RealTime IT News

Video: A Wireless LAN Killer App?

Wireless video distribution - sending multiple high-quality video streams to terminals around a home or even an airport or conference center - could be the wireless LAN killer app of tomorrow. And ViXS Systems Inc., a fabless semiconductor and software solutions start-up based in Toronto, Canada and Austin TX, hopes to cash in big time.

ViXS has developed chip designs and network control software for an 802.11a-based video distribution system that it claims will blow the competition out of the water. It hopes to have final silicon available for trialing in set-top boxes, service provider headends and TiVo-style stand-alone digital entertainment hubs by the fourth quarter of 2002.

The technology allows the transmitting device to send multiple broadcast-quality - or better - video streams to different terminal devices. A single set-top box could feed many TVs throughout a home, each showing different programming.

"What we do," says senior vice president of product development Jim Reinhart, "is allow wireless networks to carry MPEG video with quality of service - video that does not drop frames and does not pixelate. It can fail if you walk out of range. But as long as you're in range, we can deliver high quality video."

This is not already packetized video from an Internet or Internet-like source. This is video from any broadcast source, which is received at the gateway device, translated to an MPEG protocol and packetized on the fly by the ViXS technology, then sent out over an 802.11 - or other - network.

One key distinguishing feature is that it can dynamically adjust bit rate and even protocol to accommodate any kind of terminal - including PCs and PDAs - or changing network conditions. And it provides guaranteed quality of service (QoS).

A likely first application is in next-generation television set-top boxes. ViXS-enabled set-top boxes would help digital television and broadband services providers solve a problem that currently holds them back.

To receive signals from a satellite- or cable-delivered service on a second - or third or fourth - TV in the home, subscribers have to run cable and attach a decoder to each. Consumers accustomed to easily split analog cable services often balk at the extra up-front expense.

A ViXS-enabled gateway device would allow the subscriber to install a relatively inexpensive "thin client" at each remote television which would allow that TV to control the service as if connected directly to the main decoder unit.

"We believe the technology answers some very important needs pertaining to the growing penetration of digital cable and satellite services - and of stand-alone consumer electronics devices like TiVo," Reinhart says.

A ViXS-enabled TiVo-like device could similarly distribute multiple stored video programs or streamed video channels to different devices around a home.

Beyond the home applications is the prospect of what Reinhart calls "video area networks." Travelers at an airport, for example, could use a laptop or PDA to log into a wireless video service and watch a CNN broadcast - much the way they can log on to a MobileStar-style high-speed Internet service now.

ViXS is by no means alone or even the first in this intriguing market space. Sony with its poorly-received Vaio MX PC already has a consumer product that does some of the things ViXS-enabled set-top boxes will do.

Unlike a ViXS device, however, the MX can only transmit one video channel over an 802.11a network - and by all accounts, it doesn't even do that very well.

Late last year, another Japanese electronics giant, Sharp Corp. (www.sharpelectronics.com), announced it had an 802.11a-based "proof of concept" product, co-developed with Cisco Systems Inc. (www.cisco.com), that could deliver real time, high-resolution video images from sources such as Hi-Vision (high-definition) TV signals.

Cirrus Logic Inc. (www.cirrus.com) announced its Wireless Spigot reference design earlier this year. The company describes Wireless Spigot as "a manufacturing platform enabling the rapid development of inexpensive consumer devices that support multiple, high-quality video streams on wireless home networks."

And San Diego CA-based start-up Magis Networks Inc. (www.magisnetworks.com), now partially funded by Matsushita Corp., has already launched its Air5 chipset technology which also uses the 5 GHz band to deliver multiple streams of cable and satellite-delivered content.

But Reinhart says the ViXS technology is superior to any of its known competitors. It has three main components. The video network control system translates from broadcast to the appropriate digital protocol, sets bit rate and looks after encryption-decryption functions.

The wireless component is "video centric," which makes it quite different from a typical WLAN implementation, Reinhart says.

"Think of a design team working on a WLAN product. Their number one priority is compatibility - how easily it fits into existing networks, how it interoperates with other vendors' equipment. Number two is cost. And way down the list is performance."

"Well, in a video network, you've got to focus on performance first. We call it the three Rs - [bit] rate, [wireless network] range and resilience."

Resilience is vitally important. A video network, especially in a service provider environment, cannot fail, he points out. "If it does, consumers will pick up their phones and say, 'Get this piece of junk out of here.'"

The third component that knits the other two together and makes the guaranteed QoS possible is the network software. It receives constant feedback from the network about traffic and capacity, and allows the system to adjust on the fly to changing network conditions by reducing (or increasing) bit rate or "transcoding" to a different protocol.

This part of the process is vital, Reinhart explains, because wireless LANs are dynamic, volatile environments. New terminal devices coming on stream, interferers such as microwaves and other devices being turned on - even doors closing and people standing in front of receivers - can change the capacity of the network.

The ViXS network control software ensures that the gateway device is never sending more data than the network can handle.

For a demonstration earlier this year, ViXS built a codec and user interface for the Compaq iPaq Pocket PC that turned the PDA into a "personal TV." It could receive "broadcast-quality" video from a prototype ViXS-enabled gateway device while the user moved around within a range of up to 120 feet.

The gateway did not send full MPEG2 or even MPEG1 video. Since the PDA could only display 320x240 pixels at 15 frames per second (fps), the system automatically choked back the data stream to something closer to 500 Kbps. All on the fly.

The demo system used the 802.11b protocol. A Wi-Fi-enabled ViXS network could deliver four to eight channels of video, Reinhart says. "Which would be useful," he allows. But the first silicon implementation of the ViXS technology will use 802.11a network technology, and it will be able to deliver "dozens" of channels - the company is not saying exactly how many yet.

The ViXS technology looks and sounds like the real thing. The only snag is that, like some of the other wireless video networking products we cited, it doesn't actually exist yet.

"We do have pre-silicon models now, so we know [the chipsets] will do exactly what we intend them to do," Reinhart says. "But the initial deployments are late this year. They should be final product, though."

He is evasive about whether the company actually has any partnerships with end product manufacturers in place, or trials definitely scheduled. We gathered not.

A lot can happen in a few months in this industry, of course. And the ViXS technology is far from vaporware - as the iPaq demo makes clear. But with Sony, Sharp, Matsushita and Cirrus in the game, ViXS is guaranteed nothing.