESG)


Especially in the mobile environment it is important for the user to be able to navigate through the various broadcast service offerings in an easy and formalized way. Electronic Service Guide (ESG) contains information of the available services and how those can be accessed. The concept of the ESG has been found to be a well-accepted way for the user on the move to discover, select, and purchase the broadcasted services he/she is interested in.

2.2.3.2 Data


The mobile TV programs may be supplemented by auxiliary data associated with the basic service. Such information could be part of the broadcast or can be accessed on demand via the interactivity link.

The additional background information may include links to the service provider’s web pages, video clips, sound tracks, games, etc.



In Table 5, an overview of currently known mobile broadcasting transmission mechanisms is provided. The technical characteristics shown are subject to change and are by no means exhaustive but provided for comparison only.

TABLE 5


Mobile digital broadcasting transport mechanisms

Standard or Spec.

Modulation

Transport stream

RF channel (MUX) size
(MHz)

Int. Broadcast bands

Terminal power reduction methodology

Regional national origin

DVB-H

QPSK or
16-QAM COFDM

IP/MPE-FEC/ MPEG2 TS

8

IV and V

Time slicing

Region 1 (Europe)

ISDB-T

QPSK or
16-QAM COFDM

MPEG2 TS

0.433

IV and V

Bandwidth shrinking

Region 3 (Japan)

T-DMB

DQPSK COFDM

MPEG2 TS

1.75

III and
1.5 GHz

Optimised narrow bandwidth

Region 3 (Rep. of Korea)



2.2.3.3 Implementation of interactivity


It is therefore natural for the mobile user community to expect interactivity as a basic characteristic of future mobile broadcasting services, an expectation that several ongoing trials have confirmed.

2.2.3.4 The interaction channel implementation

2.2.3.4.1 Digital mobile telephony

As the major part of the world standards of digital mobile telephony including IMT-2000 offer twoway data services, one approach to implement interactivity seem to be the incorporation of such mobile technology in the user terminals.

Apart from offering the user all state-of-the-art mobile telephone services, this way of implementation of interactivity with the broadcasting service offerings provide immediately a reliable control link for all such broadcasting services. It allows the user to respond and interact with the broadcasting system and to receive control codes through a secure environment.

This approach may also take advantage of the global roaming characteristics of many mobile technologies as well as of the wide-area coverage characteristics of mobile telephone technology throughout the world.

2.2.3.4.2 Interaction channel making use of the broadcast spectrum

This approach has been studied in the past, but major difficulties with global circulation of user equipment capable of transmitting into the broadcast spectrum have so far been a substantial hurdle. The development of a new two-way data transport standard may also delay the progress.
2.2.3.4.3 Summary of interaction channel methodologies

TABLE 6

Interaction channel methodologies for interactive mobile broadcasting systems



Methodology

Reference standards/
Specifications

Carrier service

Link peak bit rate (bps)

Mobile telephony

IMT-2000

Global system for mobile communications (GSM)

Other


HSDPA (Device Category 10)

HSUPA
(E-DCH)

GPRS (Device Category 10)
EGPRS


14 Mbit/s

3.84 Mbit/s


85.6 kbit/s

236.8 kbit/s


Broadcasting in-band

NA

NA

NA

Chapter 3




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