In this paper, a capacity-approaching rateless coded modulation towards ultra-reliable low latency communications (uRLLC) is proposed, including the joint design of short block-length analog fountain code (AFC) and quasi-gray constellation mapping (QGCM) modulation at the transmitter, and a limited feedback mechanism for the receiver. First, based on the nonlinear constellation and quasi-gray mapping, we design a novel rateless coded modulation scheme called AFC-QGCM, and prove it can approach to the Shannon capacity. Further, the theoretical evaluation framework of information density between the achievable rate and signal-to-noise (SNR) of the AFC-QGCM schemes is derived under short block-length. Based on the analysis, we propose a rateless transmission scheme with a limited feedback link over the fading channel without precise channel state information (CSI) at the transmitter, which could utilize the theoretical analysis to determine the optimal coding and modulation parameters during the transmission. Both analysis and simulation results shown that the proposed scheme could approaching to the Polyanskiy-Poor-Verdu (PPV) meta converse benchmark in a wide range SNRs.

中文翻译：

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具有准灰色星座映射调制的短模拟喷泉码向 uRLLC

在本文中，提出了一种面向超可靠低延迟通信（uRLLC）的容量接近无速率编码调制，包括短块长度模拟喷泉码（AFC）和准灰度星座映射（QGCM）调制的联合设计。发送器，以及接收器的有限反馈机制。首先，基于非线性星座和准灰度映射，我们设计了一种称为AFC-QGCM的新型无率编码调制方案，并证明它可以接近香农容量。此外，在短块长度下，推导出了AFC-QGCM方案的可实现速率和信噪比（SNR）之间信息密度的理论评估框架。根据分析，我们提出了一种在衰落信道上具有有限反馈链路的无速率传输方案，在发射机处没有精确的信道状态信息（CSI），可以利用理论分析来确定传输过程中的最佳编码和调制参数。分析和仿真结果都表明，所提出的方案可以在宽范围的 SNR 中接近 Polyanskiy-Poor-Verdu (PPV) 元逆基准。