A Rake-Finger Based Efficient Channel State Information Feedback Compression Scheme for the MIMO OFDM FDD Downlink

An efficient feedback compression scheme is presented for signaling of explicit channel state information (CSI) to the transmitter side for MIMO OFDM systems in general and especially with coordinated multi-point transmission (COMP). Simulation results show that the required rates can be reduced by a factor of up to 17, compared to reporting of quantized frequency domain channel representations. This is achieved by using a separation of short-term and long-term information and a time-domain representation reduced to ´rake-fingers´ for removing redundancy and irrelevant information. This novel proposed solution can be used as an important enabler for coherent network MIMO in the FDD downlink.