Question

The modulation scheme commonly used for transmission from GSM mobile terminals is
1. 4-QAM
2. 16-PSK
3. Walsh-Hadamard orthogonal codes
4. Gaussian Minimum Shift Keying (GMSK)

Answer 1

Correct Answer - Option 4 : Gaussian Minimum Shift Keying (GMSK)

Concept:

• Gaussian Minimum Shift Keying, GMSK is a form of modulation based on frequency shift keying that has no phase discontinuities and provides efficient use of spectrum as well as enabling high-efficiency radio power amplifiers.
• GMSK is probably most widely associated with the 2G GSM mobile communications system where it proved to be an effective form of modulation.
• It was one of the reasons that GSM cellphones had a long battery life in view of the high efficiency that could be obtained from the RF power amplifiers.

 Application:  In view of the concept the modulation scheme commonly used for transmission from GSM mobile terminals is Gaussian Minimum Shift Keying (GMSK)