说明：  本文主要定义了“ tＧ 时隙 kＧ 覆盖”的覆盖模型, 同时提出了基于历史移动轨迹的离线参与者选择问题,并对 该问题与集合覆盖问题之间的关系进行了说明.
(This paper mainly defines the coverage model of "tG slot kG coverage". At the same time, the problem of off-line participant selection based on historical moving trajectory is proposed, and The relationship between this problem and set cover problem is explained.)