3 Basic Types of modulation are :
1. FSK – Frequency Shift Keying.
2. ASK – Amplitude -,,-
3. PSK – Phase -,,-
All the modulation such as QPSK, GMSK etc are derieved from these basic types.
GSM uses GMSK(Gaussian Minimum Shift Keying) and WCDMA-FDD used QPSK (Quadrature Phase Shift Keying)