A Dynamic Array of Sub-Array Architecture for Hybrid Precoding in the Millimeter Wave and Terahertz Bands

In this paper, a dynamic array of sub-array (DAoSA) architecture is proposed for hybrid precoding in the millimeter wave (mmWave) and Terahertz (THz) bands. Switches are inserted in the hybrid precoding architecture, to dynamically adjust the connection between RF chains and sub-arrays, i.e., each RF chain connects to m sub-arrays. In particular, the fully connected (FC) and array of sub-array (AoSA) architectures can be realized by setting m as the number of RF chains and 1, respectively. Based on the DAoSA architecture, the intractable precoding problem is decomposed into multiple tractable FC precoding problems, to which the solutions are developed based on a low-complexity column-by-column (CBC) algorithm. In the mmWave and THz wireless channel, simulation results show that compared with the FC architecture, the power consumption of the DAoSA architecture can be substantially reduced with a negligible spectral efficiency loss. In contrast to the AoSA architecture, the spectral efficiency is significantly improved.