Abstract
Probabilistic shaping for bit-interleaved coded modulation (BICM) systems at low signal-to-noise ratio (SNR) is investigated. Using known results for BICM systems with a uniform input distribution, the combinations of input alphabet, input distribution, and binary labeling that achieve the Shannon limit -1.59 dB are fully characterized. It is found that a BICM system achieves the Shannon limit at low SNR if and only if it can be represented as a zero-mean linear projection of a hypercube, which is the same condition as for uniform input distributions. Hence, probabilistic shaping offers no extra degrees of freedom to optimize the low-SNR regime of BICM systems, in addition to what is provided by geometrical shaping.
| Original language | English |
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| Title of host publication | IEEE International Symposium on Information Theory (ISIT) |
| Place of Publication | Piscataway |
| Publisher | Institute of Electrical and Electronics Engineers |
| Pages | 2421-2425 |
| ISBN (Electronic) | 978-1-4673-2578-3 |
| ISBN (Print) | 978-1-4673-2580-6 |
| DOIs | |
| Publication status | Published - Jul 2012 |
| Event | 2012 IEEE International Symposium on Information Theory, ISIT 2012 - Cambridge, MA, USA Duration: 1 Jul 2012 → 6 Jul 2012 |
Conference
| Conference | 2012 IEEE International Symposium on Information Theory, ISIT 2012 |
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| Abbreviated title | ISIT 2012 |
| Period | 1/07/12 → 6/07/12 |