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Kazuki Maruta

Publications and source records attributed to Kazuki Maruta.

4 recordsLinked to original sources
arXiv2026

Spatio-Temporal Scheduling for Robust and Efficient Multi-Transmitter Wireless Power Transfer

In multi-user wireless power transfer (WPT), scheduling schemes that determine the allocation of transmission resources among receivers play a crucial role in improving power transfer efficiency. Scheduling can be classified into time-division (TD) and space-division (SD) schemes, with the transmission order and direction designed to control when and to whom power is delivered. TD-WPT can exploit the nonlinear characteristics of rectennas by concentrating power in time; however, a system relying on highly directional transmission from a single location reduces robustness under time-varying channel conditions. This study investigated the effectiveness of spatio-temporal scheduling in coordinated multi-transmitter WPT systems. By employing multiple transmitters, the proposed method is robust against channel variations in delivering power. Moreover, coordinated beamforming among transmitters exploits inter-cluster interference. Simulation results demonstrate the potential of the proposed scheme for robust and efficient power supply, even under shadowing conditions.

cs.NI↗
arXiv2025

Open Wireless Digital Twin: End-to-End 5G Mobility Emulation with OpenAirInterface and Ray Tracing

This study presents an end-to-end wireless digital twin platform constructed using open-source software and open data to enhance the evaluation of mobile communication systems. The proposed open wireless digital twin (OWDT) integrates OpenAirInterface (OAI) for Fifth-Generation New Radio (5G NR) protocol stack emulation and NVIDIA Sionna RT for high-resolution ray-tracing-based radio propagation modeling. This integration enables the realistic emulation of 5G wireless communication in mobility scenarios on a CPU-based Linux system, leveraging real-world building data to bridge the gap between theoretical simulations and real-world deployments. The platform also incorporates OAI FlexRIC, which is an implementation aligned with the O-RAN near-real-time RAN Intelligent Controller (near-RT RIC), to dynamically monitor key performance indicators (KPIs). Through extensive evaluation in urban environments, this study demonstrated the validity of the emulation framework, revealing its capability to replicate real-world communication dynamics with high fidelity. The results underscore the potential of the OWDT to accelerate wireless system development, reduce experimental costs, and optimize network configurations.

cs.NI↗
arXiv2022

Stochastic Image Transmission with CoAP for Extreme Environments

Communication in extreme environments is an important research topic for various use cases including environmental monitoring. A typical example is underwater acoustic communication for 6G mobile networks. The major challenges in such environments are extremely high-latency and high-error rate. They make real-time image transmission difficult using existing communication protocols. This is partly because frequent retransmission in noisy networks increases latency and leads to serious deterioration of real-timeness. To address this problem, this paper proposes a stochastic image transmission with Constrained Application Protocol (CoAP) for extreme environments. The goal of the proposed idea is to achieve approximate real-time image transmission without retransmission using CoAP over UDP. To this end, an image is divided into blocks, and value is assigned for each block based on the requirement. By the stochastic transmission of blocks, the reception probability is guaranteed without retransmission even when packets are lost in networks. We implemented the proposed scheme using Raspberry Pi 4 to demonstrate the feasibility. The performance of the proposed image transmission was confirmed from the experimental results.

cs.NI↗