作为Shannon Paradigm的突破的语义通信旨在成功传输由源传送的语义信息，而不是每种单个符号或位的准确接收，而不管其含义如何。本文提供了关于语义通信的概述。在简要审查Shannon信息理论之后，我们讨论了深入学习的理论，框架和系统设计的语义通信。不同于用于测量传统通信系统的符号/误码率，还讨论了语义通信的新性能度量。这篇文章由几个开放问题结束。

Along with the springing up of semantics-empowered communication (SemCom) researches, it is now witnessing an unprecedentedly growing interest towards a wide range of aspects (e.g., theories, applications, metrics and implementations) in both academia and industry. In this work, we primarily aim to provide a comprehensive survey on both the background and research taxonomy, as well as a detailed technical tutorial. Specifically, we start by reviewing the literature and answering the "what" and "why" questions in semantic transmissions. Afterwards, we present corresponding ecosystems, including theories, metrics, datasets and toolkits, on top of which the taxonomy for research directions is presented. Furthermore, we propose to categorize the critical enabling techniques by explicit and implicit reasoning-based methods, and elaborate on how they evolve and contribute to modern content \& channel semantics-empowered communications. Besides reviewing and summarizing the latest efforts in SemCom, we discuss the relations with other communication levels (e.g., reliable and goal-oriented communications) from a holistic and unified viewpoint. Subsequently, in order to facilitate the future developments and industrial applications, we also highlight advanced practical techniques for boosting semantic accuracy, robustness, and large-scale scalability, just to mention a few. Finally, we discuss the technical challenges that shed light on future research opportunities.

迄今为止，通信系统主要旨在可靠地交流位序列。这种方法提供了有效的工程设计，这些设计对消息的含义或消息交换所旨在实现的目标不可知。但是，下一代系统可以通过将消息语义和沟通目标折叠到其设计中来丰富。此外，可以使这些系统了解进行交流交流的环境，从而为新颖的设计见解提供途径。本教程总结了迄今为止的努力，从早期改编，语义意识和以任务为导向的通信开始，涵盖了基础，算法和潜在的实现。重点是利用信息理论提供基础的方法，以及学习在语义和任务感知通信中的重要作用。

语义通信引起了人们的兴趣，因为它可以显着减少在不丢失关键信息的情况下要传输的数据量。大多数现有作品都探索文本的语义编码和传输，并在自然语言处理（NLP）中应用技术来解释文本的含义。在本文中，我们构想了图像数据的语义通信，这些语义数据在语义和带宽敏感方面更为丰富。我们提出了一种基于增强学习的自适应语义编码（RL-ASC）方法，该方法编码超过像素级别的图像。首先，我们定义了图像数据的语义概念，该概念包括类别，空间布置和视觉特征作为表示单元，并提出卷积语义编码器以提取语义概念。其次，我们提出了图像重建标准，该标准从传统像素的相似性演变为语义相似性和感知性能。第三，我们设计了一种基于RL的新型语义位分配模型，其奖励是用自适应量化水平编码某个语义概念后的速率语义感知性能的提高。因此，与任务相关的信息得到正确保存和重建，同时丢弃了较少重要的数据。最后，我们提出了基于生成的对抗网（GAN）的语义解码器，该语义解码器通过注意模块融合本地和全球特征。实验结果表明，所提出的RL-ASC具有噪声稳定性，可以重建视觉上令人愉悦和语义一致的图像，并节省与标准编解码器和其他基于深度学习的图像编解码器相比，可以节省位置的时间。

经典的交流范式专注于准确地通过嘈杂的渠道传输位，而香农理论则对可靠通信速率提供了基本的理论限制。在这种方法中，位平均对待，并且通信系统忽略了这些位传达或如何使用的含义。可以预见的是，对智力和简洁性的未来沟通将发挥主导作用，连接的智能代理的扩散需要对编码传输范式进行根本性的重新思考，以支持地平线上的新通信形态。最近的“语义通信”概念提供了有希望的研究方向。将语义指南注入编码传输设计以实现语义感知通信，这表现出了进一步突破性和可靠性的巨大潜力。本文阐明了语义引导的源和频道编码作为语义通信的传输范式，该传输范式可以利用数据语义的多样性和无线通道多样性，以增强整个系统性能。我们介绍一般的系统体系结构和关键技术，并指出有关此主题的一些开放问题。

The current optical communication systems minimize bit or symbol errors without considering the semantic meaning behind digital bits, thus transmitting a lot of unnecessary information. We propose and experimentally demonstrate a semantic optical fiber communication (SOFC) system. Instead of encoding information into bits for transmission, semantic information is extracted from the source using deep learning. The generated semantic symbols are then directly transmitted through an optical fiber. Compared with the bit-based structure, the SOFC system achieved higher information compression and a more stable performance, especially in the low received optical power regime, and enhanced the robustness against optical link impairments. This work introduces an intelligent optical communication system at the human analytical thinking level, which is a significant step toward a breakthrough in the current optical communication architecture.

