Time-Frequency Spatial Precoding Design for TDD Massive-MIMO Systems

The computational complexity of the precoding vectors calculation in the large-scale Massive-MIMO systems is a growing up with the granularity of wideband frequency precoding. In this paper we propose a novel approach for precoder design in M-MIMO communication systems under wideband frequency-selective channel conditions. The developed method lies in new precoding scheme, which exploit the sparse structure of the channel in the delay-domain, where the amount of dominant signal tap samples significantly lower than the number of frequency subbands. Proposed time-frequency precoding scheme is aimed to reduce the complexity of the spatial precoder calculation. We shown the benefits from the developed low-cost approach of high frequency granularity spatial precoder design, which matching the performance of the baseline approach in the frequency domain across all spatial layers. The complexity reduction gain achieve more than in 2 times compared with legacy approach.