Spatial Intercell Interference Cancellation With CSI Training and Feedback
The authors investigate Inter-Cell Interference Cancellation (ICIC) with a practical downlink training and uplink Channel State Information (CSI) feedback model. The average downlink throughput for such a 2-cell network is derived. The user location has a strong effect on the Signal-to-Interference Ratio (SIR) and the channel estimation error. This motivates adaptively switching between traditional (single-cell) beamforming and ICIC at low Signal-to-Noise Ratio (SNR) where ICIC is preferred only with low SIR and accurate channel estimation, and the use of ICIC with optimized training and feedback at high SNR. For a given channel coherence time and fixed training and feedback overheads, they develop optimal data vs. pilot power allocation for CSI training as well as optimal feedback resource allocation to feed back CSI of different channels.