Investigation on CQI Definition for CoMP in LTE-Advanced Downlink

In order to support dynamic switching among different coordinated multi-point (CoMP) schemes, the eNodeB must have channel quality indicator (CQI) information for different schemes to perform scheduling. The full feedback scheme can provide accurate CQI for different CoMP schemes but it comes at the cost of a large feedback overhead. A new CQI definition of relative interference is proposed to reduce the feedback overhead while enabling the eNodeB to obtain various types of CQI for different CoMP schemes through CQI updates. In this paper, we compare the proposed scheme with other four candidate CQI definitions, and clarify their performance impact under different traffic loads. Evaluation results show that the proposed CQI definition of relative interference works effectively under different traffic loads for different CoMP schemes.