User-Centric Design of Millimeter Wave Communications for Beyond 5G and 6G

Ishibashi, Koji; Hara, Takanori; Uchimura, Sota; Iye, Tetsuya; Fujii, Yoshimi; Murakami, Takahide; Shinbo, Hiroyuki

doi:10.1587/transcom.2021mei0002

Cited by 6 publications

(4 citation statements)

References 47 publications

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“…The maximum transmit power per BS is set to P max,b = 30 [dBm], and a total of K = 36 subcarriers with W = 240 [kHz] subcarrier spacing operating at the 28 [GHz] band is assumed, which leads to a sampling period of T s = 1/ (W K) = 0.115 [µs] 6 . Pulse shaping is performed with a root-raised cosine roll-off filter with the roll-off rate of 0.8, and the equivalent pulse response p(dT s −τ c ) is calculated using the raised cosine roll-off filter.…”

Section: Performance Assessmentmentioning

confidence: 99%

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Blockage-Robust Hybrid Beamforming Enabling High Sum Rate for Millimeter-Wave OFDM Systems

Uchimura,

de Abreu,

Ishibashi

2024

IEEE Trans. Wireless Commun.

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We propose a scheme for the concomitant design of hybrid beamforming and per-carrier transmit power allocation to mitigate the effect of random path blockages in coordinated multi-point (CoMP) systems using orthogonal frequency division multiplexing (OFDM) in millimeter-wave (mmWave) channels. In order to optimize both the beamformers and power allocation while dealing simultaneously with outage minimization and sum rate maximization (SRM) requirements, a regularized sum-ofoutage minimization problem is formulated. The problem is then transformed into an empirical risk minimization (ERM) problem, solved via block stochastic learning and manifold optimization, with required learning rates derived and tuned to guarantee convergence. The method, which demands only a few radio frequency (RF) chains and relies only on knowledge of blockage probabilities, is shown via simulation results not only to outperform state-of-the-art (SotA) alternatives, but to actually achieve outage probabilities comparable to those a fully digital CoMP-SRM scheme with perfect knowledge of instantaneous blockages.

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Section: Performance Assessmentmentioning

confidence: 99%

“…For the fully-digital methods, obviously N RF = Nt = 16 6. Although we consider only 36 subcarriers to reduce the computational complexity to a level compatible with laptop computers, the sampling period is still much shorter than typical blocking times, which are on the order of milliseconds[17],[18].…”

mentioning

confidence: 99%

Blockage-Robust Hybrid Beamforming Enabling High Sum Rate for Millimeter-Wave OFDM Systems

Uchimura,

de Abreu,

Ishibashi

2024

IEEE Trans. Wireless Commun.

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“…The millimeter wave (mmWave) communications can significantly boost network capacity to make ubiquitous and on-demand interconnection possible in future wireless networks [1][2][3]. However, owing to the propagation loss of the mmWave band and the broadcast nature of wireless channels, mm Wave communication suffers from the risk of information leakage in the presence of eavesdroppers, especially when the legitimate and wiretap channels are highly correlated, which makes security an indispensable pursuit for system development.…”

Section: Introductionmentioning

confidence: 99%

Physical Layer Security Enhancement for mmWave System with Multiple RISs and Imperfect CSI

Tu,

Dong,

Zou

et al. 2024

IEICE Trans. Commun.

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Despite the appealing advantages of reconfigurable intelligent surfaces (RIS) aided mmWave communications, there remain practical issues that need to be addressed before the large-scale deployment of RISs in future wireless networks. In this study, we jointly consider the non-neglectable practical issues in a multi-RYS-aided mm Wave system, which can significantly affect the secrecy performance, including the high computational complexity, imperfect channel state information (CST), and finite resolution of phase shifters. To solve this non-convex challenging stochastic optimization problem, we propose a robust and low-complexity algorithm to maximize the achievable secrete rate. Specially, by combining the benefits of fractional programming and the stochastic successive convex approximation techniques, we transform the joint optimization problem into some convex ones and solve them sub-optimally. The theoretical analysis and simulation results demonstrate that the proposed algorithms could mitigate the joint negative effects of practical issues and yielded a tradeoff between secure performance and complexity/overhead outperforming non-robust benchmarks, which increases the robustness and flexibility of multiple RIS deployments in future wireless networks.

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“…O WING to the growing number of wireless devices and the complexity of user demands, modern wireless communications systems require increasingly larger bandwidths [1]- [3]. Fifth-generation mobile communications systems (5G) have therefore been designed to exploit available spaces in the millimeter-wave (mmWave) band within 24 [GHz] to 300 [GHz], as a means to address spectrum shortages [4]- [6], with further utilization of the mmWave band considered crucial to meet the requirements of Beyond-5G and sixth-generation mobile communications systems (6G) [7]- [11].…”

Section: Introductionmentioning

confidence: 99%

Outage-Minimization Coordinated Multi-Point for Millimeter-Wave OFDM With Random Blockages

Uchimura

Iimori

Abreu

et al. 2023

IEEE Trans. Veh. Technol.

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We consider millimeter-wave (mmWave) orthogonal frequency division multiplexing (OFDM) systems subjected to random propagation path blockages and propose a new Coordinated multi-point (CoMP) transmission scheme that minimizes the outage probability of users with respect to given target data rates. To this end, a stochastic sum-outage-probability minimization problem is formulated for joint beamforming design, data rate allocation, and power allocation over subcarriers. In order to solve this problem efficiently, a block statistic learning approach is introduced using training data generated from a priori knowledge of path blockage probabilities. To initialize the stochastic learning solver, the novel initial beamforming is also proposed based on the upper bound of the original objective function, which improves convergence without tuning hyperparameters. Numerical results confirm the effectiveness of the proposed block stochastic learning approach in terms of both convergence behavior and outage probability. Furthermore, these results confirm that the proposed approach with only blockage probabilities is comparable to the outage performance of a CoMP sum rate maximization (SRM) transmission scheme with perfect channel state information (CSI) and perfect knowledge of blockages.

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User-Centric Design of Millimeter Wave Communications for Beyond 5G and 6G

Cited by 6 publications

References 47 publications

Blockage-Robust Hybrid Beamforming Enabling High Sum Rate for Millimeter-Wave OFDM Systems

Blockage-Robust Hybrid Beamforming Enabling High Sum Rate for Millimeter-Wave OFDM Systems

Physical Layer Security Enhancement for mmWave System with Multiple RISs and Imperfect CSI

Outage-Minimization Coordinated Multi-Point for Millimeter-Wave OFDM With Random Blockages

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