In RF-based wireless powered communication networks (WPCNs), the wireless charging rate at a device is usually low or unstable because of health concerns or time-varying characteristics of wireless channels. Under a low charging rate, the data backlog at a wireless device may be continuously increasing, leading to system performance degradation and data loss. To keep a wireless powered device stable and preserve a finite data backlog, the upper limit of data arrival/acquisition rate at a wireless powered device must be solved under the given data transmission rate and wireless charging rate. Hence, in this paper a novel two-dimensional continuous-time Markov chain model was proposed for analyzing the stability condition of a wireless powered device with a finite energy storage buffer. The average number of data packets, average packet delay, and energy shortage probability at a wireless powered device were analyzed as well. Additionally, simulations were conducted to validate the analytic results and demonstrate that the obtained stability condition is necessary and sufficient for the wireless device.

在基于RF的无线通信网络（WPCN）中，由于对健康的关注或无线通道的时变特性，设备的无线充电速率通常较低或不稳定。在低充电速率下，无线设备上的数据积压可能会不断增加，从而导致系统性能下降和数据丢失。为了保持无线电力设备稳定并保留有限的数据积压，必须在给定的数据传输速率和无线充电速率下解决无线电力设备上的数据到达/获取速率的上限。因此，本文提出了一种新颖的二维连续时间马尔可夫链模型，用于分析具有有限能量存储缓冲器的无线电力设备的稳定性条件。数据包的平均数量，平均包延迟，还分析了无线供电设备的能源短缺概率。此外，进行了仿真以验证分析结果并证明所获得的稳定性条件对于无线设备而言是必要和充分的。