以彈性quorum機制解決IEEE 802.11無線隨意網路的時間不同步問題

Abstract

對於IEEE 802.11無線隨意網路下的電力管理機制而言，節點間是否達到時間同步化扮演著非常關鍵的角色。目前已有許多針對IEEE 802.11無線網路的時間同步協定被提出來了，然而，這些協定卻不能保證可以成功地解決時間不同步問題。此外，即使存在著ㄧ個完美的時間同步協定，可以在多階的無線隨意網路下達到時間同步化，時間不同步問題仍然可能會因為節點的移動而發生。因此，在這篇論文裡，我們提出了一套以quorum為基礎的協定，這套協定將可用來加強時間同步協定在IEEE 802.11無線隨意網路下的時間不同步問題。根據模擬結果顯示，我們提出的協定將可以有效地改善IEEE 802.11無線隨意網路下的時間不同步問題。

In wireless mobile ad hoc networks (MANETs), it is essential that all nodes are synchronized to a common clock for power saving mechanism (PSM). Many protocols have been proposed to fulfill clock synchronization for IEEE 802.11 MANETs. However, all these protocols can not guarantee that they can completely solve the asynchronism problem in a highly mobile ad hoc network. Besides, even if there exists a perfect clock synchronization protocol which can guarantee that it can fulfill clock synchronization in a multi-hop network, the asynchronism problem may still arise because of mobility. Therefore, in this work, we propose a quorum-based mechanism to assist the existing clock synchronization protocols in solving the clock asynchronism problem in IEEE 802.11 MANETs. Our simulation results show that our proposed protocol can effectively improve the clock asynchronism problem for highly mobile IEEE 802.11 MANETs.