基于QoS保障的低轨卫星星座设计

School of Communication and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China

低轨卫星星座设计是部署低轨卫星网络的前提和关键。然而,不均匀的地面用户分布和不合理的卫星资源配置对卫星网络的服务质量提出了重大挑战。针对以上问题,通过构建服务质量(QoS)指标体系,提出了一种基于QoS保障的低轨卫星星座设计方法。首先,建立了低轨卫星网络模型和星座覆盖模型,通过星间链路的建链准则来定义星座抗毁性指标。其次,通过建立用户链路以及定义用户匹配度来分析星座对目标区域用户的资源匹配情况。接着,建立了以QoS指标为约束最大化效费比的低轨卫星星座设计优化问题,定义的QoS指标包括信噪比、误码率、抗毁性以及星座覆盖率和用户匹配度。此外,通过遗传禁忌智能算法求得了所设计的低轨卫星星座的轨道参数。仿真结果表明,提出的低轨卫星星座设计方案在满足指定QoS约束的同时具有最大星座效费比。

The design of LEO(low earth orbit)satellite constellation is the prerequisite and key to deploy LEO satellite network.However,the uneven distribution of ground users and the unreasonable allocation of satellite resources pose a major challenge to the service quality of satellite networks.To solve the above problems,a method of LEO satellite constellation based on QoS(quality of service)was proposed by establishing a QoS metrics system.Firstly,the LEO satellite network model and constellation coverage model were established,and the metric of constellation invulnerability was defined via the building criteria of inter satellite link.Secondly,the resource matching between satellite constellation and target area users was analyzed by establishing user links and defining user matching degree.Following that,the LEO constellation design problem was established to maximize the cost-effectiveness ratio under the constraints of QoS metrics.The defined QoS metrics included signal-to-noise ratio,bit error rate,invulnerability,constellation coverage rate and user matching degree.In addition,the orbital parameters of the designed LEO satellite constellation were obtained through the genetic tabu intelligent algorithm.The simulation results show that the proposed LEO satellite constellation design scheme can maximize the constellation cost-effectiveness ratio while meeting the specified QoS constraints.