Classification of Wireless LANs according to the transmission techniques are as follows:

• Infrared (lR) LANs: An individual cell of an IR LAN is limited to a single room, because infrared light does not penetrate opaque walls.

• Spread spectrum LANs: This type of LAN makes use of spread spectrum transmission technology. In most cases, these LANs operate in the ISM bands so that no FCC licensing is required for their use.

• Narrowband microwave: These LANs operate at microwave frequencies but do not use spread spectrum. Some of these products operate at frequencies that require FCC licensing, while others use one of the unlicensed ISM bands.