Abstract: According to the situation that non-ideal factors of analog front-end in wideband Orthogonal Frequency Division Multiplexing（OFDM） system exit at the same time, this paper presents an estimation algorithm of Carrier Frequency Offset（CFO） with presence of I/Q mismatch（I/Q-M）. The scheme utilizes 3 consecutive preambles and processes them at frequency domain to acquire 2 different estimation algorithms and the carrier frequency offset is divided into two scopes using different algorithms respectively on the basis of I/Q mismatch degree and noise. Simulation results show that the proposed scheme is able to estimate the offset accurately to both Frequency Independent（F-I） and Frequency Dependent（F-D） I/Q mismatch.

Key words: Orthogonal Frequency Division Multiplexing（OFDM）, wideband system, Carrier Frequency Offset（CFO）, I/Q mismatch

摘要： 针对正交频分复用系统中非理想前端因素同时存在的情况，提出一种在I/Q失配存在的条件下载波频偏的估计算法。该算法利用三个连续的前导符在频域推导出两种不同估计算法，根据噪声及I/Q失配程度将载波频偏划分为两区间分别选用不同算法进行估计。仿真结果表明，该算法在频率相关和频率无关I/Q失配条件下均能有效地准确估计载波频偏。

关键词: 正交频分复用, 宽带系统, 载波频偏估计, I/Q失配