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oai:www.ideals.illinois.edu:2142/26050 2023-07-10 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

2011-08-25T22:10:51Z 2011-08 Mitra, Sayan Carrasco, Maria B. 2011-08-25T22:10:51Z 2011-08-25T22:10:51Z An ad hoc network is a collection of computing nodes communicating over wireless channels without relying on any fi xed infrastructure such as servers and towers. Such networks are useful in rescue operations, and in rural and military settings. Clock synchronization is an essential building block for many ad hoc wireless network applications. It provides the participating computing nodes with logical clocks whose di erences can be bounded. Several traditional distributed clock synchronization algorithms use strict communication structures such as spanning trees. In such protocols, a node corrects its logical clock when it receives a new time-stamped message from its parent. In this thesis, we present a new clock synchronization protocol that exploits the broadcast medium in wireless networks, allowing nodes to opportunistically correct their logical clocks in order to converge to a reference time provided by a designated root node. Our protocol does not rely on a communication structure and is lightweight due to its low overhead. We also propose a variation of our opportunistic protocol, which further reduces overhead through randomized broadcast techniques. Our simulation-based experimental evaluation of the protocols illustrates that our opportunistic algorithms improve the accuracy of the nodes' logical clocks, when compared to a tree-based protocol. However, we show that the level of improvement is a function of the density of the wireless network. Additionally, the results show that our algorithms can produce around half the overhead, compared to an existing protocol that achieves higher levels of precision. Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2011-07-09T17:20:58Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 ecethesis.tex: 90427 bytes, checksum: 97838b751ecdadf684d41b996a1ab52e (MD5) Carrasco_Maria.pdf: 11432025 bytes, checksum: 591e5d8bf3754c49672a52eb19786752 (MD5) Made available in DSpace on 2011-08-25T22:10:51Z (GMT). No. of bitstreams: 3 Carrasco_Maria.pdf: 11432025 bytes, checksum: 591e5d8bf3754c49672a52eb19786752 (MD5) license.txt: 4064 bytes, checksum: 41b15a8e433f04684c85786720770356 (MD5) ecethesis.tex: 90427 bytes, checksum: 97838b751ecdadf684d41b996a1ab52e (MD5) http://hdl.handle.net/2142/26050 en Copyright 2011 Maria B. Carrasco clock synchronization Ad hoc opportunistic broadcasts window of opportunity randomized Opportunistic clock synchronization for ad hoc networks Electrical & Computer Eng 1933 Electrical & Computer Engr 1200 University of Illinois at Urbana-Champaign Thesis M.S. MS:Electr & Computer Eng-UIUC 10KS1200MS