DocumentCode :
423432
Title :
Fairness and its impact on delay in 802.11 networks
Author :
Berger-Sabbatel, Gilles ; Duda, Andrzej ; Gaudoin, Olivier ; Heusse, Martin ; Rousseau, Franck
Author_Institution :
LSR-IMAG Lab., Grenoble, France
Volume :
5
fYear :
2004
fDate :
29 Nov.-3 Dec. 2004
Firstpage :
2967
Abstract :
We analyze in this paper the fairness of the 802.11 DCF (distributed coordination function) access method. Short-term fairness is an important property of a MAC layer for obtaining short delays. We show that contrary to the common wisdom, a 802.11 cell with two hosts does not exhibit short-term unfairness. We propose a new fairness index: the number of inter-transmissions that other hosts may perform between two transmissions of a given host. By means of this index, we analyze the fairness of 802.11 for the case of two hosts and derive the probability distribution of the number of inter-transmissions. Our results show that even on the short term time scale the 802.11 DCF access method provides fairness to competing hosts. When compared with slotted ALOHA, a multiple access randomized protocol with good fairness properties, 802.11 presents even better fairness. To validate the model, we compare the analytical results with experimental histograms obtained via simulations and measurements.
Keywords :
access protocols; multi-access systems; statistical distributions; wireless LAN; 802.11 network delays; DCF access method; DCF fairness index; MAC layer short-term fairness; competing host intertransmission probability distribution; distributed coordination function; multiple access randomized protocol; shared link medium; Access protocols; Analytical models; Degradation; Delay; Extrapolation; Histograms; Intelligent networks; Laboratories; Multiaccess communication; Probability distribution;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Global Telecommunications Conference, 2004. GLOBECOM '04. IEEE
Print_ISBN :
0-7803-8794-5
Type :
conf
DOI :
10.1109/GLOCOM.2004.1378897
Filename :
1378897
Link To Document :
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