Abstract:
Nowadays, the development of wireless communication technology is rapidly evolved and increasing varieties of services also result in higher amount of users which subsequently causes network congestion. One scenario of providing such services to users is combining several types of network to one system that is called Heterogeneous Wireless Network, using multi-mode equipment which can connect through many technologies. However, if the users are allowed to select to connect to any networks by themselves, the congestion problem cannot be solved even we have already used those equipments. This circumstance affects the system in a way that it could not satisfy the guaranteed Quality of Service (QoS). Therefore, this thesis emphasized on this problem and proposed an algorithm by using network selection strategy which includes Call Admission Control (CAC) and Utility Function based Network Selection (UFNS) that were selected by the operator in order to improve system performance indices. In our study, the Heterogeneous Wireless Network, combining with cellular network, Wi-Fi, WiMAX, was considered to provide multi services and we created simulation system to test capability of the proposed algorithm. We considered three main issues; comparing types of user distribution, relationship of weighting in utility function and comparing our strategies with others.The result of this simulation showed us that the proposed algorithm can help improving various network performance indices.