Adaptive Channel Estimation for MBOFDM Systems under Interfering Environments

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Adaptive Channel Estimation for MB-OFDM Systems
under Interfering Environments

• Presented by ???
• 2006.06.30

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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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System description
TFC
S/P
Insert pilot FFT
Add GI P/S
SignalMapper
scrambler / convolutional encoder / puncturer /
interleaver
DAC
Channel h ( t)
Channel Estimator
S/P remove GI
FFT
P/S
SignalDemapper
Channel EQ
de-interleaver / viterbi decoder / de-scrambler
ADC
TFC
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UWB preamble format
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Time Frequency Code Table
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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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Scenarios of UWB preamble collisions(1/2)
preamble
interference
Case (a)
Case (b)
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Scenarios of UWB preamble collisions(2/2)
Case (a)
Case (b)
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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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The property exploited(1/3)
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The property exploited(2/3)
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The property exploited(3/3)
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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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Proposed estimator-TR estimator

• TR estimator
• LSE
• Linear Interpolation
• Combination Schemes
• Equal Gain Combining
• Maximum Ratio Combining
• Select and Repeat Combining

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Equal Gain Combining(1/2)
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Equal Gain Combining(2/2)
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Maximum Ratio Combining(1/2)
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Maximum Ratio Combining(2/2)
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Select and Repeat Combining(1/2)
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Select and Repeat Combining(2/2)
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TREO estimator

• Time Redundancy Even Odd (TREO)
• First symbol ? even sub-carriers
• Second symbol ? odd sub-carriers

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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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Simulation environment Criteria

• OFDM symbol with N128. ZP length 32. UWB channel
  CM1 CM4. 528M chip rate.
• UWB symbol with N128. ZP length 32. UWB channel
  CM1 CM4. 528M chip rate.

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Simulation result one symbol ZP noise only
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Simulation result one symbol ZP low SIR low SNR
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Simulation result one symbol ZP low SIR high
SNR
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Simulation result one symbol ZP low SIR random
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Simulation result one symbol ZP high SIR random
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Simulation result UWB noise only
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Simulation result UWB low SIR
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Simulation result UWB high SIR
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Simulation result UWB low SIR
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Simulation result UWB high SIR
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Outline

• System Descriptions
• Motivations
• The time redundancy properties
• TR Estimators
• Simulations
• Conclusions

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Conclusions

• We can introduce time redundancy by frequency
  decimation and apply diversity combining.
• We can expect the improvement by TR estimator.
• TR estimator can also work well for other
  applications