Abstract: Various networks overlay in the three-dimensional space. Under the driving factor in return and user experience, operators for seamless handoff are imperative in the heterogeneous network. But in some environments, such as contacting with the outside world in case of emergency, return can’t be the only condition for triggering switch; network congestion will also be one of the factors that affect the communication. This paper proposes a new congestion identification method merging SIP technology for heterogeneous network handover. Based not only on the intensity of the signal, but also the status of the target network, it proposes the SIP message as the new switching strategy. Because the SIP protocol has nothing to do with the lower layer protocol, so it can be easily configured to the operator’s environment and will have a certain practicality. The simulation results show that, the method can be used to switch to the target network under the premise of QoS with lower cost.

Key words: heterogeneous network, congestion identification, network switching

摘要： 当前立体空间内多种网络重叠覆盖，在收益率、用户体验等因素的驱动下，运营商在其掌握的异构网络间进行无缝切换势在必行。但在一些安全环境中，例如遇到一些需要与外界联系的紧急情况，收益和并不能成为触发切换的唯一条件，网络拥堵也会是影响通信至关重要的一个因素。提出一个新的基于SIP协议的异构网络拥塞识别切换的技术。不仅基于信号的强度，而且还基于目标网络的状态来融入新的SIP消息切换策略。由于SIP协议与下层协议无关，因此可以比较容易地配置到运营商的环境，具有一定的实用性。仿真结果表明，使用该机制可以在保证QoS的前提下，让用户以较小的代价切换到目标网络。

关键词: 异构网, 拥塞识别, 网络切换