Research On Link Trigger And Call Admission Control In Heterogeneous Wireless Networks

With the rapid development of mobile communication and broadband wireless access technology, a variety of wireless access technologies have emerged. They have different characteristics and ability of service offering, compete and complement with each other, commonly form a heterogeneous network environment. In order to meet the needs of the growing wireless data service, accommodate more users and provide wireless access anytime and anywhere, these wireless networks need to work together to achieve the integration of heterogeneous wireless networks. This paper aims to do research on link trigger handover decision mechanism and admission control problems in heterogeneous wireless networks, and provide solutions.Firstly, this paper pays attention to the link trigger handover decision mechanism in heterogeneous wireless networks, a LGD trigger mechanism based on grey prediction is proposed. According to the message of neighbor networks, the required handover time is estimated. Then establish grey prediction model based on the required handover time to get the Received Signal Strength (RSS) of mobile terminal, so the trigger time can be dynamically determined. Meanwhile, in order to reduce the prediction cost, a grey prediction modeling method based on signal decay detection is proposed. The simulation results show that this method improves the accuracy of the link trigger handover decision, and triggers LGD timely and effectively, and can reduce the unnecessary prediction cost, avoiding the waste of terminal resources.In order to maximize the utilization of system resources in heterogeneous wireless networks, this paper also pays attention to Admission Control in heterogeneous wireless networks. At present, multi-mode smart terminals are being widely used, but at the meantime, a large number of single-mode mobile terminals still exist, compared to single-mode terminals, the multi-mode mobile terminals can ensure their own Quality of Service (QoS) through the collaboration of different networks; but the single-mode mobile terminals are often in a very disadvantageous position for competing for system resources, their QoS can not be guaranteed. Therefore, in order to ensure the QoS of different types of users, an effective Admission Control mechanism is needed to control service request of mobile terminals that have different mode. First, the models of the heterogeneity of mobile terminals and network coverage are built, and then multi-level access threshold is set to allocate bandwidth reasonably in different wireless network; and then load transfer is introduced to maximize the utilization of system resources to meet the QoS requirements of different mobile terminals and different service. The simulation result shows that, this method can improve the utilization of entire system resource.