Gram–Schmidt orthogonalisation aided hybrid precoding in millimetre-wave massive MIMO systems

• Published in: IET communications Vol. 14; no. 3; pp. 387 - 396
• Main Authors: Zhan, Jinlong, Dong, Xiaodai, Huo, Yiming, Zhang, Yu
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 18.02.2020
• Subjects: array response matrix; array response vector; candidate analogue precoders; columns selection; error statistics; fully digital architectures; fully‐digital precoder; Gram–Schmidt orthogonalisation; GSO process; hybrid precoding solutions; iterative methods; matrix algebra; matrix columns; matrix inversion; millimetre‐wave massive MIMO systems; MIMO communication; OMP; optimal analogue; precoding; recursive process; Research Article; traditional orthogonal matching pursuit; uniform linear arrays; iterative methods; matrix columns; candidate analogue precoders; optimal analogue; Gram–Schmidt orthogonalisation; millimetre-wave massive MIMO systems; array response matrix; matrix inversion; recursive process; traditional orthogonal matching pursuit; precoding; matrix algebra; array response vector; OMP; hybrid precoding solutions; columns selection; fully-digital precoder; GSO process; uniform linear arrays; MIMO communication; error statistics; fully digital architectures
• ISSN: 1751-8628; 1751-8636; 1751-8636
• DOI: 10.1049/iet-com.2018.6090

The authors introduce a novel hybrid precoding algorithm based on Gram–Schmidt orthogonalisation (GSO) in millimetre-wave massive MIMO systems. Specifically, the columns of array response matrix orthogonalised by the GSO process are considered as a set of candidate analogue precoders, then traditional orthogonal matching pursuit (OMP) is utilised to find the optimal analogue and digital precoders. Since GSO is a recursive process that depends on the order in which the matrix columns are selected. A heuristic solution to the order of columns selection is suggested according to the array response vector along which the fully-digital precoder has the maximum projection. The proposed algorithm, not only constrained to uniform linear arrays, can avoid the matrix inversion in designing the digital precoder compared to OMP. Simulation results show that the spectral efficiency and bit error rate of the proposed hybrid precoding solutions are close to that obtained with fully digital architectures. Furthermore, the results indicate that the proposed hybrid precoding solutions outperform the orthogonality-based matching pursuit, which uses the columns of the DFT matrix as a set of candidate analogue precoders.