Supplementary Index Bit Aided Transmit Diversity Scheme for Enhanced DCT-OFDM With Index Modulation
Supplementary Index Bit Aided Transmit Diversity Scheme for Enhanced DCT-OFDM With Index Modulation
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DOI：
10.1109/lcomm.2022.3181601
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发表时间：
2022-08
期刊：
影响因子：
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通讯作者：
Aijun Cao;Lixia Xiao;Xiaobin Wei;Pei Xiao;R. Tafazolli
中科院分区：
文献类型：
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作者：
Aijun Cao;Lixia Xiao;Xiaobin Wei;Pei Xiao;R. Tafazolli
本文提出了一种新的辅助索引比特辅助发射分集(SIB-TD)方法，用于基于增强离散余弦变换的索引调制正交频分复用(EDCT-OFDM-IM)系统。具体地，对于第一天线，即主分支，采用常规的索引调制(IM)，并且利用一个索引调制组中未激活的副载波的索引，用于将第二天线的相同索引调制组上的IM映射，即，分集分支。因此，不能在两个天线上同步激活每个副载波。最后，一个天线的非激活副载波将发送与另一个天线相同的调制符号，以利用分集增益。在接收端，还通过联合检测主分支和分集分支来实现最大似然分组接收器。仿真结果表明，即使在信道估计不理想的情况下，该方案也比传统的EDCT-ofdm-IM和带或不带IM码的DFT-ofdm具有更好的性能。
In this letter, a novel supplementary index bit aided transmit diversity (SIB-TD) approach is proposed for an enhanced discrete cosine transform based orthogonal frequency division multiplexing with index modulation (EDCT-OFDM-IM) system. Specifically, conventional index modulation (IM) is employed for the first antenna, i.e., the main branch, and the non-activated subcarriers’ indices in one index modulation group are utilized for the IM mapping on the same index modulation group for the second antenna, i.e., the diversity branch. Hence, each subcarrier can not be synchronously activated on the two antennas. Finally, the non-activated subcarriers of one antenna will transmit the same modulated symbols of the other antenna to exploit the diversity gain. At the receiver, a maximum likelihood group-wise receiver is also developed by detecting the main and diversity branches jointly. Simulation results demonstrate the superiority of the proposed scheme over both the conventional EDCT-OFDM-IM and the DFT-OFDM with Alamouti code either with or without IM respectively, even under the imperfect channel estimation.