基于二阶Markov预测的星地链路切换策略

Handover Strategy of Satellite-Ground Link Based on Second-Order Markov Prediction

由于LEO卫星和高速终端都处于高速移动状态,在通信时LEO卫星和高速终端频繁切换导致切换准确率低,提出基于二阶马尔科夫预测的星地链路切换策略。在软件定义网络(SDN)架构基础上,将控制器部署在GEO卫星控制切换决策。通过对高速终端移动轨迹进行二阶Markov建模,预测其下一轨迹。GEO卫星通过轨迹预测结果结合卫星星历确定候选目标卫星集合。结合切换要素,根据灰色关联和专家评判结合的权重法计算候选目标卫星集合中卫星权重。GEO卫星选择权重最大的卫星作为切换卫星进行切换。仿真结果表明,上述策略在切换预测准确率、平均切换次数和切换失败率方面优于传统切换策略,提高了切换准确率,减少了切换次数,降低了切换失败率。

Since LEO satellites and high-speed terminals are in a high-speed moving state,and frequent switching of LEO satellites and high-speed terminals during communication leads to low switching accuracy,this paper proposes a satellite-to-ground link switching strategy based on second-order Markov prediction.Based on the software-defined networking(SDN)architecture,the controller is deployed in GEO satellite to control the switching decision.By modeling the high-speed terminal movement trajectory in second-order Markov,its next trajectory is predicted.GEO satellites determine the set of candidate target satellites by combining trajectory prediction results with satellite ephemeris.Combined with the switching elements,the satellite weights in the candidate target satellite collection are calculated according to the weight method combined with gray correlation and expert evaluation.GEO satellites select the satellite with the largest weight as the switching satellite to switch.Simulation results show that the proposed strategy is better than the traditional switching strategy in terms of switching prediction accuracy,average switching number and switching failure rate,which improves the switching accuracy,reduces the number of switching times,and reduces the switching failure rate.