Modeling the effect of transmission errors on TCP controlled transfers over infrastructure 802.11 wireless LANs

Krishnasamy, Subhashini and Kumar, Anurag (2011) Modeling the effect of transmission errors on TCP controlled transfers over infrastructure 802.11 wireless LANs. In: Proceedings of the 14th ACM international conference on Modeling, analysis and simulation of wireless and mobile systems, 2011, New York, NY, USA.

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Abstract

There have been several studies on the performance of TCP controlled transfers over an infrastructure IEEE 802.11 WLAN, assuming perfect channel conditions. In this paper, we develop an analytical model for the throughput of TCP controlled file transfers over the IEEE 802.11 DCF with different packet error probabilities for the stations, accounting for the effect of packet drops on the TCP window. Our analysis proceeds by combining two models: one is an extension of the usual TCP-over-DCF model for an infrastructure WLAN, where the throughput of a station depends on the probability that the head-of-the-line packet at the Access Point belongs to that station; the second is a model for the TCP window process for connections with different drop probabilities. Iterative calculations between these models yields the head-of-the-line probabilities, and then, performance measures such as the throughputs and packet failure probabilities can be derived. We find that, due to MAC layer retransmissions, packet losses are rare even with high channel error probabilities and the stations obtain fair throughputs even when some of them have packet error probabilities as high as 0.1 or 0.2. For some restricted settings we are also able to model tail-drop loss at the AP. Although involving many approximations, the model captures the system behavior quite accurately, as compared with simulations.

Item Type:	Conference Paper
Publisher:	Association for Computing Machinery
Additional Information:	Copyright of this article belongs to Association for Computing Machinery.NEW YORK.
Keywords:	WLANs;Performance Analysis;Modeling TCP Over 802.11 CSMA/CA;Channel Errors
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	27 Mar 2013 09:52
Last Modified:	27 Mar 2013 09:52
URI:	http://eprints.iisc.ac.in/id/eprint/46119

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