System Cost Analysis of Scalable Cell-Free Massive MIMO Architectures for 6G Networks

While scalable cell-free massive MIMO (CF-mMIMO) holds great promise to provide both high and uniform throughput performance for 6G networks, the system cost of this novel network architecture has not yet been fully addressed. In this paper we propose a network deployment cost model for CF-mMIMO to evaluate the economic efficiency of the uplink performance and a fronthaul signalling and computational cost model for scalable CF-mMIMO with different cluster cooperation levels. We use our models to compare the system cost and the economic efficiency of the CF-mMIMO architectures against the baseline of small cell networks. Our results show that scalable CF-mMIMO can yield the best trade-off between throughput performance and system cost, but only with a carefully selected cluster size and cooperation level.