DFT-S-OFDM系统发射端IQ失衡的广义迭代均衡器

Widely Turbo Equalizer for DFT-S-OFDM Systems with Transmitter IQ Imbalance

该文研究了离散傅里叶变换扩展正交频分复用(DFT-S-OFDM)系统的零中频(ZIF)射频(RF)前端非理想特性导致同相与正交分路失衡(IQI)干扰时,改进的频域迭代均衡技术。利用广义正交原理和迭代均衡原理,本文推导了频域广义线性最小均方误差(WLMMSE)迭代均衡器,并通过矩阵变换降低其复杂度。仿真结果表明,在DFT-S-OFDM系统发射端IQ失衡的情况下,所提出的迭代均衡算法性能显著优于常规迭代均衡算法,而复杂度只有少量提高。

In this paper the frequency turbo equalization is investigated for Discrete Fourier Transformation Spread Orthogonal Frequency Division Multiplexing（DFT-S-OFDM） systems with transmitter In-phase and Quadrature Imbalance（IQI） interference caused by imperfect Zero Intermediate Frequency（ZIF） Radio Frequency（RF） front ends.Based on the widely orthogonal principle and the turbo equalization principle,the frequency Widely Linear Minimum Mean Square Error（WLMMSE） turbo equalizer for DFT-S-OFDM systems with transmitter IQI is derived.Matrix transformations are employed to further reduce the complexity.Simulation results confirm that with transmitter IQI,the proposed turbo equalizer significantly outperforms the conventional counterpart turbo equalizer with only slightly increasing of the computation complexity.