一种改进的宽带自适应波束形成器

An Improved Adaptive Wideband Beamformer

针对宽带空时自适应波束形成中,增加抽头延迟线(TDL)数目导致空时维度增大从而计算量增加的问题,提出了一种改进的宽带自适应波束形成器。此改进结构基于Frost空时自适应处理的线性约束最小方差(LCMV)准则,抽头数目为空时Frost结构的一半,将阵列分为两类通道,奇通道和偶通道,奇通道选择抽头奇数阶时延间隔,偶通道选择抽头偶数阶时延间隔,在保证具有相同干扰性能基础上可大大降低空时维度与运算量。在理论上进行了干扰抑制性能分析,证明了改进结构与Frost空时结构干扰抑制之后的输出期望功率相同,亦证明了在阵元数目满足大于等于4的偶数时,其抗宽带噪声干扰后干扰剩余功率也与Frost空时结构的相同,影响两种结构输出信干噪比(SINR)的只有噪声部分。最后对比仿真证实了此改进结构的性能与理论分析的正确性与一致性。此结构可应用于宽带空时自适应处理中,具有一定的高效性。

A high efficient adaptive wideband beamformer with half tap number is proposed.This structure can reduce the calculation for wideband array beamforming,which is caused by the increase of tapped-delay-line.This beamformer is based on Frost’s linear constraint minimum variance(LCMV)criterion structure for wideband beamforming by using different TDLs with different channels.Owing to fact that even channel using even TDLs and odd channel using odd TDLs in the improved beamformer,the tap number nearly reduces to half.Then,the interference rejection performance is analyzed in theory.It proves that the interest signal’s power after array beamforming is the same with Frost structure and the remaining interference power is equal to that of Frost structure with the conditions that the number of array elements is no less than 4 and the interference is wideband noise jammer.In this way,the only performance difference for these two structures is the noise power.Finally,the comparative simulation results verify this new structure’s performance and confirm that the correctness is consistent of theory analysis.This structure can be applied to broadband space-time adaptive processing with high efficiency.