本論文提出了一種基於多接入邊緣計算（MEC）架構協助下之車載環境中的SVC-DASH來進行基於HTTP協定的自適應影音串流服務。針對串流服務的控制，本論文提出了一種自適應的影音串流控制方法，稱為以QoS/QoE為導向之緩衝區感知及比特率自適應（QQ-BABA）方法; 另外，針對移動性問題，本論文提出了一種基於模糊邏輯的多屬性決策（MADM-FL）的小型基地台影音串流資料分流（SC-VSO）控制方法，採用基於多屬性模糊的決策機制來決定是否可以將SVC-DASH影音串流的流量從大型基地台卸載到 4G/5G 行動網路的小型基地 台。為了達到適當的比特率自適應和穩定的畫質變化，在 MEC 服務器中執行的 QQ-BABA 方法考慮的三個因素是（i）估計頻寬，（ii）緩衝區長度和（iii）畫質變化。在估計頻寬方面，是根據客戶端回報的歷史記錄計算得出的。在緩衝區長度方面，為了（i）避免緩衝區時間長度不足或超過最大容量，（ii）提高畫質，（iii）最大化地提高畫質, 一些閾值被定義為下載的規則，以決定應下載哪些影片片段和哪些片段中的層。由於車輛在移動中會穿越多種類型的基地台 (BS)，因此在 MEC 服務器中執行的 MADM-FL 方法可以透過 （i） 相應大型基地台和小型基地台的網路情況以及 （ii） 車輛 X 使用模糊邏輯機制報告的上下文，讓車輛 X 在進入前方小型基地台信號覆蓋範圍之前決定是否執行 SC-VSO。本論文是基於實驗室規模的 eNB 設備和相關軟體構建的 4G LTE 網路中執行效能評估，實驗結果顯示所提出的方法對於在車載環境中通過無線移動網路傳輸之 SVC-DASH 影片串流具有更高的畫質和畫質穩定性。

This thesis proposed an SVC-DASH video streaming method over the vehicular environment based on the Multi-access Edge Computing (MEC) architecture. For the streaming control concern, a streaming control scheme, which is called QoS/QoE-oriented Buffer-Aware Bitrate Adaptation (QQ-BABA), using the Segment-Set-based buffer-aware bitrate adaptation with the backward quality’s increment control was proposed; for the mobility concern, a Small Cell Video Streaming Offloading (SC-VSO) control scheme, which is called Multiple Attribute Decision Making based on the Fuzzy Logic (MADM-FL), adopting the multiple attribute fuzzy-based decision mechanism for deciding whether it can offload the SVC-DASH video streaming traffic from a macro cell to a small cell of the 4G/5G cellular network or not was proposed. To have the suitable bitrate adaptation and stable quality variation, three factors that the proposed QQ-BABA control scheme executed in the MEC server considers are (i) estimated bandwidth, (ii) buffer occupancy and (iii) quality variation. In the aspect of estimated bandwidth, it is calculated based on the historical records that the clients reported. In the aspect of buffer occupancy, some thresholds are defined as the downloading rules to decide which video segments and which video layers should be downloaded to (i) avoid buffer underflow or overflow, (ii) enhance the video quality, and (iii) try to supplement the quality to the maximum. Since the vehicle is moving across many types of Base Stations (BSs), the proposed MADM-FL control scheme executed in the MEC server can decide whether to have SC-VSO or not before vehicle X entering into the ahead small cell’s signal coverage based on (i) the networking situations of the corresponding macro and small cells and (ii) the reported context from vehicle X using the fuzzy logic mechanism. Based on the performance evaluation that was executed in a 4G LTE emulation network, which was built on the lab-scaled eNB devices and related software, the proposed method has the higher video quality and quality stability for the SVC-DASH video streaming over the wireless mobile network in the vehicular environment.

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