M. S Duhan
DDG(E)
Doordarshan

Tapestry Of DTT Waves

A variety of media compete everyday across multiple channels to tell us things, targeting fragmented and segmented audiences according to profiles of interest, for a very high consumption capacity and hectic pace of life and  for the importance of time. In the television industry, content has always been very important. Digital Terrestrial Television (DTT)  and digital Radio services rely on a network of transmitters and towers spaced around a given region. Digital broadcasting mission is to convert users and consumers of digital television into digital citizens, familiar with the benefits of the information society, with more mature and quite different habits of consumption and social behavior. Now we are quickly heading towards a digital society.

The majority of digital terrestrial technologies use multiple carrier orthogonal frequency division multiplexing (OFDM) techniques. Adding forward error correction (FEC) produces coded OFDM (COFDM) to improve the robustness of transmission. The terrestrial in digital mode provides unique potential for various fronts. The difficulty of satellite looks angles in high rise buildings and the risk of catastrophic satellite failures necessities alternative platform of DTT. With built in tuners in TV or portable devices with indoor or cable antenna, DTT is the easiest mode of reception. Some nations which are migrating, or have already migrated, to DTT, have changed the landscape of broadcasting.

Program repertoire and trends

DTT leverages local content and local advertisements, which is a factor of significant importance. These days, popular sports like cricket, football and concerts, documentaries, cinema etc. in high definition are available in multi-angle broadcast. They may be free, thanks to sponsorship and pay-per-view, of any commercial advertising and they can be accessible through DTT platform. Catch-Up and VoD/AoD, games, e-government, e-learning, e-payment-health, rating/voting application etc. are emerging trends for broadcasters whom want to get feedback from their viewers. Labelling is essential for consumer guidance.It enables them to do polls and voting, that are synchronized with the TV program.

The development of digital terrestrial television, with its offers of generalist and thematic contents, through free-to-air broadcasting and at no cost to consumer, will keep interest in the consumption of entertainment, information, and commercial contents. The unique, innovative, and exclusive contents can be a catalyst for sound start of digital platforms. Further with development of the new systems like MHP system and HbbTV system, capable of supporting different types of applications such as electronic program guides (EPG), services of information —teletext or teletypes news, synchronized applications for television contents or social, educational, health, or financial applications, T-commerce, e-education, interactive contents, knowing who is watching what, etc. has potential to revolutionize broadcasting.

Challenges

For a successful model of DTT and digital radio, there are lot of milestones to be covered. A precise ASO roadmap need to be evolved and viewers must understand what will happen, when, and, how to prepare. Local contents, thematic content and interactive advertising, song based contents, popular sports, E-education etc. are some of possible killer contents.  Sufficient DTT penetration is the principal requirement; for this, sufficient financial resources will be required. Adequate digital receivers need to be available at a reasonable price. It should be ensured that all television sets sold after a set date can receive DTT services.

In France, by law, all TV sets sold since March 6, 2008 had to include a DTT tuner; similarly, in Italy, by law, all TV sets sold since June 09 had to include a DTT tuner as well. Financial support has proved to be necessary. Intended recipients of aid include low-income households, general public, or households with communal antennas. Attractive programe offer combined with competitive pricing has allowed Boxer to effectively compete with other television operators. For smooth coexistence between LTE and DTT the vital considerations are; the protection ratio (PR) (minimum C/I ratio needed) and the overloading threshold (Oth)  (maximum level not to be exceeded).

Spectrum

From written history, it appears that many of the concepts now familiar in EM theory were explored and developed during a time when many modern high-tech investigative and detection tools and methods did not exist. Historically, broadcasters have had unopposed use of large bands of the VHF and UHF frequency, enabling them to broadcast in terrestrial mode over whole countries using many different frequency channels and reducing the potential for co-channel interference. Spectrum is a scarce resource and it is needed for introducing new services, so that the DTT platform keeps its attractiveness in comparison with other platforms. With the advent of digital techniques and the abundance of transmitter stations, the ability to multiplex many transmissions into a single RF channel still allowed the use of multi-frequency networks (MFN).

For continuity of signals from one region to other, single frequency networks (SFN) have been planned. Now, with the mobile wireless fraternity putting pressure on regulators to force broadcasters to relinquish much of their traditional frequency bandwidth, especially in the UHF range — the so-called digital dividend — it is becoming essential for them to consider planning for single frequency networks (SFN).

DTT Businesses: Global Orientation

The DTT using powerful DVB-T2, ISDB-T, or ATSC 3.0,  in combination with  HbbTV standard, provides exciting offerings and  aims to enable consumers to enjoy a variety of entertainment services including video on demand (VoD), interactive advertising, personalization, voting, games and social networking as well as program-related services such as digital text and EPGs through a single access point. Some of other classical business orientations across various countries with DTT are worth following. Few practically tested examples are as below:

Indonesia has innovatively introduced disaster awareness and management system using DVB-T2 transmitters. Malaysia’s broadcast television industry is knocking on the doors of every household nationwide, greeting viewer with crystal clear video and sound quality, under the DTT Project. Viewers will also have access to multiple interactive services such as shopping, video-on-demand, subscription as well as internet services in the future.

Italy has introduced interactive advertising, thematic channels with targeted advertising, live interactions, EPG, games, T-commerce, pay per view of football matches, revenue sharing with telecom operators, purchase of packet of events etc. T-government services for healthcare, public administration, local public services etc. are important milestones of DTT.

Vietnam has started DTT services in buses using telco and DVB-T2 platform. Germany has started HbbTV with DVB-T2. The immersive engagement of viewers and interactive advertisements has redefined the broadcasting.

For an example, Hyundai got 680 clicks daily during German TV Pro 7 via red button on commercial.  South African nations are using the DVB-T2 for school education in a positive way.

South Korea and Japan have offered a variety of services on mobile and e-Governance etc. HDTV services are relayed and successful experiment for UHD TV has been carried out. Japan has also experimented with 8K TV.

Thailand has successful DTT operations for fixed and mobile devices. 

Denmark and many other countries are relaying radio services on DVB-T/T2 transmissions.

In the LTE Mobile Offload (LMO), the basic idea is to offload popular services, especially live video, from cellular networks. For example, if any popular content is attracting large audience from say an internet platform, it may be aired on HPHT platform for ensuring uninterrupted service and crystal clear video and sound quality . The LTE Mega cell Overlay model has been proven to work using the DVB-T2 broadcast standard today.

Similar possibilities exist for incorporation into other advanced modulations (ATSC 3.0). This facilitates a technology and business model for off-loading payload from low tower, low power networks to high tower, and high power networks.

In several countries, the highway information for moving vehicles are broadcasted using digital radios or DTTs. The information includes petrol stations, restaurants, hospitals, traffic, weather, alternative routes etc. besides entertainment.

Doordarshan and All India Radio have already established Transmitters for DTT and digital radio. An intelligent and close co-ordination by broadcasters, content providers, advertisers, regulators, and device manufactures is the key for success of DTT platform. It will lead to transformation of digital society. The DTT and digital radios, with its astounding applications for viewers and audience, will be stirring tales, which will live forever in the annals of broadcasting. Tapestry of DTT waves is thus fascinating.

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