An enhanced interference measurement scheme for CoMP in LTE-Advanced downlink

This paper proposes an enhanced interference measurement method that provides accurate channel quality indicators (CQIs) to improve the system performance in coordinated multi-point (CoMP) transmission and reception. In CoMP operations, user equipments (UEs) need to report different CQIs based on different interference hypotheses. Even though a variety of interference measurement schemes are proposed, they always suffer higher complexity, inaccuracy or restriction in terms of the number of available interference measurement resource (IMR) configurations. In the proposed method, phase rotations are introduced for channel state information reference signals (CSI-RSs) before mapping to the resource grid. Both theoretical analysis and simulation results show that the proposed method improves the accuracies of both signal estimation and interference measurement, and consequently yields accurate CQIs. Moreover, it can provide a large number of IMR configurations.