Predictor antenna (PA) system is referred to as a system with two sets of antennas on the roof of a vehicle, where the PAs positioned in the front of the vehicle are used to predict the channel state observed by the receive antennas (RAs) that are aligned behind the PAs. In this work, we study the effect of spatial mismatch on the accuracy of channel state information estimation, and analyze the delay-constrained average rate of hybrid automatic repeat request (HARQ)-based PA systems. We consider variable-length incremental redundancy (INR) HARQ protocols, and derive a closed-form expression for the maximum average rate subject to a maximum delay constraint. Also, we study the effect of different parameters such as the vehicle speed, the antenna distance and the rate allocation on the system performance. The results indicate that, compared to the open-loop case, the delay-limited average rate is considerably improved with the proposed PA and HARQ-based scheme.

中文翻译：

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基于HARQ的预测天线系统时延限制平均速率

预测器天线（PA）系统是指在车顶有两组天线的系统，其中位于车辆前方的PA用于预测接收天线（RA）观察到的信道状态。排列在 PA 后面。在这项工作中，我们研究了空间失配对信道状态信息估计精度的影响，并分析了基于混合自动重传请求 (HARQ) 的 PA 系统的延迟约束平均速率。我们考虑可变长度增量冗余 (INR) HARQ 协议，并导出受最大延迟约束的最大平均速率的封闭形式表达式。此外，我们还研究了不同参数（如车速、天线距离和速率分配）对系统性能的影响。结果表明，