According to embodiments herein an ambiguity problem when compensating for frequency offset may be solved by compensating a received reference symbol according to two different frequency offset hypotheses; the estimated frequency offset and the a mirrored version of the same. Then by comparing the compensated reference symbol of the different frequency hypotheses with a target reference symbol, which is known at the receiver node 12, the frequency offset hypothesis which is most likely is used to compensate a received data symbol.