【摘要】 研究多频带正交频分复用超宽带(MB-OFDM UWB)接收机的IQ不平衡和载波频偏对系统性能的影响,提出一种时频域结合的IQ不平衡和载波频偏参数估计和补偿方法.接收机利用同一频带上的3个重复前导符号在时域作载波频偏估计和IQ不平衡估计,对数据单元预补偿;接收机利用数据单元的导频在频域进行残余IQ不平衡的逐段估计和补偿.仿真结果表明,这种时频域结合的参数估计和补偿方法能够克服IQ不平衡和载波频偏所带来的影响,当归一化CFO设定为40PPM时,可以实现幅度不平衡因子g=1.1和相位不平衡因子θ=10°以内的有效补偿.所设计方法具有较高的精度,并且适用于长符号MB-OFDM UWB系统.更多还原

【Abstract】 Studying the influence of IQ imbalance and carrier frequency offset(CFO)on the system performance in multi-band orthogonal frequency division multiplexing ultra wideband(MB-OFDM UWB)receiver,ajoint estimation and compensation method of IQ imbalance and CFO was proposed in time domain and frequency domain.First,three repeat preambles were used to estimate and compensate the CFO and IQ imbalance in time domain.Second,pilots of data unit were used to estimate and compensate the residual IQ imbalance in frequency domain.The simulation results show that the method can overcome the influence of IQ imbalance and CFO,when CFO is 40 PPM,IQ imbalance factor is g=1.1 andθ=10°,the IQ imbalance and CFO can be compensated.The design method is of high accuracy,and is suitable for long symbol MB-OFDM UWB system.更多还原