A Comprehensive Survey on Massive MIMO Systems

V Arunarashmi; Dr. Shashidhara HR

Abstract

During the last decades with the mobile data traffic exponentially growing, demands for increased cell density or increased number of antennas per access point. Massive multiple input multiple output (MIMO) was found to be one of the solution for the ever increasing data traffic demand. However due to the inter cell interference and largely varying quality of service , massive MIMO lacks to meet the expectations of the demands of the sixth generation(6G). Cell-free massive MIMO is one of the key enabler in solving the said problems. In cell-free massive MIMO each user equipment (UE) is served by a set of surrounding access points (APs) cooperatively. This paper provides a survey of massive MIMO concept followed by significance of cell-free massive MIMO. A brief study of resource allocation and signal processing aspects of massive MIMO and cell-free massive MIMO is discussed. Future challenges and research problems are discussed