Performance Analysis of Handover Algorithms in Scalable Cell-Free Massive MIMO Systems

Abstract

In this study, we analyze the performance of handover algorithms in scalable cell-free massive multiple-input multiple-output (CF-mMIMO) systems under mobility scenarios. To facilitate a comparative performance analysis considering mobility, we introduce a mobility-aware spectral efficiency metric. We then evaluate two baseline access point (AP) clustering methods and two mobility-aware handover algorithms. The simulation results reveal a significant decrease in minimum spectral efficiency across all algorithms and mobility scenarios, with differences of up to 7.5 times observed. This degradation is primarily due to existing algorithms prioritizing APs with the highest large-scale fading coefficients (LSFCs) when forming clusters, which prevents certain user equipments (UEs) from forming adequate AP clusters. The findings emphasize the need to design AP clustering algorithms that enhance minimum spectral efficiency, thereby ensuring the principle of CF-mMIMO in providing uniform performance.