报告题目:Robust and Efficient Broadcasting in Multihop
Wireless Networks
报告人: Thomas Kunz 教授
主持人: 陈仪香 教授
报告时间:2014年10月15日（周三）15：00
报告地址:中北校区数学馆201报告厅
主办单位:软件学院 科技处
报告摘要：
Broadcasting (communicating information from one to all or many to all nodes in a network) is an important communication primitive. It is used as a building block in many MANET routing protocols, for example. In addition, broadcasting is a key primitive in multihop networks to support applications of all-informed voice, group push-to-talk, situational information sharing etc. Supporting one-to-all and many-to-all communication patterns in multihop wireless networks efficiently is therefore important. The key metric we are interested in our work is the number of packet transmissions at the MAC layer: if a protocol can deliver data packets to all nodes with fewer packet transmissions at the MAC/PHY layer, this will lower energy and network resource consumption and mitigate the traffic congestion problem in the network, compared to simply flooding the network. Many researchers have addressed that problem by having only a subset of nodes re-broadcast data packets. For example, the recent IETF RFC 6621 describes SMF (Simplified Multicast Forwarding), a broadcast/multicast protocol that selects a subset of nodes, called MPRs, to re-broadcast the packets, establishing an approximation of the Minimum Connected Dominating Set for a given topology. However, such protocols need to learn at least the local 2-hop topology, and their selection of MPRs will be poor when this neighborhood changes due to mobility. In addition, packet transmission is highly unreliable as wireless links may suffer from fading and interference, and random access MAC protocols such as IEEE 802.11 may cause packet collisions. In this talk I will give discuss our recent work in this area, where we have studied both lower bounds and the efficiency and robustness of actual broadcasting protocols. The work has explored both routing/packet forwarding solutions as well as approaches based on network coding. I will particularly highlight our most recent work, exploring how broadcast protocols such as SMF are impacted by unreliable packet transmissions and topology changes. This will be contrasted with a broadcast protocol we developed, based on network coding, that performs consistently well, even under adverse conditions, and that is more efficient in many cases.
报告人简介：
Professor Kunz received his Diplom in Wirtschafts informatik in 1990 and his Dr.Ing. inInformatik in 1994, both from the Technische Hochschule Darmstadt, Germany. He is currently a full professor in the Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada and Associate Chair for Graduate Studies. He heads the Mobile Computing Group, researching wireless network architectures (Manets. wireless mesh networks, and wireless sensor networks), network protocols (for example MAC, routing, localization, clock synchronization, and OoS support), and middleware layers for innovative wireless applications. He has served on more than 60 TPCs of international conferences and workshops in the mobile and wireless domain and has collaborated extensively with both industry and government research labs. He is the author or coauthor of more than 200 technical papers and received a number of awards and best paper prizes. Professor Kunz is a senior member of both ACM and IEEE.