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Infotech Oulu Lecture Series
On information theoretic aspects of single- and multi-carrier communications
(by Michele Franceschini, Riccardo Pighi, Gianluigi Ferrari, Riccardo Raheli)
Lecturer: Professor Riccardo Raheli, University of Parma, Italy
Date: Thursday, January 17, 2008
Time: 14:15 - 15:45
Room: TS128
The aim of this talk is to analyze the ultimate performance limits of single-carrier (SC) and multi-carrier (MC) communication systems in terms of the achievable information rate (IR). From an engineering viewpoint, this performance measure is appealing because it provides a realistic information-theoretic benchmark in the fact that it takes inherently into account specific design constraints, such as the modulation format or the transmitted power spectrum. We analyze the
IR performance of SC and MC systems in frequency selective channels impaired by additive white Gaussian noise (AWGN) and possibly impulsive noise.
For the frequency selective AWGN channel, our analysis indicates that SC may significantly outperform MC systems under the additional constraint of uniform transmission power across the signal spectrum. This finding may be viewed as the information-theoretic counterpart of the known fact that water-filling and bit-loading schemes are mandatory in MC systems. It also raises the question of the true efficiency of MC schemes in broadcast systems.
For the impulsive noise channel, our analysis shows that MC schemes, not accounting for the noise statistics, exhibit an unavoidable loss with respect to SC schemes at information rates of practical significance. Interestingly, this result does not contradict previous findings obtained for uncoded systems, which show that MC schemes may outperform SC ones, because the loss manifests itself at rates of typical coded systems.
In order to validate our theoretical results, we also analyze the bit error rate (BER) performance of SC and MC schemes for trellis-coded modulation (TCM) and low-density parity-check (LDPC)-coded schemes. The obtained results suggest that a clever IR analysis can provide useful insights into system performance and design in several scenarios of interest in current applications.
More information: Matti Latva-aho and Aarne.Mammela(at)vtt.fi