Intelligent reflecting surface (IRS) and device-to-device (D2D) communication are two promising technologies for improving transmission reliability between transceivers in communication systems. In this paper, we consider the design of reliable communication between the access point (AP) and actuators for a downlink multiuser multiple-input single-output (MISO) system in the industrial IoT (IIoT) scenario. We propose a two-stage protocol combining IRS with D2D communication so that all actuators can successfully receive the message from AP within a given delay. The superiority of the protocol is that the communication reliability between AP and actuators is doubly augmented by the IRS-aided first-stage transmission and the second-stage D2D transmission. A joint optimization problem of active and passive beamforming is formulated, which aims to maximize the number of actuators with successful decoding. We study the joint beamforming problem for cases where the channel state information (CSI) is perfect and imperfect. For each case, we develop efficient algorithms that include convergence and complexity analysis. Simulation results demonstrate the necessity and role of IRS with a well-optimized reflection matrix, and the D2D network in promoting reliable communication. Moreover, the proposed protocol can enable reliable communication even in the presence of stringent latency requirements and CSI estimation errors.

中文翻译：

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D2D 网络中 IRS 辅助 URLLC 的鲁棒波束成形设计


智能反射表面（IRS）和设备到设备（D2D）通信是两种有前途的技术，可提高通信系统中收发器之间的传输可靠性。在本文中，我们考虑工业物联网（IIoT）场景中下行链路多用户多输入单输出（MISO）系统的接入点（AP）和执行器之间的可靠通信设计。我们提出了一种将 IRS 与 D2D 通信相结合的两阶段协议，以便所有执行器都能在给定的延迟内成功接收来自 AP 的消息。该协议的优越性在于，通过IRS辅助的第一阶段传输和第二阶段D2D传输，AP和执行器之间的通信可靠性得到双重增强。提出了主动和被动波束形成的联合优化问题，其目的是最大化成功解码的执行器数量。我们研究了信道状态信息（CSI）完美和不完美情况下的联合波束成形问题。对于每种情况，我们都开发有效的算法，包括收敛和复杂性分析。仿真结果证明了具有良好优化的反射矩阵的IRS以及D2D网络在促进可靠通信方面的必要性和作用。此外，即使存在严格的延迟要求和 CSI 估计错误，所提出的协议也可以实现可靠的通信。