Downlink Beamforming for Energy-Efficient Heterogeneous Networks With Massive MIMO and Small Cells

作者：Nguyen Long D; Hoang Duong Tuan; Duong Trung Q^*; Dobre Octavia A; Poor H Vincent

来源：IEEE Transactions on Wireless Communications, 2018, 17(5): 3386-3400.

DOI：10.1109/TWC.2018.2811472

• Heterogeneous networks
• massive MIMO
• small cell
• beamformer design
• energy efficiency
• optimization

A heterogeneous network (HetNet) of a macrocell base station equipped with a large-scale massive multiin multi-out (MIMO) antenna array overlaying a number of small cell base stations (small cells) can provide high quality of service (QoS) to multiple users under low transmit power budget. However, the circuit power for operating such a network, which is proportional to the number of transmit antennas, poses a problem in terms of its energy efficiency (EE). This paper addresses the beamforming design at the base stations to optimize the network EE under the QoS constraints and a transmit power budget. Beamforming tailored for weak, strong, and medium cross-tier interference HetNets is proposed. In contrast to the conventional transmit strategy for power efficiency in meeting the users' QoS requirements, which suggest the use of a few hundred antennas, it is found out that the overall network EE quickly drops if this number exceeds 50. It is found that, for a given number of antennas, HetNet is more energy efficient than massive MIMO when considering the overall energy consumption.

• 出版日期2018-5