Abstract: Universal Mobile Telecommunications System（UMTS） provides wider coverage for mobile users，while WiMAX can provide higher bandwidth access in the local hot spots.The combination of the distinct advantage of the two networks，offers seamless connection for areas in heterogeneous wireless networks.Based on analysis for convergence configuration and handoff technology of UMTS and WiMAX，this paper proposes a mechanism that uses Received Signal Strength（RSS），delaying level and delay time as a handoff benchmark judgment，the real-time traffic and non real-time traffic are distinguished during the judgment.The simulation results show that new mechanism effectively prevents the occurrence of a ping-pong effect，and decreases the delay meanwhile.

Key words: Universal Mobile Telecommunications System（UMTS）, Worldwide Interoperability for Microware Access（WiMAX）, heterogeneous networks, handoff, convergence

摘要： 通用移动通信系统（UMTS）为移动用户提供了较广阔的覆盖范围，而无线广域网WiMAX能在局部热点地区提供较高的接入带宽。两种网络的显著优势能够相互结合，为处于异构网络覆盖的地区提供无缝连接。在分析WiMAX与UMTS 的融合结构和切换的基础上，提出了一种以接收信号强度（RSS）、迟滞电平和迟滞时间的结合作为切换判决基准的切换策略，并且在判决过程中，对实时与非实时业务进行了区分。仿真结果表明，该切换决策能有效减少“乒乓效应”和时延。

关键词: 通用移动通信系统（UMTS）, 全球微波互联接入（WiMAX）, 异构网, 切换, 融合