Standard-independent I/Q imbalance estimation and compensation scheme in OFDM direct-conversion transceivers  

OFDM直接变频接收机中通用的I/Q不平衡估计与补偿方法（英文）

作　　者：Fang-lin GU Shan WANG Wen-wu WANG 

机构地区：[1]College of Electronic Science and Engineering, National University of Defense Technology [2]Department of Electronic Engineering, University of Surrey

出　　处：《Frontiers of Information Technology & Electronic Engineering》2018年第3期388-397,共10页信息与电子工程前沿（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(No.61601477)

摘　　要：Direct-conversion transceivers are gaining increasing attention due to their low power consumption. However, they suffer from a serious in- and quadrature-phase （I/Q） imbalance problem. The I/Q imbalance can severely limit the achievable operating signal-to-noise ratio （SNR） at the receiver and, consequently, the supported constellation sizes and data rates. In this paper, we first investigate the effects of I/Q imbalance on orthogonal frequency division multiplexing （OFDM） receivers, and then propose a new I/Q imbalance compensation scheme. In the proposed method, a new statistic, which is robust against channel distortion, is used to estimate the I/Q imbalance parameters, and then the I/Q imbalance is corrected in the frequency domain. Simulations are performed to verify the effectiveness of the proposed method for I/Q imbalance compensation. The results show that the proposed I/Q imbalance compensation method can achieve bit error rate （BER） performance close to that in the ideal case without I/Q imbalance in additive white Gaussian noise （AWGN） or multipath environments. Furthermore, because no pilot information is required, this method can be applied in various standard communication systems.直接变频接收机由于具有低功耗的特点,受到广泛关注,但是它存在较严重的同相/正交(I/Q)分量不平衡问题:I/Q不平衡会恶化接收信号的信噪比,进而影响系统的传输容量和能够支持的调制方式。本文首先分析了I/Q不平衡对OFDM接收机接收信号的影响,在此基础上,定义了一个统计量用于刻画OFDM系统的I/Q不平衡特性,并提出一种实现I/Q不平衡参数估计与补偿的方法。特别地,进一步证明该统计量不受传输信道影响,因而该方法适用于高斯白噪声和多径衰落信道等不同场景。仿真结果表明,该方法可以实现对OFDM系统I/Q不平衡的准确估计与补偿,使补偿后系统的误比特率性能接近于不存在I/Q不平衡的情形。更重要的是,由于该方法不依赖于导频信号,因而可以应用于采用不同标准的OFDM系统。

关 键 词：In-and quadrature-phase（I/Q）imbalance Orthogonal frequency division multiplexing（OFDM） Standard-independent 

分 类 号：TN92[电子电信—通信与信息系统]