A non-intrusive estimation of the carrier frequency in GMSK signals

The paper presents an efficient technique for evaluating the carrier frequency in GMSK communication systems. This technique operates in a non-intrusive way and is based on measurement of the frequency shift from the expected value. It utilizes the Learning Vector Quantisation neural network based demodulator for reconstructing the transmitted phase. From this and the received phase the mean value of the frequency shift is estimated. The technique does not require a high frequency sampling rate because the base-band signal is processed. Tests performed on experimental GSMK signals show that the technique is quite attractive and is also fast and more accurate compared to others