Channel estimation with Zadoff-Chu sequences in the presence of phase errors

Due to their perfect periodic autocorrelation property, Zadoff-Chu sequences are often used as stimulus signals in the measurement of radio channel responses. In this letter, the cross-correlation of a linear shift-invariant system's response to a Zadoff-Chu sequence is derived for the case that a multiplicative perturbation such as phase noise is present at its output. The perturbation signal is shown to incur a spurious discrete Fourier transform, thus degrading the correlation's peak to sidelobe ratio. The implications for the performance limits of channel measurement systems are discussed. Due to their perfect periodic autocorrelation property, Zadoff-Chu sequences are often used as stimulus signals in the measurement of radio channel responses. In this letter, the cross-correlation of a linear shift-invariant system's response to a Zadoff-Chu sequence is derived for the case that a multiplicative perturbation such as phase noise is present at its output. The implications for the performance limits of channel measurement systems are discussed.image