This survey paper focuses on modulation aspects of molecular communication, an emerging field focused on building biologically-inspired systems that embed data within chemical signals. The primary challenges in designing these systems are how to encode and modulate information onto chemical signals, and how to design a receiver that can detect and decode the information from the corrupted chemical signal observed at the destination. In this paper, we focus on modulation design for molecular communication via diffusion systems. In these systems, chemical signals are transported using diffusion, possibly assisted by flow, from the transmitter to the receiver. This tutorial presents recent advancements in modulation and demodulation schemes for molecular communication via diffusion. We compare five different modulation types: concentration-based, type-based, timing-based, spatial, and higher-order modulation techniques. The end-to-end system designs for each modulation scheme are presented. In addition, the key metrics used in the literature to evaluate the performance of these techniques are also presented. Finally, we provide a numerical bit error rate comparison of prominent modulation techniques using analytical models. We close the tutorial with a discussion of key open issues and future research directions for design of molecular communication via diffusion systems.

中文翻译：

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通过扩散进行分子通信的调制技术研究

这份调查论文集中在分子通讯的调制方面，这是一个新兴领域，致力于构建将数据嵌入化学信号中的生物启发系统。设计这些系统的主要挑战是如何将信息编码和调制为化学信号，以及如何设计一种可以从目的地观测到的损坏的化学信号中检测和解码信息的接收器。在本文中，我们专注于通过扩散系统进行分子通信的调制设计。在这些系统中，化学信号是通过扩散（可能是借助流动）从发射机传输到接收机的。本教程介绍了通过扩散进行分子通信的调制和解调方案的最新进展。我们比较了五种不同的调制类型：基于浓度的调制，基于类型，基于时序，空间和高阶调制技术。给出了每种调制方案的端到端系统设计。此外，还介绍了文献中用于评估这些技术性能的关键指标。最后，我们使用分析模型提供了重要调制技术的数值误码率比较。在结束本教程时，我们将讨论主要的开放性问题以及通过扩散系统进行分子通信设计的未来研究方向。我们使用解析模型提供了著名调制技术的数值误码率比较。在结束本教程时，我们将讨论主要的开放性问题以及通过扩散系统进行分子通信设计的未来研究方向。我们使用解析模型提供了著名调制技术的数值误码率比较。在结束本教程时，我们将讨论主要的开放性问题以及通过扩散系统进行分子通信设计的未来研究方向。