Automatic frequency correction for mobile radio receivers

A receiving unit for mobile radio transmission, comprising:

• a channel estimator for determining channel coefficients h0, . . . hL for modeling a transmission channel, where L is a channel memory;
• a frequency estimation unit connected to said channel estimator, said frequency estimation unit determining a sequence of phase differences p(k) between received data symbols x(k) and frequency-error-free data symbols y(k) derived from a training sequence and determining a frequency shift Δω of the received data symbols x(k) from the sequence of phase differences p(k), said frequency estimation unit performing in a case where a sequence value of the sequence of phase differences p(k) deviates from a mean value pmean of the sequence of phase differences by more than a predetermined threshold value, a smoothing of the sequence of phase differences p(k) by replacing the sequence value with a linear combination of a preceding sequence value p(k−1) and of a subsequent sequence value p(k+1), said frequency estimation unit further performing a linear regression analysis of the sequence of phase differences p(k) plotted against time and determining the frequency shift Δω from a slope of the linear regression analysis;
• a frequency correction unit for correcting a phase of the received data symbols x(k) in dependence on the frequency shift Δω resulting in phase-corrected data symbols {overscore (x)}(k), said frequency correction unit connected to said frequency estimation unit;
• and
• a channel equalizer for equalizing the phase-corrected data symbols {overscore (x)}(k) using the channel coefficients h0, . . . hL determined by said channel estimator, said channel equalizer connected to said channel estimator and to said frequency correction unit.