Spread OFDM-IM With Precoding Matrix and Low-Complexity Detection Designs
Spread OFDM-IM With Precoding Matrix and Low-Complexity Detection Designs
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DOI：
10.1109/tvt.2018.2872873
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发表时间：
2018-10
影响因子：
6.8
通讯作者：
Thien Van Luong;Y. Ko
中科院分区：
文献类型：
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作者：
Thien Van Luong;Y. Ko
提出了一种新的具有索引调制的扩频正交频分复用(S-OFDMIM)，它利用沃尔什-哈达玛(WH)和Zadoff-Chu(ZC)等预编码矩阵对活动子载波的非零数据符号及其索引进行扩频，然后将其压缩到所有可用的子载波中。这旨在利用多径和索引分集来增加发射分集。在性能分析方面，我们推导了误比特率(BEP)，以便深入了解分集和编码增益，特别是不同扩展矩阵的选择对这些增益的影响。有趣的是，这揭示了使用原始WH和ZC矩阵的旋转版本来进一步提高BEP性能的机会。更具体地说，旋转矩阵可以使S-OFDMIM获得最大的分集增益，即子载波数，而基准方案的分集增益被限制为两个。此外，我们还提出了三种低复杂度的检测器，即最小均方误差对数似然比、索引模式MMSE(IP-MMSE)和增强型IP-MMSE，它们实现了不同程度的复杂度和可靠性。仿真结果证明了S-OFDMIM算法的优越性。
We propose a new spread orthogonal frequency division multiplexing with index modulation (S-OFDM-IM), which employs precoding matrices such as Walsh-Hadamard (WH) and Zadoff-Chu (ZC) to spread both non-zero data symbols of active sub-carriers and their indices, and then compress them into all available sub-carriers. This aims to increase the transmit diversity, exploiting both multipath and index diversities. As for the performance analysis, we derive the bit error probability (BEP) to provide an insight into the diversity and coding gains, and especially impacts of selecting various spreading matrices on these gains. This interestingly reveals an opportunity of using rotated versions of original WH and ZC matrices to further improve the BEP performance. More specifically, rotated matrices can enable S-OFDM-IM to harvest the maximum diversity gain, which is the number of sub-carriers, while benchmark schemes have diversity gains limited by two. Moreover, we propose three low-complexity detectors, namely minimum mean square error log-likelihood ratio, index pattern MMSE (IP-MMSE), and enhanced IP-MMSE, which achieve different levels of complexity and reliability. Simulation results are presented to prove the superiority of S-OFDM-IM over the benchmarks.