尽管语义通信对大量任务表现出令人满意的性能，但语义噪声和系统的鲁棒性的影响尚未得到很好的研究。语义噪声是指预期的语义符号和接收到的语义符号之间的误导性，从而导致任务失败。在本文中，我们首先提出了一个框架，用于稳健的端到端语义通信系统来对抗语义噪声。特别是，我们分析了样品依赖性和样本无关的语义噪声。为了打击语义噪声，开发了具有重量扰动的对抗训练，以在训练数据集中纳入带有语义噪声的样品。然后，我们建议掩盖一部分输入，在该输入中，语义噪声经常出现，并通过噪声相关的掩蔽策略设计蒙版vector量化量化的量化自动编码器（VQ-VAE）。我们使用发射器共享的离​​散代码簿和接收器用于编码功能表示。为了进一步提高系统鲁棒性，我们开发了一个功能重要性模块（FIM），以抑制与噪声相关和任务无关的功能。因此，发射器只需要在代码簿中传输这些重要的任务相关功能的索引即可。仿真结果表明，所提出的方法可以应用于许多下游任务，并显着提高针对语义噪声的鲁棒性，并显着减少了传输开销。

6G时代的语义沟通被认为是一个有希望的沟通范式，可以突破传统通信的瓶颈。但是，其在多用户方案中的应用程序，尤其是广播案例，仍未探索。为了有效利用语义沟通启用的好处，在本文中，我们提出了一个一对一的语义通信系统。具体而言，我们建议使用一个启用的深神经网络（DNN），称为MR \ _DeepSc。通过为不同用户的语义功能利用语义功能，基于预训练的模型即Distilbert的语义识别器是为了区分不同用户的。此外，采用转移学习来加快新接收器网络的培训。仿真结果表明，在不同的通道条件下，提出的MR \ _DeepSc可以比其他基准测试获得最佳性能，尤其是在低信噪比（SNR）方面。

现有的深度学习的语义通信系统通常依赖于包含经验数据及其相关语义信息的发射器和接收器之间的共同背景知识。实际上，语义信息是由接收器的务实任务定义的，发射器不能知道。发射机上的实际可观察​​数据也可以具有与共享背景知识库中的经验数据相同的分布。为了解决这些实际问题，本文提出了一个新的基于神经网络的语义通信系统，用于图像传输，该任务在发射器上不知道，并且数据环境是动态的。该系统由两个主要部分组成，即语义编码（SC）网络和数据适应（DA）网络。 SC网络学习如何使用接收器领导训练过程提取和传输语义信息。通过使用传输学习的域适应技术，DA网络学习了如何将观察到的数据转换为SC网络可以在不进行重新验证的情况下进行处理的类似形式的经验数据。数值实验表明，所提出的方法可以适应可观察的数据集，同时在数据恢复和任务执行方面保持高性能。

6G无线网络可以预见，以加快物理和网络世界的融合，并以我们部署和利用通信网络的方式实现范式换档。机器学习，尤其是深度学习（DL），将通过提供具有高水平智能的网络的新范式来成为6G的关键技术推动力之一。在本文中，我们介绍了一种新兴的DL体系结构，称为Transformer，并讨论了其对6G网络设计的潜在影响。我们首先讨论变压器和经典DL体系结构之间的差异，并强调变压器的自我发挥机制和强大的代表能力，这使其在应对无线网络设计的各种挑战方面特别有吸引力。具体而言，我们提出了基于变压器的解决方案，用于大规模多输入多输出（MIMO）系统和6G网络中的各种语义通信问题。最后，我们讨论了基于变压器的解决方案中的关键挑战和开放问题，并确定未来在智能6G网络中部署的研究方向。

Virtual reality (VR) over wireless is expected to be one of the killer applications in next-generation communication networks. Nevertheless, the huge data volume along with stringent requirements on latency and reliability under limited bandwidth resources makes untethered wireless VR delivery increasingly challenging. Such bottlenecks, therefore, motivate this work to seek the potential of using semantic communication, a new paradigm that promises to significantly ease the resource pressure, for efficient VR delivery. To this end, we propose a novel framework, namely WIreless SEmantic deliveRy for VR (WiserVR), for delivering consecutive 360{\deg} video frames to VR users. Specifically, deep learning-based multiple modules are well-devised for the transceiver in WiserVR to realize high-performance feature extraction and semantic recovery. Among them, we dedicatedly develop a concept of semantic location graph and leverage the joint-semantic-channel-coding method with knowledge sharing to not only substantially reduce communication latency, but also to guarantee adequate transmission reliability and resilience under various channel states. Moreover, implementation of WiserVR is presented, followed by corresponding initial simulations for performance evaluation compared with benchmarks. Finally, we discuss several open issues and offer feasible solutions to unlock the full potential of WiserVR.

