Optimization of discontinuous reception (DRX) operation during intra-LTE handover

Long Term Evolution (LTE) is being widely deployed to support real-time applications, such as voice over IP and video games. These applications require low latency guarantee during handover since long handover latency can severely impact user satisfaction. As a result, providing seamless communication when UE moves from one eNodeB to another while a session is in progress is an important design goal of the LTE network. The Discontinuous Reception (DRX) mechanism, which is widely adopted in LTE to conserve the mobile phone´s battery resources, results in higher handover latency due to its sleep period. In this paper, we present a detailed analysis on the impact of DRX on intra-LTE handover. Based on the analysis, we propose a new method, which is named Longer Awake Time, to minimize the handover latency without increasing the power consumption. Based on simulation analysis, we show that while the existing DRX method increases the user´s battery lifetime, it also increases the handover latency. By using Longer Awake Time method to adjust On Duration Timer appropriately, the handover latency decreases to the same level as when the DRX is disabled without decreasing the UE´s battery lifetime.