A study on CSI feedback to support Coordinated Multi-point operation for LTE-Advanced system

摘要

In this paper, we investigate feedback scheme of channel state information (CSI) to support single user joint transmission (SU-JT) for Long-Term Evolution (LTE)-Advanced systems studied in the 3rd Generation Partnership Project (3GPP). SU-JT, which improves cooperative transmission among network nodes (transmission points: TPs) and reduces or eliminates inter-TP interference, enables performance improvement in cell edge throughputs. Although, CSI feedback on LTE system is well designed from single cell operation perspective, its extension to SU-JT requires further analysis of contents added to per-TP CSI feedback with minimizing feedback overhead increase. To this end, we propose to take 2 different approaches i.e. 1) modified CQI calculation accounting JT gain and 2) inter-node phase information. To evaluate the benefits of them, multi-cell system level simulations with a realistic traffic model are carried out. This confirms the improved performance of the system's average and cell edge throughputs.