视频编码技术已不断改进，以更高的分辨率以更高的压缩比。但是，最先进的视频编码标准（例如H.265/HEVC和多功能视频编码）仍在设计中，该假设将被人类观看。随着深度神经网络在解决计算机视觉任务方面的巨大进步和成熟，越来越多的视频通过无人参与的深度神经网络直接分析。当计算机视觉应用程序使用压缩视频时，这种传统的视频编码标准设计并不是最佳的。尽管人类视觉系统对具有高对比度的内容一直敏感，但像素对计算机视觉算法的影响是由特定的计算机视觉任务驱动的。在本文中，我们探索并总结了计算机视觉任务的视频编码和新兴视频编码标准，机器的视频编码。

Motivated by recent success of Machine Learning (ML) tools in wireless communications, the idea of semantic communication by Weaver from 1949 has received considerable attention. It breaks with the classic design paradigm of Shannon by aiming to transmit the meaning of a message, i.e., semantics, rather than its exact copy and thus allows for savings in channel uses or information rate. In this work, we extend the fundamental approach from Basu et al. for modeling semantics from logical to probabilistic entailment relations between meaning and messages. Thus, we model semantics by means of a hidden random variable and define the task of semantic communication as transmission of messages over a communication channel such that semantics is best preserved. We formulate the semantic communication design either as an Information Maximization or as an Information Bottleneck optimization problem. Finally, we propose the ML-based semantic communication system SINFONI for a distributed multipoint scenario: SINFONI communicates the meaning behind multiple messages that are observed at different senders to a single receiver for semantic retrieval. We analyze SINFONI by processing images as an example of messages. Numerical results reveal a tremendous rate normalized SNR shift up to 20 dB compared to classically designed communication systems.

Semantic communication is not focused on improving the accuracy of transmitted symbols, but is concerned with expressing the expected meaning that the symbol sequence exactly carries. However, the measurement of semantic messages and their corresponding codebook generation are still open issues. Expansion, which integrates simple things into a complex system and even generates intelligence, is truly consistent with the evolution of the human language system. We apply this idea to the semantic communication system, quantifying semantic transmission by symbol sequences and investigating the semantic information system in a similar way as Shannon's method for digital communication systems. This work is the first to discuss semantic expansion and knowledge collision in the semantic information framework. Some important theoretical results are presented, including the relationship between semantic expansion and the transmission information rate. We believe such a semantic information framework may provide a new paradigm for semantic communications, and semantic expansion and knowledge collision will be the cornerstone of semantic information theory.

鉴于无线频谱的有限性和对无线通信最近的技术突破产生的频谱使用不断增加的需求，干扰问题仍在继续持续存在。尽管最近解决干涉问题的进步，但干扰仍然呈现出有效使用频谱的挑战。这部分是由于Wi-Fi的无许可和管理共享乐队使用的升高，长期演进（LTE）未许可（LTE-U），LTE许可辅助访问（LAA），5G NR等机会主义频谱访问解决方案。因此，需要对干扰稳健的有效频谱使用方案的需求从未如此重要。在过去，通过使用避免技术以及非AI缓解方法（例如，自适应滤波器）来解决问题的大多数解决方案。非AI技术的关键缺陷是需要提取或开发信号特征的域专业知识，例如CycrationArity，带宽和干扰信号的调制。最近，研究人员已成功探索了AI / ML的物理（PHY）层技术，尤其是深度学习，可减少或补偿干扰信号，而不是简单地避免它。 ML基于ML的方法的潜在思想是学习来自数据的干扰或干扰特性，从而使需要对抑制干扰的域专业知识进行侧联。在本文中，我们审查了广泛的技术，这些技术已经深入了解抑制干扰。我们为干扰抑制中许多不同类型的深度学习技术提供比较和指导。此外，我们突出了在干扰抑制中成功采用深度学习的挑战和潜在的未来研究方向。

