Another contender for mobile phone TV was unveiled in London on Wednesday, when IPWireless demonstrated its TDtv system transmitting multiple channels over the air from a cellular base station.
Based on MBMS, the Multimedia Broadcast and Multicast Standard, TDtv is designed to work alongside the current 3G WCDMA standard.
Using part of the 3G spectrum put aside for data transmission, IPWireless says that it is relatively easy to adapt existing base stations and other network infrastructure to integrate TV broadcast services with existing voice, data and video. This compares with O2's trial of a mobile TV service, which used entirely independent spectrum in the UHF TV band, and BT's DAB-based experiment in the digital radio band.
By the end of 2007, IPWireless claims, the cost of adding TDtv to a handset will be around $10. "We're working on an integrated solution with a major chip manufacturer," Chris Gilbert, chief executive of IP Wireless, told journalists in London on Wednesday. "Much of the technology exists already, we're using a lot of the sophistication we've developed for the uplink, where a base station has to work hard to pick up a weak signal from a mobile, and using it on the downlink."
The company says that because all the standards involved are part of the 3GPP global standards project, the technology will work worldwide and thus be attractive to handset manufacturers and international operators who want to encourage roaming.
"We'll be trialling with Sprint in the US, IPmobile in Asia Pacific and four international operators in Europe in the first half of 2006," said Gilbert.
"We estimate that upgrading the 3G networks will cost around €10,000 [£7,000] per base station, less than HSDPA. If operators offer TV over their existing 3G service first, they can spot what channels are popular where and then upgrade by postcode as necessary. Success-driven capital expenditure is what operators want to talk about at the moment."
In the UK, there is 20 MHz of data spectrum allocated in 5MHz slots to four of the five 3G operators — only Vodafone lacks this sub-band. IPWireless says that 5MHz is sufficient for more than fifty TV channels suitable for mobile phone sized screens, fifteen channels designed for PDA/handheld video devices, or a mixture thereof.
"TDtv can support any IP datacasts", said Gilbert, "including audio and clipcasting. Operators are free to develop their own mix."
"TDtv is a very good solution for multichannel offerings", said Alastair Brydon of consultancy Sound Partners, who presented at the launch. "You can broadcast your most popular channels saving bandwidth on your WCDMA network, while using that network to offer a wide selection of minority interest content. Users need not even be aware which system is carrying their channel, and operators can reallocate content according to popularity or local demand."
More bandwidth will be available shortly, said Gilbert. "There's another three lots of 5MHz yet to be auctioned at 2.010 to 2.025 GHz. In Japan, that's already been allocated with 5MHz dedicated to MBMS. And in the next two to three years, the UMTS extension bands will become available with hundreds of extra megahertz".
