Double-directional radio channel estimation using mD-RARE

A novel estimation method for fast fading MIMO channels is presented. The proposed method is based on the double directional channel model as described. The directional characteristics of transmitter antenna and receiver antenna are jointly estimated together with the time delays of the dominant discrete propagation paths using a multi-dimensional extension of the rank reduction estimator (RARE), originally developed for DOA estimation in partly calibrated arrays. The new estimation method is computationally efficient due to its rooting-based implementation and shows improved estimation performance compared to conventional search-free methods for mD harmonic retrieval problems. The proposed estimator is analyzed in simulations on synthetic data and finally applied to measured data recorded from the RUSK vector channel sounder at 2 GHz.