一方面，行動通訊，例如長期演化 (LTE)，已經成為人們生活中風行且不可或缺的一部分。然而，據估計，未來的行動流量將要比現在大幾個數量級，這會降低LTE的服務品質。另一方面，無線區域網路(Wi-Fi)的頻寬比 LTE 的頻寬要寬得多，而且更便宜。為了保持 LTE 的服務品質，有人已經提出了一種稱為 LTE 和 Wi-Fi 聚合 (LWA) 的機制。在 LWA 中，必要時可以將 LTE 系統的流量分流到 Wi-Fi 系統。 具體來說，LWA Wi-Fi 進接點(AP)既可以向LTE用戶發送LTE封包，也可以向Wi-Fi用戶發送Wi-Fi封包。此外，為了提高傳輸的成功機率，我們應用疊加碼（SC）來允許同時傳輸LTE封包和Wi-Fi封包。在我們的研究中，我們研究了具有飽和或非飽和 Wi-Fi流量的 LWA Wi-Fi AP 的排隊模型。 LTE封包和 Wi-Fi封包可以使用疊加碼技術在同一個時槽裡傳輸。我們關注具有兩個佇列的 LWA Wi-Fi AP，其中包含用於LTE封包的 LTE 佇列和用於 Wi-Fi封包的 Wi-Fi 佇列。在飽和流量的情況下，Wi-Fi佇列中總會有一個Wi-Fi封包，而在不飽和流量的情況下，Wi-Fi佇列可能是空的。是否傳送 Wi-Fi封包取決於 LTE 佇列中的 LTE封包的數量。LTE封包傳輸成功的機率取決於Wi-Fi封包是否在同一時槽傳輸，反之亦然。首先，我們推導出所考慮系統的解析模型。接下來，我們使用迭代演算法來尋找穩態機率分佈和關注的效能指標。其次，我們研究了系統參數（例如 LTE封包到達率）對關注的效能指標的影響。最後但並非最不重要的是，我們編寫模擬程式以表示在大多數研究案例中，解析結果與模擬結果合理地接近。

On one hand, the mobile communication, e.g., LTE (long term evolution), has become popular and inevitable in people’s life. However, it is widely estimated that the mobile traffic volume in the future will be several magnitudes of order larger than that of the present, which will degrade the quality of service in LTE. On the other hand, the bandwidth of the Wi-Fi network is much wider and cheaper than that of LTE. To maintain quality of service of LTE, a mechanism called LTE and Wi-Fi aggregation (LWA) has been proposed. In LWA, the traffic of LTE system can be offloaded to Wi-Fi system if necessary. Specifically, an LWA Wi-Fi AP can transmit both LTE packets to LTE users and Wi-Fi packets to Wi-Fi users. Furthermore, to improve the successful probability of transmission, the superposition code (SC) is applied to allow the transmission of an LTE packet and a Wi-Fi packet at the same time. In our work, we study the queueing models of the LWA Wi-Fi AP with saturated or non-saturated Wi-Fi traffic. An LTE packet and a Wi-Fi packet can be transmitted at the same time slot using SC. We focus on an LWA Wi-Fi AP that has two queues, LTE queue for LTE packets and Wi-Fi queue for Wi-Fi packets. In the saturated traffic scenarios, there is always a Wi-Fi packet in the Wi-Fi queue, whereas in the non-saturated traffic scenarios, the Wi-Fi queue may be empty. Whether to transmit a W-Fi packet depends on the number of LTE packets in LTE queue. The probability that an LTE packet transmits successfully depends on whether a Wi-Fi packet is transmitted at the same time slot, and vice versa. First, we derive the analytical models for the considered system. Next, an iterative algorithm is used for finding the steady state probability distribution and the interested performance measures. Second, we study the influence of system parameters, e.g., the arrival rate of LTE packets, on interested performance measures. Last but not least, the simulation program is written to show that in most cases studied, the analytical results are reasonably close to the simulation results.

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