First Mile Access Networks and Enabling Technologies

WLAN Device

The most common WLAN device is a PC adapted with a PCMCIA card. This is suitable for direct connection to a PC or a laptop or any other application. The WLAN card is divided into two major sections: the PHY layer and the MAC processing area (see Figure 4-9). An antenna receives the 802.11b signal, and this is often sent through frequency doublers (squaring loops) so that the signal can be properly extracted from the carrier. If DSSS is used, a local synthesizer generates the code word and subsequently demodulates the bit stream. Typically, intermediate frequency gain modulation is used for extracting the bit stream. In such a case, a local frequency generator generates the frequency (carrier), and it is mixed with the incoming signal. ...