A high-precision frequency offset estimation method for GMSK under the condition of signal starting position deviation

In the receiver, Accurate frequency offset estimation determines the precision of signal demodulation. In frequency-selective channels, accurately determining the starting position of a single-carrier GMSK signal is challenging, thereby affecting the accuracy of existing frequency offset estimation methods. To address this issue, a high-precision interpolation estimation method which takes Fast Fourier Transform (FFT) as a foundation is proposed. This method is a non-data-aided method that can operate without a preamble sequence. Computer simulations comparing traditional methods with the interpolation estimation method demonstrate that the proposed method achieves better results than classic method in terms of estimation accuracy when there is a deviation in the starting position judgment. Therefore, it can be used for frequency offset estimation of GMSK signals in frequency-selective channels.