Wireless Systems Design

WLANs Get Boost From Multimedia Applications

Wireless home-entertainment systems hold the promise of mass appeal for consumers. They also flaunt the possibility of large revenue streams for WLAN equipment vendors. Yet this potentially huge market has yet to be realized. One issue is limited bandwidth. Although estimates vary, most multimedia systems need upwards of 100-Mbps bandwidth. The highest current data rate for 802.11g or 802.11a is just 54 Mbps.

In response to this need for high-bandwidth multimedia applications, the IEEE 802.11 Working Group is considering a new standard: 802.11n. This specification would boost the current WLAN bandwidth to at least 100 Mbps. Unfortunately, this proposed standard would not be ratified until 2005 at the earliest.

Many of the current 802.11 commercial vendors are unwilling to wait that long. These companies have already come out with extensions to the current 802.11b/g/a standard. Those extensions provide proprietary speed boosts of 72 and even 108 Mbps. Though impressive, their efforts may have been topped by GlobespanVirata, which purchased Intersil's wireless operations. (A merger between GlobespanVirata and Conexant Systems was just recently finalized.)

This company has developed upgrades to its 802.11g and 802.11a chips that will supposedly push network speeds to 140 Mbps. Boasting speeds that are 40 times faster than existing 802.11b products, GlobespanVirata's Prism Nitro Xtreme Multimedia (XM) is said to be fully compatible with all 802.11g and 802.11a/g devices. The Prism Nitro XM upgrades combine previous Prism Nitro technology, which supported the co-existence of 802.11b and 802.11g networks. The speed enhancements are spearheaded by a software performance package, which is called Prism DirectLink.

In addition, Prism Nitro XM is not supposed to interfere with other networks. Apparently, it also reduces overhead throughput loss. Such loss is typically associated with an access point (AP), which must support a number of users. To accomplish this feat, the system enables a high-speed data link between wireless clients once they're within communication range. This approach is intended to allow clients to communicate directly with each other while maintaining a simultaneous network connection with the AP. It remains unclear if this high data rate applies only to multimedia applications—compressed audio and video—or if encrypted data also is transmitted at these higher rates.

As more vendors announce proprietary ways to boost today's 802.11 throughput for multimedia applications, compatibility issues will emerge. Ultimately, consumers will have to decide which products and price levels best fit their needs. More information about GlobespanVirata's Prism Nitro XM can be found at www.globespanvirata.com.

TAGS: Intersil
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