Figure 3DSSS with CDMA Source: WLANA 65 2.2.2 NARROWBAND MICROWAVE LANs This involves the use of relatively narrow bandwidth microwave radio frequency band to transmit signals. Most of the available narrowband microwave LAN products operate at frequencies that require FCC licensing - uses the 18.82 to GHz of the radio spectrum. It has two bandwidth, they are • Licensed Narrowband RFA typical narrowband scheme makes use of cell configuration in which adjacent cells use nonoverlapping frequency bands within the overall 18 GHz band. One advantage of licensed narrowband LAN is that it guarantees interference-free communication. Also, all communications are encrypted to avoid eavesdropping.