(from the point of view of using multiplexing and spread spectrum)
- First generation: FDMA (FDM Access), where each cell supports a number of channels of equal bandwidth, and each cellphone uses two channels (one up and another down).
- Second generation in two groups:
- TDMA (TDM Access): GSM (Global System for Mobile) and D-AMPS (IS-136). GSM is basically circuit-switching based, but GPRS (general packet radio service) was added to support data: SGSN (serving GPRS support node) and GSSN (gateway GPRS support node).
- CDMA (CDM Access): CDMA comply with IS-95 (also known as cdmaOne). Uses DSSS combined with CDM. Designed by Qualcomm Inc, which holds IP over CDMA.