Bernhard Baumgartner /
12.01.2005 12:00 PM
Mobile video transmission standards: Is there a clear winner?

Many technological battles such as VHS vs. Betamax, or DAT vs. MiniDisc, were finally decided not solely by technology but also by clever marketing initiatives. And the technology tussles continue, most notably today with the intense battle between Blu-ray and HD-DVD. The shifting landscape delineating supporters of competing mobile video standards threatens to create yet another format dispute, and the stakes are high.

The ability to provide mobile video efficiently, economically and in a commercially viable way is the common target that unites all involved players. However, many parts of the industry are still questioning which track to take to generate broad end-user acceptance of mobile TV and finally to get consumers to pay for watching live mobile video services on small handheld devices such as mobile phones.

Having said that, early assessments in the UK, Finland, Germany and other countries around the globe have indicated a considerable consumer interest in mobile video services. A full-scale, six-month trial of mobile TV has been launched in Oxford, UK, run by O2 in partnership with Nokia and Arqiva (formerly ntl Broadcast), with transmission equipment provided by Harris.

Four hundred Oxford residents are using Nokia 7710 smartphones to watch 16 channels, including all the terrestrial channels, BBC News 24, CNN, MTV and British EuroSport.

Graphic/with bigger sent.



Figure 1. Shown here are the mobile video standards adopted by different regions. While DVB-H dominates Europe, Forward Link Only (FLO) technology continues to gain ground in North America. However, Korean T-DMB is challenging both these standards. Click here to see an enlarged diagram.



The service is based on DVB-H technology, which allows digital television signals to be received by handheld devices. The big advantage in comparison to video download and streaming services so far implemented with 3G technology is that instead of a point-to-point connection to each receiver, the video programs are streamed to the handheld devices in the same point-to-multipoint way that analogue and digital TV are transmitted.

DVB-H currently dominates the European theatre, while Qualcomm subsidiary MediaFLO USA continues to gain traction in North America with its so far proprietary Forward Link Only (FLO) technology. Both are being challenged by the Korean T-DMB (Digital Multimedia Broadcasting) standard, which is based on the DAB digital radio standard.

Views vary on the efficacy of each standard, and we'll look at the two main challengers in a moment. But for now, the most significant differences are more clearly defined by geography than technology. (See Figure 1.)

DVB-H essentially rides on the back of DVB-T, which is now widely used and adopted across Europe. DVB-T wasn't originally developed and optimized for the reception with handheld, battery-powered devices in mind. DVB-H is seen as a “European” standard because its development and ongoing support stems from the offices of the DVB Organization in Geneva, Switzerland. This international cross-industry body developed and championed all DVB standards, including DVB-T and DVB-H. The organization has worked hard in an open forum to ensure an interoperability of standards that provides the best possible delivery of digital content over all available distribution channels. In essence, DVB-H is an extension of the basic DVB-T television standard, adding certain technologies such as time slicing for extended battery life of handheld devices and additional error correction for improved reception in moving vehicles.

FLO is more prevalent in North American markets, with increasing interest from other parts of the world, including Asia. Not only is MediaFLO already making commercial chipsets to complement its technology developments, but also it is taking the innovative move of acquiring spectrum and building its own network with a view to a commercial launch in 2006.

So far, regular operation for T-DMB is limited to South Korea, but it is no less supported by industry heavyweights such as LG and Samsung. The deployment of T-DMB using existing DAB transmission infrastructure results in high interest of international broadcasters to add T-DMB compliant mobile video streams to their DAB transmission networks.

Marketing projections

So, which is most likely to end up being the better value proposition? First, we need to consider a few near-term marketing projections for mobile video, keeping in mind that such projections are often fairly wide of the mark — if not utterly wrong.

Industry pundits and prognosticators predict that as many as 125 million mobile handsets could be in use within the next five years, generating as much as E6.6 billion in revenue. And because early studies indicate that users would be happy to pay for content at prices between E10 to E20 per month plus extra charges for premium services, the market stakes, on paper, appear enormous.

