Modulation GMSK with I/Q

1. What is GMSK in wireless communication?
2. What is the need of Gaussian filter in GMSK?
3. What is GMSK used for?
4. What is the difference between MSK and GMSK?

What is GMSK in wireless communication?

Gaussian minimum shift keying (GMSK) is a form of frequency shift keying (FSK) used in GSM systems. The tone frequencies are separated by exactly half the bit rate. It has high spectral efficiency.

What is the need of Gaussian filter in GMSK?

The Gaussian Minimum Shift Keying (GMSK) modulation is a modified version of the Minimum Shift Keying (MSK) modulation where the phase is further filtered through a Gaussian filter to smooth the transitions from one point to the next in the constellation.

What is GMSK used for?

GMSK is most notably used in the Global System for Mobile Communications (GSM), in Bluetooth, in satellite communications, and Automatic Identification System (AIS) for maritime navigation.

What is the difference between MSK and GMSK?

GMSK is the derivative of MSK modulation scheme and MSK is derived from Offset QPSK modulation. In MSK modulation scheme instead of rectangular pulse wave; half cycle sine wave is used. Frequency of logical zero and logical one differs by half of data rate. Modulation index is 0.5 here.