An Efficient Interference-Aware Constrained Beamforming and Receiver Design for mm-Wave Hybrid Massive MIMO with Non-Orthogonal Multiple Access

2021-7-13
Bayraktar, Murat
This thesis investigates efficient interference-aware beamformer design for mm-wave massive multiple-input and multiple-output (MIMO) systems. Furthermore, adaptation of code-domain non-orthogonal multiple access (NOMA) to mm-wave massive MIMO is studied. The first part of the thesis concentrates on interference-aware pre-beamformer (analog beamformer) design for joint spatial division and multiplexing (JSDM) which is a user-grouping based two-stage beamforming method. Single-carrier frequency domain equalization (SC-FDE) is employed in uplink wideband channels. First, unconstrained statistical analog beamformer of each group, namely, generalized eigenbeamformer (GEB) which has strong interference suppression capability is designed. Then, constant-modulus constrained approximations of unconstrained beamformer are obtained by utilizing alternating minimization algorithms. Moreover, a dynamic subarray algorithm is proposed where the connections between radio frequency (RF) chains and antennas are dynamically changed. Minimum mean square error (MMSE) criterion based iterative block decision feedback equalization (IB-DFE) method, which takes the residual interference in reduced dimension into account, is proposed for intra-group processing. Simulation results verify the superiority of the proposed interference-aware constrained design over existing approaches in terms of beampattern, spectral efficiency, outage capacity, bit-error rate (BER) and channel estimation accuracy. The second part of the thesis is devoted to the development of a novel wideband signal model in beamspace for code-domain NOMA with SC-FDE transmission in JSDM framework. Based on this signal model, a code-beamspace IB-DFE receiver is proposed for joint equalization and multiuser detection, and it is shown that code-domain NOMA is beneficial, especially for mm-wave massive MIMO systems with limited number of RF chains and spatial correlation.
Citation Formats
M. Bayraktar, “An Efficient Interference-Aware Constrained Beamforming and Receiver Design for mm-Wave Hybrid Massive MIMO with Non-Orthogonal Multiple Access,” M.S. - Master of Science, Middle East Technical University, 2021.