【作者】 胡鹏；

【导师】 李红艳；

【作者基本信息】 西安电子科技大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 未来的后3G(B3G)移动通信系统是不同通信技术的融合,实现了人们总能享受最佳通信服务的愿望。然而,要实现不同通信技术的真正融合,必须强调移动性层面上的全面融合。异构网间切换技术正是解决该问题的有效方法,也是建设B3G的关键技术挑战之一。本文首先分析了UMTS和WLAN的网络特性,深入研究了这两种网络内部的切换技术。之后,在分析紧耦合和松耦合方案下的异构网间切换技术的基础上,提出了两种行之有效的切换机制:(1)P-scan,一种快速可靠的WLAN MAC层切换机制;(2)FVHS,一种高效的异构网切换决策算法。仿真结果表明,P-scan切换机制在不加重网络负担的前提下减少了WLAN MAC层的切换时延,保证了各业务在MAC层的无缝切换。FVHS综合考虑了网络、用户和业务等因素,使异构网间的切换更加高效可靠。仿真分析表明该算法不但节省了终端功耗,而且减少了切换时延,提高了切换的可靠性。更多还原

【Abstract】 The B3G mobile communication system interworks several communication technologies, which will realize people’s dream of“always best connected”. However, in order to integrate roundly different communication systems, the mobility should be considered first. Vertical handoff mechanism is a valid method to the question, and also one of main technical challenges to the construction of B3G.First, the characteristics of UMTS and WLAN and their handoff mechanisms are analyzed in the paper. Second, we introduce two efficient handoff approaches after studying vertical handoff technologies of tight/loose couple architectures. One is a fast handoff method which is applied to WLAN MAC layer, named P-scan; the other is an effective vertical handoff strategy, called FVHS. Both methods will be applied to tight couple architecture.The simulation results indicate that P-scan method reduces handoff latency of WLAN MAC layer without increasing the traffic load of networks. On the other hand, since FVHS takes into account networks, users, applications and other factors, the vertical handoffs will be more efficient. The analyses indicate that this algorithm saves the terminal power loss, reduces the latency of handoff and enhances the reliability of handoff.更多还原