Ultra-reliable short-packet communication is a major challenge in future wireless networks with critical applications. To achieve ultra-reliable communications beyond 99.999%, this paper envisions a new interaction-based communication paradigm that exploits feedback from the receiver. We present AttentionCode, a new class of feedback codes leveraging deep learning (DL) technologies. The underpinnings of AttentionCode are three architectural innovations: AttentionNet, input restructuring, and adaptation to fading channels, accompanied by several training methods, including large-batch training, distributed learning, look-ahead optimizer, training-test signal-to-noise ratio (SNR) mismatch, and curriculum learning. The training methods can potentially be generalized to other wireless communication applications with machine learning. Numerical experiments verify that AttentionCode establishes a new state of the art among all DL-based feedback codes in both additive white Gaussian noise (AWGN) channels and fading channels. In AWGN channels with noiseless feedback, for example, AttentionCode achieves a block error rate (BLER) of $10^{-7}$ when the forward channel SNR is 0 dB for a block size of 50 bits, demonstrating the potential of AttentionCode to provide ultra-reliable short-packet communications.

基于深度学习的渠道代码设计最近引起了人们的兴趣，可以替代传统的编码算法，尤其是对于现有代码不提供有效解决方案的渠道。通过反馈渠道进行的沟通就是一个这样的问题，最近通过采用各种深度学习体系结构来获得有希望的结果。在本文中，我们为反馈渠道介绍了一种新颖的学习辅助代码设计，称为广义块注意反馈（GBAF）代码，i）使用模块化体系结构，可以使用不同的神经网络体系结构实现；ii）与现有设计相比，错误的可能性提高了误顺序；iii）可以以所需的代码速率传输。

基于深度学习（DL）的联合源通道编码（DEEPJSCC）的最新进展导致了语义通信的新范式。基于DEEPJSCC的语义通信的两个显着特征是直接从源信号中对语义感知功能的开发以及这些功能的离散时间模拟传输（DTAT）。与传统的数字通信相比，与DEEPJSCC的语义通信在接收器上提供了出色的重建性能，并具有较高的频道质量降解，但在传输信号中也表现出较大的峰值功率比（PAPR）。一个空旷的问题是，DeepJSCC的收益是否来自高PAPR连续振幅信号带来的额外自由。在本文中，我们通过在图像传输的应用中探索三种PAPR还原技术来解决这个问题。我们确认，基于DEEPJSCC的语义通信的出色图像重建性能可以保留，而传输的PAPR被抑制至可接受的水平。该观察是在实用语义通信系统中实施DEEPJSCC的重要一步。

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。

Effective and adaptive interference management is required in next generation wireless communication systems. To address this challenge, Rate-Splitting Multiple Access (RSMA), relying on multi-antenna rate-splitting (RS) at the transmitter and successive interference cancellation (SIC) at the receivers, has been intensively studied in recent years, albeit mostly under the assumption of perfect Channel State Information at the Receiver (CSIR) and ideal capacity-achieving modulation and coding schemes. To assess its practical performance, benefits, and limits under more realistic conditions, this work proposes a novel design for a practical RSMA receiver based on model-based deep learning (MBDL) methods, which aims to unite the simple structure of the conventional SIC receiver and the robustness and model agnosticism of deep learning techniques. The MBDL receiver is evaluated in terms of uncoded Symbol Error Rate (SER), throughput performance through Link-Level Simulations (LLS), and average training overhead. Also, a comparison with the SIC receiver, with perfect and imperfect CSIR, is given. Results reveal that the MBDL receiver outperforms by a significant margin the SIC receiver with imperfect CSIR, due to its ability to generate on demand non-linear symbol detection boundaries in a pure data-driven manner.

