無線網狀網路下結合多頻道連結層與多路徑路由之協定設計

Abstract

近年來，無線網狀網路越來越受矚目，並將成為下一世代的無線寬頻存取技術。但如何增加網路吞吐量仍然公認為一關鍵且極具挑戰性的研究題目。其中一的解決方法是把無線收發器動態地切換到多個無線頻道上，以減少相互之間的干擾。但過往的研究只假設上層使用單一路徑的路由方法，像AODV或DSR等。而本論文則探討在這種多頻道環境下，使用多重路徑路由以提高其端對端的吞吐量。介於媒體存取控制層和網路層，我們提出了新的網路協定─Joint Multi-channel and Multi-path control (JMM)，它結合了多頻道連結層與多路徑路由的功能。藉由把時間軸切割成很多固定大小的時間槽，JMM能有效地決定每個時間槽應該停留在哪一頻道上，並把封包合理安排到兩條路徑中。全面把競爭的封包分散到不同的頻道，不同的時間，以至不同的路徑上，以大幅度提升其吞吐量。以我們的認知，此為第一個在無線網狀網路下把多頻道與多路徑路由兩者結合的設計。

In recent years, the wireless mesh network (WMN) attracts the interest of many people as a new broadband Internet access technology. However, increasing throughput is still an open and challenging research issue. One potential solution is to enable transceivers to utilize multiple channels dynamically. However, most of existing works do not consider the routing issue, and trivially use some popular single-path routing protocols like AODV and DSR. In this thesis, we exploit the benefit of multi-path routing in multi-channel WMNs from the aspect of end-to-end throughput. Between medium access control and network layers, we propose a novel protocol named Joint Multi-channel and Multi-path control (JMM) which combines multi-channel link layer with multi-path routing. Dividing the time into slots, JMM coordinates channel usage among slots and schedules traffic flows on dual paths. Our scheme efficiently decomposes contending traffics over different channels, different time, and different paths, and hence leads to significant throughput improvement. To the best of our knowledge, this is the first work discussing the joint design of multi-channel control and multi-path routing for WMNs.