The article "A Kalman based Hybrid Precoding for Multi-User Millimeter Wave MIMO Systems" has been accepted for publication in IEEE Access: http://ieeeaccess.ieee.org/

The authors are: Anna Vizziello, Pietro Savazzi (TLC&RS lab), and Kaushik R. Chowdhury (Northeastern University, Boston MA)

ABSTRACT: Millimeter wave (mmWave) communication in the 60 GHz band requires large antenna arrays at both the transmit and receive terminals to achieve beamforming gains, in order to counteract the severe pathloss. Fully digital techniques are infeasible with large antenna arrays due to hardware constraints at such frequencies, while pure analog solutions have severe performance limitations. Hybrid analog/digital beamforming is a promising solution, especially when extended to a multi-user scenario.

This paper makes three main contributions: (i) a Kalman-based formulation for hybrid analog/digital precoding in multi-user environment is proposed, (ii) a novel expression of the error between the transmitted and estimated data is formulated, so that the Kalman algorithm at the base station (BS) does not require any detail on the estimated data at the mobile stations (MSs), but only the precoding/combining matrix, (iii) an iterative solution is designed for the hybrid precoding scheme with affordable complexity. Simulation results confirm a significant improvement of the proposed approach with respect to the existing solutions, in terms of both BER and spectral efficiency. As an example, almost 7 bps/Hz, at 20 dB with 10 channel paths, with respect to the analog-only beamsteering, and almost one bps/Hz with respect to the hybrid minimum mean square error (MMSE) precoding, in the same conditions.