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Mobile TV disappoints World Cup fans

Posted: 19 Jun 2006 ?? ?Print Version ?Bookmark and Share

Keywords:World Cup? mobile TV? DVB-H? Joost Verhoeks? backlighting?

If the climax of the Brazil-Croatia World Cup match in Germany last week was sound!the deafening roar of 72,000 fans cheering the only goal by Brazil's Kaka!the anticlimax was definitely video, and the disappointing user experience of trying to watch a mobile handset in the stadium.

The jerky pictures, dropped frames and frozen images on my mobile handset took me back a decade to my first headache-inducing struggle viewing "moving" pictures inside a postage-stamp frame on a PC screen.

I almost waxed nostalgic.

Admittedly, I have followed the development of mobile TV technologies more intently than the average user. I've built up perhaps unreasonably great expectations for mobile TV. So I had high hopes that World Cup '06 would be the defining moment for mobile TV.

The key, I thought, was actually watching mobile TV broadcast signals on a mobile phone in a real-world setting, not the controlled environment of a trade-show demonstration.

I should have known better.

Using a mobile TV handset here, I learned a hard truth: Signal conditions trump everything. If all you've got is a weak signal, there is little to see or appreciate in a mobile TV broadcast.

The handset in question was a Pocket PC made by HTC. I used a Philips Semiconductors RF TV tuner/demodulator system-in-a-package housed in an SD card to enable DVB-H reception. All I had to do to watch the match was insert the tiny SD card, which included a third-party antenna, into the handset.

The mobile TV signal was generated by T-System, which currently serves as a DVB-H platform operator. It broadcasts 14 TV and six radio programs. DVB-H-based mobile TV signals are now available in Berlin, Hamburg, Hannover and Munich during the World Cup as part of German trials.

Admittedly, the handset and DVB-H receiver/demodulation chip I used weren't among the official devices currently being used in the German DVB-H trials. Moreover, what I was seeing was somewhat contrived: signals were broadcast in a real world setting, but they were restricted to the trials.

T-System was most likely exploring exactly how many more low-power transmission towers it will need before "reasonable" mobile TV reception is possible.

Still, I had to ask myself as I squinted at the match on the Pocket PC: "I'm supposed to be excited about this?"

Reality bites. You can't enjoy mobile TV with lousy signal conditions.

Flip side
There is a flip side: The World Cup broadcasts underscored that mobile TV design engineers and device vendors have their work cut out for them!and they know what they have to do.

Joost Verhoeks, international product marketing manager for TV-on-mobile at Philips Semiconductors, acknowledged the poor signal conditions around the stadium, but added, "You [also] need an optimized antenna that can tune better." He added, "Obviously, the coverage area needs to be learned better by broadcasters."

At the same time, the experience taught me that tuner sensitivity is crucial. If your mobile TV drops signals, forget anything else. You get nothing.

Well, that's not exactly accurate. The software in the Pocket PC system was smart enough to read out from memory when it dropped signals. In short, the screen didn't go dark because the system was designed to keep the last frame of the signal.

Yes, there were 14 TV channels available on my Pocket PC, but they were very slow to change. Largely because of poor signal conditions, it took more than ten seconds to change channels.

Theoretically for the DVB-H standard, using "one-time slice," means it should take five to ten seconds for a channel change, according to Verhoeks. The time, however, can be reduced significantly "if you take more time slices," he explained. The penalty is greater power consumption.

Another problem is ambient light. If you are trying to watch a live game in broad daylight, you see nothing. Most digital camera users are familiar with this when trying to see a still image displayed on the camera's small LCD.

What's the solution? "We are exploring adaptive backlighting," Verhoeks said. Philips' backlighting algorithms are already used in consumer LCD TVs to get "more brightness out of LCD while keeping power consumption down," he explained. "We have an FPGA working to explore the issue," he added.

A spokesman for 3 Italia, which began commercial DVB-H broadcasts in Italy in time for the World Cup, claimed its "outdoor" DVB-H mobile TV reaches 70 percent of Italian subscribers!both those in large cities and popular vacation destinations for Italians like the beach.

Back in Berlin, mobile TV reception was less than 10fps. Verhoeks of Philips asserted that picture improvement technologies used in home DTVs can be transferred to mobile TV.

Philips's "Natural Motion" algorithm!essentially a line-doubling technology with an intelligent motion-estimation algorithm!is being pitched to operators and mobile handset vendors to help increase frame rates on handset screens.

The problem is how to implement this on tiny, power-hungry handsets? Philips is exploring the possibility of running its algorithm either in an application processor in a handset or adding a separate chip closer to the phone display.

We'll see!hopefully better than I saw in Berlin.

- Junko Yoshida
EE Times

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