Effect of Noisy Estimation on Turbo-Coded Modulation over Flat Rayleigh Fading Channels

Tadashi MINOWA  Hideki IMAI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E85-A   No.10   pp.2211-2219
Publication Date: 2002/10/01
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Information Theory and Its Applications)
Category: Coding Theory
flat-Rayleigh fading channel,  noisy channel estimate,  channel capacity,  turbo-coded modulation,  

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The effects of noisy estimates of fading on turbo-coded modulation are studied in the presence of flat Rayleigh fading, and the channel capacity of the system is calculated to determine the limit above which no reliable transmission is guaranteed. This limit is then compared to the signal-to-noise ratio required for a turbo-coded modulation scheme to achieve a bit-error-rate of 10-5. Numerical results are obtained, especially for QAM signals. Our results show that even slightly noisy estimates significantly degrade the theoretical limits related to channel capacities, and that an effective use of capacity-approaching codes can lower the sensitivity to noisy estimates, though noise that exceeds a certain threshold cannot be offset by the performance improvement associated with error-correcting capability.