Applying Sparse Array in Massive MIMO via Convex Optimization

Massive multiple-input multiple-output (MIMO) technology enables higher data rate and capacity in the fifth generation (5G) and beyond. However, exploiting a number of antenna elements at both base station (BS) and user equipment (UE) makes efficient implementation of massive MIMO challenging. Therefore, it is important to consider practical limits like the size and the weight of the BS. In this paper, we introduce and investigate sparse array under realistic simulation settings. Although link-level results prove that sparse array can effectively reconstruct the desired radiation pattern, extensive system-level results show that sparse array leads to certain performance loss. In order to practically deploy sparse array, this paper proposes to comprehensively consider a trade-off between performance loss and reduction of antenna elements.