Estimation of the angle parameter in FRFT domain for FRFT-OFDM systems

A new method of calculating the angle parameter in FRFT domain based on the eigenfunction of time-varying channel is proposed in this letter for FRFT-OFDM systems. The new scheme can estimate the angle parameter in real time based on the variation of the wireless channel. The relationship between the time-variant frequency of G-eigenfunction and time is approximated by linear function. Both theoretical analysis and computer simulation demonstrate that the new scheme has a low complexity compared with the traditional method. When the number of subcarriers is 128, the new scheme can reduce the complexity by 10⁴ compared with the traditional method. This new scheme has advantage when the Doppler spread is large or the time variation of the channel is fast.