What modulation scheme is used in 3G?

LTE uses the popular orthogonal frequency division multiplex (OFDM) modulation scheme. It provides the essential spectral efficiency to achieve high data rates but also permits multiple users to share a common channel. OFDM divides a given channel into many narrower subcarriers.8 Oca 2013

Both QAM and QPSK are modulation techniques used in IEEE 802.11 (Wi-Fi*), IEEE 802.16 (WiMAX*) and 3G (WCDMA/HSDPA) wireless technologies. The modulated signals are then demodulated at the receiver where the original digital message can be recovered.

Then comes the 2G technology which uses digital signal transmission technology with time division multiplexing technique (TDMA) and code division multiple access technique (CDMA) .

The first generation mobile systems are based on analog technology. The first technology uses frequency modulation (FM) and frequency division duplexing (FDD), frequency division multiple access (FDMA) . The common signalling channels were used in first generation cellular systems.