Beamforming algorithms are designed for generating main beams in the direction of interest and place nulls in the direction of interferences. Adaptive beamforming can be achieved by various optimization criteria. The criteria for an efficient design of algorithm is the speed of convergence, deeper null placement, better signal to noise ratio, and robustness. Motivated by the reduction in the computational complexity a new adaptive beamforming algorithm based on variable step size is proposed in this paper called sign variable step size LMS algorithm. The proposed algorithm is applied to the uniform linear array antenna. Simulation results show that it gives a better null placement in the direction of interference and the signal to noise ratio is improved upon the existing algorithms with less computational complexity.

波束成形算法被设计用于在感兴趣的方向上生成主波束，并在干扰方向上放置零位。自适应波束成形可以通过各种优化标准来实现。有效设计算法的标准是收敛速度，更深的零位放置，更好的信噪比和鲁棒性。为了降低计算复杂度，本文提出了一种新的基于可变步长的自适应波束成形算法，称为符号可变步长LMS算法。将该算法应用于均匀线性阵列天线。仿真结果表明，该算法在干扰方向上具有更好的零点位置，并且在现有算法的基础上以较低的计算复杂度提高了信噪比。