Three major mobile networks in the United Kingdom plan to trial a new approach to mobile television using currently unused 3G spectrum. O2, Orange and Vodafone plan to test the service in West London from October for three months. If mobile television is to succeed in the market, a step change in quality is required.

The network operators plan to use the unpaired 3G spectrum they already have licensed, which is currently unused by most network operators. They have up to 20MHz of this Time Division Duplex or TDD spectrum available between them, although not all of this may be usable in order to avoid interference.

The trial will employ Integrated Mobile Broadcast, a 3GPP standard endorsed by the GSM Association last September.

IPWireless, Ericsson and Streamezzo will provide the technology for the pilot, which will be shared by the network operators.

IMB provides a way of multicasting on cellular networks, as with previous trials of Multimedia Broadcast Multicast Service or MBMS technology.

The same operators conducted a four month trial of the predecessor to IMB, with a system known as TDtv, in Bristol in 2006.

The European Union has favoured DVB-H for use across Europe, based on broadcast standards, but following numerous trials and deployments, it has so far failed to become established. One issue has been lack of available broadcast spectrum.

Previous approaches to mobile television have delivered relatively low quality, low resolution pictures, as a result of the limited bandwidth available. As a result the consumer proposition has been less than compelling.

Meanwhile, smartphones such as the Apple iPhone have demonstrated consumer demand for high quality mobile video on increasingly high resolution displays, dramatically increasing data traffic on networks. It is already possible to stream many channels over WiFi and 3G mobile networks, but delivering broadcast television over a unicast mobile network is simply not a scalable proposition for the mass market.

Multicast approaches allow a single instance of a channel to be received by any number of compatible devices within the transmission range. This is ideal for live news, sports and events, and prime time programming on primary channels. Multicast can also be used to deliver data and multimedia files to support non-linear services. Seamless handover to unicast services should also be possible.

The GSMA estimates that each 5Mhz of unpaired spectrum could provide around 20 broadcast channels at 256Kbps for each one. In practice that is unlikely to deliver anything like the resolution, frame rate or quality that consumers now expect. This is more likely to require around 800-1200Kbps, allowing 4-5 high quality channels.

Mobile television has yet to take off in most markets, often for business and much as technical reasons. Users may expect to be able to access broadcast television channels on mobile devices, but they will not necessary pay a premium to do so, particularly if it is not presented at high quality.

If mobile television is to be successful, informitv believes a step change in quality is required. That means pictures that are comparable to standard definition terrestrial television transmissions.

For operators, that may mean they are able to offer fewer channels, but in most markets there are generally only a few channels that are worth watching live. Most other programming can be delivered better by other means.