A Tight Upper Bound for Enhanced DCT-OFDM With Index Modulation
A Tight Upper Bound for Enhanced DCT-OFDM With Index Modulation
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DOI：
10.1109/tvt.2020.3035183
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发表时间：
2020-12-01
影响因子：
6.8
通讯作者：
Tafazolli, Rahim
中科院分区：
文献类型：
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作者：
Cao, Aijun;Xiao, Lixia;Tafazolli, Rahim
正交频分复用 (OFDM) 与索引调制 (IM) (OFDM-IM) 采用激活的子载波索引来传递信息，与传统 OFDM 系统相比，具有更高的能源效率和更低的峰均功率比 (PAPR)。为了进一步提高基于离散傅里叶变换（DFT）的 OFDM-IM（DFT-OFDM-IM）的吞吐量，可以采用基于离散余弦变换（DCT）的 OFDM-IM（DCT-OFDM-IM）以及给定相同带宽的双子载波。然而，DCT-OFDM-IM 的主要缺点之一是其在色散信道上缺乏循环卷积特性。为了解决这个问题，提出了一种增强型 DCT-OFDM-IM (EDCT-OFDM-IM) 系统，通过在发射机引入对称前缀和后缀以及在接收机引入预滤波器，在误码率 (BER) 方面比 DFT-OFDM-IM 具有更好的性能。然而，由于其特殊的结构，很难得出准确的平均误码概率（ABEP）上限，而这对于性能评估至关重要。在本文中，使用矩生成函数 (MGF) 导出了严格的 ABEP 上限。我们的理论分析通过模拟结果得到验证，并被证明是非常准确的。因此，进一步分析证明了EDCT-OFDM-IM系统相对于经典OFDM-IM系统的优势。
Orthogonal frequency division multiplexing (OFDM) with index modulation (IM) (OFDM-IM), which employs the activated sub-carrier indices to convey information, exhibits higher energy efficiency and lower peak-to-average power ratio (PAPR) than conventional OFDM systems. To further improve the throughput of discrete Fourier transform (DFT) based OFDM-IM (DFT-OFDM-IM), discrete cosine transform (DCT) based OFDM-IM (DCT-OFDM-IM) can be employed with double subcarriers given the same bandwidth. However, one of the main disadvantage of DCT-OFDM-IM is its lack of circular convolutional property over a dispersive channel. To address this issue, an enhanced DCT-OFDM-IM (EDCT-OFDM-IM) system has been proposed by introducing symmetric prefix and suffix at the transmitter and a pre-filter at the receiver leading to better performance than DFT-OFDM-IM in terms of bit error rate (BER). However, due to its special structure, it is difficult to derive the accurate average bit error probability (ABEP) upper bound, which is essential for the performance evaluation. In this paper, a tight ABEP upper bound is derived using the moment-generating-function (MGF). Our theoretical analysis is validated by simulation results and proven to be very accurate. Consequently the advantages of the EDCT-OFDM-IM system over the classic OFDM-IM system are further demonstrated analytically.