迭代优化最小化唯相位波束形成

Phase-only Beamforming via Iterative Majorization Minimization

为了增强唯相位波束形成(Phase-Only Beamforming,POB)的干扰和噪声抑制性能,提高非凸POB权值求解的实时性,该文设计了迭代优化最小化(Iterative Majorization Minimization,IMM)唯相位最小方差无失真响应波束形成器(Minimum Variance Distortion-less Response Beamformer,MVDRB)。将无失真响应约束转化成最大化期望方向阵列响应,推导了二次型目标函数的上界,得到IMM-POB优化模型,并进一步推导出每次迭代的闭式最优解。仿真分析表明所设计的IMM-POB:在相同输入信噪比下,可获得高于现有迭代算法和最优MVDRB的信干噪比改善;干扰抑制性能几乎完全逼近最优MVDRB,且具有更优的噪声抑制性;受快拍数影响较小;闭式最优权仅包含单次矩阵和向量乘法,使算法具有较强的实时性,可应用于大规模阵列。

To improve the interference and noise suppression ability of Phase-Only Beamforming（POB） and the real-time performance to obtain the optimal weight of the uon-convex POB, a phase-only Minimum Variance Distortion-less Response Beamformer（MVDRB） via the Iterative Majorization Minimization（IMM） algorithm is designed. The distortion-less response constraint is transformed into maximizing array response in the desired direction. The upper bound function of the objective function in quadratic form is derived which generates the IMM-POB model. The optimal weight in closed-form for each iteration is further deduced. Simulation analysis illustrates that the proposed IMM-POB can obtain better signal to interference and noise ratio improvement compared with the existing iterative POB algorithms and the optimal MVDRB; its interference suppression ability approximates the optimal MVDRB with better noise suppression ability; it is much less sensitive to the number of array taps compared with the optimal MVDRB; it has strong real-time performance and can be applied to large-scale array.