计算机科学 ›› 2025, Vol. 52 ›› Issue (12): 285-293.doi: 10.11896/jsjkx.250100016
李志坷, 徐涴砯
LI Zhike, XU Wanping
摘要: 针对无人机(Unmanned Aerial Vehicle,UAV)辅助多簇非正交多址(Non-Orthogonal Multiple Access,NOMA)下行网络中有限资源下的服务质量(Quality of Service,QoS)保障问题,提出了一种优化方案。UAV作为空中移动基站,向地面用户提供通信业务。由于能量有限,为使更多能量用于通信,将通信(悬停)时间作为优化变量,通过分别优化用户分簇、簇内用户功率分配和通信时间分配来最大化总吞吐量。由于其非凸性,将其分解为3个子问题,其中功率分配问题采用逐次凸逼近方法(Successive Convex Approximation,SCA)求解,而通信时间分配通过线性规划求解。首先,采用均值偏移(Mean Shift)算法进行用户分簇,相较于K-means算法,它通过计算局部密度峰值实现分簇,确保簇内用户相对集中;随后,考虑到该算法导致簇间用户数量不均衡,影响个体用户QoS,提出改进Mean Shift分簇算法,将用户数量较多的簇分裂为多个小簇;最后,为避免新增子簇增加飞行距离,提出本簇头悬停方案,并采用遗传算法(Genetic Algorithm,GA)进行轨迹优化,在保证用户QoS的前提下,通过减少UAV悬停节点的非通信能耗,来提升总吞吐量。该优化方案的计算复杂度较低,具有较强的实时性。仿真结果表明,改进Mean Shift算法的优化方案比K-means算法减少了非通信能耗,在不同的发射功率下,系统吞吐量平均提升了5.94%,在不同的用户数量下,能效平均提升了6.82%。
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