To supplant partial optical access networks, we study a large capacity transmission system with millimeter wave applied radio over fiber (RoF). In this system, it is desirable from the viewpoints of downsizing and power saving that the base station (BS) is simplified and the central station (CS) controls beamforming. However, this demands fiber length estimation because each wavelength must be given a different phase rotation due to chromatic dispersion in the optical fiber. This paper proposes a method to estimate fiber length from CS to BS supporting wireless terminal (WT) by utilizing time synchronization; its performance is evaluated.
In recent years, many small antennas used near a human body have been proposed in the medical field. Most of them are designed in consideration of the influence of a human body having high dielectric properties and assume use at a single frequency or a single polarization. We proposed a dual-polarized textile antenna for the 5.2 GHz band as our previous study.
In this paper, we report the design of a dual-band dual-polarized antenna using single point coplanar feeding. This antenna has excellent radiation patterns and reflection coefficients for each of the desired frequency.
This paper presents the theoretical system-level performance of multi-user multiple-input and multiple-output (MU-MIMO) Tomlinson-Harashima precoding (THP) with user scheduling. In our performance evaluation, proportional fairness (PF), which makes a reasonable compromise between fairness among users and the benefit of multi-user diversity, is implemented as a user scheduling technique, and the effect of modulo loss resulting from THP modulo operation at the receiver is taken into account using mod-Λ channel-based analysis, which provides accurate theoretical performance. Moreover, considering the application to the PF metric, the performance of the mod-Λ channel-based PF metric is compared with that of the traditional Shannon-Hartley theorem-based metric.