BIB-VERSION:: CS-TR-v2.0 ID:: ncstrl.dartmouthcs//TR2003-467 ENTRY:: July 18, 2003 ORGANIZATION:: Dartmouth College, Computer Science TITLE:: The mistaken axioms of wireless-network research TYPE:: Technical Report (paper) REVISION:: 1 AUTHOR:: Kotz, David AUTHOR:: Newport, Calvin AUTHOR:: Elliott, Chip DATE:: July 2003 RETRIEVAL:: For a paper copy, email RETRIEVAL:: For a paper copy, write to Technical Report Librarian Department of Computer Science Dartmouth College 6211 Sudikoff Laboratory Hanover, NH 03755-3510 USA RETRIEVAL:: Compressed Postscript at http://www.cs.dartmouth.edu/reports/TR2003-467.ps.Z RETRIEVAL:: PDF at http://www.cs.dartmouth.edu/reports/TR2003-467.pdf ABSTRACT:: Most research on ad-hoc wireless networks makes simplifying assumptions about radio propagation. The ``Flat Earth'' model of the world is surprisingly popular: all radios have circular range, have perfect coverage in that range, and travel on a two-dimensional plane. CMU's ns-2 radio models are better but still fail to represent many aspects of realistic radio networks, including hills, obstacles, link asymmetries, and unpredictable fading. We briefly argue that key ``axioms'' of these types of propagation models lead to simulation results that do not adequately reflect real behavior of ad-hoc networks, and hence to network protocols that may not work well (or at all) in reality. We then present a set of 802.11 measurements that clearly demonstrate that these ``axioms'' are contrary to fact. The broad chasm between simulation and reality calls into question many of results from prior papers, and we summarize with a series of recommendations for researchers considering analytic or simulation models of wireless networks. NOTE:: For more information related to this project see http://www.cs.dartmouth.edu/~campus/. END:: ncstrl.dartmouthcs//TR2003-467