Four mobile phone operators have agreed to test a new broadcast mobile-TV technology that uses idle radio frequencies acquired with their 3G (third-generation) high-speed mobile licences.

Later this year, Hutchison 3G UK, Orange, Telefónica Móviles SA and Vodafone will begin testing TDtv, a rival technology to DMB (digital multimedia broadcasting) and DVB-H (digital video broadcasting - handheld), on 12 cell sites in Bristol.

A key benefit of TDtv, developed by IPWireless is its use of idle unpaired 3G spectrum bands available across Europe and Asia at 1,900MHz and 2,010MHz. The bands were originally intended as an overflow space for 3G internet services, which have yet to materialise and are likely to be eclipsed by wireless LAN services such as Wi-Fi and WiMax.

In many European countries, frequencies required to provide broadcast mobile TV service using the DVB-H standard are currently blocked. And unlike DMB, which currently limits the number of TV channels to around five, TDtv allows operators to deliver multiple channels.

Operators using TDtv will also be able to deliver digital audio, multicast and other IP (Internet Protocol) datacast services without any impact on their 3G voice and data services.

For the trial, MobiTV Inc. will provide the mobile-TV application software, content and other operational components.

Because TDtv is based on the 3GPP (third-generation partnership project) family of standards, it easily integrates with 3G networks and devices based on the WCDMA (Wideband Code Division Multiple Access) standard