A Survey of Available Features for Mobile Traffic Offload

In order to help operators control the everincreasing mobile data volumes over their cellular networks, many offloading approaches have been proposed in the literature. In this paper, we present the two main solutions used to alleviate traffic load on the Radio Access Network (RAN), namely femtocells and wifi networks. We show that when using wifi as an offloading solutions, three degrees of integration can be distinguished. In this case, one operator concern is to provide session continuity to mobile users during vertical handover. Hence, several solutions are proposed to overcome this issue.