Performance tuning of infrastructure-mode wireless LANs

Yigal Bejerano, Hyoung Gyu Choi, Seung Jae Han, Thyaga Nandagopal

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Citations (Scopus)

Abstract

Conventional wisdom about 802.11 WLANs dictates that as the number of active users increases, the contention windows (CW) of all the contending users needs to increase to prevent collision losses. However, given the increasing data rates of 802.11 standards, the fraction of time spent not transmitting information (as a result of back-off) is also increasing, leading to reduced throughput when compared to the theoretical maximum. While there appears to be an inherent conflict between reducing collisions by increasing the CW and reducing overhead by decreasing the CW, we demonstrate in this paper that this conflict can be eliminated in Infrastructure-Mode wireless LANs (I-WLAN) where downlink TCP and UDP flows dominate. Unlike the traditional trend of WLAN performance analysis that assumes that all the stations are greedy, we consider the case in which only the access point (AP) is greedy while the mobile users in the cell react to the information sent to them. This setting captures the traffic patterns in I-WLANs more accurately as users typically utilize their WLAN connections predominantly for downloading information through TCP (i.e., web browsing) and UDP (i.e., video streaming) connections. We show via analysis and extensive experimentation that by changing the minimum CW at the APs and the users, we can achieve 25 - 30% greater throughput than the typically recommended 802.11 settings. We achieve this without requiring any changes to the MAC or PHY, and utilizing only the standard features present on current-generation 802.11 chip-sets.

Original languageEnglish
Title of host publicationWiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks
Pages60-69
Number of pages10
Publication statusPublished - 2010 Aug 27
Event8th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, WiOpt 2010 - Avignon, France
Duration: 2010 May 312010 Jun 4

Publication series

NameWiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks

Other

Other8th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, WiOpt 2010
CountryFrance
CityAvignon
Period10/5/3110/6/4

Fingerprint

Wireless LAN
Wireless local area networks (WLAN)
Local area networks
Tuning
Contention
Infrastructure
Throughput
Collision
Video streaming
Video Streaming
Browsing
Experimentation
Performance Analysis
Chip
Traffic
Cell
Demonstrate
Conflict
Standards

All Science Journal Classification (ASJC) codes

  • Computational Theory and Mathematics
  • Computer Science Applications
  • Control and Optimization

Cite this

Bejerano, Y., Choi, H. G., Han, S. J., & Nandagopal, T. (2010). Performance tuning of infrastructure-mode wireless LANs. In WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (pp. 60-69). [5520344] (WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks).
Bejerano, Yigal ; Choi, Hyoung Gyu ; Han, Seung Jae ; Nandagopal, Thyaga. / Performance tuning of infrastructure-mode wireless LANs. WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks. 2010. pp. 60-69 (WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks).
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abstract = "Conventional wisdom about 802.11 WLANs dictates that as the number of active users increases, the contention windows (CW) of all the contending users needs to increase to prevent collision losses. However, given the increasing data rates of 802.11 standards, the fraction of time spent not transmitting information (as a result of back-off) is also increasing, leading to reduced throughput when compared to the theoretical maximum. While there appears to be an inherent conflict between reducing collisions by increasing the CW and reducing overhead by decreasing the CW, we demonstrate in this paper that this conflict can be eliminated in Infrastructure-Mode wireless LANs (I-WLAN) where downlink TCP and UDP flows dominate. Unlike the traditional trend of WLAN performance analysis that assumes that all the stations are greedy, we consider the case in which only the access point (AP) is greedy while the mobile users in the cell react to the information sent to them. This setting captures the traffic patterns in I-WLANs more accurately as users typically utilize their WLAN connections predominantly for downloading information through TCP (i.e., web browsing) and UDP (i.e., video streaming) connections. We show via analysis and extensive experimentation that by changing the minimum CW at the APs and the users, we can achieve 25 - 30{\%} greater throughput than the typically recommended 802.11 settings. We achieve this without requiring any changes to the MAC or PHY, and utilizing only the standard features present on current-generation 802.11 chip-sets.",
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Bejerano, Y, Choi, HG, Han, SJ & Nandagopal, T 2010, Performance tuning of infrastructure-mode wireless LANs. in WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks., 5520344, WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, pp. 60-69, 8th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, WiOpt 2010, Avignon, France, 10/5/31.

Performance tuning of infrastructure-mode wireless LANs. / Bejerano, Yigal; Choi, Hyoung Gyu; Han, Seung Jae; Nandagopal, Thyaga.

WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks. 2010. p. 60-69 5520344 (WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Bejerano Y, Choi HG, Han SJ, Nandagopal T. Performance tuning of infrastructure-mode wireless LANs. In WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks. 2010. p. 60-69. 5520344. (WiOpt 2010 - 8th Intl. Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks).