In an Internet-of-Things (IoT) environment, congestion and scarcity problems may occur because many mobile stations (STAs) access wireless networks simultaneously. The IEEE 802.11ax/802.11be standards for large-scale wireless communications have defined a trigger frame (TF) to control multiple STAs. During resource allocation, the downlink (DL) transmission is divided in a control period from the access point (AP) to multiple STAs. The resource allocation (RA) is then assigned to an uplink (UL) transmission by a TF and a DL period from the AP to STAs. However, because the DL transmission should be considered separately in terms of the control and DL periods, it is necessary to analyze the DL transmission. We propose a scheduled MU transmission (SMT) algorithm for enhanced UL and DL MU MIMO transmissions. In this study, we analyze and systematically model medium access control (MAC) performance when the DL transmission is divided in the control and data periods when the UL coexists with the DL data transmission. To achieve this, we mathematically analyze the time-efficient throughput, estimate the transmission and collision probabilities for wireless local area network (WLAN) STAs, and generalize the transmission interval. In addition, we propose an access category (AC) for the TF that is defined in the DL transmission. All data transmissions are defined as the ACs for basic channel access, but the AC is not defined for the TF. Therefore, we clarify the transmission by defining the AC of the TF to control the UL transmissions of various STAs. Evaluation results demonstrate that the SMT algorithm can improve the MAC throughput by up to 70% – 87% compared to UL and DL MU MIMO transmissions.

在物联网 (IoT) 环境中，由于许多移动台 (STA) 同时接入无线网络，可能会出现拥塞和稀缺问题。用于大规模无线通信的 IEEE 802.11ax/802.11be 标准定义了触发帧 (TF) 来控制多个 STA。在资源分配期间，下行链路 (DL) 传输在从接入点 (AP) 到多个 STA 的控制周期内划分。然后资源分配（RA）通过TF和DL周期从AP到STA分配给上行链路（UL）传输。然而，由于DL传输应该在控制周期和DL周期方面分开考虑，因此有必要对DL传输进行分析。我们提出了一种用于增强型 UL 和 DL MU MIMO 传输的调度 MU 传输 (SMT) 算法。在这项研究中，我们分析并系统地建模了当 DL 传输被划分为 UL 与 DL 数据传输共存的控制和数据周期时的媒体访问控制 (MAC) 性能。为了实现这一点，我们从数学上分析了时间效率吞吐量，估计了无线局域网 (WLAN) STA 的传输和冲突概率，并概括了传输间隔。此外，我们为在 DL 传输中定义的 TF 提出了一个接入类别 (AC)。所有数据传输都定义为基本信道访问的 AC，但没有为 TF 定义 AC。因此，我们通过定义 TF 的 AC 来明确传输，以控制各种 STA 的 UL 传输。