认知OFDM系统旁瓣抑制新方法

针对认知正交频分复用（OFDM）系统带外辐射（OBR）严重问题，在研究基于功率谱密度的主动干扰消除算法（PSD-AIC）模型的基础上，提出了动态PSD-AIC的方法，通过对每一子载波位置OBR的计算，比较选择出OBR取值最小处，作为对消子载波的最优位置，显著改善了系统对OBR的抑制性能（增大约10dB）。对比分析了算法的计算开销，研究了设计参数对OBR的影响，提出了实际应用时的参数选择基准。仿真结果和理论分析表明，动态PSD-AIC方法可以显著减小带外干扰。与PSD-AIC方法相比，旁瓣抑制深度可增加约10dB；与传统AIC方法相比，只需相似计算量，干扰抑制性能便可明显增加。

A novel sidelobe suppression method for cognitive OFDM systems

In view of the severe out-of-band radiation(OBR) problem in cognitive orthogonal frequency division multiplexing(OFDM) systems,the model of power spectral density based active interference cancellation(PSD-AIC) algorithm is analyzed and a technique of dynamic PSD-AIC is proposed. By calculating the OBR of each subcarrier,the minimum is chosen as optimal. The new method considerably improves the suppression of OBR of about 10 dB. The computational cost is compared and analyzed. Meanwhile,the influence of design parameters on OBR is studied. Simulation results and theoretical analysis show that the technique of dynamic PSD-AIC can significantly reduce out-of-band influence. In comparison with traditional AIC,there is no dramatical increase in complexity.