论文标题
通过双IRS的无线通信：渠道估计和被动横梁成形设计
Wireless Communication via Double IRS: Channel Estimation and Passive Beamforming Designs
论文作者
论文摘要
在这封信中，我们研究了有效的通道估计和被动光束成型设计，用于双智能反射表面（IRS）辅助单用户通信系统，在该系统中，用户通过级联的用户IRS 1-IRS 2-AP 2-AP双重反思链接与访问点（AP）进行通信。首先，在任何任意IR-IRS通道下提出了系统的通道估计方案，其中估算了级联通道的所有系数。接下来，对于典型的情况，我们提出了另一种定制方案（LOS）域间INTR-IRS渠道，以估算级别级别级联通道的两个签名向量，其通道训练时间明显少于第一个方案。对于提出的两个通道估计方案，我们进一步优化了它们相应的合作无源光束，以提高数据传输，以最大程度地利用训练开销和通道估计误差，并考虑到可实现的速率。数值结果表明，与传统的IRS部署案例相比，通过提出的渠道估计和被动边界设计部署两个合作IRS可实现显着的增强率。
In this letter, we study efficient channel estimation and passive beamforming designs for a double-intelligent reflecting surface (IRS) aided single-user communication system, where a user communicates with an access point (AP) via the cascaded user-IRS 1-IRS 2-AP double-reflection link. First, a general channel estimation scheme is proposed for the system under any arbitrary inter-IRS channel, where all coefficients of the cascaded channel are estimated. Next, for the typical scenario with a line-of-sight (LoS)-dominant inter-IRS channel, we propose another customized scheme to estimate two signature vectors of the rank-one cascaded channel with significantly less channel training time than the first scheme. For the two proposed channel estimation schemes, we further optimize their corresponding cooperative passive beamforming for data transmission to maximize the achievable rate with the training overhead and channel estimation error taken into account. Numerical results show that deploying two cooperative IRSs with the proposed channel estimation and passive beamforming designs achieves significant rate enhancement as compared to the conventional case of single IRS deployment.
