Preference‐based unified criterion in virtual MIMO systems

Abstract

Virtual multiple-input multiple-output (V-MIMO) is an advanced technology in uplink systems, and a well-designed user pairing and resource allocation scheme in V-MIMO systems can effectively exploit multi-user diversity to yield a significant performance gain. Recently, main attention has been devoted to the crucial user pairing issue with consideration of three key metrics, i.e. spectrum efficiency, energy efficiency and fairness. In this study, the authors investigate the unified tradeoff among all the three metrics for V-MIMO systems with user pairing and resource allocation. They first formulate the three key metrics in a united form and derive a straightforward unified criterion based on the user-specific preference to depict system performances. Through discussing several preference-based cases, they observe that a portion of spectrum efficiency is considered redundantly. Thus, a modified unified criterion is proposed to remove the partial redundancy provided by spectrum efficiency contribution to the objective function. Based on the two unified criteria, they propose a user pairing scheme in flat fading channels and a joint user pairing and resource allocation scheme in frequency-selective fading channels to balance the tradeoff flexibly. Simulation results show that, compared with existing schemes, the proposed scheme achieves a dynamical tradeoff among spectrum efficiency, energy efficiency and fairness.