July 19, 1999

Various Wireless LAN Options

By Caryn Gillooly

ireless LANs have been available for more than a decade. The early products often used infrared technology similar to that used by a television set's remote control.

Today, however, the majority of wireless LAN products use radio frequencies to transmit information. Most products transmit information using spread spectrum, or across multiple frequencies, in the 2.4-GHz range, which is licensed by the FCC and is specified by the IEEE 802.11 wireless LAN standard.

Current products use either frequency-hopping spread spectrum technology or direct-sequence spread spectrum technology. The two approaches have become the basis for somewhat of a philosophical war and are often the differentiator between vendors' products.

Proxim Inc., for example, offers frequency-hopping products that may not offer the fastest throughput but are ideal for home use, which the company plans to target with its new Symphony wireless LAN product line. By contrast, Aironet Wireless Communications Inc. offers direct-sequence products that analysts say send information more efficiently, which means at higher throughput rates. Analysts say direct-sequence will likely become the preferred transmission mode for businesses choosing wireless LAN products.

One company, RadioLAN Inc., uses narrow-band single-frequency transmission in the 5.8-GHz range. This frequency band isn't licensed by the FCC for any specific use, which lets the company offer 10-Mbps rates before such speeds are offered by vendors staying within the licensed 2.4-GHz range. Until recently, the 2.4-GHz band was limited to a maximum transmission rate of 2 Mbps. However, standards organizations are moving to approve 11-Mbps throughput rates within the 2.4-GHz band, which would make faster wireless LANs available from a wider variety of vendors.

Return to main page, "Wireless LANs Set To Take Off"

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