Terminal-controlled Access Network Selection In Heterogeneous Wireless Networks

The integration and interworking of heterogeneous wireless networks is the inevitable trend of future mobile communication. Different wireless access technologies exhibit different features on coverage area, service quality and mobility support, and meet different requirements of users. The integration of different wireless access networks becomes the principle character of next generation mobile communication. While access network selection is a key technology to provide the best service for users and make full use of radio resources of all networks.For multi-radio parallel transmission (MRPT), we propose a novel terminal-controlled access selection scheme. It supports MRPT and is derived from mutiple attribute decision making (MADM). taking user preference, service type and network performance into consideration. We also apply utility function for the ranking of different networks. Simulation results show that our proposed algorithm is quite efficience, and it can also take advantage of parallel transmission, for higher throughput, reliability or lower cost.For the case of several traffic flows running on a terminal simultaneously, we propose a network selection algorithm, which implements network selection for each traffic flow independently, according to its QoS (Quality of Service) requirements and user preference. It uses modified TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) for choosing the best network, aiming to solving the rank abnormality phenomenon of traditional TOPSIS. Besides, we adopt random delay while accessing to a new network, to reduce handoff count and Ping-Pong effect. Finally, the simulation results show the efficiency of our proposed access selection algorithm.