IEEE_802.11e

IEEE 802.11eQuality of Service Support

Sanjay Saha Network Performance Analysis

Roll: JN 352 Dr. Md. Abdur Razzaque

MSc. Dept of CSE

University of Dhaka

26th Aprili 2015

What & Why

• Provided enhancements over legacy IEEE 802.11

• To provide quality of service support such as voice over wireless and streaming multimedia

• DCF is now EDCAEnhanced Distributed Channel Access

• Two classes of users with different priorities

Network Performance Analysis: Fayez Gebali ch#10

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Flashback (DCF)


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Flashback (DCF)


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Protocol Assumptions

• Two priority classes(class 1 & class 2)(DCF: single class users)

• Two contention windows (w1 & w2)(DCF: one contention window)

• Probability of a frame to send is ‘a’

• γ < 1 : prob. that a transmitted frame is of class 1


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Supporting eqns.

Probability that a class 1 user sends data

Population seen by each slot in a contention window


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Supporting eqns.

Probability that a ‘k’ class 1 users attempt to transmit

Probability that a ‘k’ class 2 users attempt to transmit


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Markov Chain


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Markov Chain

Channel stays idle with probability:

Class 1 user transmitting probability:

Class 2 user transmitting probability:


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Markov Chain (Dist. Vector)


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Performance(1/3)

Throughputs:

Avg. Input Traffic:

Acceptance Probability:


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Performance(2.1/3)


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Performance(2.2/3)

DCF: Throughput vs. Input Traffic Curve


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Performance(3/3)


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That’s all !!!


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IEEE_802.11e

Engineering

Transcript of IEEE_802.11e