An integer time delay estimation algorithm based on Zadoff-Chu sequence in OFDM systems

This paper presents a multiple signal classification (MUSIC)-based symbol integer delay estimation algorithm for orthogonal frequency-division multiplexing (OFDM) systems using the Zadoff-Chu (ZC) sequence. By exploiting a property of the ZC sequence, this algorithm is derived from the maximum-likelihood (ML) integer delay estimation, which retains the ability of coping with an incomplete OFDM symbol with reduced complexity. It can be realized without information on channel statistic and noise. Furthermore, taking into account the inefficiency of the MUSIC-based algorithm in estimating the integer delay if the fractional delay is compensated on local ZC, we present a real-valued delay-tracking scheme that iteratively adjusts the sampling clock phase of an analog-to-digital converter (ADC). In particular, the fractional delay is tracked via the ML scheme, whereas the integer delay is estimated via the MUSIC-based algorithm. The numerical results finally confirm the efficiency and the reliability of the proposed MUSIC-based algorithm, even in the case of a small number of samples.