Beamspace Channel Estimation for Millimeter-Wave Massive MIMO Systems with Lens Antenna Array

摘要

By employing the lens antenna array, beamspace MIMO can utilize beamselection to reduce the number of required RF chains in mmWave massive MIMOsystems without obvious performance loss. However, to achieve thecapacityapproaching performance, beam selection requires the accurateinformation of beamspace channel of large size, which is challenging,especially when the number of RF chains is limited. To solve this problem, inthis paper we propose a reliable support detection (SD)-based channelestimation scheme. Specifically, we propose to decompose the total beamspacechannel estimation problem into a series of sub-problems, each of which onlyconsiders one sparse channel component. For each channel component, we firstreliably detect its support by utilizing the structural characteristics ofmmWave beamspace channel. Then, the influence of this channel component isremoved from the total beamspace channel estimation problem. After the supportsof all channel components have been detected, the nonzero elements of thesparse beamspace channel can be estimated with low pilot overhead. Simulationresults show that the proposed SD-based channel estimation outperformsconventional schemes and enjoys satisfying accuracy, even in the low SNRregion.