Digital terrestrial broadcasting presents vast opportunities for exciting new multimedia content and widespread accessibility. Chris Jaeger, Managing Director, International Business, Broadcast Australia, explores the role that Digital Terrestrial Television could play in India's broadcasting future.

One of the clear messages emerging from the Broadcast Engineering Society (BES) Expo held recently in New Delhi is that India needs to get ready for analogue TV services to be switched off in 2017. The event provided a forum for over 75 organisations to showcase their latest state-of-the-art technologies and services. In many instances, these tantalising glimpses into what the future may hold for India rely implicitly on the foundation of a national digital terrestrial broadcasting network.

Such a network would facilitate the delivery of a broader and exciting array of content to a wider audience than is currently reached. These services would include standard definition (SD) TV channels, high definition (HD) TV channels, 'info-casting' and data-casting services, and mobile/portable TV. They would further encourage transmissions to a new generation of portable and mobile devices, as India experiences the same massive uptake of mobile wireless broadband services as the rest of the world.

Most of India's recent growth in broadcasting has been focussed in the direct-to-home (DTH) arena, with relatively modest progress made in the digitalisation of terrestrial television networks. The opportunities to increase the scope and penetration of services using digital terrestrial television (DTT) are huge; they are also particularly appropriate for India's distinctive domestic needs. Latest figures (2008) from the International Telecommunication Union indicate that just 13.4 per cent of India's population have a television, while only 3.2 percent of the population own a computer.

Low-cost portable devices

The promotion of national digital terrestrial transmission infrastructure in conjunction with new low-cost portable reception devices could address the low incidence of television ownership in India. A whole new range of viewers would potentially be able to afford the new range of receivers, creating a whole new TV audience.

It could additionally prove an innovative alternative resolution to the country's limited Internet access through info-casting/data-casting services. While not a direct replacement for the Internet, a national broadcast network could help provide government information services (local and national), health advice, education services and narrowcasting for local and ethnic communities. The effectiveness of the service would rely on an adequate number of televisions across the country; for this to be achieved, portable devices once again herald a promising future for the as-yet unreached television audiences of India.

To make this market penetration a reality, the issue of coverage needs to be explored. Broadcasting to portable and mobile devices injects additional complexity into network planning, as devices are likely to have low-performance receive antennas at variable orientation. In order to address challenges such as reduced antenna height, building penetration, reduced receive-antenna gain, and higher required-location availability, mobile TV trials have shown that field strengths need to be in excess of 30dB, higher than in a fixed-reception environment.

The most practical means of achieving such a high grade of coverage is to deploy a high-density distributed transmission network essentially a single-frequency network (SFN) comprising multiple low-power transmission sites that together provide a consistently high signal-level across the entire coverage area. Such a network also delivers signals from multiple directions, thereby improving location availability and reducing the impact of building clutter. There is a strong argument for deploying standard and high-definition television broadcast networks based on a similar architecture. This would allow anyone with an appropriate device to receive television on their portable computers or other portable TV devices.

In India's case, a high-density network would be a good solution for urban areas; however, rural areas may not require the same density of transmission infrastructure, because clutter losses are lower. Networks can therefore be configured for the specific requirements of each area, saving considerable costs compared with establishing high-density networks country-wide.

Niche broadcasting

With network coverage established, and with the provision of a sufficient number of suitable portable devices capable of receiving the transmissions, it would be a short step to provide disaster alerts and emergency information through the broadcast services. During times of regional disasters, such as earthquakes or floods, part of the network could be utilised to communicate with the local population within the disaster zone providing potentially life-saving help and information. In such circumstances, additional portable devices could be flown-in to the area to help ensure emergency broadcasts reach as many people as possible.

Similarly, niche broadcasting services could be targeted at defined audiences such as minority language or cultural groups or address specific interests, such as IPL cricket. In a nation that comprises a number of ethnic populations, the scope for varied content for distinct groups of viewers is extremely promising.

As the Delhi 2010 Commonwealth Games approaches, the time is ripe for India's first steps towards the digitisation of its broadcast infrastructure. Such major sporting events typically provide a powerful driver for progress, especially as most coverage is predicted to be broadcast in HD. While DVB-S satellite HD technology is expected to be widely used for the games' coverage, the event would provide an ideal opportunity to test terrestrial digital HD capabilities, as well as mobile and portable TV services.