Location-aided uplink transmission for user-centric cell-free massive MIMO systems: a fairness priority perspective

Abstract In this paper, we investigate the uplink transmission for user-centric cell-free massive multiple-input multiple-output (MIMO) systems. The largest-large-scale-fading-based access point (AP) selection method is adopted to achieve a operation. Under framework, propose novel inter-cluster interference-based (IC-IB) pilot assignment scheme alleviate contamination. Considering local characteristics of channel estimates and statistics, location-aided distributed combining balance relationship among spectral efficiency (SE), user equipment (UE) fairness complexity, in which partial minimum mean-squared error (LP-MMSE) some APs, while maximum-ratio (MR) remaining APs. A corresponding AP based on proposed metric representing inter-user interference proposed. We also new coefficient taking SE performance into account indicate UE fairness. Moreover, investigated under fractional power control max–min (MMF) control. Simulation results demonstrate that estimation accuracy our IC-IB outperforms conventional schemes. It shown compared with benchmark LP-MMSE combining, trades 13.45 $$\%$$ % average loss 26.61 improvement 28.58 complexity reduction when $$\gamma = 0.6$$ γ = 0.6 . And by adjusting threshold $$\gamma$$ , good trade-off between SE, computational can be provided scheme. Furthermore, better advantages than MMF full transmission.