Improved design of bit mapping based on EXIT-chart analysis for DVB-T2 system
Improved design of bit mapping based on EXIT-chart analysis for DVB-T2 system
复制标题
基于EXIT图分析的DVB-T2系统位映射改进设计
DOI：
10.1109/tce.2011.6131128
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发表时间：
2011
影响因子：
4.3
通讯作者：
Jian Song
中科院分区：
文献类型：
--
作者：
Keqian Yan;Tao Cheng;Fang Yang;Kewu Peng;Jian Song
针对第二代地面数字视频广播（DVB-T2）标准，研究了提高差错控制性能的比特映射方案设计。通常在低密度奇偶校验（LDPC）编码调制系统中，高阶调制和非规则LDPC码固有的比特可靠性不均匀，意味着解码器和解调器之间的失配。因此，在两个模块之间插入比特映射，以将不同编码比特的不等错误保护（UEP）与不同调制级别相匹配。该方案在比特交织编码调制（BICM）系统中，在不增加复杂度的情况下，性能得到了显著的改善。通过对EXIT图进行曲线拟合，提出了一种改进位映射方案的解复用器设计方法。给出了AWGN信道和Rayleigh信道下DVB-T2系统的设计实例。仿真结果表明，所提出的解复用方案甚至可以超过DVB-T2标准中规定的解复用操作的性能。
In this paper, we focus on the design of bit mapping scheme to improve the error-control performance for the second generation digital video broadcasting-terrestrial (DVB-T2) standard. Generally in the case of low-density parity-check (LDPC)-coded modulation system, the nonuniform bit reliabilities inherent to the high-order modulation and irregular LDPC code imply the mismatch between the decoder and the demodulator. Hence, the bit mapping is plugged between the two modules to match the unequal error protections (UEPs) of different coded bits to different modulation levels. This scheme gives a remarkable performance improvement with no added complexity in the bit-interleaved coded modulation (BICM) system. By performing the curve-fitting on the extrinsic information transfer (EXIT) chart, we propose a DEMUX design methodology to improve the bit mapping scheme. Design examples are given for the DVB-T2 system under the AWGN channel as well as the Rayleigh channel. Simulation results indicate that the proposed DEMUX schemes can even surpass the performance of the DEMUX operation specified in the DVB-T2 standard.