正交频分复用(OFDM)系统中的非理想特性对系统性能影响很大,针对非理想特性中的两个主要部分:同相支路和正交支路(IQ)间的不平衡及相位噪声,提出了一种新的相位噪声和IQ不平衡联合估计算法。该算法首先由一个训练符号利用简单的最小二乘(LS)准则在频域估计出IQ不平衡和相位噪声的复合参数,并从中分离得到IQ不平衡估计值,然后利用估计出的IQ不平衡参数在时域对数据符号做IQ不平衡补偿,最后对IQ不平衡补偿后的数据在频域做相位噪声公共相位误差(CPE)和子载波间干扰(ICI)的估计和补偿。理论分析和仿真结果表明,该算法能简单有效的补偿IQ不平衡和相位噪声带来的性能损失。
The non-ideal character in 0FDM systems has a huge impact on system performance, and aiming at the two main parts of non-ideal character, i. e. , IQ imbalance and phase noise, a novel phase noise and IQ imbalance joint estimation algorithm is proposed. Firstly, by one training symbol, the compound parameters of IQ imbalance and phase noise are estimated in frequency domain in accordance with LS criteria, and then IQ imbalance parameters are separated to compensate IQ imbalance on data symbols in time domain, and finally phase noise estimation and compensation of CPE and ICI are done on IQ imbalance data after compensation in frequency domain Theoretical analysis and simulation results indicate that this algorithm could effectively compensate the performance loss caused by IQ imbalance and phase noise.