Techniques, systems and apparatus are described for estimating a frequency shift. An apparatus for estimating a frequency shift includes a fast Fourier transform unit to transform a signal of a time domain into a frequency domain and output fast Fourier transform symbols. A complex conjugate multiplier is in communication with the fast Fourier transform unit and output a continual pilot correlation between every two of the fast Fourier transform symbols output from the fast Fourier transform unit. A correlation memory unit is in communication with the complex conjugate multiplier to store the continual pilot correlation output from the complex conjugate multiplier. An adder is in communication with the correlation memory unit to add the continual pilot correlations stored in the correlation memory unit and generate an output signal comprising estimated values of the frequency shift.