'Most 3G operators own at least 5 MHz of TDD spectrum that they're not using,' says Jon Hambidge, marketing VP for IPWireless. 'If you look at this from the operators' point of view, how would you feel if after all that 3G spectrum you bought, the killer app for 3G requires you to buy new spectrum‾'
IPWireless expects to have equipment available in mid- to late-2007 to support the multimedia broadcast multicast service (MBMS) standard that the 3GPP has defined for W-CDMA Release 6, which can use TDD spectrum and is well suited for operators that already have deployed 3G. The IPWireless offering, dubbed TDtv, can be deployed on a network operator's existing tower infrastructure, and purportedly deliver up to 50 channels per 5-MHz block of TDD spectrum (assuming 100 kbps per stream).
The other benefit, Hambidge adds, is that it doesn't require users to buy all new handsets. 'You don't want to have to force the subscriber to buy a new handset just for this service. With TDTv, you're looking at a $10 maximum upgrade in handset costs.'
Although MBMS has been defined, it's not expected to be finalized before the end of 2007, although vendors like IPWireless and Huawei Technologies are selling prestandard MBMS solutions. In May this year, Hong Kong's PCCW launched a mobile TV service using Huawei's cell media broadcast (CMB) technology, which is based on MBMS.
With many technological choices facing operators, an inevitable question is: to what extent should cellcos be worried about interoperability‾
The prospect of a harmonized mobile TV standard - at least at the RAN layer - is decidedly slim, according to Toni Paila, broadcast chair for the Open Mobile Alliance.
'There's not likely to be a harmonized RAN standard for mobile TV because of various regional issues like spectrum availability,' Paila says.
Consequently, the OMA is focusing more on developing standard specs at the service/application layer of mobile TV. 'The usage case we see is to combine DVB-H and MBMS at the service layer so that consuming mobile TV services is transparent to both the user and the network.'
Paila says the three critical components to look at in developing an apps-layer standard are the program guide, content/service protection and content delivery. Smaller items to look at include specs for purchasing services, roaming, device management and interaction.
Paila declined to give a timetable for the arrival of such a standard, as it's early days for mobile TV in general. In the meantime, the next few months are likely to see a flurry of activity as service providers weigh their options and place their bets on mobile TV.
Whatever technology operators choose, advises Motorola's Pilbeam, they should tailor the network's design and capacity around how users consume mobile TV content. 'Mobile TV was originally envisioned as a primarily outdoor service, but in fact trials suggest that people are more likely to use it indoors. Also, unlike traditional broadcasting, the antenna is moving much if not all of the time.'
Lara van Rooyen, marketing manager at Ericsson, agrees.