隨著車用網路日新月異的發展，車內提供用的網路服務也日漸多元化，然而車隊間網路傳遞的穩定及可靠性在車輛高速移動下也同時提升其困難度。再者，對於多媒體串流服務系統而言，車輛使用3G/3.5G無限網介面亦可能無法達到良好的影音觀看品質，因此本論文試圖探究在車隊網路下的單/多躍點(one-hop/k-hop)協力式串流情境。當車隊成員中要求者(Requester)尋求其他在傳遞範圍內的成員(幫忙者)，利用3G/3.5G介面協助下載H.264/SVC串流影片資料並再透過車對車DSRC車用網路介面透過單/多躍點(one-hop/k-hop)的方式傳回其下載之資料給要求者(Requester)。鑒於車輛網路的拓樸可能有動態變化，基於可調式的影音傳輸協定對於以下應有更好的輸出表現: (1)要求者(Requester)與幫忙者(Helper)之間的下載與傳輸(2)在播放緩衝內從影音提供者(server)重傳遺失的片段給要求者以改善影音品質。在實驗部分，我們則利用EstiNet網路模擬器及NCTUns系統模擬器進行環境模擬。透過模擬結果，在單躍點(One-hop)的實驗中優先重傳的排程(PFRS)在低位元錯誤率(BER)下呈現高效的PSNR數值,而DCRS在高位元錯誤率呈現出高PSNR數值。同樣地，在多躍點(K-hop)的實驗結果中PF傳送模組配PFRS則呈現出最佳效能。

With the development of vehicular networks, new types of networking services arise for automotive users. Since vehicles have high mobility, it is difficult to keep stable and reliable network connections between vehicles. With regard to multimedia streaming services, a vehicle may not have good QoS of video streaming using its own individual 3G/3.5G wireless interface. This thesis is motivated to investigate the one-hop/k-hop cooperative streaming scenario in a fleet-based vehicular network. When a vehicle, which is called requester, requests a video stream encoded in H.264/SVC from the Internet using its 3G/3.5G network, it asks helps from vehicles belonging to the same fleet within its one-hop/k-hop transmission range, in which these vehicles are called helpers, to download the requested video data cooperatively through these vehicles’ 3G/3.5G network and then forward these downloaded video to the requested vehicle through V2V Dedicated Short-Range Communication (DSRC) networks. Since the topology of a vehicular network may change dynamically, an adaptive video transmission protocol is proposed to have better throughput by (1) downloading video data from helpers and then forwarding these video data to the requester and (2) retransmitting the lost video data from the video server to helpers and then forwarding these re-transmitted video data to the requester before the playback deadline to improve the quality of video. We utilize EstiNet Network Simulator and Emulator (NCTUns) to simulate the proposed schemes. Based on the simulation results, in one-hop experiment the proposed priority first retransmission scheduling (PFRS) has higher PSNR values in the network condition with lower BER, and the dependency cost retransmission scheduling (DCRS) has higher PSNR values in the network condition with higher BER. Likewise, in k-hop experiment results, PF assignment scheme with PFRS retransmission scheme has the best performance.

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