Network selection in heterogeneous environment: A step toward always best connected and served

Service delivery in a heterogeneous wireless environment requires the selection of an optimal access network. In order for users to be always connected through the optimal available network, it is necessary to develop an adequate technique for its selection. This paper deals with network selection concept as a perspective approach to the always best connected and served paradigm in heterogeneous wireless environment. It provides a survey on fundamental aspects of network selection process and mainly focuses on decision making mechanisms. After presenting the related standards, the perspective vertical handover approaches from the open literature are analyzed and compared. The paper concludes with a case study related to the influence of traffic conditions on network selection, which reveals the advantages of the always best connected and served concept.