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POWER CONTROL FOR MC-CDMA

UNDER IMPERFECT KNOWLEDGE

OF CHANNEL STATE INFORMATION

Presented by

M.SURESH

Under the guidance of

Dr. P. DANANJAYAN

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CONTENT

OBJECTIVE.

MC-CDMA.

NEED FOR POWER CONTROL.

MC-CDMA TRANSMITTER AND RECEIVER. POWER ALLOCATION IN MC-CDMA

IMPERFECT CSI.

DRAWBACK OF EXISTING WF ALGORITHM.

IMPROVED WATER-FILLING ALGORITHM.

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OBJECTIVE

To improve capacity of the MCCDMA system under

imperfect knowledge of channel state information through

power allocation using water filling game theory and further

capacity improvements through MIMO diversity scheme.

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MC-CDMA

Combination of OFDM and CDMA.

ADVANTAGES:

High spectral efficiency.

High data rate.

DISADVANTAGES

Multiple Access Interference

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NEED FOR POWER CONTROL

To overcome Multiple Access Interference(MAI).

To improve capacity of the system.

To improve SINR.

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PHASE-1

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MC-CDMA TRANSMITTER & RECEIVER

channel

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POWER ALLOCATION IN MC-CDMA

WATER FILLING ALGORITHM

Power allocation to subcarriers to improve capacity.

Perfect Channel State Information(CSI) at Transmitter.

LIMITATION

Imperfect CSI in realistic environment.

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IMPERFECT CSI

CSI feedback Delay.

CSI estimation error.

Partial CSI feedback.

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CSI FEEDBACK DELAY

Distance between transmitter and receiver.

Time taken for Channel estimation .

Time taken for power allocation.

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CSI ESTIMATION ERROR & LIMITED FEEDBACK

CSI ESTIMATION ERROR.

Error in the channel estimation.

PARTIAL CSI FEEDBACK

Feedback data is directly proportional to subcarrier number.

Reduce feedback by subcarrier correlation.

Quantization error.

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PHASE-2

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DRAWBACK OF EXISTING WF ALGORITHM

Need to search for water level results in computational

complexity.

Time consumption is high.

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IMPROVED WATER FILLING ALGORITHM Remove the need for water level searching.

Reduce computational complexity.

Multiple time faster than existing water-filling algorithm.

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REFERENCES

[1] Amod J. G. Anandkumar, Animashree Anandkumar, Sangarapillai

Lambotharan, and Jonathon A. Chambers Robust Rate Maximization Game

Under Bounded Channel Uncertainty ,IEEE Transactions On Vehicular

Technology, Vol. 60, No. 9, November 2011

[2] Rajiv Devaraja, Anjana Punchihewa and Vijay K. Bhargava,Energy-

Aware Power Allocation in Cooperative Communication Systems with

Imperfect CSI,IEEETransactions On Communications, Vol. 61, No. 5, May

2013.

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Contd..[3] Xiang Ling, Bin Wu, Pin-Han Ho, Fengya Luo, and Lili PanFast Water-

Filling for Agile Power Allocation in Multi-Channel Wireless

Communications ,IEEE Communications Letters, Vol. 16, No. 8, August

2012.

[4] Chunhui Liu, Anke Schmeink and Rudolf Mathar Efficient Power

Allocation for OFDM with Imperfect Channel State Information,5th

International Conference on Wireless Communications, Networking and

Mobile Computing,WiCom '09,2009.

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Contd..[5] Yi Liu,Qi Ma,Hailin Zhang PowerAllocation and Adaptive Modulation

for OFDM Systems with Imperfect CSI ,IEEE 69th Vehicular Technology

Conference,VTC Spring2009.

[6] Hanna BoguckaGame Theoretic Model for the OFDM Water-Filling

Algorithm with Imperfect Channel State Information,IEEE International

Conference on Communications ICC '08,2008.

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THANK YOU