Bit-Interleaved Coded Modulation
Bit-Interleaved Coded Modulation
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DOI：
10.1561/0100000019
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
G. Caire;G. Taricco;E. Biglieri
中科院分区：
文献类型：
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作者：
G. Caire;G. Taricco;E. Biglieri
信号空间中的编码原理直接来自香农对受输入约束的波形高斯信道的分析。通信系统的早期设计分别集中于调制，即信号设计和检测，以及纠错码，其处理在基础波形信道的解调器处引入的错误。信号空间编码的正确观点，虽然从未脱离信息理论家的视线，但Imai和Ungerbock关于编码调制的开创性工作使编码理论家和系统设计师重新关注。最近，已经（重新）发现了在性能和解码复杂度之间具有良好折衷的强大的二进制码族。比特交织编码调制（BICM）是一种实用的方法，它结合了两个世界的最佳效果：它利用了信号空间编码的角度，同时允许使用几乎任何调制格式的强大的二进制码族。BICM避免了对编码调制典型的复杂和稍微不太灵活的设计的需要。事实上，当今大多数实现高频谱效率的系统（诸如DSL、无线局域网、WiMax及其演进）以及基于低频谱效率正交调制的系统都以BICM为特征，使得BICM成为波形信道的事实上的通用编码技术。BICM的理论表征是基于有效的编码设计技术以及改进的BICM解码器，例如，基于置信传播迭代算法及其近似的那些。在本文中，我们回顾了BICM的理论基础下的错误指数不匹配解码的统一框架。该框架允许准确的分析，而无需对交织器的长度或符号中多个比特之间的独立性进行任何特定的假设。我们进一步考虑BICM容量相对于信噪比（SNR）的灵敏度，并获得宽带制度（或低SNR制度）的表征。我们审查的错误概率分析的BICM，超越了考虑无限交织的标准方法，并考虑到调制所引入的编码位观测的依赖性的有效工具。我们还提出了界限，提高了联盟的界限，在该地区以外的截止率，是必不可少的现代randomlike码的级联与BICM的性能特征。最后，我们把我们的注意力转向BICM迭代译码，我们审查外部信息传递图，面积定理和代码设计通过曲线拟合。最后，我们概述了一些应用BICM超越经典相干高斯信道。
The principle of coding in the signal space follows directly from Shannon's analysis of waveform Gaussian channels subject to an input constraint. The early design of communication systems focused separately on modulation, namely signal design and detection, and error correcting codes, which deal with errors introduced at the demodulator of the underlying waveform channel. The correct perspective of signal-space coding, although never out of sight of information theorists, was brought back into the focus of coding theorists and system designers by Imai's and Ungerbock's pioneering works on coded modulation. More recently, powerful families of binary codes with a good tradeoff between performance and decoding complexity have been (re-)discovered. Bit-Interleaved Coded Modulation (BICM) is a pragmatic approach combining the best out of both worlds: it takes advantage of the signal-space coding perspective, whilst allowing for the use of powerful families of binary codes with virtually any modulation format. BICM avoids the need for the complicated and somewhat less flexible design typical of coded modulation. As a matter of fact, most of today's systems that achieve high spectral efficiency such as DSL, Wireless LANs, WiMax and evolutions thereof, as well as systems based on low spectral efficiency orthogonal modulation, feature BICM, making BICM the de-facto general coding technique for waveform channels. The theoretical characterization of BICM is at the basis of efficient coding design techniques and also of improved BICM decoders, e.g., those based on the belief propagation iterative algorithm and approximations thereof. In this text, we review the theoretical foundations of BICM under the unified framework of error exponents for mismatched decoding. This framework allows an accurate analysis without any particular assumptions on the length of the interleaver or independence between the multiple bits in a symbol. We further consider the sensitivity of the BICM capacity with respect to the signal-to-noise ratio (SNR), and obtain a wideband regime (or low-SNR regime) characterization. We review efficient tools for the error probability analysis of BICM that go beyond the standard approach of considering infinite interleaving and take into consideration the dependency of the coded bit observations introduced by the modulation. We also present bounds that improve upon the union bound in the region beyond the cutoff rate, and are essential to characterize the performance of modern randomlike codes used in concatenation with BICM. Finally, we turn our attention to BICM with iterative decoding, we review extrinsic information transfer charts, the area theorem and code design via curve fitting. We conclude with an overview of some applications of BICM beyond the classical coherent Gaussian channel.