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Ahmed Helmy, Ph.D.

Professor, Director of the Mobile Networking Lab E401

  • Ph.D., University of Southern California, 1999
  • M.S., University of Southern California, 1995
  • B.S., University of Cairo, Egypt, 1992
Research Interests: 

Wireless Networks Design, Mobility Modeling, Network Simulation, Protocol Architecture & Design, Sensor Networks, Mobile Social Networks, Mobile Networks Measurement

  • For the latest publications and more complete list please visit
  • W. Hsu, A. Helmy, "On Nodal Encounter Patterns in Wireless LAN Traces", IEEE Transactions on Mobile Computing (TMC), June 2010 (to appear).
  • S. Moghaddam, A. Helmy, S. Ranka, M. Somaya, "Data-driven Co-clustering Model of Internet Usage in Large Mobile Societies", 13th ACM Int'l Conf on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWIM), Oct 2010.
  • W. Hsu, T. Spyropoulos, K. Psounis, A. Helmy, TVC: "Modeling Spatial and Temporal Dependencies of User Mobility in Wireless Mobile Networks", IEEE/ACM Transactions on Networking, pp. 1564-1577, Vol. 17, No. 5, October 2009. [Conference version appeared in IEEE INFOCOM, pp.758-766, May 2007]
  • M. Zuniga, K. Seada, B. Krishnamachari, A. Helmy, "Efficient Geographic Routing over Lossy Links in Wireless Sensor Networks", ACM Transactions on Sensor Networks (TOSN), pp. 12:1-33, Article 12 (33 pages), Vol. 4, No. 3, May 2008.
  • K. Seada, A. Helmy, R. Govindan, "Modeling and Analyzing the Correctness of Geographic Face Routing under Realistic Conditions", Ad Hoc Networks Journal - Elsevier, Special issue on Recent Advances in Wireless Sensor Networks, pp. 855-871, Vol. 5, Issue 6, August 2007.
  • K. Nahm, A. Helmy, C.-C. Kuo, "Cross-layer Interaction of TCP and Ad Hoc Routing Protocols in Multihop 802.11 Networks", IEEE Transactions on Mobile Computing (TMC), pp. 458 - 469, Vol. 7, Issue 4, April 2008.
  • F. Bai, N. Sadagopan, A. Helmy, "The IMPORTANT Framework for Analyzing the Impact of Mobility on Performance of Routing for Ad Hoc Networks", AdHoc Networks Journal - Elsevier Science, Vol. 1, Issue 4, pp. 383-403, November 2003. [Also in IEEE INFOCOM, April 2003.]
  • F. Bai, N. Sadagopan, B. Krishnamachary, A. Helmy, "Modeling Path Duration Distributions in MANETs and their Impact on Routing Performance", IEEE Journal on Selected Areas in Communications (JSAC), Vol. 22, No. 7, pp. 1357-1373, September 2004. [Also in ACM MobiHoc, May 2003.]
  • A. Helmy, "Small Worlds in Wireless Networks", IEEE Communications Letters, pp. 490-492, Vol. 7, No. 10, October 2003.
  • A. Helmy, "Efficient Resource Discovery in Wireless AdHoc Networks: Contacts Do Help", Book chapter in "Resource Management in Wireless Networking", Springer, ISBN: 0-387-23807-7, Vol. 16, 2005. [Also in the IEEE Transactions on Vehicular Technology, pp. 307-319, January 2005.]
  • Karim Seada, Ahmed Helmy, Ramesh Govindan, "Modeling and Analyzing the Correctness of Geographic Face Routing under Realistic Conditions", IEEE/ACM (IPSN), pp. 71-80, April 2004.
  • N. Sadagopan, B. Krishnamachari, A. Helmy, "Active Query Forwarding in Sensor Networks (ACQUIRE)", AdHoc Networks Journal - Elsevier, Vol.3, No.1, pp.91-113, January 2005 [Also in IEEE ICC SNPA workshop, May 2003.]
  • A. Helmy, S. Gupta, D. Estrin, "The STRESS Method for Boundary-point Performance Analysis of End-to-end Multicast Timer-Suppression Mechanisms", IEEE/ACM Transactions on Networking, Volume 12, Issue 1, pp. 44-58, February 2004.
  • K. Seada, M. Zuniga, A. Helmy, B. Krishnamachari, "Energy-Efficient Forwarding Strategies for Geographic Routing in Lossy Wireless Sensor Networks", The Second ACM Conference on Embedded Networked Sensor Systems (SenSys), pp. 108-121, November 2004.
  • A. Helmy, M. Jaseemuddin, G. Bhaskara, "Multicast-based Mobility: A Novel Architecture for Efficient Micro-Mobility", IEEE Journal on Selected Areas in Communications (JSAC), Special Issue on All-IP Wireless Networks, Vol. 22, No. 4, pp. 677-690, May 2004.
  • The NS Simulator: L. Breslau, D. Estrin, K. Fall, S. Floyd, J. Heidemann, A. Helmy, P. Huang, S. McCanne, K. Varadhan, Y. Xu, H. Yu, "Advances in Network Simulation", IEEE Computer, vol.33, No.5, pp. 59-67, May 2000.
  • The PIM-SM Spec: D. Estrin, D. Farinacci, A. Helmy, D. Thaler, S. Deering, V. Jacobson, M. Handley, C. Liu, P. Sharma, L. Wei, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification", RFCs 2362 & 2117 of the Internet Engineering Task Force (IETF), Inter-Domain Multicast Routing (IDMR), June 1998.
  • NSF CAREER Award, 2002-2007