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 ...
Email: bougardb@imec.be
Home Page: http://www.imec.be
Other information: Copyright IMEC, 2001