A method for investigating a signal in an OFDMA transmission is disclosed. The method comprises receiving the OFDMA transmission and obtaining a resource grid comprising resource elements of the transmission; determining a set of pairs of the resource elements, wherein the resource elements of the pair are disjoint; for each pair, comparing signals of the resource elements of the pair; determining a statistical test value based on the comparisons; and processing the statistical test value to obtain a desired output about the signal. A computer program for implementing the method, a receiver arrangement adapted to perform such investigation, and a communication apparatus using such receiver arrangement are also disclosed.