Systems and techniques relating to wireless communications are described. A described technique includes receiving a plurality of symbols, observing a plurality of data samples in adjacent symbols, and calculating an estimate of an integer portion of a carrier frequency offset based on a cyclic shift and a phase shift of the data samples between symbols. Calculating the estimate can include calculating sum values corresponding to respective symbol indices. Each of the sum values can be based on a summation of max values that correspond to respective data subcarrier indices, the max values being based on a maximum of an absolute value of a real component of a base value and an absolute value of an imaginary component of the base value, where the base value is based on at least one of the data samples.