Despite the universally positive results of early consumer marketing surveys, what the public says it wants and what it actually does once it's available are often two different realities. Engineering-led marketing plans often fail to ask the question: “Will anyone want it?” Marketing-led research, on the other hand, tends to support a foregone “Who wouldn't?” conclusion. This is what all of the players, regardless of standard, are attempting to find out. Technical and commercial trials using DVB-H for mobile TV are now under way in Australia, France, Germany, Malaysia, the Netherlands, Singapore, South Africa, Spain, Switzerland and the UK — as well as the United States via Crown Castle's currently completed trial in Pittsburgh, PA. The trials are designed to determine the potential market reception, most efficient network structures and the most reliable delivery mechanism. The results are fundamental to the future of mobile video and those who expect to generate revenue from content, carriage and consumer acceptance.

Comparing standards

DVB-H enjoys strong and organized support. As a natural extension of the proven DVB-T standard, DVB-H has been relatively straightforward to implement. As already mentioned, DVB-H is less power-hungry because it uses the technique of time slicing. This special technique inserts the different video channels into the transmitted transport stream in bursts of data. This allows a handheld device to receive only those parts of the transport stream that contain the data of the channel being watched at the time and to remain “switched off” during the periods that other data would be received. The result is a handset in which the RF receiver is only actually “on” 10 percent or less of the time while in use. An additional level of forward error correction (MPE-FEC) inserted in the DVB-H front-end contributes to the outstanding robustness of the DVB-H signal. And the newly added 4k mode offers a good compromise between the maximum allowed distance of transmitters in single-frequency networks and the speed limitations in mobile environments resulting from the Doppler Effect.

However, DVB-H detractors, perhaps not surprisingly from supporters of other standards, regularly dispute the performance of DVB-H. They add that DVB-H channel switching is slow, unlikely to be able to deliver the stated data rates, and is susceptible to signal variations and problems with synchronization. Even DVB-H supporters acknowledge that the up to six seconds to change a channel is an issue, but not insurmountable. However, leading DVB-H receiver manufacturers are confident they can drive down the channel switching to approximately 1.5 seconds as already achieved with DVB-T receivers. MediaFLO claims that over a 6MHz channel, FLO can fit 20 mobile video channels. DVB-H proponents (as you may suspect) dispute this figure. And for some, there remain considerable questions about FLO's proprietary nature.

To address this, FLO proponents established “The FLO Forum,” an organisation of MediaFLO supporters who in many ways emulate their European counterparts by courting FLO technology standardization with ETSI and the U.S.-based Telecommunications Industry Association. At this point, it would appear that DVB-H and T-DMB have a head start in demonstrating technical feasibility. With MediaFLO's stated intention of operating in 30 cities by late 2006, however, they may have the opportunity to demonstrate large-scale commercial and technical viability before too long.



In a six-month trial of mobile TV in the UK, 400 Oxford residents are using Nokia 7710 smartphones to watch 16 channels.


T-DMB supporters argue that the paucity of available spectrum could cripple the implementation and acceptance of DVB-H and MediaFLO, whereas T-DMB, due to its association with DAB, already has most of the required spectrum and infrastructure in place. T-DMB backers claim that it requires even less power than DVB-H or MediaFLO.

Successful T-DMB trials in Korea and China have been running for some time. Harris provided its DAB 660 transmitters already successfully used in Korea for DMB trials currently conducted by Beijing Radio.

Despite the perceived advantages and disadvantages of each of the standards, it may remain a case of “better the standard you know.” In this scenario, the better established and more widely deployed DVB-H standard is the clear frontrunner. However, it is unlikely that the spectrum necessary for a full fledged roll-out of DVB-H transmitted content will be available for a few years yet, as analogue spectrum is gradually switched off in favour of digital.

MediaFLO aims to begin European trials in the near future, if possible within the next year. Also by that time, first results will be available of the MediaFLO's network operation in the United States on UHF channel 55.

Summary

Whatever standard “wins,” mobile TV will require a willingness of operators, regulators, broadcasters and handset suppliers to strike new deals. Regulators need to licence new spectrum to allow economic nationwide network implementations. Likewise, broadcasters and publishers will need to tackle digital rights issues, and operators will need to develop workable revenue-sharing partnerships.

Unfortunately, a dogfight between standards may be a pointless exercise. Market forces, not technical nuances, will decide. It's the carriers who are most likely to dictate which standard (or standards) emerge as the industry leader. Each standard has perceived advantages and disadvantages, so it may not be the best technology, or even the best marketing program, that wins the day.

In the end, the system that provides the best mix of technical performance, attractive content and clever promotional strategies will win the most users and, therefore, dominate the marketplace.




Bernhard Baumgartner is director product management for Harris Broadcast Systems Europe.



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