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Issue No. 11 - Nov. (2013 vol. 12)
ISSN: 1536-1233
pp: 2206-2218
Fung Po Tso , University of Glasgow, Glasgow
Lin Cui , City University of Hong Kong, Hong Kong
Lizhuo Zhang , City University of Hong Kong, Hong Kong
Weijia Jia , City University of Hong Kong, Hong Kong
Di Yao , City University of Hong Kong, Hong Kong
Jin Teng , The Ohio State University, Columbus
Dong Xuan , Ohio State University, Columbus
Wide range wireless networks often suffer from annoying service deterioration due to ever-changing wireless environments. This is especially the case with passengers on long-distance trains (LDT, such as intercity, interprovincial, and international commuter trains) connecting to the Internet. To improve the service quality of wide-area wireless networks, we present the DragonNet system and protocol with practical implementations. The DragonNet system is a chained gateway that consists of a group of interlinked DragonNet routers running the DragonNet protocol for node failure amortization across the long stretching router chain. The protocol makes use of the spatial diversity of wireless signals when not all spots on a surface see the same level of radio frequency radiation. In the case of an LDT of around 500 meters, it is highly possible that some of the DragonNet routers in the gateway chain still see sound signal quality when the LDT is partially blocked from the wireless Internet. The DragonNet protocol fully utilizes this feature to amortize single-point router failure over the whole router chain by intelligently rerouting traffic on failed ones to sound ones. We have implemented the DragonNet system and tested it in real railways over a period of three months. Our results have pinpointed two fundamental contributions of the DragonNet protocol. First, DragonNet significantly reduces the average temporary communication blackout (i.e., no Internet connection) to 1.5 seconds compared with 6 seconds without the DragonNet protocol. Second, DragonNet nearly doubles the aggregate system throughput compared with gateway without running the DragonNet protocol.
Protocols, Internet, Wireless communication, Servers, Mobile communication, IEEE 802.11 Standards, Power system faults

F. P. Tso et al., "DragonNet: A Robust Mobile Internet Service System for Long-Distance Trains," in IEEE Transactions on Mobile Computing, vol. 12, no. 11, pp. 2206-2218, 2013.
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