DFT Based Beam-Time Delay Sparse Channel Representation for Channel State Information (CSI) Compression in 5G FDD Massive MIMO Systems

Massive MIMO is currently a very hot topic for mobile R&D industry due to its large capabilities of high throughput and enhanced coverage for multiple users simultaneously. In the following article a proposal for dealing with the Channel State Information (CSI) overhead for FDD MIMO systems is presented. The idea consists of using a Multidimensional Discrete Fourier Transform (DFT) compression, which exploits the frequency and spatial correlations in order to provide a fully sparse Beam-Time Delay Channel Representation. The proposed idea provides high scalability in a long range of channel compression regimes while presents low computational complexity. Simulation results are presented showing the feasibility of implementation for Full dimensional massive MIMO systems.