随着深度学习（DL）的发展，自然语言处理（NLP）使我们可以分析和理解大量语言文本。因此，在NLP的帮助下，我们可以在联合语义源和噪声频道上进行联合语义源和信道进行语义通信。然而，实现这一目标的现有方法是使用NLP的固定变压器，同时忽略每个句子中包含的语义信息的差异。为了解决这个问题，我们提出了一种基于通用变压器的新语义通信系统。与传统变压器相比，在通用变压器中引入了自适应循环机制。通过引入循环机制，新的语义通信系统可以更灵活地传输具有不同语义信息的句子，并在各种信道条件下实现更好的端到端性能。

Our experience of the world is multimodal -we see objects, hear sounds, feel texture, smell odors, and taste flavors. Modality refers to the way in which something happens or is experienced and a research problem is characterized as multimodal when it includes multiple such modalities. In order for Artificial Intelligence to make progress in understanding the world around us, it needs to be able to interpret such multimodal signals together. Multimodal machine learning aims to build models that can process and relate information from multiple modalities. It is a vibrant multi-disciplinary field of increasing importance and with extraordinary potential. Instead of focusing on specific multimodal applications, this paper surveys the recent advances in multimodal machine learning itself and presents them in a common taxonomy. We go beyond the typical early and late fusion categorization and identify broader challenges that are faced by multimodal machine learning, namely: representation, translation, alignment, fusion, and co-learning. This new taxonomy will enable researchers to better understand the state of the field and identify directions for future research.

Most semantic communication systems leverage deep learning models to provide end-to-end transmission performance surpassing the established source and channel coding approaches. While, so far, research has mainly focused on architecture and model improvements, but such a model trained over a full dataset and ergodic channel responses is unlikely to be optimal for every test instance. Due to limitations on the model capacity and imperfect optimization and generalization, such learned models will be suboptimal especially when the testing data distribution or channel response is different from that in the training phase, as is likely to be the case in practice. To tackle this, in this paper, we propose a novel semantic communication paradigm by leveraging the deep learning model's overfitting property. Our model can for instance be updated after deployment, which can further lead to substantial gains in terms of the transmission rate-distortion (RD) performance. This new system is named adaptive semantic communication (ASC). In our ASC system, the ingredients of wireless transmitted stream include both the semantic representations of source data and the adapted decoder model parameters. Specifically, we take the overfitting concept to the extreme, proposing a series of ingenious methods to adapt the semantic codec or representations to an individual data or channel state instance. The whole ASC system design is formulated as an optimization problem whose goal is to minimize the loss function that is a tripartite tradeoff among the data rate, model rate, and distortion terms. The experiments (including user study) verify the effectiveness and efficiency of our ASC system. Notably, the substantial gain of our overfitted coding paradigm can catalyze semantic communication upgrading to a new era.

内容的离散和连续表示（例如，语言或图像）具有有趣的属性，以便通过机器的理解或推理此内容来探索或推理。该职位论文提出了我们关于离散和持续陈述的作用及其在深度学习领域的作用的意见。目前的神经网络模型计算连续值数据。信息被压缩成密集，分布式嵌入式。通过Stark对比，人类在他们的语言中使用离散符号。此类符号代表了来自共享上下文信息的含义的世界的压缩版本。此外，人工推理涉及在认知水平处符号操纵，这促进了抽象的推理，知识和理解的构成，泛化和高效学习。通过这些见解的动机，在本文中，我们认为，结合离散和持续的陈述及其处理对于构建展示一般情报形式的系统至关重要。我们建议并讨论了几个途径，可以在包含离散元件来结合两种类型的陈述的优点来改进当前神经网络。

场景图是一个场景的结构化表示，可以清楚地表达场景中对象之间的对象，属性和关系。随着计算机视觉技术继续发展，只需检测和识别图像中的对象，人们不再满足。相反，人们期待着对视觉场景更高的理解和推理。例如，给定图像，我们希望不仅检测和识别图像中的对象，还要知道对象之间的关系（视觉关系检测），并基于图像内容生成文本描述（图像标题）。或者，我们可能希望机器告诉我们图像中的小女孩正在做什么（视觉问题应答（VQA）），甚至从图像中移除狗并找到类似的图像（图像编辑和检索）等。这些任务需要更高水平的图像视觉任务的理解和推理。场景图只是场景理解的强大工具。因此，场景图引起了大量研究人员的注意力，相关的研究往往是跨模型，复杂，快速发展的。然而，目前没有对场景图的相对系统的调查。为此，本调查对现行场景图研究进行了全面调查。更具体地说，我们首先总结了场景图的一般定义，随后对场景图（SGG）和SGG的发电方法进行了全面和系统的讨论，借助于先验知识。然后，我们调查了场景图的主要应用，并汇总了最常用的数据集。最后，我们对场景图的未来发展提供了一些见解。我们相信这将是未来研究场景图的一个非常有帮助的基础。