June 5, 2006 4:00 AM PDT
IPTV prepares for prime time
(continued from previous page)
The challenge for carriers is finding enough bandwidth on their network to deliver not just one but multiple HD channels into a single home. Unlike Verizon Communications, which is spending billions of dollars to build a fiber network directly to people's houses, AT&T has only extended its fiber into neighborhoods. It is using existing copper DSL infrastructure to deliver IPTV the rest of the way into homes.
While Verizon's network is costing about five times more to build than AT&T's, it will offer almost limitless bandwidth. AT&T's network, on the other hand will initially offer about 15Mbps to 20Mbps. And even though advances in DSL technology will allow it to push up these speeds, it will always be more limited than Verizon's fiber network.
"Verizon is using a big pipe to deliver service," said Matthew Flanigan, president of the Telecommunications Industry Association. "But AT&T has to be a bit more clever in how it uses technology, since the pipe it's using isn't ever going to be as fat. This is where companies like Microsoft, Alcatel and Cisco Systems can help deliver more content through skinnier pipes."
One of the first enhancements that will help AT&T deliver HDTV is a new compression codec known as MPEG-4, which gets bandwidth usage for the high-definition signals down to about 8Mbps per channel.
MPEG-4 technology is available today, and many vendors will be showing off their gear at the GlobalComm show. Tut Systems, for instance, will launch a MPEG-4 transcoder for high-definition content, which converts signals from the MPEG-2 standard in real time. Optibase, a provider of advanced digital video products, will demonstrate its live encoding of MPEG-4 high-definition technology, as well.
But Kishore said that AT&T and other IPTV providers will need to do more than just rely on MPEG-4 compression technology. Those companies may have to look at technologies such as channel bonding, which combines multiple downstream channels to increase the overall throughput that can be received in the home. The technology, which is used in cable networks, has the potential to more than quadruple currently available speeds.
"HDTV may not be a big concern for AT&T right now," said Kishore. "But it will definitely need to do something to increase bandwidth and use the bandwidth it has more efficiently. And I don't see MPEG-4 being enough."
5 commentsJoin the conversation! Add your comment