中文摘要：

Geocast是一种基于方向性投递的无线多播路由协议,能够减少冗余数据包,缩短多播时延。现有Geocast协议并不适用于稀疏网络环境,存在时延较大、数据冗余较高等缺陷。为了提高GeoGRID协议在稀疏网络中的性能,提出了GeoGRID-LBM和A-GeoGRID两种新型协议,利用网关节点掌握两跳网关节点邻居的信息,减少信道竞争和数据包碰撞概率,仿真实验表明,这两种改进型GeoGRID能够将数据端到端时延减少14%,降低冗余数据包数量达26%。

英文摘要：

Geocast is a wireless multicast routing protocols with directional delivery.It can reduce the end to end transmission delay.However,many existing geocast protocols take poor performance in the sparse network with long delay and the large data redundancy.In order to improve the performance of GeoGRID in sparse networks,this paper proposes the GeoGRID-LBM and A-GeoGRID protocols.The main idea is that the information of neighbors in two hops helps gateways to decrease the channel competition and the probability of packet collision.The simulation results show that the new protocols can decrease the end to end delay by 14%,and reduce the data redundancy by 26%.