Cluster Formation in Scalable Cell-free Massive MIMO Networks
Charmae Franchesca Mendoza, Štefan Schwarz, Markus Rupp
Abstract
Inter-cell interference remains to be a bottleneck for conventional cellular networks as cell-edge users continue to suffer from poor performance. Cell-free massive MIMO is a novel network architecture that suppresses inter-cell interference by eliminating cell boundaries. It promises uniform performance throughout the coverage area, enabled by the coherent joint transmission from multiple distributed antennas. To make the network scalable, a user-centric approach is adopted where each user is served by a cluster of nearby access points (APs). In this work, we study the impact of cluster formation on the total fronthaul requirement, which is a limiting factor in practical coordinated distributed systems. We also investigate its effect on the guaranteed quality of service (QoS) of the network. Using our proposed algorithms, we look into the optimal cluster sizes for a given scenario and show that good performance can be achieved even with relatively small user-centric clusters, which then translates to fronthaul savings.