The relentless demand for data in our society has driven the continuous evolution of wireless technologies to enhance network capacity. While current deployments of 5G have made strides in this direction using massive multiple-input-multiple-output (MIMO) and millimeter-wave (mmWave) bands, all existing wireless systems operate in a half-duplex (HD) mode. Full-duplex (FD) wireless communication, on the other hand, enables simultaneous transmission and reception (STAR) of signals at the same frequency, offering advantages such as enhanced spectrum efficiency, improved data rates, and reduced latency. This article presents a comprehensive review of FD wireless systems, with a focus on hardware design, implementation, cross-layered considerations, and applications. The major bottleneck in achieving FD communication is the presence of self-interference (SI) signals from the transmitter (TX) to the receiver, and achieving SI cancellation (SIC) with real-time adaption is critical for FD deployment. The review starts by establishing a system-level understanding of FD wireless systems, followed by a review of the architectures of antenna interfaces and integrated RF and baseband (BB) SI cancellers, which show promise in enabling low-cost, small-form-factor, portable FD systems. We then discuss digital cancellation techniques, including digital signal processing (DSP)- and learning-based algorithms. The challenges presented by FD phased-array and MIMO systems are discussed, followed by system-level aspects, including optimization algorithms, opportunities in the higher layers of the networking protocol stack, and testbed integration. Finally, the relevance of FD systems in applications such as next-generation (xG) wireless, mmWave repeaters, radars, and noncommunication domains is highlighted. Overall, this comprehensive review provides valuable insights into the design, implementation, and applications of FD wireless systems while opening up new directions for future research.

中文翻译：

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加倍无线容量：全双工集成电路、系统和网络回顾


社会对数据的不断需求推动了无线技术的不断发展，以增强网络容量。虽然当前的 5G 部署已经利用大规模多输入多输出 (MIMO) 和毫米波 (mmWave) 频段在这个方向上取得了长足进步，但所有现有无线系统都以半双工 (HD) 模式运行。另一方面，全双工 (FD) 无线通信可以在同一频率下同时传输和接收信号 (STAR)，具有增强频谱效率、提高数据速率和减少延迟等优势。本文对 FD 无线系统进行了全面回顾，重点关注硬件设计、实现、跨层考虑因素和应用。实现 FD 通信的主要瓶颈是从发射器 (TX) 到接收器的自干扰 (SI) 信号的存在，而通过实时自适应实现 SI 消除 (SIC) 对于 FD 部署至关重要。审查首先建立对 FD 无线系统的系统级理解，然后审查天线接口以及集成射频和基带 (BB) SI 消除器的架构，这些架构显示出实现低成本、小尺寸的前景，便携式FD系统。然后我们讨论数字消除技术，包括数字信号处理 (DSP) 和基于学习的算法。讨论了 FD 相控阵和 MIMO 系统带来的挑战，然后讨论了系统级方面，包括优化算法、网络协议栈高层的机会以及测试台集成。 最后，强调了 FD 系统在下一代 (xG) 无线、毫米波中继器、雷达和非通信领域等应用中的相关性。总的来说，这次全面的综述为 FD 无线系统的设计、实现和应用提供了宝贵的见解，同时为未来的研究开辟了新的方向。