Communication and computation are often viewed as separate tasks. This approach is very effective from the perspective of engineering as isolated optimizations can be performed. On the other hand, there are many cases where the main interest is a function of the local information at the devices instead of the local information itself. For such scenarios, information theoretical results show that harnessing the interference in a multiple-access channel for computation, i.e., over-the-air computation (OAC), can provide a significantly higher achievable computation rate than the one with the separation of communication and computation tasks. Besides, the gap between OAC and separation in terms of computation rate increases with more participating nodes. Given this motivation, in this study, we provide a comprehensive survey on practical OAC methods. After outlining fundamentals related to OAC, we discuss the available OAC schemes with their pros and cons. We then provide an overview of the enabling mechanisms and relevant metrics to achieve reliable computation in the wireless channel. Finally, we summarize the potential applications of OAC and point out some future directions.

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。

最近的作品表明，现代机器学习技术可以为长期存在的联合源通道编码（JSCC）问题提供另一种方法。非常有希望的初始结果，优于使用单独的源代码和通道代码的流行数字方案，已被证明用于使用深神经网络（DNNS）的无线图像和视频传输。但是，此类方案的端到端培训需要可区分的通道输入表示。因此，先前的工作假设可以通过通道传输任何复杂值。这可以防止在硬件或协议只能接收数字星座规定的某些频道输入集的情况下应用这些代码。本文中，我们建议使用有限通道输入字母的端到端优化的JSCC解决方案DeepJSCC-Q。我们表明，DEEPJSCC-Q可以实现与允许任何复杂的有价值通道输入的先前作品相似的性能，尤其是在可用的高调制订单时，并且在调制顺序增加的情况下，性能渐近接近无约束通道输入的情况。重要的是，DEEPJSCC-Q保留了不可预测的渠道条件下图像质量的优雅降级，这是在频道迅速变化的移动系统中部署的理想属性。

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.

在多输入多输出（MIMO）系统中使用深度自动码器（DAE）进行端到端通信，是一种具有重要潜力的新概念。在误码率（BER）方面，已示出DAE-ADED MIMO以占地识别的奇异值分解（SVD）为基础的预编码MIMO。本文提出将信道矩阵的左右奇异矢量嵌入到DAE编码器和解码器中，以进一步提高MIMO空间复用的性能。 SVD嵌入式DAE主要优于BER的理论线性预编码。这是显着的，因为它表明所提出的DAES通过将通信系统视为单个端到端优化块来超出当前系统设计的极限。基于仿真结果，在SNR = 10dB，所提出的SVD嵌入式设计可以实现近10美元，并将BER减少至少10次，而没有SVD，相比增长了18倍的增长率最高18倍具有理论线性预编码。我们将这一点归因于所提出的DAE可以将输入和输出与具有有限字母输入的自适应调制结构匹配。我们还观察到添加到DAE的剩余连接进一步提高了性能。

State-of-the-art performance for many emerging edge applications is achieved by deep neural networks (DNNs). Often, these DNNs are location and time sensitive, and the parameters of a specific DNN must be delivered from an edge server to the edge device rapidly and efficiently to carry out time-sensitive inference tasks. In this paper, we introduce AirNet, a novel training and transmission method that allows efficient wireless delivery of DNNs under stringent transmit power and latency constraints. We first train the DNN with noise injection to counter the wireless channel noise. Then we employ pruning to reduce the network size to the available channel bandwidth, and perform knowledge distillation from a larger model to achieve satisfactory performance, despite pruning. We show that AirNet achieves significantly higher test accuracy compared to digital alternatives under the same bandwidth and power constraints. The accuracy of the network at the receiver also exhibits graceful degradation with channel quality, which reduces the requirement for accurate channel estimation. We further improve the performance of AirNet by pruning the network below the available bandwidth, and using channel expansion to provide better robustness against channel noise. We also benefit from unequal error protection (UEP) by selectively expanding more important layers of the network. Finally, we develop an ensemble training approach, which trains a whole spectrum of DNNs, each of which can be used at different channel condition, resolving the impractical memory requirements.

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.

