Analytical Study of TCP Performance over IEEE 802.11e WLANs

IEEE 802.11 Wireless LAN (WLAN) has become a prevailing solution for broadband wireless Internet access while the Transport Control Protocol (TCP) is the dominant transport-layer protocol in the Internet. Therefore, it is critical to have a good understanding of the TCP dynamics over WLANs. In this paper, we conduct rigorous and comprehensive modeling and analysis of the TCP performance over the emerging 802.11e WLANs, or more specifically, the 802.11e Enhanced Distributed Channel Access (EDCA) WLANs. We investigate the effects of minimum contention window sizes and transmission opportunity (TXOP) limits (of both the AP and stations) on the aggregate TCP throughput via analytical and simulation studies. We show that the best aggregate TCP throughput performance can be achieved via AP’s contention-free access for downlink packet transmissions and the TXOP mechanism. We also study the effects of some simplifying assumptions used in our analytical model, and simulation results show that our model is reasonably accurate, particularly, when the wireline delay is small and/or the packet loss rate is low.

Daji QiaoEmail:

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Jeonggyun Yu   received his B.E. degree in School of Electronic Engineering from Korea University, Seoul, Korea in 2002. He is currently working toward his Ph.D. in the School of Electrical Engineering at Seoul National University (SNU), Seoul, Korea. His research interests include QoS support, algorithm development, performance evaluation for wireless networks, in particular, IEEE 802.11 wireless local-area networks (WLANs). He is a student member of IEEE. Sunghyun Choi   is currently an associate professor at the School of Electrical Engineering, Seoul National University (SNU), Seoul, Korea. Before joining SNU in September 2002, he was with Philips Research USA, Briarcliff Manor, New York, USA as a Senior Member Research Staff and a project leader for three years. He received his B.S. (summa cum laude) and M.S. degrees in electrical engineering from Korea Advanced Institute of Science and Technology (KAIST) in 1992 and 1994, respectively, and received Ph.D. at the Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor in September, 1999. His current research interests are in the area of wireless/ mobile networks with emphasis on wireless LAN/MAN/PAN, next-generation mobile networks, mesh networks, cognitive radios, resource management, data link layer protocols, and cross-layer approaches. He authored/coauthored over 120 technical papers and book chapters in the areas of wireless/mobile networks and communications. He has co-authored (with B. G. Lee) a book “Broadband Wireless Access and Local Networks: Mobile WiMAX and WiFi,” Artech House, 2008. He holds 15 US patents, nine European patents, and seven Korea patents, and has tens of patents pending. He has served as a General Co-Chair of COMSWARE 2008, and a Technical Program Committee Co-Chair of ACM Multimedia 2007, IEEE WoWMoM 2007 and IEEE/Create-Net COMSWARE 2007. He was a Co-Chair of Cross-Layer Designs and Protocols Symposium in IWCMC 2006, 2007, and 2008, the workshop co-chair of WILLOPAN 2006, the General Chair of ACM WMASH 2005, and a Technical Program Co-Chair for ACM WMASH 2004. He has also served on program and organization committees of numerous leading wireless and networking conferences including IEEE INFOCOM, IEEE SECON, IEEE MASS, and IEEE WoWMoM. He is also serving on the editorial boards of IEEE Transactions on Mobile Computing, ACM SIGMOBILE Mobile Computing and Communications Review (MC2R), and Journal of Communications and Networks (JCN). He is serving and has served as a guest editor for IEEE Journal on Selected Areas in Communications (JSAC), IEEE Wireless Communications, Pervasive and Mobile Computing (PMC), ACM Wireless Networks (WINET), Wireless Personal Communications (WPC), and Wireless Communications and Mobile Computing (WCMC). He gave a tutorial on IEEE 802.11 in ACM MobiCom 2004 and IEEE ICC 2005. Since year 2000, he has been a voting member of IEEE 802.11 WLAN Working Group. He has received a number of awards including the Young Scientist Award (awarded by the President of Korea) in 2008; IEEK/IEEE Joint Award for Young IT Engineer of the Year 2007 in 2007; the Outstanding Research Award in 2008 and the Best Teaching Award in 2006 both from the College of Engineering, Seoul National University; the Best Paper Award from IEEE WoWMoM 2008; and Recognition of Service Award in 2005 and 2007 from ACM. Dr. Choi was a recipient of the Korea Foundation for Advanced Studies (KFAS) Scholarship and the Korean Government Overseas Scholarship during 1997–1999 and 1994–1997, respectively. He is a senior member of IEEE, and a member of ACM, KICS, IEEK, KIISE. Daji Qiao   is currently an assistant professor in the Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa. He received his Ph.D. degree in Electrical Engineering-Systems from The University of Michigan, Ann Arbor, Michigan, in February 2004. His current research interests include modeling, analysis and protocol/algorithm design for various types of wireless/mobile networks, including IEEE 802.11 Wireless LANs, mesh networks, and sensor networks. He is a member of IEEE and ACM.