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Гибридное широкополосное формирование луча с низкой сложностью для массовых MIMO-OFDM-систем миллиметрового диапазона
In this paper, a single-user, fully-connected hybrid architecture with a low complexity wideband hybrid precoding technique for mmWave massive MIMO multicarrier systems is investigated. We demonstrate that, in order to optimize the sum rate of spectral efficiency, the radio frequency (RF) precoding/combining vectors can be directly obtained from the eigenvectors of the perfect fully-digital covariance matrix over all subcarriers. To increase the performance in the scenario where the number of RF chains is more than the number of streams, we also propose a novel approach that iteratively decreases the residual error between the covariance matrix and the sum of products of precoding matrices over all the subcarriers. The simulation results demonstrate that the suggested schemes' complexity is lower than that of the current approaches, and their performance can almost reach the upper bound achieved by the optimal full-baseband design.