Cell-free massive MIMO (CF-mMIMO) provides wireless connectivity for a large number of user equipments (UEs) using access points (APs) distributed across a wide area with high spectral efficiency (SE). The energy efficiency (EE) of the uplink is determined by (i) the transmit power control (TPC) algorithms, (ii) the numbers, configurations, and locations of the APs and the UEs, and (iii) the propagation channels between the APs and the UEs. This paper investigates all three aspects, based on extensive (~30,000 possible AP locations and 128 possible UE locations) channel measurement data at 3.5 GHz. We compare three different TPC algorithms, namely maximization of transmit power (max-power), maximization of minimum SE (max-min SE), and maximization of minimum EE (max-min EE) while guaranteeing a target SE. We also compare various antenna arrangements including fully-distributed and semi-distributed systems, where APs can be located on a regular grid or randomly, and the UEs can be placed in clusters or far apart. Overall, we show that the max-min EE TPC is highly effective in improving the uplink EE, especially when no UE within a set of served UEs is in a bad channel condition and when the BS antennas are fully-distributed.
翻译:大型无细胞大型MIMO(CF-MMIMO)为大量用户设备(UES)提供无线连通性(UES),使用在宽广区域分布的高光谱效率(SE)分布的接入点(APs),高链路的能源效率(EE)由以下因素决定:(一) 传输电源控制算法(TPC),(二) APs和UES的数量、配置和位置(三) APs和Ues之间的传播渠道。本文调查了三大方面,包括完全分布式和半分布式的天线安排,APs可以设在固定的网格或随机的128个UE地点)频道测量数据,在3.5 GHz,我们比较了三种不同的TPC算法,即最大限度地增加传输能力(最大功率),最大限度地增加最低的SEEE(最大功率),最大限度地增加EEEE(最大功率),同时保证目标S。我们还比较了各种天线安排,包括完全分布式和半分布式分布式的天线,APs可以放在固定的电网格或随机的频道上,而在E-CE-CRireaddrevildal 上,我们完全将E-s 完全安装在E-l,在E-trelock的E-s 完全在E-tretrel,在E-s在E-taltlv 完全在E-l。