We consider a wireless communication system, where a transmitting source is assisted by both a reconfigurable intelligent reflecting surface (IRS) and a decode-and-forward half-duplex relay (hybrid IRS-relay scheme) to communicate with a destination receiver. All devices are equipped with multiple antennas, and transmissions occur in two stages. In stage 1, the source splits the transmit message into two sub-messages, transmitted to the destination and the relay, respectively, using block diagonalization to avoid interference. Both transmissions will benefit from the IRS. In stage 2, the relay re-encodes the received sub-message and forwards it (still through the IRS) to the destination. We optimize power allocations, beamformers, and configurations of the IRS in both stages, in order to maximize the achievable rate at the destination. We compare the proposed hybrid approach with other schemes (with/without relay and IRS), and confirm that high data rate is achieved for the hybrid scheme in case of optimal IRS configurations.

中文翻译：

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混合智能反射面和中继系统的最大速率优化

我们考虑一个无线通信系统，其中发射源在可重构智能反射面 (IRS) 和解码转发半双工中继（混合 IRS 中继方案）的协助下与目标接收器进行通信。所有设备都配备了多个天线，传输分两个阶段进行。在阶段 1 中，源将传输消息分成两个子消息，分别传输到目的地和中继，使用块对角化来避免干扰。两种传输都将受益于 IRS。在第 2 阶段，中继重新编码接收到的子消息并将其转发（仍然通过 IRS）到目的地。我们在两个阶段都优化了 IRS 的功率分配、波束成形器和配置，以最大限度地提高目的地的可实现速率。