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Flexible Channelization for 802.11 Wireless LANs. Zafar Ayyub Qazi*, Zhibin Dou and Prof. Samir Das* *Department of Computer Science (WINGS lab), Stony Brook University Department of Computer Science, Tianjin University. Problem. 802.11 b/g Wireless LANs becoming increasingly crowded
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Flexible Channelization for 802.11 Wireless LANs Zafar AyyubQazi*, Zhibin Dou and Prof. Samir Das* *Department of Computer Science (WINGS lab), Stony Brook University Department of Computer Science, Tianjin University
Problem • 802.11 b/g Wireless LANs becoming increasingly crowded • Only certain predefined channels and fixed channel widths used • Improve spectrum efficiency bychoosing a channel width and center frequency for each transmission • Goal: To understand how to employ flexible channelization when using multiple potentially interfering links
Challenges • Increasing channel width potentially increases throughput • However for a constant transmit power, increasing channel width reduces Signal to Noise Ratio.
Observations • Asymmetrical Carrier Sensing • No one configuration provides best performance in all the cases • Impact on Carrier Sensing • Impact on Hidden and Exposed terminals
Possible Ways Forward • Modeling Link Capacity using SINR at the Receiver and the Interference level at the Sender: • Challenge: Computing a conflict graph for all channel widths, center frequencies—huge overhead! • TDMA Based Approach