In some examples, an apparatus includes a transmitter configured to apply input data as a frequency-domain data sequence to modulate a set of subcarriers, and separate the frequency-domain data sequence into a first subsequence of elements and a second subsequence of elements. A first conjugate symmetric subsequence that is based on inserting a zero value into the first subsequence is formed, and a second conjugate symmetric subsequence that is based on inserting a zero value into the second subsequence is formed, where the zero values are inserted at different positions in the first and second subsequences. A time-domain sequence comprising a first component that is a function of the first conjugate symmetric subsequence, and a second component that is a function of the second conjugate symmetric subsequence is generated.