摘要 : Paralleling the increasing traffic and the associated degradation of services in operators' networks, there have been numerous research initiatives to explore potential solutions to better optimize network resources and maintain a... 展开 Paralleling the increasing traffic and the associated degradation of services in operators' networks, there have been numerous research initiatives to explore potential solutions to better optimize network resources and maintain a high quality of experience (QoE) for subscribers. Although several possible solutions do exist, the focus of this paper is to survey one specific emerging family of solutions, called offload. Offloading's primary goal is to avoid transporting low priority traffic in costly networks in order to avoid degrading the perceived QoE. In particular, mobile operators target traffics that cause network congestion without creating any additional revenue. Offloading is based on traffic redirection from parts of the network where congestion could occur to other low-cost parts of the network where capacity is available and less expensive. In this paper, we present a survey on the offload approaches at different parts of the global network (access, core, and gateway). The aim of these approaches is to help mobile operators to face challenges such as capacity crunch, radio access saturation, average revenues per user decrease, and lack of indoor coverage. 收起