As reported last year, it has been long felt that delivery of signals to smaller portable TV sets with indoor antennas was as important to the future of off-air DTV as delivering HDTV to big screen TV sets. The massive efforts of QUALCOMM and Crown Castle to build out terrestrial DTV transmission networks to reach cell phone users indicates that others feel the same way, especially when content providers can charge for it. Broadcasters are likely to provide programming for cell phones, but their content will be transmitted over the QUALCOMM MediaFLO or Crown Castle DVB-H networks, rather than the broadcasters' high power ATSC 8-VSB DTV transmitters.
How will broadcasters participate in what many companies feel will be a boom in small screen TV viewing? Getting their signals on a MediaFLO or DVB-H network is certainly one option. However, if the station wishes to maintain control over the distribution chain, more robust modulation schemes such as 2-VSB (not part of the US ATSC standard) or e-VSB can work well in mobile environments. A potential problem in a broadcast infrastructure is the difficulty in delivering a reliable signal to hand-held devices. Actually, there are multiple problems here. One is that the broadcast model uses a single high power transmitter to cover a market, leading to dead spots in congested urban areas. Distributed transmission could solve this problem, but that raises another issue. "Fifth generation" VSB receivers rely on a lot of processing power to handle multipath, which requires more electrical power and larger batteries in portable devices. The rapidly changing propagation characteristics encountered in mobile 8-VSB DTV reception stresses the ability of the receivers to compensate for multipath.
More ATSC products should be arriving in 2006. After looking at such products at this year's CES, hand-held ATSC DTVs may not be among these. However, the portable TV audience seems posed to grow faster than the off-air ATSC DTV audience. One problem in this arena is the amount of power required for the more advanced ATSC decoders. One manufacturer showed a combination DVD player, digital media player and portable ATSC receiver in a notebook-like package, which was about the same size as a portable DVD player. It used an external snap-on battery pack and could operate for over two hours. If consumers get used to viewing TV on cell phones, if and when a company does figure out how to build a hand-held ATSC receiver, unlimited content with local news and weather at no charge may look very attractive.
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