Improving throughput by tuning carrier sensing in 802.11 wireless networks

Computer Communications 2009

Qiang Shena, Xuming Fanga,

Rongshen Huangb, Pan Lib, Yuguang Fangb

a: Provincial Key Lab of Information Coding and Transmission, Southwest Jiaotong University b: Department of ECE, University of Florida

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Outline Introduction Wireless network models Solution to the blocking problem Performance evaluation Conclusions

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IntroductionIn 802.11 MAC protocol

Physical carrier sensing thresholdHidden terminal problem

Exposed terminal problem Spatial reuse

Tuning carrier sensing threshold(range) && Channel rateImprove the network throughput

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Wireless network models A successful reception

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Interference model Chain topology

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Wireless network models A successful reception

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How to determine the k

k = 3, S0=6.02

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Solution to the blocking problem Optimum sensing range for RTS Optimum sensing range for CTS Maximization of the achievable data

rate

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Optimum sensing range for RTS

SS RR11 22 33 44

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d

Optimum sensing range for CTS

SS RR11 22 33 44

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Maximization of the achievable data rate

The relationship between the spatial reuse and the max achievable data rate

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Simulator: NS2Payload : 8000 bitsChain topologyK = 3rc = 6Mbps

Performance evaluation

11 22 33 44

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Out of TR

Throughput of node 1-2 and 4-3

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Throughput of Node 1-2 and 3-4

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End-to-end throughput with different values of k

Chain topology: 7 nodesAlleviate intra-flow contention

Increasing the RTS sensing range of the source node (IRSR)

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End-to-end throughput comparison of different methods

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Throughput comparison of IRSR and DAW

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Delay comparison of IRSR and DAW

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Conclusions In this paper

Tuning physical carrier sensing Maximizing channel rate

Improving network throughput Increasing spatial reuse

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Thank You!!

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