Energy-Efficient Hybrid Beamforming with Variable and Constant Phase Shifters

Abstract

In this paper, the authors propose a novel partially connected hybrid beamforming (PC-HBF) architecture, which employs variable phase shifters (VPSs) and constant phase shifters (CPSs) for analog beamforming to harness the potential of these two types of phase shifters. In the proposed architecture, the system sum rate optimization to determine the analog precoders can be formulated as a combinatorial problem. However, its exact solution is intractable, and in massive multiple-input multiple-output systems, exhaustive search to solve the corresponding combinatorial problem is practically infeasible. To resolve this problem, we employ a greedy algorithm that provides a near-optimal solution with reduced complexity. The simulation results obtained herein show that by optimally combining VPSs and CPSs, the proposed architecture achieves performance close to that of the VPS-based PC-HBF architecture. Furthermore, its energy efficiency is up to 27.3% higher than that of the CPS-based fully connected HBF scheme.

Asymptotic Performance Analysis of the MUSIC Algorithm for Direction-of-Arrival Estimation

“…where δ (P) kl are defined in (24) and (25), respectively. The analytic expression of MSE of δθ (3) n in (39) is expressed as…”

“…In [25], a hybrid beamforming employing variable phase shifters (VPSs) and constant phase shifters is proposed. To optimally combine VPSs and CPSs, greedy algorithm is adopted to get a near-optimal solution, since getting exact solution is intractable.…”

“…In Table 1, algorithms, applications, main ideas and contributions of the recently published works are tabulated. In Table 2, it is tabulated how the schemes presented in [17][18][19][20][21][22][23][24][25][26] are validated. In Table 2, it is also described how the explicit expressions of the azimuth estimate and the MSE of the azimuth estimation error derived in this paper can be applied to the problems in [17][18][19][20][21][22][23][24][25][26].…”

“…How to validate the schemes presented in [17][18][19][20][21][22][23][24][25][26], and how to apply the derivations of this paper to the problems in [17][18][19][20][21][22][23][24][25][26]. [17][18][19][20][21][22][23][24][25][26] to the Problems in [17][18][19][20][21][22][23][24][25][26] [17] Agreement between analytic MSE [17]: Performance analysis of amplitude and simulation-based MSE comparison monopulse algorithm. This paper: Performance analysis of the MUSIC algorithm [18] Reduction in estimation error of the The analytic expression of the MSE of motion compensated conventional motion-compensated Bartlett beamforming beamforming algorithm in comparison with algorithm can be obtained by modifying the estimation error of original the derivation in this paper conventional beamforming algorithm without motion compensation in the DOA spectrum [19] Superiority of performance of SCC-The analytic expression of the MSE of MVDR algorithm over MVDR algorithm SCC-MVDR algorithm can be o...…”

Iterative Analog–Digital Multi-User Equalizer for Wideband Millimeter Wave Massive MIMO Systems

“…Transmit and receive beamforming approaches designed for narrowband multi-user mmWave communications systems have also been proposed in [14][15][16][17][18][19][20][21]. The authors of [14] designed an uplink receive beamforming with single antenna user terminals (UTs) that consider the multi-user interference at two stages: analog and digital.…”