News
Issue #2002 - 30 (August 2002)
(Updated Aug. 7, 2002)

OUTLOOK and TRENDS 

Dual- & Tri-band on Handheld Devices and Phones - Way of the Future - Opinions by Dave Molta in NWC newsletter with editing and commentary by MobileInfo.Com

Wireless LAN users face an obvious need to roam between different wireless LANs as the industry expands beyond the 11-Mbps 802.11b technology that may one day become an important component of hybrid wireless networks. But implementing multi-band wireless systems in a seamless manner will likely be a significant challenge.

As a result, many chip developers have thrown their hats into the dual-band ring. Atheros' AR5001X Combo WLAN solution, which is currently sampling, took home the Best of Interop grand prize at May's NetWorld+Interop tradeshow. And Atheros certainly isn't alone: Broadcom, Systemonic, Synad, Envara and Intersil have each announced a dual-band product.

Although none is shipping in volume, this impediment hasn't stopped some vendors from developing dual-mode access points. Intel, Agere and D-Link, for instance, are offering products that integrate both 11a and 11b functionality on a single access point. Rather than using dual-mode chipsets, these vendors are integrating multiple radios that share a single Ethernet backbone connection into a single box.

Is this a workable solution? In some cases, the answer is yes. If, for example, you have a conference room used by people from multiple departments and perhaps by visitors, installing one dual-mode AP
provides some flexibility to accommodate both 11a and 11b standards. And because the physical coverage area is confined to a single room, you don't really need to worry about radio propagation differences between the 2.4-GHz 11b and 5-GHz 11a radios.

For more ambitious projects, such as providing coverage throughout an office building, today's dual-mode products may not be an optimal solution. In our experience, the coverage area provided by enterprise-class 11b access points is at least twice that of 11a offerings -- especially in a traditional, walled office environment. In these cases, the advantage of an integrated AP is limited. To provide full coverage for both 11a and 11b, you'll need to add 11a access points to fill in the dead spots.

While this solution may be workable, it's still not optimal. If you are designing 11a and 11b WLANs from the ground up, you might very well find that you don't want to collocate radios anywhere. Instead, what you really want is an integrated environment that allows you to manage policy on both 11a and 11b access points from a single console. Proxim has taken such an approach, and it's one we expect to see
becoming more popular in the future.

So where do dual-mode chipsets come into play? On the client. In the future, you'll be able to purchase wireless NICs that support 11a, 11b and 11g simultaneously. Your client will connect to the AP that
provides the best possible service, so you will be able to roam transparently between APs at different frequencies. It's an appealing goal, indeed. But a number of security, performance and management
issues must be resolved before this approach becomes practical.

In the meantime, it's good to see so many vendors jumping into the dual-mode chip market. At the very least, this will result in greater competition and lower prices for everyone.


For more information: Go to vendor websites http://www.atheros.com,   http://www.broadcom.com

MobileInfo Advisory & Comments:  We think that there is a lot of potential for multi-mode chip development to allow transparent roaming between different wireless LANs and beyond that to wireless wide area networks.

Note: This news release may contain forward-looking statements. Readers should take appropriate caution in developing plans utilizing these products, services and technology architectures.  All trademarks used in this summary are the property of their respective owners.