Cellular WAN Communications
Deﬁnition: A cellular WAN is a WAN technology that uses cellular radio signals to transmit network data over the cellular telephone system. Cellular-enabled computers have a cellular radio built in. Coverage can be regional, national, or global, depending on the service chosen and the capabilities of the cellular service provider. Signal ﬁdelity will vary depending on interference and the distance from a cell site.
Figure: A cellular WAN.
Cellular Transmission Technologies
Some of the cellular transmission technologies and standards in use include Code Division Multiple Access (CDMA) and the Global System for Mobile Communications (GSM). CDMA is a spread-spectrum implementation that uses the full frequency spectrum for each channel rather than assigning speciﬁc frequencies to particular users. It separates the calls using digital encoding. GSM uses time-division multiplexing (TDM), which transmits multiple calls on the same frequency by dividing each call into separate time slices.