Low-Complexity Mean-Delay Estimation for OFDM Systems

In this paper, we propose two simple orthogonal frequency-division multiplexing (OFDM) mean-delay estimation schemes, i.e., a channel impulse response (CIR)-based scheme and a differential scheme, which are applicable for adaptive algorithms including improved channel estimation and fast handover. Instead of time-domain processing which requires additional inverse fast Fourier transform (IFFT), the mean delay can be obtained in the proposed CIR-based scheme using the estimated frequency-domain CIR. When cell-specific preamble sequences are employed, the mean delay can also be estimated without CIR estimation in the proposed differential scheme using cross correlation of differentially correlated received signals, enabling further complexity reduction and performance improvement when the CIR estimation is not sufficiently accurate. The performance of the proposed schemes is verified by computer simulation.