In this paper, we characterize the combined channel state information (CSI) and re-transmission feedback on wireless communication. Feedback, often assumed free, has traditionally been used to either learn the channel state, or to request the re-transmission of a failed reception. We propose here a generalized framework for feedback that captures the channel time-variation. We consider two-way communication model where all the resources needed for training, feedback (CSI and automatic repeat request), and data. In order to maximize the throughput and optimize resource allocations, we provide the expressions of outage probabilities for different rate/power adaptation and re-transmission protocols. The simulation results show that, besides signal-to-noise ratio (SNR) and Doppler, the optimal pilot overhead depends on whether we are using rate/power adaptation and the number of re-transmissions. We also prove that in slow-fading channels with high SNR regimes, varying the rate provides the best throughput. When dealing with fast time-varying channels and low SNR regimes, using constant power and rate gives the best throughput performance.

中文翻译：

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结合CSI和H-ARQ反馈的无线通信吞吐量研究。

在本文中，我们表征了组合信道状态信息（CSI）和无线通信中的重传反馈。反馈通常被认为是免费的，传统上已被用于了解信道状态或请求重新发送失败的接收信号。我们在这里提出一个通用的反馈框架，以捕获通道时变。我们考虑双向通信模型，其中训练，反馈（CSI和自动重复请求）和数据所需的所有资源。为了最大化吞吐量并优化资源分配，我们提供了针对不同速率/功率自适应和重传协议的中断概率的表达式。仿真结果表明，除了信噪比（SNR）和多普勒（Doppler）之外，最佳导频开销取决于我们是否使用速率/功率自适应以及重传次数。我们还证明，在具有高SNR机制的慢衰落信道中，改变速率可提供最佳吞吐量。当处理快速时变信道和低SNR方案时，使用恒定功率和速率可提供最佳的吞吐量性能。