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G. Matz:
"LLR quantization - Principles and applications in digital communications";
Talk: Gastvortrag Univ. Erlangen-Nürnberg, Erlangen (Germany) (invited); 10-12-2010.

Log-likelihood ratios (LLR) are of fundamental importance
in many modern communication system designs. In spite of this fact,
the practically relevant question of how to efficiently represent
LLRs in digital implementations has received very little attention.
In this talk, we summarize some of our recent results regarding LLR
quantization in digital communications. Using information-theoretic
considerations, we first describe the design and implementation of LLR
quantizers for point-to-point transmissions based on multiple-input
multiple-output bit-interleaved coded modulation (MIMO-BICM). The
performance of the LLR quantizers is assessed in terms of the overall
system's mutual information. We further propose a computationally
efficient MIMO-BICM demodulator that directly delivers quantized
LLRs. The last part of the talk illustrates the application of LLR
quantization to cooperative wireless networks in the context of
relaying and physical layer network coding.