|
GMSK (Gaussian Minimum Shift Keying) is a special form of (continuous phase) frequency shift keying (FSK). GMSK achieves an approximately optimum compromise between the amounts of power out of the desired bandwidth of the modulated carrier signal and still allows the binary data to be accurately demodulated from the received radio signal in the presence of noise.
The advantages of using GMSK are it increases spectral efficiency with sharper cutoff and excellent power efficiency due to constant envelope. Therefore it is widely used in 2nd generation digital cellular phone such as GSM system. Two properties of the GMSK modulation scheme will be investigated in this project:
(a)Spectral Efficiency
To investigate the high spectral efficiency properties of GMSK, we will develop a computer simulation and modeling of the spectrum of GMSK as a plot of power spectrum as a function of frequency. The result will be compared to the standard BPSK and QPSK modulation schemes.
(b)Quantification of Error-free Demodulation
To quantify error-free demodulation of the binary data in the presence of noise, we will develop a computer simulation and modeling of GMSK as a plot of bit error rate (BER) as a function of signal over noise ratio. The result will be compared to the standard BPSK and QPSK modulation schemes.
|
|
