Multi-user hybrid precoding for mmWave massive MIMO systems with sub-connected structure

Abstract

Hybrid precoding achieves a compromise between the sum rate and hardware complexity of millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems. However, most prior works on multi-user hybrid precoding only consider the full-connected structure. In this paper, a novel multi-user hybrid precoding algorithm is proposed for the sub-connected structure. Based on the improved successive interference cancellation (SIC), the analog precoding matrix optimization problem is decomposed into multiple analog precoding sub-matrix optimization problems. Further, a near-optimal analog precoder is designed through factorizing the precoding sub-matrix for each sub-array. Furthermore, digital precoding is designed according to the block diagonalization (BD) technology. Finally, the water-filling power allocation method is used to further improve the communication quality. The extensive simulation results demonstrate that the sum rate of the proposed algorithm is higher than the existing hybrid precoding methods with the sub-connected structure, and has higher energy efficiency compared with existing approaches. Moreover, the proposed algorithm is closer to the state-of-the-art optimization approach with the full-connected structure. In addition, the simulation results also verify the effectiveness of the proposed hybrid precoding design of the uniform planar array (UPA).

A Reduced Complexity Hybrid Precoding for mmWave Systems

“…It is very important to know that we are working on the magnitude of the channel in this work as the amplitudes are positive values. All the simulations in this section will present spectral efficiency results in fig (1), fig (2), fig (3) and fig(4) with different system, and algorithms parameters. To generate these results, the channel parameters are estimated using the algorithms presented in [19].…”

“…For Multiuser MU-MIMO systems, [1] presented a hybrid precoding technique. The system transfer the maximum possible rate optimization problem into a series of sub-rate optimization problems based on the structure of the ideal hybrid precoding matrix.…”

“…Nowadays,there is increasing research in the area of mmWave MIMO systems ( [5,6,7,8,9,10,11,12,13,14]). In this work, we propose low-complexity channel decomposition precoding techniques for a mmWave system with large antenna arrays at both the base station (BS) and mobile station MS in this research.…”

Spectral-efficient hybrid precoding for multi-antenna multi-user mmWave massive MIMO systems with low complexity

“…Moreover, the digital precoding and analog beamforming are asynchronous process in practical application. Therefore, to eliminate the hardware restrictions and consider the asynchronism of analog and digital precoding process, the two-stage algorithms are used in practical design [29][30][31][32]. Although the two-stage method may not achieve optimal precoding design compared to the joint optimization with comprehensiveness of problem formulation, the solution of the two-stage method needs less feedback and training signals for being considered as a non-synchronous process.…”

“…Therefore, the two-stage method has been widely appreciated in recent years. [29] proposed an alternating optimization scheme to design the analog precoder and combiner, and [30] sorted the antenna sub-arrays according to the capacity of the channel before optimization. The above two algorithms adopt the iterative optimization theory, which increases the computational complexity of implementation.…”