这是两部分纸的第二部分，该论文着重于具有非线性接收器的多用户MIMO（MU-MIMO）系统的链接适应（LA）和物理层（PHY）抽象。第一部分提出了一个新的指标，称为检测器，称为比率解码率（BMDR），是非线性接收器的等效量等效的信号与交换后噪声比率（SINR）。由于该BMDR没有封闭形式的表达式，因此有效地提出了基于机器学习的方法来估计其。在这一部分中，第一部分中开发的概念用于开发LA的新算法，可用检测器列表中的动态检测器选择以及具有任意接收器的MU-MIMO系统中的PHY抽象。提出了证实所提出算法的功效的广泛仿真结果。

我们呈现深度，第一端到端联合源通道编码（JSCC）视频传输方案，其利用深神经网络（DNN）的力量直接将视频信号映射到信道符号，组合视频压缩，信道编码并且调制步骤进入单个神经变换。我们的DNN解码器预测无失真反馈的残差，这通过占闭塞/脱离和相机运动来提高视频质量。我们同时培训不同的带宽分配网络，以允许变量带宽传输。然后，我们使用强化学习（RL）训练带宽分配网络，该钢筋学习（RL）优化视频帧之间的有限可用信道带宽的分配，以最大限度地提高整体视觉质量。我们的研究结果表明，深度可以克服悬崖效应，这在传统的分离的数字通信方案中普遍存在，并在估计和实际信道质量之间取得不匹配来实现优雅的降级。 DeepWive优于H.264视频压缩，然后在所有信道条件下的低密度奇偶校验（LDPC）代码在多尺度结构相似性指数（MS-SSIM）方面平均达到0.0462，同时跳动H.265 + LDPC平均高达0.0058。我们还说明了通过显示我们的最佳带宽分配策略优于NA \“IVE统一分配来优化JSCC视频传输中的带宽分配的重要性。我们相信这是实现端到端潜力的重要一步优化的JSCC无线视频传输系统优于当前的基于分离的设计。

最近的作品表明，可以通过使用机器学习技术来学习图像的无线传输的任务。已经通过训练了自动化器，非常有前沿图像质量，优于利用源和信道编码分离的流行数字方案，以具有中间的不可培训的沟道层，优于利用源和信道编码分离。然而，这些方法假设可以通过信道传输任何复数，这可以防止硬件或协议只能承认某些信道输入的场景中的算法，例如使用数字星座的使用。这里，我们提出了DeepJSCC-Q，用于无线图像传输的端到端优化的联合源信道编码方案，其能够用固定信道输入字母操作。我们表明DeepJSCC-Q可以对使用连续值通道输入的模型来实现类似的性能。重要的是，在信道条件恶化的情况下，保留在现有工作中观察到的图像质量的正常劣化，使DeepJSCC-Q在实际系统中部署更具吸引力。

深度神经网络（DNN）具有嘈杂的权重，我们将其称为嘈杂的神经网络（Noisynns），从DNN的存在下存在噪声的训练和推理。 Noisynns在许多新应用中出现，包括DNN的无线传输，模拟设备中的DNN的有效部署或存储，以及DNN权重的截断或量化。本文研究了Noisynns的根本问题：如何从嘈杂的表现形式重建DNN重量。虽然所有先前的作品都依赖于最大可能性（ML）估计，但本文提出了一种去噪方法来重建DNN，目的是最大化重建模型的推理准确性。我们的脱氮机的优越性在两个小规模问题中经过严格经过严格地证明，其中我们考虑了二次神经网络功能和浅前馈神经网络。当应用于具有现代DNN架构的高级学习任务时，我们的Denoiser表现出比ML估算器的性能显着更好。考虑去噪DNN模型的平均测试准确性与噪声功率比（WNR）性能的重量方差。当去噪产生从嘈杂推理引起的嘈杂的BERT模型时，我们的脱氮机以1.1 dB的估计优于ML估计，以获得75％的测试精度。当去噪产生从嘈杂训练产生的嘈杂reset18模型时，我们的丹机优于13.4 dB和8.3 dB的ML估计，以分别实现60％和80％的测试精度。

