2 citations · 2 across the 8 of their papers we have counts for
10 papers
Physical-Layer Aspects of Repeater-Assisted MIMO
Diana P. M. Osorio, Kohei Ueda, Anubhab Chowdhury +4
Network-controlled repeaters (NCRs) are emerg- ing as low-cost, band-selective active scatterers that can re- shape the wireless propagation environment without backhaul or tight p…
On Optimal Strategies for Joint Reciprocity Calibration in Distributed MIMO
Kohei Ueda, Anubhab Chowdhury, Koji Ishibashi +1
This paper investigates the impact of reciprocity calibration errors on the downlink spectral efficiency (SE) of multi-user large antenna systems. Specifically, we consider two cal…
Repeater-Assisted Massive MIMO Downlink Performance with Calibration Errors
Kohei Ueda, Anubhab Chowdhury, Koji Ishibashi +1
Reciprocity-based downlink beamforming is imperative for a scalable time-division duplex massive multiple-input multiple-output~(MIMO) deployment. Specifically, for a dual-antenna…
Expectation Propagation-Based Signal Detection for Highly Correlated MIMO Systems
Kabuto Arai, Takumi Yoshida, Takumi Takahashi +1
Large-scale multiple-input-multiple-output (MIMO) systems typically operate in dense array deployments with limited scattering environments, leading to highly correlated and ill-co…
Joint Pilot Allocation and Sequence Design for MIMO-OFDM Systems With Channel Sparsity
Kabuto Arai, Koji Ishibashi, Hiroki Iimori +3
This paper proposes a joint optimization of pilot subcarrier allocation and non-orthogonal sequence for multiple-input-multiple-output (MIMO)-orthogonal frequency-division multiple…
Revisiting Beamforming Design for Stable Millimeter-Wave Communications Under Blockages
Kanta Terui, Kabuto Arai, Koji Ishibashi
This paper investigates robust analog beamforming for millimeter-wave (mmWave) communications under stochastic path blockages using multi-panel arrays. Conventional designs concent…
Adaptively Weighted Averaging Over-the-Air Computation and Its Application to Distributed Gaussian Process Regression
Koya Sato, Koji Ishibashi
This paper introduces a noise-tolerant computing method for over-the-air computation (AirComp) aimed at weighted averaging, which is critical in various Internet of Things (IoT) ap…
Channel Estimation for Hybrid MIMO Systems With Array Model Errors and Beam Squint Effects
Kabuto Arai, Koji Ishibashi
This paper proposes a channel estimation method for hybrid wideband multiple-input-multiple-output (MIMO) systems in high-frequency bands, including millimeter-wave (mmWave) and su…
Joint Channel and Data Estimation for Multiuser Extremely Large-Scale MIMO Systems
Kabuto Arai, Koji Ishibashi, Hiroki Iimori +2
This paper proposes a joint channel and data estimation (JCDE) algorithm for uplink multiuser extremely large-scale multiple-input-multiple-output (XL-MIMO) systems. The initial ch…
Robust Symbol Detection in Overloaded NOMA Systems
Hiroki Iimori, Giuseppe Thadeu Freitas de Abreu, Hara Takanori +5
We present a framework for the design of low-complexity and high-performance receivers for multidimensional overloaded NOMA systems. The framework is built upon a novel compressive…