GMSK (Gaussian Minimum Shift Keying) Modulation is used in the GSM (Global System for Mobile Communications) Cellular Telephone System. The modulation is implemented in a serial form by encoding, passing a binary baseband signal through a Gaussian shaping filter, and then into a continuous phase frequency shift keyed modulator. In this way, the frequency occupancy of the modulated signal is limited. However, there is a power efficiency penalty paid for this improvement in bandwidth efficiency. The modulated GMSK signal may be conveniently demodulated using a parallel, inphase and quadrature phase MSK demodulator. Cellular telephone signal transmission performance is often degraded by multipath transmission channels. This paper considers the bit error rate performance of GMSK compared to MSK modulation when a low complexity demodulator is used. Channels are considered for which there is a combination of direct path transmission and a Rayleigh multipath transmission. A semi-analytical simulation technique is used to determine the performance. This technique is generally applicable to the bit error rate performance evaluation for any channel fading characteristic.
|Number of pages||4|
|Journal||National Conference Publication - Institution of Engineers, Australia|
|Issue number||94 /9|
|Publication status||Published - 1994|