Towards Optimal Spectral Efficiency of Cell Free Massive MIMO Based Linear Detectors in 5G

摘要

The 5G generation of wireless communication can make a radical change in how we use wireless things. This generation provides various developed features (very high data rates, ultra-reliable low-latency, high spectral efficiency (SE)), and several emerged technology to obtain higher performance compared to current 4G LTE networks. Cell-free massive MIMO is a key technology that has been used to enhance the SE, energy efficiency (EE), reliability, and quality of services (QoS), for 5G communications and beyond. This new paradigm consists of a large number of distributed access points (APs) that serve a small number of users in the network. Precoding/detectors are one of the most important components of cell-free massive MIMO systems to eliminate the problems of pilot contamination and inter-user interference. The aim of this paper is to carry out the performance analysis of SE of cell-free massive MIMO uplink (UL) receiver under different detectors, maximum-ratio combining (MRC), zero-forcing (ZF), and minimum mean-square error (MMSE), with imperfect channel state information (CSI) cases, in comparison with the performance of both small-cell massive MIMO and cellular massive MIMO systems in one simulation, taking into account the same parameters and same different linear receivers. The simulation results are discussed in detail and have confirmed that the cell-free massive MIMO system provides effective spectral efficiency by using both ZF / MMSE detectors compared to the cellular massive MIMO and small-cell massive MIMO systems, even under imperfect CSI.