OFDM and turbo codes are complementary

5/14/01


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Table of Contents

PPT Slide

OFDM and turbo codes are complementary

OFDM modulates on parallel carriers by (I)FFT operations

But: Uncoded performance is bad in frequency selective fading

OFDM needs good error correction

Forward error correction is performed over the carriers

The performances on AWGN and flat fast fading channels are excellent

Never trust a wireless channel: What in frequency selective fading?

The bad carriers are still show breakers

Turbo trellis modulation may solve the problem

Turbo trellis modulation performs better indeed

Trellis solution has nice statistics, but is less flexible

OFDM naturally enables solutions to frequency selective problems

Let the turbo decoder profit from OFDM

Adaptive loading avoids bad carriers

Adaptive decoding is (almost) for free

Also the ‘bad’ carriers have to surrender

Performance is increased significantly

We put the emphasis on ‘real’ bit-based turbo codes at the moment

We further investigate product codes and trellis coded modulation

What are we waiting for?

Practical impediments need to be tackled

IMEC’s effort should lead to T@MPO (Turbo @ Minimum POwer)

Please spread the good news ...

Author: imec

Email: bougardb@imec.be

Home Page: http://www.imec.be

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Copyright IMEC, 2001

 

Wireless Communication, 2001. © Marc Engels, Liesbet van der Perre et al., IMEC Leuven