On Using Probabilistic Forwarding to Improve Data Transfer in Opportunistic People Networks
Date Issued
2007
Date
2007
Author(s)
Tseng, Cheng-Long
DOI
zh-TW
Abstract
On Using Probabilistic Forwarding to Improve Data Transfer in Opportunistic People Networks
Abstract
With wireless networking technologies extending into every part of our working and living environments, proper handling of intermittent wireless connectivity and network disruptions is important. We use the term “opportunistic networks”or“opportunistic people networks”to refer to data exchanges based on the connection opportunities that arise whenever mobile devices happen to come into wireless range due to the mobility of their users. Propose proper strategies for dealing with communication in such opportunistic network environments are of significance and remained desirable. In this study, we investigated two applications in opportunistic people networks, namely file transfer and Web surfing applications. We propose the HEC-PF scheme, an enhancement of our previous H-EC [12] scheme for effective data forwarding in opportunistic networks. The enhanced scheme modifies the aggressive forwarding phase of the H-EC scheme by implementing a new Probabilistic Forwarding feature, which decides whether to forward a message to a newly encountered node based on the delivery probability. Moreover, targeting Web surfing applications, we designed LMDC (Layered Multiple Description Coding) based techniques that immensely improve the perceived Web quality for end users. Using simulations as well as realistic network scenarios, we evaluate the proposed schemes in terms of latency, and completion ratio. The results show that the HEC-PF scheme outperforms the EC and H-EC schemes in all test cases, and the performance gain is even more substantial when network connectivity is extremely poor. By varying the parameters of the HEC-PF scheme, we show that its completion ratio improves as the maximum forwarding distance or the hop distance considered when calculating the delivery probability increases. Furthermore, we show that using Layered MDC-based techniques leads to higher user perceived quality, since the end user is allowed to “preview” web content, even before the data has been completely transferred. The effectiveness and robustness of our proposed algorithm and their corresponding content dissemination techniques make them ideal solutions that can go a long way toward effective data dissemination in opportunistic people networks.
Subjects
資料路由
網頁瀏覽
階層式多重描述編碼
臨機網路
耐延遲網路
Data Routing
Web Surfing
Layered Multiple Description Coding
Opportunistic Networks
Delay Tolerant Networks
Type
thesis
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