A method of identifying, by a receiver of Orthogonal Frequency Division Multiplexing, OFDM, signals transmitted via a channel of a wireless communications system, a sequence of received reference symbols transmitted at different sub-carriers as one of a number of known complex orthogonal sequences, comprising the steps of: • receiving said sequence of received reference symbols serially over a given time interval; • receiving, in addition to said sequence of received reference symbols, at least one known signal at a time instant (t) in said given time interval; wherein the method of identifying is characterized by: • dividing said sequence of received reference symbols into a first part comprising reference symbols received before said time instant (t) and a second part comprising reference symbols received after said time instant (t), such that reference symbols in the first part are distorted by a phase shift having a first sign, and reference symbols in the second part are distorted by a phase shift having a second sign that is opposite to the first sign; • calculating from said sequence of received reference symbols a modified received sequence by replacing at least some of the received reference symbols from one of said parts by their complex conjugate values; • calculating for each of said known complex orthogonal sequences a modified known sequence by replacing, by their complex conjugate values, the reference symbol values that are to be correlated with the replaced received reference symbol values; • correlating the modified received sequence with each one of the modified known sequences to obtain a correlation result for each of said known sequences; and • identifying the sequence of received signals as the known orthogonal sequence having the largest correlation result. • receiving said sequence of received reference symbols serially over a given time interval; • receiving, in addition to said sequence of received reference symbols, at least one known signal at a time instant (t) in said given time interval; • dividing said sequence of received reference symbols into a first part comprising reference symbols received before said time instant (t) and a second part comprising reference symbols received after said time instant (t), such that reference symbols in the first part are distorted by a phase shift having a first sign, and reference symbols in the second part are distorted by a phase shift having a second sign that is opposite to the first sign; • calculating from said sequence of received reference symbols a modified received sequence by replacing at least some of the received reference symbols from one of said parts by their complex conjugate values; • calculating for each of said known complex orthogonal sequences a modified known sequence by replacing, by their complex conjugate values, the reference symbol values that are to be correlated with the replaced received reference symbol values; • correlating the modified received sequence with each one of the modified known sequences to obtain a correlation result for each of said known sequences; and • identifying the sequence of received signals as the known orthogonal sequence having the largest correlation result.