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Stochastic Models of TCP Flows over 802 11 WLANs

This technical report develops an analytical framework to model the interaction between TCP and 802:11 MAC protocol over a WLAN, when concurrent TCP downlink and uplink connections are active. Assuming a TCP advertised window equal to one, we formulate a Markov model to characterize the dynamic network contention level, de ned as the expected number of wireless stations having at least a frame to transmit. Exploiting the stochastic characterization of the dynamic contention level induced by the TCP ow control, we develop an accurate model of the MAC protocol behavior to evaluate the TCP throughput performance. Comparison with simulation results validates the model, which provides the analytical basis for the optimization of the system performance. In particular, we prove that using a TCP advertised window equal to one ensures a fair access to the TCP ows of the channel bandwidth, irrespective of the number of TCP downlink or uplink connections. Moreover, we show that the aggregate TCP throughput is almost independent of the number of wireless stations in the network.


2005

Autori: Bruno R., Conti M., Gregori E.
Autori IIT:

Tipo: Rapporti tecnici, manuali, carte geologiche e tematiche e prodotti multimediali
Area di disciplina: Information Technology and Communication Systems
Technical Report IIT TR-11/2005