Proprietary QoS Technology

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A few vendors have attempted to provide proprietary QoS enhancements to Wi-Fi's technology. Sharewave's (acquired by Cirrus Logic) attempt can be found in its Whitecap technology. Whitecap has been incorporated into products from Panasonic, Netgear, and others, but since the products were not interoperable with other 802.11-based products, they didn't do too well. Nonetheless, Cirrus Logic continues to offer Whitecap technology; but this time the vendor sought Wi-Fi Alliance certification for its Whitecap2 product. Thus the latest version can interoperate with other 802.11b products.

The challenges of delivering high quality multimedia traffic over a wireless network include the distance a remote client is from the access point, impediments such as doors and walls that are typically found in most wireless networking environments and, most importantly, the number of client devices in use. Just one client device receiving video over a Wi-Fi network can use the full capacity of the available bandwidth.

Many of the large video-oriented electronics companies hope to support wireless video as adoption of wireless networks takes hold. And after many years of false starts and exaggerated promises, it appears that high-quality digital video will play a significant role in wireless networkings. The reason? At the 2003 International Consumer Electronics Show, upstart Magis Networks showed off its new "Air5 chipset." Using the same unlicensed 5 GHz spectrum that is the foundation for the 802.1 la wireless networks standard, Magis Networks has its own trump card in the form of a proprietary MAC sublayer that is optimized for wireless delivery of high-quality video, TCP/IP data, and audio.

Even though the 802.11e QoS standard is just around the corner, many CES attendees felt that Magis could be holding a winning hand with its 802.11a radio and proprietary time domain multiplexed (TDM) Media Access Controller, and novel seven-antenna radio that can extend the useful range of a wireless network device. With claims that Air5-based networks can support several simultaneous streams of high-quality video, audio, and TCP/IP data throughput of up to 40 Mbps at ranges of up to 250 feet, the company has created a groundswell of interest.

Others are tackling the same issues, using different kinds of technology. ViXS Systems' Matrix 802.11a wireless communications processor optimizes multiple streams of wireless video for delivery over an 802.11a network. The Matrix processor is designed for "gateway" appliances. It uses two 802.11a channels to enable the distribution of quality video to multiple wireless devices. When combined with ViXS' Xcode MPEG/video network processor, Matrix can provide robust video distribution with guaranteed broadcast-quality video streams at 30 frames per second. According to ViXS, this combination will allow the construction of network media gateways and access points to stream video simultaneously to a variety of digital and analog devices such as laptops, PDAs, TVs, and next-generation HDTVs. All the receiving device needs is the basic off-the-shelf 802.11a network interface card (NIC).

XCode's MPEG chip is a multistream transcoder that maintains QoS for up to eight real-time digital video streams. ViXS' Matrix/XCode chipset can support two 802.11a channels in a wireless video network, which is key to supporting multiple broadcast-quality video streams with guaranteed QoS. Also included is network management software for QoS. The management software monitors and manages the video stream in real-time. In addition, it provides DES, Triple DES and AES encryption technologies for content security.

A WLAN with a Smart Edge?

Cisco believes that there should be a smart "edge" to the wireless network. Toward that end this networking giant is giving away its Cisco Client Extensions (CCX) software.

In doing so, Cisco is fundamentally opposing the trend to centralize the intelligence of wireless LANs, while leaving the edge "dumb." According to Cisco Consultant Martin Cook, such an architecture makes a WLAN's deployment and management more expensive.

"When you're rolling out a WLAN you want to take some of the pain away from the difficult job of network deployment," says Cook. "If for example you take the business of managing the radio frequency problems—how are you going to do that, if you have a dumb edge? You have to have intelligence distributed around the network. We think you can't know anything about the RF environment if you have a dumb edge. We want intelligence in the AP."

Cook listed several silicon makers who produce WLAN chips, who have signed up for the CCX software. On that list are Intel, Atheros, Intersil, Texas Instruments, Atmel, Marvell and Agere.

CCX also addresses the QoS issue. According to Cook, Cisco believes that CCX addresses the need for a more intelligent infrastructure that will be needed for mobile voice devices to use voice over Internet (VoIP) technology.

Cook also cites another example of the advantage of having intelligence distributed around the wireless LAN—fast roaming. He explains, "If we have intelligence in the PC, in the access point, in the PDA, the handshakes that make up authentication don't have to take so much time; we can leverage the intelligence out there at the edge and improve performance. We can give our WLAN smarts to other people out there, so that the device can communicate as if it were a Cisco client, to the infrastructure."

Cisco also believes it already has the key collaborator signed up in its push to claim dominance on WLAN technology. And, according to Cook, that key collaborator is Intel.

"Intel will be out largest partner with respect to delivering; they are currently buying our access points," asserts Cook. Cisco believes that all Centrino based PCs will be CCX comformant.

There probably will be other technological approaches to achieve similar solutions to the ones mentioned in this section. So it may not be long before multimedia over wireless is actually available to everyone. That, of course, will only cause the market to clamor for more.

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