車載網路之緊急合作式資料交換

以往學者考慮合作式資料交換（cooperative data exchange，簡稱CDE）問題時，僅考慮網路為完全圖或至多只有2-hop的relay環境。本論文考慮車載網路上的CDE問題，稱為urgent CDE問題，或簡稱UCDE問題；此一問題和傳統CDE問題的主要差別有二：第一，由於車載網路為多跳（multi-hop）網路，因此我們須額外考量co-channel interference的問題；第二，由於車輛移動速度快，我們要求處理UCDE問題的資料傳輸須在三回合內結束。窮盡我們所知，目前尚未有任何文獻探討UCDE問題。本論文貢獻如下：由於UCDE問題為NP-complete，為了快速求出高品質的可行解，我們提出新的媒介存取控制（media access control，簡稱MAC）協定，稱為UCDE-MAC。在UCDE-MAC中，access point採用倒推法和貪婪演算法求出上傳與下傳階段的資料傳輸排程。模擬實驗結果顯示UCDE-MAC確實達成預期目標，且效能遠勝沒有網路編碼或速率調控的情況。

關鍵字

車載網路；網路編碼；資料交換；倒推法

並列摘要

Prior work on cooperative data exchange (CDE) problem focuses only on the environment which is either a complete graph or a two-hop relay network. This paper considers a new type of CDE problem, called the urgent CDE (UCDE) problem, which is a CDE problem on a vehicular network. The differences between UCDE problem and CDE problem are mainly twofold: 1) Since the vehicular network is a multi-hop network, UCDE problem should additionally consider the co-channel interference; 2) Since the topology of a vehicular network is fast-changing, we require that the number of transmission rounds of a feasible solution to the UCDE problem is no more than three. The contributions of this paper are as follows: We model the UCDE problem as an integer linear programming problem, which is generally NP-complete. To tackle the UCDE problem, we propose a new MAC (medium access control) protocol, called UCDE-MAC, which uses backward induction and greedy approach to efficiently find out the near-optimal feasible solution. Finally, we conduct simulations to validate the superiority of UCDE-MAC.

並列關鍵字

vehicular network ； network coding ； data exchange ； backward induction

國際替代計量

車載網路之緊急合作式資料交換

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