DTV Broadcasts to Cellphones Succeed in Nokia Live Trials

At the IAAF games, users operated Nokia 7710 smartphones fitted with a module to receive mobile TV broadcasts by YLE, the Finnish Bcstg. Co. YLE transmitted a 14-channel package, including domestic coverage of the games, a compilation for international distribution, and 5 special broadcasts of individual championship events, enabling viewers to follow each start to finish without break. Also available on the DVB-H service was regular TV programming from YLE and other broadcasters, including BBC World, CNN, Eurosport TV and MTV3. BBC and CNN, for example, offered live coverage of space shuttle Discovery’s return landing Wed.

Although Finland’s Nokia hosted the Helsinki trial, there was cooperation from Motorola, NEC, Philips and Sony Ericsson, all founding members of the Open Mobile Alliance formed in Sept. 2004. The Broadcast Mobile Convergence Group, including Nokia, Philips, Universal and Vodafone, also was involved. To date, limited DVB-H mobile tests have been run or are planned for Australia, Finland, France, Germany, Malaysia, the Netherlands, S. Africa, Spain, Switzerland and Taiwan. Tests are being run in the U.S. in Pittsburgh, via a joint effort between Nokia and U.K. multiplexer Crown Castle.

But the Helsinki games were the most extensive and high-profile DVB-H trial yet, and the first framed around an international sporting event. Nokia showed confidence in the system by letting 300 guests and journalists loose with first-generation prototype receivers in the form of its SU-22 DVB-H modules neatly clipped to the backs of Model 7710 smartphones like thin batteries.

Overall, the DVB-H mobile system worked better than we and others thought possible -- and gave a glimpse of the future convergence of CE, telecom and traditional terrestrial broadcasting. Reception in Helsinki was remarkably good, with clear pictures and no breakup or loss in hotels or on moving city buses -- even outdoors during a severe thunderstorm that temporarily stalled the games. Signal strength and quality showed at 70% most times on the receiver’s display. The data transfer rate used was 180-190 kbps for video, plus AAC audio, for a total of 250 kbps.

The module-equipped smartphones generally worked well, albeit with occasional lockups. Those apparently were caused by a strange design decision not to allow individual shutdown one by one of applications such as the digital camera feature or Internet access. Instead, an all-or-nothing shutdown was required, sapping system memory and slowing processing to a crawl or to go haywire, necessitating a re-boot. We presume system firmware will be improved by the time production phones become available for the system launch.

The DVB-H mobile TV standard, set in Nov. 2004 by the European Telecom Standards Institute (ETSI, is based on the DVB-T standard used for digital terrestrial TV in Europe and elsewhere. DVB-H is a datacast, using Internet Protocol (IP) standards, with a return channel carried by the cellphone networks. The return channel controls decryption and provides interactivity -- and lets the network charge fees. But the return channel isn’t needed if TV programming isn’t encrypted, and there’s no more interactivity than with normal one-way DVB-T.

Conventional DVB-T for home viewing uses MPEG-2 compression, with each TV frequency or multiplex capable of a 24 Mbps data transfer rate. That translates into 3-7 TV channels delivered at 3-5 Mbps each. In comparison, DVB-H’s compression is MPEG-4/H.263. DVB-H also uses QPSK with 8k modulation, to put up to 11 Mbps in the multiplex, with each program using 12-384 kbps. The net result is 20-50 channels for mobile viewing on small screens typical of cellphones, PDAs and other portable handheld devices. For the Helsinki trials, a 5.5-Mbps stream carried 14 programs. Dynamic bit-allocation is used to share bits between fast action sports programming and “talking heads” studio programs.

In the trials, the compression used was MPEG-4/H.263 with the Real decoder in the receiver -- Real being the standard player for Nokia smartphones. But, using the newer MPEG-4/H.264 codec will reduce bit rate by 1/3, said Riku Karlsson, Nokia mgr.-rich media program. “We are not committed to Real, but it is already used in Nokia smartphones,” he told us. Asked if Nokia might use Microsoft’s Windows Media Player, Karlsson was noncommittal: “There has been no discussion on using Windows Media Player.” The Microsoft platform’s compression has been used experimentally and successfully to send motion video to PDAs over Digital Audio Broadcast radio frequencies in the U.K., as well as by U.S. satellite radio broadcaster Sirius.

DVB-H signals are transmitted on the UHF band, compared with the VHF widely used in the U.S. for commercial broadcasting. “Using VHF is not practical,” said Jouni Kamarainen, Nokia dir.-industry affairs. “The antenna would be too large to fit in the device. The high UHF band between 470-700 MHz is best for mobile TV.” For the Helsinki trials, broadcast service provider Digita installed 3 main transmitters, one at 1 kw and 2 at 4 kw, with half a dozen 100 w repeaters and more simple repeaters inside buildings with RF-shielding windows -- Nokia hq had 2 such simple repeaters. All transmitters broadcast on the same single frequency, at 610 MHz, to cover 188 sq km, enough to give coverage to the local population of 350,000 viewers.

Compared with the 25-30 fps scanning rate of PAL and NTSC broadcasts, the DVB-H broadcast signal is 15 fps -- slowed to about 10 fps for full-frame viewing on smartphones. The signal is broadcast as Quarter SIF, about 176 x 144 pixels, but upscaled from QSIF to 320 x 240 pixels in 4:3 aspect ratio on the receivers. The widescreen format is 392 x 320 pixels.

DVB-H broadcast signals are encrypted, with decryption controlled via the cellphone’s back channel. That would allow for conditional access by service providers seeking to charge subscription fees. A recent test-market among consumers in Helsinki charged 5 per month for basic viewing, plus 4 for premium content and

2 for weekend viewing of Formula 1 racing.

Unresolved issues include the question of whether content now broadcast free to homes -- or to viewers in markets such as Finland and the U.K., who pay an annual license fee for reception -- will be offered free over DVB-H. Richard Sharp, Nokia vp-rich media, confirmed to us that, “yes, it would be technically possible to broadcast with encryption for free viewing. But no one has requested it yet.” Jari Lahti, head of new media at YLE, said the broadcaster hadn’t heard from viewers who might object to being charged a subscription fee for content they've already bought licenses to view. Broadcasting unencrypted for free viewing on cellphones “has not been considered,” Lahti told us.

Debate is underway in Europe about gatekeeper cellphone networks charging to pass along free-to-air TV programming -- or content already paid for through mandatory annual viewer licenses. The sentiment is that such programming should be free as part of a basic “tier” of programming, with consumers charged more for premium programming. Chargeable items could include interactive features and functions -- such as voting or viewer polling -- using the “back” or return channel.

Battery life is a more practical concern about DVB-H service to cellphones. If a user needs to make an emergency call on his smartphone, the last thing needs is to see that viewing a lengthy football match in DVB-H has drained his phone’s battery. Nokia claims the standard 1,500 mAH battery for its 7701 smartphone offers 3 hours of juice with the DVB-H function running at maximum brightness and full audio volume. However, our hands-on evaluation found the cell died after less than 3 hours of continuous video running without sound -- and that for a battery reasonably new and in good working condition. Battery efficiency only diminishes with age.