Sleep mode strategies for energy efficient cell-free massive MIMO in 5G deployments

This paper investigates the use of cell-free massive MIMO (CF-M-MIMO) processing over the regular macrocellular deployments typically found in current 5G networks, and proposes a new energy saving mechanism to maximize energy efficiency while meeting user rate requirements under this network architecture. Towards this end, it contemplates the connection of all macro base stations to a central processing unit through fronthaul links, thus enabling a coordinated dynamic (de)activation and joint processing of all transmitters and users in the coverage area. This solution avoids the expensive deployment and maintenance of a massive number of randomly scattered small access points (APs) proposed in the traditional CF-M-MIMO literature. Results show that CF-M-MIMO is suitable for macrocellular network architectures, doubling the energy efficiency in comparison to classical macrocellular massive MIMO.