关键词: 移动无线传感器网络, 信标交换协议, 邻居节点表, 过期节点, 两跳信标交换

Abstract: Periodical Hello protocol is widely used in geographic routing protocols to obtain and maintain neighbor table. However in highly dynamic networks, the information stored in the neighbor table is often outdated, causing retransmissions and rerouting that consume bandwidth and increase latency. A new Two-hop Hello protocol (T-Hello) was proposed aiming to improve the accuracy of neighbor table. By exchanging beacon messages within two-hop scope, location information can be obtained even if a neighbor node has moved out of communication range, so that the corresponding entry in neighbor table can be removed explicitly rather than waiting for time out. The impacts of various factors (node density, beacon interval, node speed, transmission radius, et al.) were extensively studied and the conclusion is that the T-Hello protocol can shorten the lifetime of outdated neighbors by 50%, and hereby improve the performance of GPSR protocol significantly.

Key words: mobile wireless sensor network, hello protocol, neighbor table, outdated neighbor, two-hop beacon