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Full-Text Articles in Physical Sciences and Mathematics
Simulation Of Capture Behaviour In Ieee 802.11 Radio Modems, C. Ware, Joe F. Chicharo, Tadeusz A. Wysocki
Simulation Of Capture Behaviour In Ieee 802.11 Radio Modems, C. Ware, Joe F. Chicharo, Tadeusz A. Wysocki
Faculty of Informatics - Papers (Archive)
In this paper we investigate the performance of common capture models in terms of the fairness properties they reflect across contenting hidden connections. We propose a new capture model, Message Retraining,as a means of providing an accurate description of experimental data. Using two fairness indices we undertake a quantitative study of the accuracy with which each capture model is able to reflect experimental data. Standard capture models are shown to be unable to accurately reflect the fairness properties of empirical data. The Message Retraining capture model is shown to provide a good estimate of actual system performance in varying signal …
Hidden Terminal Jamming Problems In Ieee 802.11 Mobile Ad Hoc Networks, C. Ware, Tadeusz A. Wysocki, Joe F. Chicharo
Hidden Terminal Jamming Problems In Ieee 802.11 Mobile Ad Hoc Networks, C. Ware, Tadeusz A. Wysocki, Joe F. Chicharo
Faculty of Informatics - Papers (Archive)
This paper addresses experimental measurements from an IEEE 802.11 ad hoc network testbed, which indicate a strong signal strength dependence in the ability of a hidden terminal to gain access to the radio channel. We present analytical results investigating the `hidden terminal jamming' ability of the IEEE 802.11 DSSS physical layer. Results indicate that in a hidden terminal topology, the presence of an interfering transmission with a signal strength marginally greater than the transmission currently being received will result in an intolerable increase in BER, effectively jamming the ongoing transmission. These results confirm previous experimental measurements which show that after …
Unfairness And Capture Behaviour In 802.11 Adhoc Networks, C. Ware, J. Judge, Joe F. Chicharo, E. Dutkiewicz
Unfairness And Capture Behaviour In 802.11 Adhoc Networks, C. Ware, J. Judge, Joe F. Chicharo, E. Dutkiewicz
Faculty of Informatics - Papers (Archive)
We address issues with the performance of IEEE 802.11, when used in the adhoc mode, in the presence of hidden terminals. We present results illustrating the strong dependence of channel capture behavior on the SNR observed on contending hidden connections. Experimental work has illustrated that in a hidden terminal scenario, the connection having the strongest SNR is able to capture the channel, despite the use of the RTS-CTS-DATA-ACK 4-way handshake designed to alleviate this problem. Our results indicate that the near-far SNR problem may have a significant effect on the performance of an adhoc 802.11 network.