基于改进最小均方算法的卫星多波束形成技术

Improved least mean square algorithm based in satellite multi-beamforming

高通量卫星采用多波束技术实现极化隔离和空间隔离以复用频率资源,从而使通信容量成倍增加,但这对快速的自适应波束形成算法提出了更高的要求。为了解决采用LMS算法进行波束形成时收敛速度与稳态误差不能同时满足的缺点,提出一种改进的最小均方算法,它使用统计平均进行梯度更新解决瞬时梯度导致的形成波束不稳定问题,旨在波束形成开始阶段加快速度,而在收敛达到稳定状态后保持小的误差值。考虑在高通量卫星强降雨衰减的环境中,仿真应用61阵元正六边形排布相控阵天线形成7点波束。结果显示改进算法在仅少量增加复杂度的情况下大幅提高了收敛速度并获得了更优的稳态性能,可应用于应急通信场景下存在严重波束间同频干扰的高通量卫星波束形成技术。

High-throughput satellites use multi-beam technology to achieve polarization isolation and spatial isolation to reuse frequency resources, resulting in increased traffic capacity, but this presents a higher demand for fast adaptive beamforming algorithms. In order to solve the shortcoming that the convergence rate and steady-state error can not be sa-tisfied simultaneously when using the LMS algorithm, an improved least mean square algorithm was proposed, which used the statistical average gradient update to solve the problem of the formation of beam instability caused by the in-stantaneous gradient, which can speed up at the beginning of the beamforming and maintain a small error value after the convergence has reached a steady state. The use of 61-element hexagonal array phased array antenna to form a 7-point beam in an environment where high-throughput satellites have a strong rainfall attenuation was considered. The results show that the improved algorithm can greatly improve the convergence speed and obtain better steady state performance under the condition of only a small increase in complexity, which can be applied to high-throughput satellite beamform-ing technology with severe inter-beam co-channel interference in emergency communication scenarios.