Title: A new time-frequency synchronisation algorithm based on preamble sequence in OFDM system

Authors: Weimin Hou; Yan Wang; Yanli Hou

Addresses: School of Information Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China ' School of Information Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China ' School of Information Science and Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei, China

Abstract: Aiming at the problems of high computational complexity in the timing synchronisation phase and poor frequency offset estimation performance of existing time-frequency synchronisation algorithms, this paper proposes an improved time-frequency synchronisation algorithm based on preamble sequence for OFDM systems. The preamble sequence is designed by using the property that the cross-correlation value of the Constant Amplitude Zero Auto Correlation (CAZAC) sequence with different root values is close to zero. Based on its features, a timing metric function and the frequency offset estimation function are designed. The frequency offset estimation function is used to obtain the coarse fractional frequency offset, and the fine fractional frequency offset is obtained by combining Cyclic Prefix (CP) and Cyclic Suffix (CS). Then, the time domain sliding correlation between receiving sequence and the local preamble sequence is used to estimate the integer frequency offset. The results indicate that the proposed method has better synchronisation capability than existing algorithms.

Keywords: OFDM system; timing synchronisation; frequency offset estimation; preamble sequence; CAZAC sequence.

DOI: 10.1504/IJWMC.2025.147588

International Journal of Wireless and Mobile Computing, 2025 Vol.29 No.1, pp.19 - 30

Received: 04 Jul 2022
Received in revised form: 10 Jun 2023
Accepted: 21 Sep 2023
Published online: 24 Jul 2025 *

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