IEEE802.11中移动速度优先的快速切换的研究

Moving Speed Aware of Fast Handoff Investigation in IEEE802.11 Networks

针对无线局域网中节点移动速度和方向的不确定性,在分析现有研究不足的基础上,提出了一种基于移动速度优先的快速切换机制。该机制通过资源的集中分配,将空闲信道信息通知需要切换的节点,避免了由于节点主动发起接入造成的接入冲突,实现了切换节点的快速调度,有效地改善了切换的服务质量。仿真显示,该机制将分组丢失率、切换失败率和切换时延分别提高了14%、14%和55%左右。

Wireless Local Area Networks （WLANs） could provide possibilities to mobile users benefiting wireless services through Access Points （APs）.Furthermore,mobile users could move freely in such wireless environment.However,handoffs could be triggered while crossing different WLANs.In the most of existing literatures,the authors did not consider the case that mobile users change suddenly the moving direction during handoff procedures,to enter another WLAN.This paper proposed a Fast Handoff algorithm based moving speed （FHBS） with taking into account the moving direction and moving velocity.Since the network resources are scheduled by Access Control Centers （ACCs）,a fast scheduling mechanism is established.Because information of all available channels is broadcasted by ACCs,the access collisions caused by nodes which initiate handovers are eliminated.As the consequence,an outstanding performance is achieved.Simulation results show that FHBS can improve the packet loss,the handoff blocking probability and the handoff latency by about 14％,14％ and 55％,respectively.