A method of operating a communication system, comprising: receiving a first data stream; mapping the first data stream into a first series of quadrature amplitude modulated, QAM, symbols; producing, by a first pseudorandom noise generator in an apparatus, a first pseudorandom noise, PN, sequence; mapping, by a first symbol mapper circuit in the apparatus, a plurality of bits of the first PN sequence to a first phase pilot symbol; inserting, by a first phase pilot symbol insertion circuit in the apparatus, the first phase pilot symbol into the first series of QAM symbols including a plurality of phase pilot blocks, the first phase pilot symbol being inserted into each phase pilot block; converting, by a first discrete Fourier transform, DFT, circuit in the apparatus, the first data stream to a first frequency-domain data stream by a discrete Fourier transform, DFT, having N DFT0 size after the step of inserting, wherein N DFT0 is a positive integer; receiving a second data stream in parallel with the first data stream; mapping the second data stream into a second series of QAM symbols in parallel with mapping the first data stream into the first series of QAM symbols; producing, by a second pseudorandom noise generator in the apparatus, a second pseudorandom noise PN sequence; mapping, by a second symbol mapper circuit in the apparatus, a plurality of bits of the second PN sequence to a second phase pilot symbol; inserting, by a second phase pilot symbol insertion circuit in the apparatus, the second phase pilot symbol into the second series of QAM symbols including a plurality of phase pilot blocks, the second phase pilot symbol being inserted into each phase pilot block; converting, by a second DFT circuit in the apparatus, the second data stream to a second frequency-domain data stream by a discrete Fourier transform, DFT, having N DFT1 size, after the step of inserting, wherein N DFT1 is a positive integer; and mapping, by a subcarrier mapping circuit in the apparatus, the first and second frequency-domain data streams to respective first and second subcarriers; converting, by an inverse discrete Fourier transform, IDFT, circuit in the apparatus, the first subcarriers and second subcarriers to a first time-domain data stream by an inverse discrete Fourier transform, IDFT, having size N FFT, where N FFT is a positive integer; and further comprising adding a cyclic prefix to the time-domain data stream. receiving a first data stream; mapping the first data stream into a first series of quadrature amplitude modulated, QAM, symbols; producing, by a first pseudorandom noise generator in an apparatus, a first pseudorandom noise, PN, sequence; mapping, by a first symbol mapper circuit in the apparatus, a plurality of bits of the first PN sequence to a first phase pilot symbol; inserting, by a first phase pilot symbol insertion circuit in the apparatus, the first phase pilot symbol into the first series of QAM symbols including a plurality of phase pilot blocks, the first phase pilot symbol being inserted into each phase pilot block; converting, by a first discrete Fourier transform, DFT, circuit in the apparatus, the first data stream to a first frequency-domain data stream by a discrete Fourier transform, DFT, having N DFT0 size after the step of inserting, wherein N DFT0 is a positive integer; receiving a second data stream in parallel with the first data stream; mapping the second data stream into a second series of QAM symbols in parallel with mapping the first data stream into the first series of QAM symbols; producing, by a second pseudorandom noise generator in the apparatus, a second pseudorandom noise PN sequence; mapping, by a second symbol mapper circuit in the apparatus, a plurality of bits of the second PN sequence to a second phase pilot symbol; inserting, by a second phase pilot symbol insertion circuit in the apparatus, the second phase pilot symbol into the second series of QAM symbols including a plurality of phase pilot blocks, the second phase pilot symbol being inserted into each phase pilot block; converting, by a second DFT circuit in the apparatus, the second data stream to a second frequency-domain data stream by a discrete Fourier transform, DFT, having N DFT1 size, after the step of inserting, wherein N DFT1 is a positive integer; and mapping, by a subcarrier mapping circuit in the apparatus, the first and second frequency-domain data streams to respective first and second subcarriers; converting, by an inverse discrete Fourier transform, IDFT, circuit in the apparatus, the first subcarriers and second subcarriers to a first time-domain data stream by an inverse discrete Fourier transform, IDFT, having size N FFT, where N FFT is a positive integer; and further comprising adding a cyclic prefix to the time-domain data stream.