Channel gain survey

報告者 : 李杰修指導教授 : 劉宏煥

References Ki-Dong Lee and Victor C. M. Leung, “capacity planning for group-mobile user in OFDMA

wireless networks,” EURASIP Journal. Wireless Communications and Networking, vol. 2006, pp. 1-12.

Zhu ji, K.j. Ray Liu, “Fair Multiuser channel allocation for OFDMA Networks Using Nash Bargaining Solutions and Coalitions,” IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 53 NO. 8, AUGUST 2005.

Seong Taek Chung, Andrea J. Goldsmith, “Degrees of Freedom in Adaptive Modulation : A Unified View,” IEEE TRANSACTIONS ON COMMUNICATIONS, VOL. 49 NO. 9,

SEPTEMBER 2001.

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Outline

• Introduction• System model

– Cost function– Parameter matrix– Bit-error rate(BER) – Transmission rate

• Simulation result• Conclusion && future work 112/04/13 3

Introduction

Planned admission capacity should be adjust with channel gain

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Introduction(cont)

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Depend on channel gain choose multi-subcarrier for multi-user

Cost function

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K : user numberN : subcarrier number

Cost function(cont)• i user transmission rate

• Subcarrier-assignment matrix [A]ij = a ij (i user, j subcarrier)

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i : user j : subcarrierN: subcarrier number

Bit-error rate(BER) of MQAM

ith user SNR at jth subcarrier P : power G : channel gain σ : noise power

Bit-error rate(BER) of MQAM C1 = 0.2 C2 = 1.5

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2

ij

ij

Transmission rate

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ij

W :Subcarrier bandwidth

Simulation result

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Simulation result(cont)

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Simulation result(cont)

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Average rate per connection

• Achievable rate of user j using subcarrier i

• Average rate per connection when y connections are ongoing as follows

)σ

PGa(WC ijij

ij 22 1log

)σ

)P(y/cGa(W

y

CR(y)

22 1log

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Conclusions

• We need “transmission rate” to planned admission control scheme

• “Channel gain” is the necessary parameter for compute transmission rate

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Future work

• Channel gain – flat Rayleigh fading model– Jakes model

• Autocorrelation channel gain

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