臺灣大學: 電機工程學研究所廖婉君陳欣群Chen, Hsin-ChunHsin-ChunChen2013-03-272018-07-062013-03-272018-07-062010http://ntur.lib.ntu.edu.tw//handle/246246/254081機會路由是近年來一項能在具有高封包遺失率的無線網路中達到高吞吐量的傳輸機制。引入隨機線性網路編碼後，更大大地降低了機會路由的設計複雜度。為了減少交換回饋訊息造成的頻寬花費，現在主流的網路編碼機會路由，MORE，採用的機制是依據各個連結間的平均封包遺失率預先計算各個轉發節點預計的發送次數。 儘管MORE能在單一流量的環境中有很好的表現，但在多個流量同時傳輸的情況下，其效能將會大為降低。其主要原因是MORE的設計當中，並未考量到同時多流量的情況。 在本篇論文中，我們將討論一個以最小花費回饋上游目前收到的隨機網路編碼資訊的方法，以及一個背壓式傳輸策略使得各個網路流之間的負載較為均衡。接著，我們會結合上述的兩個機制，提出一個新的機會路由。藉由ns-2的模擬驗證，我們提出的協定平均流量在單一流量的環境下高出MORE 27%，而且在兩個、三個、四個等多流量的環境下高出31%、51%、以及54%的吞吐量。Opportunistic routing is a recent technique that achieves high throughput in lossy wireless links. The use of random linear network coding has further reduced the design complexity by removing coordination among transmitting nodes. To avoid the overhead of feedback exchange among forwarding nodes, the state-of-the-art network coding based opportunistic routing protocol, MORE, computes the expected number of transmissions for each forwarding nodes using offline heuristic based on the measurements of the average link loss rate and the ETX metrics. Although MORE shows good throughput in single flow results, the design suffers significant performance degradation in scenarios with multiple traffic flows. In this work, a method to feedback received random network coding information with minimal overhead and a backpressure policy approach to make load more balanced among traffics are discussed. Combining the above two mechanisms, a novel opportunistic routing protocol is then proposed. Verified by NS-2 simulation, our protocol in average outperforms MORE 27% in single flow comparison, and 31%, 51%, 54% higher in 2-, 3-, 4-flow scenarios, respectively.934668 bytesapplication/pdfen-US網路編碼機會路由負載平衡回饋無線網路network codingopportunistic routingload-balancingfeedbackwireless networkthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/254081/1/ntu-99-R97921032-1.pdf