CHAIN: Introducing Minimum Controlled Coordination into Random Access MAC

Zheng Zeng, Yan Gao, Kun Tan, and P. R. Kumar


IEEE 802.11 DCF is the dominant protocol used in

existing WLANs. However, the efficiency of DCF progressively

degrades with the increase of contending clients in the network

as well as the wireless link rate. To address this issue, in this

paper, we present a distributed random media access protocol,

named CHAIN, which significantly improves uplink performance

of WLANs. CHAIN mainly uses overhearing to coordinate clients

in a network, and thus introduces little control overhead. The

key in CHAIN is a novel piggyback transmission opportunity.

In CHAIN, clients maintain a precedence relation among one

another, and a client can immediately transmit a new packet

after it overhears a successful transmission of its predecessor,

without going through the regular contending process. When

the network load is low, CHAIN behaves similar to DCF; But

when the network becomes congested, clients automatically start

chains of transmissions to improve efficiency. CHAIN is derived

from DCF and co-exists friendly with it. Moreover, it possesses

all the advantages of the 802.11 DCF standard - simplicity,

robustness, and scalability. We analytically prove the correctness

and fairness of CHAIN. Our extensive simulations on J-SIM verify

our analytical results, and demonstrate significant performance

gain of CHAIN over DCF.


Publication typeInproceedings
Published inThe 30th IEEE International Conference on Computer Communications (INFOCOM 2011)
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