重叠滤波多音系统的频偏性能分析及优化

Frequency Offset Performance Analysis and Optimization of Overlapped Filtered Multitone Systems

重叠滤波多音(O-FMT)是针对滤波多音(FMT)系统频谱利用率低的缺点而根据超奈奎斯特(FTN)概念引入子载波重叠得到的方案。鉴于O-FMT系统在频偏环境下的性能缺陷,理论分析了频偏对系统信号各部分的影响,比较了O-FMT与正交频分复用(OFDM)系统的抗频偏性能。针对频偏性能优化问题,提出了基于最佳线性无偏估计(BLUE)的改进盲估计算法,设计了基于频域滤波器系数的内嵌结构进行频偏补偿。仿真实验表明,O-FMT相比OFDM具有更好的抗频偏能力,改进的盲估计算法估计值精度更高,抗干扰、抗衰落能力更强,设计的频偏补偿结构可以使系统获得更好的性能。

Overlapped Filtered Multitone(O-FMT)is proposed by introducing controlled overlapped sub-carriers according to the Faster-than-Nyquist(FTN)concept,which aimes at improving the spectral efficiency of Filtered Multitone(FMT)systems.In view of the performance defects of O-FMT over the frequency offset scene,the influence of frequency offset on each part of the system signal is analyzed theoretically and the anti-frequency offset performance between O-FMT and OFDM is compared.For the optimized problem of frequency offset performance,the improved blind estimation algorithm based on the Best Linear Unbiased Estimation(BLUE)is proposed,and an embedded structure based on filter coefficients in frequency domain is designed for frequency offset compensation.Simulation results show that O-FMT has better anti-frequency offset capability than OFDM system.Compared with the traditional algorithm,the improved blind estimation algorithm has higher accuracy,anti-interference and anti-fading ability.The designed frequency offset compensation structure makes the system get better performance.