文档介绍：BICM in HARQ with Mapping Rearrangement: Capacity and Performance of Practical Schemes Leszek Szczecinski, Fatou-Kin ′e Diop ?, Mustapha Benjillali, Andres Ceron ?, and Rodolfo Feick ? INRS-EMT, University of Quebec, Montreal, Canada ?INPT, Rabat, o ?UTFSM, Valparaiso, Chile Abstract—Hybrid ARQ with bining for high-order modulations (such as 16-QAM) may be signi?cantly enhanced if the bits-to-symbols mappings are appropriately changed through- out the transmissions. In this paper, we analyze the relationship between such mapping rearrangement (or mapping diversity) and channel coding. We calculate the capacity of the popular bit-interleaved coded modulation (BICM) to draw qualitative and approximate quantitative conclusions that are valid for strong codes approaching the capacity limits. We conclude that the choice/design of the appropriate mapping depends on the targeted spectral ef?ciency and we demonstrate that certain forms of mapping rearrangement may be counterproductive. We also show that iterative demapping may be essfully applied to signi?cantly reduce the gap between the BICM and coded modulations capacities. The analysis presented is illustrated with the results obtained when the mapping rearrangement bined with practical turbo codes. I. I NTRODUCTION The objective of this paper is to analyze the fundamental limits attainable by channel coding in bit-interleaved co