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Effective Use of Network Coding in Multi-hop Wireless Networks

Posted on:2014-08-03Degree:Ph.DType:Dissertation
University:University of CincinnatiCandidate:Chi, YangFull Text:PDF
GTID:1458390008952937Subject:Computer Science
Abstract/Summary:
Multi-hop network has been envisioned to be a key technology in the next generation wireless networks. It offers the most flexible characteristic of the networks, requires no centralized or very small control, and very little configuration, thereby enjoying the quick deployment property. Yet, it has been named as the "next generation" for so many times that its usefulness is being questioned. The difficulty mainly comes from the inferiority in the performance being poor enough to make such networks overshadowed by other type of networks, unless quick deployment is a requirement, or performance is not a major concern.;In this dissertation, we investigate the performance issues in multi-hop wireless networks. Some new architectures of multi-hop wireless networks with network coding are thoroughly explored. We first revisit network coding briefly. Being the latest revolution in the wireless world, network coding has evolved into a more practical shape, and has matured to a level so as to be adopted. A general introduction of network coding (network information theory) is covered for better understanding of how this technology would change the computer networks, and why we pick this topic for our research.;The first work this dissertation covers is Murco, an opportunistic framework that brings the benefits of both multi-radio multi-channel technology and network coding to the multi-hop wireless networks. This combination, though it seems natural, faces many challenges. We address them with a loose collaboration between network coding and multi-radio technology coordinated by our framework. Our framework requires few changes or compromises on either side, and the simulation results demonstrate enhanced throughput.;Following this work, we get into a more complex problem. Coding-aware routing in multi-hop wireless networks is vital for network coding's possible boom. We address this problem with a heuristic routing metric ETOX and a hybrid routing protocol HyCare. ETOX combines coding opportunities with other factors to provide both link and path measurements. HyCare employs ETOX as the routing metric and functions in both link-state routing and revrese forwarding manner. A cross-layer implementation is examined to validate our design paradigm.;Our routing metric, ETOX, is inspired by a long-existing network traffic characteristic, namely Network Locality. During our research, we found that most previous works in Network Locality were conducted many years ago, and this area has been overlooked in wireless networks. To fully understand our routing metric, and to provide a foundation to other works that take Network Locality in wireless networks as granted, we also examine Network Locality in both single-hop and multi-hop wireless networks.;The last work we introduced in this dissertation is TCP-Forward, a new transport layer protocol that gives TCP-like congestion control protocols a new life in lossy networks, like multi-hop wireless networks, with the help from network coding. Instead of using the most common intra-session network coding, the Random Linear Network Coding, we introduce Fountain Codes into the transport layer to provide both reliability and decoding efficiency. Due to the very nature and complexity of both congestion control and Fountain Codes, such a protocol can be a practicability headache. Our protocol is no exception and exposes great complexity in design and implementation. Our current implementation and results, though preliminary, has already showed some benefits over previous works.
Keywords/Search Tags:Wireless networks, Routing metric, ETOX, Technology
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