WLAN vendors debate 802.11g spec, coexistence issues

WLAN vendors debate 802.11g spec, coexistence issues
Though security has been getting the lion's share of attention in discussions of wireless local-area and personal-area networking, it is, paradoxically, the easiest problem to fix through basic attention to keys and virtual private networking. But three other vexing issues facing designers who plan to incorporate wireless LAN and PAN connectivity — the IEEE-802.11g specification, the coexistence of LANs and PANs, and power consumption — are the subjects on the minds of contributors to this week's InFocus section.

Coexistence has long been a thorn in the side of WLAN-/WPAN designers, and Jim Lansford of Mobilian (Hillsboro, Ore.), chair of the IEEE Coexistence Study Group, does a good job of laying out the issues, real and imagined. Meanwhile, power comes to the forefront as WLANs migrate to portable applications, locking Bluetooth into the cable-replacement category.

Of the three major sticking points, however, none is as immersed in controversy and politics as the IEEE-802.11g effort. Nor has any been the cause of as much confusion and rancor on the part of OEMs, IT managers and designers hungry for a clear-cut upward-migration path.

The final .11g draft proposal, which is described by Jim Zyren of Intersil (Palm Bay, Fla.), seems technically sound and is as much a tribute to the IEEE's democratic principles as to the organization's persistence. The proposal offers a solid migration path from .11b to .11a wireless networking, while providing higher data rates in the 2.45-GHz band,with theoretically greater reach than .11a. The reach issue is a contentious one, and would benefit greatly from a standard, real-world test bed implemented by a third party such as the University of New Hampshire, in which all WLAN implementations could be compared.

The issues swirling around .11g have more to do with market timing. With .11b deployments skyrocketing and .11a chips coming on the market now, the question of "why 802.11g?" remains — especially when one considers that the standard won't be finalized until late this year at the earliest.

Some analysts, such as Farpoint Group's Craig Mathias, are adamant that the .11g effort is going nowhere and is just causing confusion for IT managers and OEMs. Others, such as Stellcom CTO Larry Mittag, take the argument against .11g a step further. Mittag has argued that IEEE 802.11g is simply a delaying tactic to allow its proponents to catch up with .11a chip set deployments. That's sure to ruffle a few feathers.

However, as the debates go on, developments are taking place on a broader scale that will benefit all concerned. Cellular operators are realizing that it's time to get in on the WLAN public hot-spot game. Their goal is to augment their voice coverage with high-speed data while allowing seamless migration from one network type to another — with single billing for all.

Later, when wireless voice-over-Internet Protocol becomes a reality (thanks to the enterprising efforts of Symbol Technologies and others), the WLANs can be used to carry voice, thereby taking the load off urban basestations. To this end, VoiceStream has picked up MobileStar's assets and almost every Scandinavian operator has some sort of wireless WAN/LAN IP mobility scheme in the works.

On the solutions side, Airify (Mountain View, Calif.) recently announced it has entered into a strategic partnership with Greece's Helic to co-develop a multiband chip set that supports both the GSM/GPRS Class 12 and 802.11 WLAN standards. And Airify and Helic are not alone. Almost every RF-IC manufacturer professes to be working on a similar, two-chip solution, with plans to migrate to a single chip as the technology gets refined and the market develops.

So, while the WLAN vendors debate the pros and cons of their individual solutions, the operators' sewing needles are quietly knitting together the capacity- and data-rate-starved wide-area networks with the bandwidth-heavy public WLANs. Together with the myriad IP-mobility software vendors, the whole of the wireless-connectivity world will soon become much, much greater than the individual parts. n