G-DCF: Improving System Spectral Efficiency through Concurrent Transmissions in Wireless LANs

Concurrent Access in Wireless LANs

Achieving Fairness in Wireless LANs by Enhanced 802.11 DCF

Over the past few years, Wireless Local Area Networks (WLANs) have gained an increased attention and a large number of WLANs are being deployed in universities, companies, airports etc. Majority of the IEEE 802.11 based WLANs employ Distributed Coordination Function (DCF) in Wireless Access Points (AP) to arbitrate the wireless channel among Wireless Stations (STAs). However, DCF poses serious ...

Power Efficiency Improvements for Wireless Transmissions

To my parents, and my wife Lin Sun. iii ACKNOWLEDGEMENTS I would like to express my gratitude to all whose direct and indirect support helped me complete my thesis. First, I would like to thank my advisor, Prof. G. Tong Zhou who has continuously supported my work and ideas throughout my studies at Georgia Institute of Technology. I appreciate her close guidance and great efforts to prepare me t...

Improving packet delivery efficiency using multi-radio diversity in wireless LANs

Data transmissions in Wireless Local Area Networks (WLANs) often suffer from bit errors that arise from the notoriously complex and time-varying signal propagation characteristics of the wireless medium. A number of physical factors such as attenuation and multi-path are prevalent indoors and can lead to high bit-error rates at the link layer. These in turn lead to packet losses, low throughput...

Piggybacked-Ack-aided Concurrent Transmissions in Wireless Networks

It is well-known that MAC protocols for multihop wireless networks face the problems of hidden and exposed nodes due to the limited transmission range of wireless nodes. The Distributed Coordination Function (DCF) mechanism of the IEEE 802.11 standard [2] addresses the issue of hidden node problem by employing a four-way handshake of RTS-CTSDATA-ACK frames. In this exchange, the transmitter emi...