TXOP Exchange: A Mechanism for Cooperation in CSMA Networks

Takayuki NISHIO  Ryoichi SHINKUMA  Tatsuro TAKAHASHI  Narayan B. MANDAYAM  

IEICE TRANSACTIONS on Communications   Vol.E95-B   No.6   pp.1944-1952
Publication Date: 2012/06/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E95.B.1944
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Towards Management for Future Networks and Services)
cooperative mechanism,  TXOP Exchange,  CSMA/CA,  wireless local area network,  legacy neutrality,  

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Conventional mechanisms proposed for enhancing quality of service (QoS) in 802.11 networks suffer from a lack of backward compatibility and fairness with and to legacy devices. In this paper, we present a cooperative mechanism, called TXOP (transmission opportunity) Exchange, that provides a legacy-neutral solution in which only stations (STAs) participating in TXOP Exchange cooperatively use their available bandwidth to satisfy their required throughputs, while other legacy devices continue to get the same throughput performance as before. Specifically, we discuss the implementation of TXOP Exchange in legacy 802.11 networks. We show that this mechanism can be realized with minor modifications to the RTS (request-to-send) frames of only the STAs participating in TXOP Exchange and without any replacement of legacy access points or STAs. We show an example of a proportional fair algorithm for fair and efficient MAC cooperation using a Nash bargaining solution (NBS). A simulation study using a realistic simulator verifies that the TXOP Exchange mechanism ensures legacy neutrality and fair and efficient cooperation even when a large number of legacy STAs coexist.