In this section, we introduce the analysis method of this paper followed by a brief overview of 2G/3G cellular data network architecture and how the data is collected from network. The data set used in our study is also illustrated and the flow metrics extracted from the collected traffic data are shown for the purpose of providing an overview of the traffic characteristics.
A. Analysis Dimension
We analyze the traffic data from three perspectives: flow metrics, time and user behavior, as shown in Fig. 1. The considered flow metrics include: bytes, packet number, flow number, duration and user number. Noting that the traffic characteristics always follows clear daily pattern [7], we focus on analyzing data ranging from a time slot in a day, weekdays and weekends. For user behavior analysis, we consider the visited applications, the mobility pattern and the data usage (traffic volume).