802.11G: The next step in wireless LAN deployment

There`s a new WiFi standard on the block that has more muscle than its 802.11b and 802.11a siblings. Graham Vorster, chief technology officer at Duxbury Networking, takes a closer look at the latest addition to the WiFi standard - 802.11g, discussing the obvious benefits and the not-so-obvious drawbacks.

Wireless LAN shoppers take note: the newly ratified 802.11g WiFi standard is fast, affordable and compatible with its popular but slower 802.11b sibling. For the past year of so, commercial 11.g products have been plagued by controversy due to a number of vendors releasing "802.11g-based" products before the IEEE ratified the final version of the standard in June this year.

However, now the 11g specifications are legitimate and already the WiFi Alliance - a vendor consortium that certifies interoperability among different wireless LANs - has announced that a number of products have successfully completed WiFi certification testing.

Certified products include offerings from Proxim and Sun Microsystems` Texas Instruments.

Proxim, for example, has integrated 802.11g into its existing product line, including client cards, and start shipments. The company currently offers several models of its Orinoco AP-2000, which is designed to give corporate users flexibility in deploying any combination of 802.11b, 802.11g and 802.11a access points.

In addition, a recent Dell`Oro Group report comments that the market for IEEE 802.11 wireless LAN equipment continues to grow, driven in part by users embracing 802.11g.

"Revenue from 802.11g products grew 48 percent sequentially and made up 24% of the total market revenue," says Dell`Oro.

OK, now that we`ve reflected on 802.11g`s history and growth, let`s look at the more technical aspects of this wireless standard.

802.11g is essentially an "amendment" - or improvement depending on you interpretation - to the original 802.11b, which itself is an amendment to the original 802.11 standard.

This standard runs in the 2.4GHz range at a maximum theoretical speed of 54Mbps, although early lab tests estimate speeds to be more around 22Mbps 23Mbps, and has a range of approximately 50m when communicating through interior walls.

802.11g wireless LANs use the same modulation technique - orthogonal frequency division multiplexing (OFDM) - as 802.11a, the 54Mbps standard that runs in the 5GHz band.

OFDM transmits large amounts of data over a radio wave by splitting a signal into multiple small sub-signals and transmitting them simultaneously at different frequencies. Due to the multi-frequency nature of OFDM, 802.11g and 802.11a networks offer high data rates and reliability even when experiencing severe signal distortion due to multipath.

The reality is that as with most technologies, 802.11g does have drawbacks that wireless LAN implementers must take into consideration.

For one, 802.11g-based devices use slower modulation techniques when transmitting traffic in order for 802.11b devices to understand them .This subsequently adds to transmission times and prevents 802.11g networks from realising their maximum throughput potential.

Also, for 802.11g networks to be backwards compatible with 802.11b devices, both must use the 2.4GHz frequency.

In the US, for example, there are only three available non-overlapping channels that can be used for data transmission and 802.11g environments.

This is by no means a lot - especially when you consider that radio waves propagate in three dimensions.

Despite the drawbacks, 802.11g should play an active role in your wireless LAN environment.

The bottom line is, it improves performance and protects your 802.11b network investment.

Indeed, when all the 802.11b devices are gone, your 802.11g network will no longer be anchored by backward compatibility, but will reach its full potential with a little additional investment.

So, if you`re planning to buy WiFi equipment soon, invest in 802.11g - the risk is minimal and the future benefits clear.