通过大量多输入和多重输出实现的许多性能增长取决于发射机（基站）下链路通道状态信息（CSI）的准确性，这通常是通过在接收器（用户终端）估算并馈入的。到发射器。 CSI反馈的开销占据了大量的上行链路带宽资源，尤其是当传输天线数量较大时。基于深度学习（DL）的CSI反馈是指基于DL的自动编码器的CSI压缩和重建，并且可以大大减少反馈开销。在本文中，提供了有关该主题的最新研究的全面概述，首先是在CSI反馈中广泛使用的基本DL概念，然后对一些现有的基于DL的反馈作品进行分类和描述。重点是新型的神经网络体系结构和沟通专家知识的利用来提高CSI反馈准确性。还介绍了有关CSI反馈和CSI反馈与其他通信模块的联合设计的作品，并讨论了一些实际问题，包括培训数据集收集，在线培训，复杂性，概括和标准化效果。在本文的最后，确定了与未来无线通信系统中基于DL的CSI反馈相关的一些挑战和潜在的研究方向。

我们考虑无上行赠款非正交多访问（NOMA）中的多用户检测（MUD）问题，其中访问点必须确定活动互联网（IoT）设备的总数和正确的身份他们传输的数据。我们假设IoT设备使用复杂的扩散序列并以随机访问的方式传输信息，按照爆发 - 距离模型，其中一些物联网设备以高概率在多个相邻的时间插槽中传输其数据，而另一些物联网设备在帧中仅传输一次。利用时间相关性，我们提出了一个基于注意力的双向长期记忆（BILSTM）网络来解决泥浆问题。 Bilstm网络使用前向和反向通过LSTM创建设备激活历史记录的模式，而注意机制为设备激活点提供了基本背景。通过这样做，遵循了层次途径，以在无拨款方案中检测主动设备。然后，通过利用复杂的扩散序列，对估计的活动设备进行了盲数据检测。所提出的框架不需要对设备稀疏水平和执行泥浆的通道的先验知识。结果表明，与现有的基准方案相比，提议的网络的性能更好。

直接到 - 卫星（DTS）通信最近已获得支持全球连接的物联网（IoT）网络的重要性。但是，地球周围密集部署的卫星网络相对较长的距离会导致高路径损失。此外，由于必须部分在物联网设备中进行诸如光束成型，跟踪和均衡之类的高复杂性操作，因此硬件复杂性和对物联网设备的高容量电池的需求都会增加。可重新配置的智能表面（RISS）具有增加能源效率并在传输环境而不是物联网设备上执行复杂的信号处理的潜力。但是，RIS需要级联通道的信息，以更改事件信号的阶段。这项研究将试点信号评估为图形，并将此信息纳入图表网络（GATS），以通过试点信号来跟踪相位关系。提出的基于GAT的通道估计方法研究了DTS IoT网络的性能，以解决不同的RIS配置，以解决具有挑战性的通道估计问题。结果表明，与常规深度学习方法相比，在变化条件下，拟议的GAT均表现出更高的性能，并且在变化的条件下具有更高的鲁棒性，并且计算复杂性较低。此外，根据提议的方法，在通道估计下具有离散和不均匀相移的RIS设计研究了位错误率性能。这项研究的发现之一是，必须在RIS设计期间考虑操作环境的渠道模型和通道估计方法的性能，以尽可能利用性能改进。

Channel estimation is a critical task in multiple-input multiple-output (MIMO) digital communications that substantially effects end-to-end system performance. In this work, we introduce a novel approach for channel estimation using deep score-based generative models. A model is trained to estimate the gradient of the logarithm of a distribution and is used to iteratively refine estimates given measurements of a signal. We introduce a framework for training score-based generative models for wireless MIMO channels and performing channel estimation based on posterior sampling at test time. We derive theoretical robustness guarantees for channel estimation with posterior sampling in single-input single-output scenarios, and experimentally verify performance in the MIMO setting. Our results in simulated channels show competitive in-distribution performance, and robust out-of-distribution performance, with gains of up to $5$ dB in end-to-end coded communication performance compared to supervised deep learning methods. Simulations on the number of pilots show that high fidelity channel estimation with $25$% pilot density is possible for MIMO channel sizes of up to $64 \times 256$. Complexity analysis reveals that model size can efficiently trade performance for estimation latency, and that the proposed approach is competitive with compressed sensing in terms of floating-point operation (FLOP) count.