Performance analysis of mobile data offloading in heterogeneous networks

An unprecedented increase in the mobile data traffic volume has been recently reported due to the extensive use of smartphones, tablets and laptops. This is a major concern for mobile network operators, who are forced to often operate very close to (or even beyond) their capacity limits. Recently, different solutions have been proposed to overcome this problem. The deployment of additional infrastructure, the use of more advanced technologies (LTE), or offloading some traffic through Femtocells and WiFi are some of the solutions. Out of these, WiFi presents some key advantages such as its already widespread deployment and low cost. While benefits to operators have already been documented, it is less clear how much and under what conditions the user gains as well. Additionally, the increasingly heterogeneous deployment of cellular networks (partial 4G coverage, small cells, etc.) further complicates the picture regarding both operator- and user-related performance of data offloading. To this end, in this paper we propose a queueing analytic model that can be used to understand the performance improvements achievable by WiFi-based data offloading, as a function of WiFi availability and performance, user mobility and traffic load, and the coverage ratio and respective rates of different cellular technologies available.We validate our theory against simulations for realistic scenarios and parameters, and provide some initial insights as to the offloading gains expected in practice.