Mixed-mode simulation for IEEE 802.11-operated WLANs

Hwangnam Kim, Jennifer C. Hou

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


In this paper, we address the issue of integrating packet-level simulation with fluid-model-based simulation for IEEE 802.11-operated wireless LANs (WLANs), so as to combine the performance gain of the latter with the accuracy and packet-level detail afforded by the former. In mixed-mode simulation, foreground flows operate in the packet mode, while the other background flows are approximated into a collection of fluid chunks and simulated in the fluid mode. As these two types of flows influence each other at the point of interaction, e.g. the wireless channel in a WLAN, we derive the model of interaction at the wireless medium. We then implement mixed-mode simulation in ns-2 as well as MATLAB, and conduct a comprehensive simulation study to evaluate its performance with respect to the capability of keeping track of network dynamics (in terms of the TCP behavior), accuracy (in terms of the error discrepancy in throughput), and efficiency (in terms of the speed-up in carrying out simulation). Simulation results indicate that, for IEEE 802.11-operated WLANs, mixed-mode simulation significantly expedites the simulation, and yet provides the same level of packet details and accuracy as packet-level simulation does for flows of interest. Specifically, the error discrepancy incurred in mixed-mode simulation is within 2% of the maximum channel bandwidth, and reduces the execution time, in the best case, by two orders of magnitude.

Original languageEnglish
Pages (from-to)1379-1402
Number of pages24
JournalComputer Networks
Issue number6
Publication statusPublished - 2007 Apr 25

Bibliographical note

Funding Information:
Jennifer C. Hou received her Ph.D. degree in EECS in 1993 from The University of Michigan, Ann Arbor, MI. She was an assistant professor in Electrical and Computer Engineering at The University of Wisconsin, Madison, WI in 1993–1996, and an assistant/associate professor in Electrical Engineering at The Ohio State University in 1996–2001. Since August 2001, she has been with the Department of Computer Science at University of Illinois at Urbana Champaign, IL, where she is currently an associate professor. She was a recipient of the Lumley Research Award from Ohio State University in 2001, the NSF CAREER award from NSF in 1996–2000 and the Women in Science Initiative Award from The University of Wisconsin – Madison in 1993–1995. She has published over one hundred papers in archived journals and peer-reviewed conferences. She has been on the TPC of several major networking, real-time, and distributed systems conferences/symposiums, and was the Technical Program Chair of IEEE RTAS 2000 and IEEE IPSN 2004, a Program Vice Chair of IEEE ICDCS 2002, IEEE ICPADS 2004, IEEE RTSS 2004, and the General Co-Chair of IEEE RTAS 2001. She is on the editorial board of IEEE Trans. on Wireless Communications, IEEE Trans. on Parallel and Distributed Systems, ACM/Kluwer Wireless Networks, Kluwer Computer Networks, and ACM Trans. on Sensor Networks. Her most recent research focus is in the areas of network modeling and simulation, network measurement and diagnostics, and wireless sensor networks. She is a senior member of IEEE and a member of ACM.


  • Mixed-mode simulation
  • Performance evaluation
  • Simulation
  • Wireless LANs (WLANs)

ASJC Scopus subject areas

  • Computer Networks and Communications


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