Index modulation (IM) provides a novel way for the transmission of additional data bits via the indices of the available transmit entities compared with classical communication schemes. This study examines the flexible utilization of existing IM techniques in a comprehensive manner to satisfy the challenging and diverse requirements of 5G and beyond services. After spatial modulation (SM), which transmits information bits through antenna indices, application of IM to orthogonal frequency-division multiplexing (OFDM) subcarriers has opened the door for the extension of IM into different dimensions, such as radio frequency (RF) mirrors, time slots, codes, and dispersion matrices. Recent studies have introduced the concept of multidimensional IM by various combinations of 1-D IM techniques to provide higher spectral efficiency (SE) and better bit error rate (BER) performance at the expense of higher transmitter (Tx) and receiver (Rx) complexity. Despite the ongoing research on the design of new IM techniques and their implementation challenges, proper use of the available IM techniques to address different requirements of 5G and beyond networks is an open research area in the literature. For this reason, we first provide the dimensional-based categorization of available IM domains and review the existing IM types regarding this categorization. Then, we develop a framework that investigates the efficient utilization of these techniques and establishes a link between the IM schemes and 5G services, namely, enhanced mobile broadband (eMBB), massive machine-type communications (mMTCs), and ultrareliable low-latency communication (URLLC). In addition, this work defines key performance indicators (KPIs) to quantify the advantages and disadvantages of IM techniques in time, frequency, space, and code dimensions. Finally, future recommendations are given regarding the design of flexible IM-based communication systems for 5G and beyond wireless networks.

中文翻译：

---

5G 及以后无线网络的多维索引调制

与经典通信方案相比，索引调制 (IM) 提供了一种通过可用传输实体的索引传输附加数据位的新方法。本研究以全面的方式检验了现有 IM 技术的灵活利用，以满足 5G 及以后服务具有挑战性和多样化的需求。在通过天线索引传输信息比特的空间调制 (SM) 之后，将 IM 应用于正交频分复用 (OFDM) 子载波为将 IM 扩展到不同维度打开了大门，例如射频 (RF) 镜子，时隙、代码和色散矩阵。最近的研究通过一维 IM 技术的各种组合引入了多维 IM 的概念，以提供更高的频谱效率 (SE) 和更好的误码率 (BER) 性能，但代价是更高的发射机 (Tx) 和接收机 (Rx) 复杂性. 尽管对新 IM 技术的设计及其实施挑战正在进行研究，但正确使用可用的 IM 技术来满足 5G 及以后网络的不同要求是文献中的一个开放研究领域。为此，我们首先提供可用 IM 域的基于维度的分类，并审查有关此分类的现有 IM 类型。然后，我们开发了一个框架来研究这些技术的有效利用，并在 IM 方案和 5G 服务之间建立联系，即，增强型移动宽带 (eMBB)、大规模机器类型通信 (mMTC) 和超可靠低延迟通信 (URLLC)。此外，这项工作定义了关键性能指标 (KPI)，以量化 IM 技术在时间、频率、空间和代码维度上的优势和劣势。最后，给出了关于为 5G 及以后的无线网络设计灵活的基于 IM 的通信系统的未来建议。