Two-Stage Vacation Queue-Based Active DRX Mechanism in an LTE System

When using a Discontinuous Reception (DRX) mechanism in Long Term Evolution (LTE) for wireless communication of high-speed data, two different operational modes are employed: Idle DRX and Active DRX. In this chapter, we propose an enhanced energy saving strategy based on the Active DRX mechanism in an LTE system to improve the sleep strategy for a better balance between response performance and energy efficiency by introducing a sleep-delay timer. We build a discrete-time multiple-vacation queueing model with a vacation-delay period and a set-up period by addressing the busy period, the queue length, the waiting time and the busy cycle. We derive performance measures of the system in terms of the handover rate, the energy saving rate of the system and the average response time of data packets, respectively. We present numerical results to show the impact of the thresholds of the short DRX stages, the time lengths of the sleep-delay timer, the short DRX stage and the long DRX stage on the system performance so that we can evaluate the influence of the configuration parameters on the system performance. Finally, by considering the trade-off between different performance measures, we optimize the enhanced energy saving strategy for the Active DRX.