机会网络中基于节点相遇间隔的缓存管理策略

Node Encounter Interval Based Buffer Management Strategy in Opportunistic Networks

采用存储-携带-转发方式的机会网络不考虑消息在传递过程中经历节点与目的节点的相遇概率,对消息传播状态的估计结果存在较大误差。文中提出一种基于节点相遇间隔的缓存管理策略,利用节点相遇间隔服从指数分布的特性,结合消息在网络中的副本数量,估计出消息的平均投递概率。在节点缓存溢出时,根据估算的消息投递概率对缓存中的消息进行排序,优先删除投递概率低的消息,达到缓存管理的目的。仿真结果表明,使用该方法对节点缓存进行管理,在提高网络中消息投递成功率的同时,有效降低了消息的平均投递延迟和网络负荷。

Opportunistic network which employs store-carry-and-forward pattern doesn’t consider encounter possibility of destination nodes and passing nodes during message transmission,leading to a large deviation for the estimation on message transmission status.This paper proposed an encounter interval based buffer management strategy.It facilitates the characteristic of exponential distribution for the encounter intervals between nodes,and the number of message co-pies is also considered.So the average delivery probability is estimated.All messages stored in the buffer are sorted according to the average delivery probability when the buffer is overflow,and the messages with low delivery probability will be dropped first for buffer management intent.Simulation results show that the proposed strategy achieves better performance compared to existing schemes in respect of the delivery ratio,average latency and overhead ratio.