Mobile television promises to be a hot topic at the NAB convention this year, with terrestrial broadcasters seeking to make the most of their existing spectrum as their traditional business model comes under increasing threat. Beyond the complexities of competing technical standards, the future of broadcast mobile television has yet to be defined.

Many American broadcasters are pinning their hopes on the ATSC Mobile DTV candidate standard, approved late last year and due for ratification this summer, as promoted by the Open Mobile Video Coalition.

This alliance of broadcasters, including affiliates of all the major television networks, has committed to launch services in 22 markets across the United States, covering over a third of households in the country.

The Mobile DTV system, previously known as ATSC-M/H, takes some of the MPEG packets in existing digital broadcasts and uses them to deliver data to mobile and handheld devices.

This has the advantage of using existing broadcast towers and already allocated spectrum. It allows broadcasters to use some of the 19.4Mbps of capacity in each 6MHz channel for transmissions for portable and handheld devices, in addition to existing high definition or supplementary standard definition channels. It is suggested that this could enable a broadcast signal to carry anything from a couple to a dozen mobile streams.

The target devices envisaged include compatible mobile phone handsets, portable media players and laptop computers, as well as in-vehicle devices, including data services for navigation and information systems.

As well as premium data services, like updates on local weather and traffic, various interactive services are envisaged, but currently only broadly described.

Local news and sports coverage, together with weather warnings and public safety announcements, are seen by some as fundamental to the mass appeal and adoption of mobile television, providing a platform on which to launch premium, enhanced and interactive services.

While free-to-air broadcast mobile television has proved relatively popular in South Korea and Japan, using the T-DMB and 1-seg standards, the same cannot be said for subscription services also launched in those markets, which have suffered by comparison.

Elsewhere, subscription services offered by mobile network operators on their existing cellular infrastructure have failed to ignite mass consumer demand. For broadcasters, this could support the view that free-to-air services will be essential to drive the adoption of mobile television.

“Mobile DTV will be an important building block in the future of broadcasting, allowing TV stations additional revenue opportunities along with the chance to better serve their local communities,” according to David Rehr, the president and chief executive of the National Association of Broadcasters, which promotes the interests of free-to-air broadcasters and hosts the NAB Show convention being held in Las Vegas.

Among those that could stand to gain from growth in mobile television are chip and device manufacturers. LG Electronics and Samsung both contributed to the development of the ATSC mobile standard and are unsurprisingly among its advocates.

It is claimed that the Mobile DTV candidate standard benefits from experience with other international systems developed for mobile television, including the European DVB-H standard.

LG Electronics has demonstrated prototype devices that claim to enable up to four hours of viewing from a single battery charge.

A potential problem could be that the use of existing broadcast frequencies may require a relatively long antenna. That may not be an issue for use in vehicles but could be a significant factor in the fickle and fashion conscious mobile phone market.

The Mobile DTV initiative faces competition on a number of fronts, not least from a competing proprietary system from Qualcomm, known as mediaFLO. Branded as FLO TV, this has already launched in the United States in partnership with Verizon and AT&T, although the full rollout still awaits the final end of analogue broadcasting which has been delayed until June.

The FLO TV service will comprise a consistent core set of ten channels with programming from a number of national networks.

Of course, it is possible that receivers could support more than one system, covering both national networks and local channels. The chip manufacturers certainly suggest that this is technically feasible. In large volumes, the cost of adding television reception to devices could be relatively trivial.

Then again, there is the additional prospect of satellite delivered services with additional terrestrial transmission networks, akin to subscription satellite radio services, and aimed mainly at the automotive market.

ICO Global Communications is proposing a mobile interactive multimedia service, including 10-15 live television channels, delivered using the European DVB-S/H standard, of which Alcatel Lucent is a strong proponent. ICO has an an agreement with Qualcomm to support the system in future multimode chipsets, enabling manufacturers to support multiple mobile television systems. Again, these could be complementary or competitive to local mobile television services.

Use cases
At the moment, there is much talk about technology and standards but relatively little real debate or understanding of the potential use cases for mobile television.

On the face of it, mobile television appears an obvious application of technology. After all, we had had portable radios for decades, in cars and in portable receivers, indeed in many mobile phones.However, the usage of radio, and the way that programming has developed around that is different to television and video.

Many consumers might simply expect to be able to be able to receive television on a portable device. Yet portable and handheld televisions have been around for decades, and we have not seen massive adoption. On the contrary, people have been buying ever larger and flatter screens to hang on their walls and watch in the home.

Many of the international studies of mobile television trials and launches have shown that usage has been as much in the home and in the office as on the move. It seems important that mobile television is seen as being a personal and private experience.

Then there is the apparent trend away from linear, scheduled channels to more selective viewing and listening from recorded media that can be delivered by many means other than broadcasting. That really leaves live and local as the main differentiators for broadcasting, whether it is news, sports, weather or entertainment events.

Of course, broadcasters still have powerful brands and valuable spectrum to exploit as they extend their traditional, legacy, business models into the digital age.

Arguably, the precious spectrum that broadcasters currently use to deliver television, mainly viewed on fixed screens, is actually best employed for providing mobile services, while satellite, cable, telephone and fibre networks are better at providing high-definition, three-dimensional, on-demand viewing experiences in the home. That may be particularly pertinent in the United States, where only a minority of viewers still receive television through free-to-air broadcasts.

So mobile television is about a lot more than the relative merits of competing technical standards. It could be the future of broadcast television.

William Cooper, the founder of informitv, will be moderating the Super Session on Mobile Video — entertainment to go at the NABShow in Las Vegas on 21 April.