Discontinuous reception (DRX) is a way for user equipment (UE) to save energy. DRX forces a UE to turn off its transceivers for a DRX cycle when it does not have a packet to receive from a base station, called an eNB. However, if a packet arrives at an eNB when the UE is performing a DRX cycle, the transmission of the packet is delayed until the UE finishes the DRX cycle. Therefore, as the length of the DRX cycle increases, not only the amount of UE energy saved by the DRX but also the transmission delay of a packet increase. Different applications have different traffic arrival patterns and require different optimal balances between energy efficiency and transmission delay. Thus, understanding the tradeoff between these two performance metrics is important for achieving the optimal use of DRX in a wide range of use cases. In this paper, we mathematically analyze DRX to understand this tradeoff. We note that previous studies were limited in that their analysis models only partially reflect the DRX operation, and they make assumptions to simplify the analysis, which creates a gap between the analysis results and the actual performance of the DRX. To fill this gap, in this paper, we present an analysis model that fully reflects the DRX operation. To quantify the energy efficiency of the DRX, we also propose a new metric called a real power-saving (RPS) factor by considering all the states and state transitions in the DRX specification. In addition, we improve the accuracy of the analysis result for the average packet transmission delay by removing unrealistic assumptions. Through extensive simulation studies, we validate our analysis results. We also show that compared with the other analysis results, our analysis model improves the accuracy of the performance metrics.

不连续接收（DRX）是用户设备（UE）节省能源的一种方式。当DRX没有要从称为eNB的基站接收的数据包时，DRX会强制UE在DRX周期内关闭其收发器。然而，如果当UE正在执行DRX周期时分组到达eNB，则分组的传输被延迟直到UE完成DRX周期为止。因此，随着DRX周期的长度增加，不仅DRX节省的UE能量的量，而且分组的传输延迟也增加。不同的应用程序具有不同的流量到达模式，并且在能效和传输延迟之间需要不同的最佳平衡。因此，了解这两个性能指标之间的折衷对于在广泛的用例中实现DRX的最佳使用非常重要。在本文中，我们通过数学分析DRX来了解这种权衡。我们注意到，先前的研究是有限的，因为它们的分析模型仅部分反映了DRX的操作，并且它们做出了简化分析的假设，从而在分析结果和DRX的实际性能之间造成了差距。为了填补这一空白，在本文中，我们提出了一个完全反映DRX操作的分析模型。为了量化DRX的能效，我们还考虑了DRX规范中的所有状态和状态转换，提出了一种新的度量标准，称为真实节能（RPS）因子。另外，通过消除不现实的假设，我们提高了平均分组传输延迟的分析结果的准确性。通过广泛的仿真研究，我们验证了我们的分析结果。