[Nets-seminars] Talk 4:00 Friday 4th December GS/302

Richard G. Clegg richard at richardclegg.org
Fri Nov 27 13:54:39 GMT 2009


Wireless Network Performance Analysis by Fixed-point Approximations

Abstract:
With various types of wireless network becoming integral parts of the 
network infrastructure, their performance analysis becomes important for 
all aspects of network design and engineering. This talk revolves around 
the fixed-point methods as a general framework for the performance analysis 
of communication protocols over different types of wireless networks. Based 
on formulations derived for wired networks in the literature, we expand 
them to accommodate properties that are more frequently, though not 
exclusively, met in wireless networks including error-prone, broadcast and 
MAC-shared links, link asymmetry and transport protocol mechanisms such as 
Transmission Control Protocol (TCP) proxies. We illustrate the application 
of fixed-point approximations on different wireless scenarios. First, we 
show the use of the method in the context of closed-loop TCP traffic over 
bandwidth on demand satellite networks (e.g. DVB-RCS satellite networks). 
Then, we apply the approach to address the problem of analytically 
predicting the performance of flows such as TCP or TCP-friendly rate 
controlled (TFRC) over wireless local area networks (WLAN) with IEEE 802.11 
DCF scheduled links. In both cases, the analytical results are compared 
against simulation results. We demonstrate the applicability of fixed-point 
techniques to the study of interactions between protocols at different 
layers of the protocol stack, giving pointers to related work in the 
literature. Finally, the talk discusses the limitations of the method as 
well as directions for future work.

-- 
Richard G. Clegg,
Dept of Elec. Eng.,
University College London
http://www.richardclegg.org/



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