U.S. Robotics doubles speed of 802.11b wireless LAN

U.S. Robotics Corp. (USR) has boosted the speed of its latest range of wireless LAN products for small businesses to 22Mbps, while retaining compatibility with existing 2.4GHz systems built to the IEEE 802.11b standard, the Schaumburg, Ill., company announced April 16.

Although a faster alternative, the 54Mbps IEEE 802.11a, has been on the market for over a month, systems based on that standard are not backward-compatible because they operate in a different frequency band, 5GHz, said USR’s networking product line manager, Juan Lopez.

But USR’s 22Mbps products – a wireless access point or base station, a PC Card and a PCI adapter – are fully backward-compatible with existing 802.11b wireless LAN (WLAN) systems, Lopez said. That means that the new products can communicate with one another at 22Mbps, and slow down to 11Mbps to communicate with older products.

This backwards compatibility with other 2.4GHz equipment is important, as many of the service providers offering WLAN coverage in public spaces such as airports and hotels are already using 802.11b systems.

Older gear can still benefit from some of the other performance improvements offered by the new range. Thanks to a more powerful radio and some other tweaks, the new products offer 30 per cent greater linear range, or around 70 per cent better area coverage, than existing systems, Lopez said.

The three products use the ACX100 chip from Texas Instruments Inc. of Dallas. In addition to meeting the existing standard, the chip also supports a new modulation scheme developed by TI, called PBCC (packet binary convolutional code). It’s this that gives the products the extra kick: even at lower speeds, PBCC provides better performance at greater distances, and it can also work at 22Mbps.

USR doesn’t expect to be alone for long in using the ACX100 chip.

“I suspect you will see more 22Mbps products launched as a result of our announcement,” Lopez said. Other announcements could appear in a matter of weeks, he said.

For now, TI is the only supporter of the 22Mbps PBCC-22 technology, which it had hoped to get adopted into yet another high-speed WLAN standard under discussion at the IEEE, 802.11g. However, the standards committee voted to use a rival modulation scheme, OFDM (orthogonal frequency division multiplexing) proposed by Intersil Corp. of Irvine, Calif., according to TI and Intersil. TI’s PBCC-22 remains as an optional part of the still-unfinished standard, which means products will not have to support it.

Although no finished standard exists for the 22Mbps WLANs, Lopez is confident that USR’s systems will interoperate with those of its competitors when they arrive on the market.

“They will all talk to each other at 22Mbps and at all downshift speeds, since they all use the TI ACX100 chipset,” he said.

The market would probably appreciate that. One of the driving forces of interoperability in wireless networking, the Wireless Ethernet Compatibility Alliance (WECA), won’t be testing equipment using the new devices for compatibility at the higher speed, according to spokesman Brian Grimm.

“WECA has decided only to test the mandatory components of the IEEE standard,” he said.

WECA typically sets a minimum bar of two chipset providers and four implementations before it will test any technology enhancements that come to market, he said.

WLANs conforming to the proposed 802.11g will run at up to 54Mbps, just like 802.11a – but unlike 802.11a, they will be backwards-compatible with existing products, because 802.11g uses the same 2.4GHz frequency band as 802.11b.

TI has said that when it begins offering 54Mbps 802.11g devices around the middle of this year, they will also support its PBCC-22 modulation scheme.

That means, said Lopez, that USR’s 22Mbps products will be able to operate with its future 802.11g products at 22Mbps, and both will be able to operate with all existing 802.11b products at 11Mbps.

The average user at home will scarcely notice the difference, as cable or DSL connections typically max out at 1Mbps or 2Mbps. However, in crowded offices or conference theatres where dozens of users are trying to connect over the same wireless base station, the benefits of the newer WLAN technologies will really be felt.

USR’s 22Mbps products will all be available in June, the company said. The 22Mbps Wireless Access Point will have a suggested retail price of US$199.99, the 22Mbps Wireless Access PC Card US$99.99 and the 22Mbps Wireless Access PCI Adapter Card US$119.99.

That’s a premium of around US$20 over 11Mbps cards already on the market, Lopez said, or in some cases even the same price, but for that “you’re not only getting faster speed, you’re getting a stronger radio, better range,” he said.