Optimized symbol mapping for bit-interleaved coded modulation with iterative decoding
ABSTRACT Symbol mapping is very crucial for the performance of bit-interleaved coded modulation with iterative decoding (BICM-ID). In this paper, a new scheme of symbol mapping called Cross-8PSK-Quasi-Gray is proposed. The optimization scheme of Cross-8PSK is composed of two QPSK with different radius and phases. Through analysis and comparisons with three previously mentioned symbol mappings in terms of channel capacity and error performance, simulation results show that Cross-8PSK-Quasi-Gray mapping significantly outperforms set partitioning, semi set partitioning labeling maps in the aspects of both channel capacity and error performance. The overall performance of Cross-8PSK-Quasi-Gray mapping is nearly close to gray mapping in conventional 8PSK. Thus, Cross-8PSK-Quasi-Gray mapping is a good scheme for designing the power-efficient BICM.
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ABSTRACT: Bit-interleaved coded modulation (BICM) is a bandwidth-efficient coding technique consisting of serial concatenation of binary error-correcting coding, bit-by-bit interleaving, and high-order modulation. The author addresses the problem of finding the signal sets that are most suitable for designing power-efficient BICM schemes over an additive white Gaussian noise channel. To this end, the expression of the BICM capacity limit is exploited and evaluated for several 8- and 16-ary constellations. It is also shown that the bit error probability curves of the modulation schemes without coding can be used to determine the most attractive constellations. Finally, the bit error rate performance of some BICM schemes made up of turbo codes and various signal sets is investigated to illustrate the theoretical results.IEE Proceedings - Communications 07/2003; · 0.32 Impact Factor
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ABSTRACT: Mutual information transfer characteristics of soft in/soft out decoders are proposed as a tool to better understand the convergence behavior of iterative decoding schemes. The exchange of extrinsic information is visualized as a decoding trajectory in the extrinsic information transfer chart (EXIT chart). This allows the prediction of turbo cliff position and bit error rate after an arbitrary number of iterations. The influence of code memory, code polynomials as well as different constituent codes on the convergence behavior is studied for parallel concatenated codes. A code search based on the EXIT chart technique has been performed yielding new recursive systematic convolutional constituent codes exhibiting turbo cliffs at lower signal-to-noise ratios than attainable by previously known constituent codesIEEE Transactions on Communications 11/2001; · 1.75 Impact Factor
Conference Proceeding: Near Shannon limit error-correcting coding and decoding: Turbo-codes. 1[show abstract] [hide abstract]
ABSTRACT: A new class of convolutional codes called turbo-codes, whose performances in terms of bit error rate (BER) are close to the Shannon limit, is discussed. The turbo-code encoder is built using a parallel concatenation of two recursive systematic convolutional codes, and the associated decoder, using a feedback decoding rule, is implemented as P pipelined identical elementary decodersCommunications, 1993. ICC 93. Geneva. Technical Program, Conference Record, IEEE International Conference on; 06/1993