Improving session continuity through user mobility tracking for EPS inter-serving gateway handover

The Evolved Packet System (EPS) is standardized to support a common IP-based core network with heterogeneous radio accesses in the latest 3GPP release. In the EPS, the Policy and Charging Control (PCC) framework provides dynamic policy control combined with real-time charging management. Long core network signaling for PCC degrades session continuity performance during handover. In this paper, we investigate the handover for an EPS session. Based on the results, we propose a proactive scheme along with a user mobility tracking model to improve session continuity. More specifically, our proposed scheme attempts to reduce PCC reauthorization signaling delay during the handover procedure. Then, we formulate a Markov process to model the user mobility pattern and to derive the session continuity probability. Numerical results show that our scheme can significantly keep the session continuity at a user acceptable level even when the mobility pattern is high. We also provide guidelines for operators to set up the network configuration parameters according to various traffic conditions.