arXiv subjects

Tomotaka Kimura

Publications and source records attributed to Tomotaka Kimura.

2 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↗

arXiv2020

Global Optimization of Relay Placement for Seafloor Optical Wireless Networks

Optical wireless communication is a promising technology for underwater broadband access networks, which are particularly important for high-resolution environmental monitoring applications. This paper focuses on a deep sea monitoring system, where an underwater optical wireless network is deployed on the seafloor. We model such an optical wireless network as a general queueing network and formulate an optimal relay placement problem, whose objective is to maximize the stability region of the whole system, i.e., the supremum of the traffic volume that the network is capable of accommodating. The formulated optimization problem is further shown to be non-convex, so that its global optimization is non-trivial. In this paper, we develop a global optimization method for this problem and we provide an efficient algorithm to compute an optimal solution. Through numerical evaluations, we show that a significant performance gain can be obtained by using the derived optimal solution.

cs.NI↗