Enhanced Direction-Sensing Methods and Performance Analysis in Low-Altitude Wireless Network via a Rotating Antenna Array
旋转天线阵列增强的低空无线网络方向感知方法与性能分析
Jinbing Jiang, Feng Shu, Minghao Chen, Jiatong Bai, Maolin Li, Yan Wang, Jiangzhou Wang
AI总结 针对旋转阵列感知中计算复杂度高和时间效率低的问题,提出基于预旋转初始化与迭代贪婪空间谱搜索的低复杂度增强方向感知框架,并推导了简化旋转模型下的CRLB,仿真表明所提方法在均方误差上优于递归旋转方法并达到CRLB。
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由于每个天线单元的指向性,当发射器偏离阵列法线方向时,接收信号功率会严重衰减,导致沿相应方向的感知性能严重下降。尽管现有的可旋转阵列感知方法(如递归旋转RR-Root-MUSIC)通过迭代旋转和感知可以缓解这一问题,但需要多次机械旋转和重复的特征分解操作,导致计算复杂度高、时间效率低。为解决此问题,提出了一种以接收功率为准则的预旋转初始化方法,显著降低了计算复杂度并提高了时间效率。基于此思想,开发了一种低复杂度的增强方向感知框架,包括预旋转初始化和迭代贪婪空间谱搜索(PRI-IGSS),分为三个阶段:(1)将阵列法线旋转到一组候选方向,以找到具有最大感知能量的最优方向,并通过Root-MUSIC算法计算对应的DOA值;(2)将阵列机械旋转到初始估计方向并保持固定;(3)设计一种受强化学习启发的迭代贪婪空间谱搜索或接收波束成形方法,通过缩小搜索范围并将所有先前采样协方差矩阵与当前矩阵求和,随着迭代过程持续提供递增的性能增益。为评估所提方法的性能,在简化旋转模型下推导了相应的CRLB。仿真结果表明,所提出的PRI-IGSS方法在均方误差方面远优于RR-Root-MUSIC,并达到CRLB,原因是后者没有样本累积。
Due to the directive property of each antenna element, the received signal power can be severely attenuated when the emitter deviates from the array boresight, which will lead to a severe degradation in sensing performance along the corresponding direction. Although existing rotatable array sensing methods such as recursive rotation (RR-Root-MUSIC) can mitigate this issue by iteratively rotating and sensing, several mechanical rotations and repeated eigendecomposition operations are required to yield a high computational complexity and low time-efficiency. To address this problem, a pre-rotation initialization with recieve power as a rule is proposed to signifcantly reduce the computational complexity and improve the time-efficiency. Using this idea, a low-complexity enhanced direction-sensing framework with pre-rotation initialization and iterative greedy spatial-spectrum search (PRI-IGSS) is develped with three stages: (1) the normal vector of array is rotated to a set of candidates to find the opimal direction with the maximum sensing energy with the corresponding DOA value computed by the Root-MUSIC algorithm; (2) the array is mechanically rotated to the initial estimated direction and kept fixed; (3) an iterative greedy spatial-spectrum search or recieving beamforming method, moviated by reinforcement learning, is designed with a reduced search range and making a summation of all previous sampling variance matrices and the current one is adopted to provide an increasiong performance gain as the iteration process continues. To assess the performance of the proposed method, the corresponding CRLB is derived with a simplified rotation model. Simulation results demonstrate that the proposed PRI-IGSS method performs much better than RR-Root-MUSIC and achieves the CRLB in term of mean squared error due to the fact there is no sample accumulation for the latter.