ABSTRACT
Equipment that adheres to the specifications as set out in the 802.11 series of standards can use the unlicensed ISM and U-NII frequency bands only if certain rules are observed regarding transmitted power and signal modulation. For instance the original 802.11 standard was crafted for use in the ISM 2.4 GHz to 2.485 GHz band, because there was (and is) no licensing requirement so long as the transmitted power of the 802.11 equip ment is no more than one Watt and the transmitter uses a “Spread Spectrum” trans mission technique. The one Watt power restriction serves to limit the range where one radio may interfere with another. The spread spectrum requirement is intended to make the WLAN signal appear as background noise to a narrowband or narrow spectrum receiver.
