异构无线系统中一种改进的垂直切换方案

针对异构无线系统垂直切换需要综合考虑多种因素的特点，提出了一种改进的垂直切换方案。方案首先考虑网络费用，对原方案的代价函数进行改进。然后根据电池电量，分别采用不同的切换方法。最后将切换语音呼叫留在原网络，以达到减小频繁切换的目的。仿真结果表明，本方案较原方案很好的减小了系统阻塞率、平均切换次数和平均通话费用，有效提高了系统性能，具有现实意义。

Improved vertical handoff scheme in heterogeneous wireless networks

Vertical handoff in heterogeneous wireless networks should consider multiple factors, so an improved vertical handoff scheme is proposed in this paper. First cost function is improved for network cost in this scheme. Then according to remaining battery, different handoff method is adopted. At last handoff voice traffic remains in present network so as to reduce handoff frequently. Numerical results demonstrate that our scheme can reduce blocking rate, average handoff times, average call charge well , and improve performance of system efficiently. It can be used in practice.