| With the development of the variety of user service and radio access technology, the singlewireless network cannot afford all services with better performance. The heterogeneous wirelessnetwork is the future development trend, which is an integrated network with different wirelessaccess technologies. Thanks to the different characteristics of the wireless access technologies,they can achieve complementation to meet the diverse needs of users. It is also a very hard andlong term task. The key is the joint management of the resource in heterogeneous wirelessnetwork. To achieve efficient management, we must settle a series of key technology problems,such as network access selection, sharing of frequency spectrum, call admission control, verticalhandoff and so on.At first, we discuss several vertical handoff algorithms. Vertical handoff is one of the mostimportant part of heterogeneous wireless networks. We should provide users with seamlesshandoff to guarantee the Quality of service.Secondly, the paper studies a network selection algorithm based on multi-attribute decisionmaking. The algorithm considers the preference of user and the difference of available networks,then, calculates the weights of network attributes using analytic hierarchy process and entropytheory. Through the algorithm, we can choose the optimum network for users. Simulation resultsshow that the algorithm performs well in network selection. It can improve the throughput of thesystem and reduce the service dropping probability.In addition, a call admission control algorithm based on differentiated service is proposed.The algorithm considers two types of traffic: voice service and data service. Because differenttraffic types will have different service requirements, we give them different priorities andcertain channel reservation. The proposed scheme is evaluated through matlab simulations andthe results show that the proposed scheme can significantly improve the system performance. |
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