One of the key technologies for the future cellular networks is full-duplex (FD) enabled Integrated Access and Backhaul (IAB) networks operating in the millimeter-wave (mmWave) frequencies. The main challenge in realizing the FD-IAB networks is mitigating the impact of self-interference (SI) in the wideband mmWave frequencies. In this article, we first introduce the 3GPP IAB network architectures and wideband mmWave channel models. By utilizing the subarray-based hybrid precoding scheme, at the FD-IAB-node, multiuser interference is mitigated using zero-forcing (ZF) at the transmitter, whereas the residual SI after successfully deploying antenna and analog cancellation is canceled by minimum mean square error (MMSE) baseband combiner at the receiver. The spectral efficiency (SE) is evaluated for the RF insertion loss (RFIL) with different kinds of phase shifters and the channel uncertainty. Simulation results show that, in the presence of the RFIL, the almost double SE, which is close to that obtained from fully connected hybrid precoding, can be achieved as compared with half-duplex systems, when the uncertainties are of low strength.

中文翻译：

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全双工毫米波集成接入和回程网络的设计

未来蜂窝网络的关键技术之一是在毫米波（mmWave）频率下运行的支持全双工（FD）的集成访问和回程（IAB）网络。实现FD-IAB网络的主要挑战是减轻宽带mmWave频率中的自干扰（SI）影响。在本文中，我们首先介绍3GPP IAB网络架构和宽带mmWave信道模型。通过利用基于子阵列的混合预编码方案，在FD-IAB节点处，在发射机处使用零强迫（ZF）可以缓解多用户干扰，而在成功部署天线和模拟抵消之后的残留SI可以通过最小均方值来抵消接收器处的错误（MMSE）基带组合器。对于具有不同种类的移相器和信道不确定性的RF插入损耗（RFIL），将评估频谱效率（SE）。仿真结果表明，在RFIL存在的情况下，不确定性强度较低时，与半双工系统相比，可以实现接近从完全连接的混合预编码获得的SE几乎翻倍的SE。