In this letter, we consider an ultra-reliable low-latency communication (URLLC) scheme for one uplink massive single-input multiple-output (SIMO) system with three users. In our design, to enable all the users to update status information to the base station (BS) concurrently with an extremely low latency, we specifically decompose a cross 8-QAM constellation into one additive uniquely decomposable constellation group (AUDCG), and then devise a new multiuser space-time modulation scheme at the transmitters accordingly. For the receiver side, to assure that the BS can detect all the transmitted signals of different users simultaneously with a high reliability and a low latency, we investigate a noncoherent maximum likelihood (ML) receiver in comparison to a minimum Riemannian distance (MRD) estimator and a minimum Euclidean distance (MED) detector when the antenna array size is scaled up. Finally, extensive computer simulations are carried out to validate the effectiveness of our proposed design when the antenna array size is large.

中文翻译：

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上行链路大规模 SIMO 系统的 8-QAM 部门

在这封信中，我们考虑了一种用于具有三个用户的上行链路大规模单输入多输出 (SIMO) 系统的超可靠低延迟通信 (URLLC) 方案。在我们的设计中，为了让所有用户能够以极低的延迟同时向基站（BS）更新状态信息，我们专门将一个交叉 8-QAM 星座分解为一个可加唯一可分解星座组（AUDCG），然后设计相应地，在发射机上采用了一种新的多用户空时调制方案。对于接收端，为了保证基站能够同时检测到不同用户的所有传输信号，可靠性高，时延低，我们研究了非相干最大似然 (ML) 接收器与最小黎曼距离 (MRD) 估计器和最小欧几里德距离 (MED) 检测器相比，当天线阵列尺寸按比例放大时。最后，当天线阵列尺寸很大时，进行了广泛的计算机模拟以验证我们提出的设计的有效性。