The Study of Heterogeneous Wireless Networks Positioning Technology and Implement Based on OPNET

In the future, the communication network will be heterogeneous wireless networks that integrate various wireless access technologies, and take the advantages of the different access networks to provide ubiquitous services and meet the needs of broadband, personal and intelligent business. Positioning technology as a key technology in the wireless communication, many functions of terminal rely on this technology, such as:electronic map, the next generation message service and so on. With the rapid development of mobile communications and wireless networks, positioning technology will also be extended from the homogeneous network to heterogeneous wireless networks. In this paper, taking UMTS/WLAN heterogeneous interconnect integration as example, we will make research of positioning technologies in heterogeneous wireless networks.Vertical handoff that is the basis and the key technologies of heterogeneous networks integration is involved in the simulation platform. Therefore, a handoff scenario of UMTS/WLAN heterogeneous wireless networks is built used the OPNET, while a dual-mode terminal which can handoff between UMTS and WLAN networks is designed; then upward vertical handoff signaling process is designed on the basis of downsward vertical handoff signaling process, and the up and down vertical handoff are simulated based on RSS threshold-based vertical handoff strategy to achieve the seamless roaming in the UMTS/WLAN heterogeneous wireless networks.Then positioning algorithms for Heterogeneous Wireless Networks are studied. Firstly positioning scenario of UMTS/WLAN heterogeneous network is built and the factors that effect the performance of positioning in UMTS and WLAN network are analyzed by simulation; and the positioning mode switch based on the vertical handoff are realized. In handoff area, the positioning algorithm based on energy selection and enhanced data fusion is proposed. The results of simulation show that two kinds of algorithm both improved performance of position in that area.