To ensure system scalability and to mitigate inter-user interference in cell-free massive MIMO (CF-mMIMO), a user-centric (UC) antenna-clustering approach was investigated. In this UC approach, user-centric antenna-clusters are formed by selecting cooperating antennas for each user, and postcoding is applied by regarding users whose antenna-clusters overlap as interfering users. However, in very high user density environments, since the number of interfering users increases due to increased overlapping of antenna-clusters, the achievable link capacity may degrade. In this paper, we propose a user-cluster-centric (UCC) approach, which groups neighborhood users into a user-cluster and associates the predetermined number of antennas to the user cluster for spatial multiplexing. We evaluate, by computer simulation, the uplink capacity of UCC CF-mMIMO using zero-forcing (ZF) and minimum mean square error (MMSE) based postcoding. We confirm that the proposed UCC approach can provide higher link capacity in a high user density environment.
Evaluation of Uplink Capacity of User-Cluster-Centric Cell-Free massive MIMO
2022-09-01
575485 byte
Conference paper
Electronic Resource
English