Modeling Network Traffic in Mobile Networks Implementing Offloading

摘要

The increasing demand of mobile data traffic is starting to stress the networks of mobile network operators (MNOs). Techniques for offloading traffic (partially or totally) from the network of the MNO are currently being designed and deployed at various points of the network, which depend on the goal of each MNO. Such techniques divert traffic to offloading networks, such as Wi-Fi access networks, femto-cells, etc., or directly to the Internet. This paper presents a generic analytical approach for studying the impact that offloading techniques might have on the networks of MNOs. The model is generic in the sense that it is independent of the specific offloading technology used and may be of use to provide bounds on network dimensioning. Based on previous measurements found in the literature, our model assumes that user activity periods and periods characterizing offloading are heavy-tailed. We model them as strictly alternating independent ON/OFF processes. Therefore, the non-offloaded traffic (i.e., that traffic still being served by the MNO on a regular basis) is modeled as the product of these two processes. We prove that the resulting process is long-range dependent, with heavy-tailed ON/OFF-period durations, and its characteristic parameters can be derived from those of the initial processes. We also evaluate the network resources required to serve the traffic resulting from the aggregation of many such sources. We conclude that offloading does not always mean reduction of resource consumption, and that the distribution of offloading periods turns out to be the main design parameter to deploy effective offloading strategies in the networks of MNOs. Extensive simulations, in which the Hill's estimator was used to obtain the main parameters of the resulting process, confirm the results of our analytical study.