MACKEY II (Meta-surface inspired Antenna Chip developed by KIT EOE Laboratory) has been proposed as a functional compact antenna that is not affected by surrounding metals. The aim of the study is to further miniaturize the MACKEY. To lower the resonance frequency, we focused on increasing the capacitance of the antenna. Focusing on the laminated structure of 3 conductor layers and the surplus space in the intermediate layer of MACKEY II, two metal plates composed of conductor strips were newly installed. The antenna’s capacitance has successfully reduced the resonance frequency by increasing the antenna’s capacitance, resulting in reducing the antenna size. In this paper, the performance of the antenna is evaluated by comparing the analyzed and measured values.

I show an LTE/4G wireless cell network that uses existing OFDMA telephone mobile nodes with the ability to detect 1.5, 1.25 and 1.75 wavelength peak-to-peak distance between 2 peaks of peak voltage beyond threshold, respectively for 3 each neighbor BS 4 wavelength PSK carrier wave-form for data bit 1, enabling receiving high speed data. Also, I showed good performance of proposed methods by simulation with 4 carrier wavelength for data bit 0 by using diversity antenna far by about 0.5 wave-length distance from main antenna in case that 2 other neighbor BS 0.4 v microwave signals and 2 0.4v fading add to present BS 1v direct microwave signal after LCR resonant filter of MN microwave receive circuit.

This study investigates the system capacity of orbital angular momentum multiple-input multiple-output (OAM-MIMO) systems employing parabolic reflectors at both the transmitter and receiver and evaluates its effectiveness in comparison with conventional OAM-MIMO systems, which use a parabolic antenna only at the transmitter. Specifically, the system capacity of OAM-MIMO with parabolic antennas applied at both ends is calculated based on the planar antenna reception analysis. The impact of applying parabolic reflectors at both the transmitter and receiver is examined by varying the number of multiplexed streams and carrier frequency, using the case with a parabolic antenna at the transmitter alone as a reference. In particular, performance evaluation ensures a fair comparison by fixing the total number of antenna elements and the total transmit power, thereby considering the trade-off between stream power reduction and bandwidth expansion.

This paper proposes a positioning-enabled embedded system designed for the spatial characterization of indoor Wi-Fi propagation. The proposed system integrates received signal strength indicator (RSSI) data from a commercial off-the-shelf (COTS) device, signal-to-noise ratio (SNR) measurements from a software-defined radio (SDR), and position information from optical 2-D markers. The system was deployed in two indoor environments, and the measurements were compared with ray tracing simulations. The results show agreement in spatial trends between the measured and simulated data, supporting the validity of the proposed system.

Unmanned aerial vehicles (UAVs) are attracting attention for applications such as delivery services. In dense UAV traffic, efficient route management is critical for safe navigation. We previously proposed a distributed UAV management system based on a virtual circuit concept, where UAV routes are established over a multi-hop wireless network formed by devices installed in individual houses. To avoid collisions, the system reserves both UAV routes and their crossing links. However, as the number of UAVs increases, link availability decreases, leading to frequent route construction failures. This letter proposes an improved method that reserves only the links currently used by UAVs in flight and their crossing links. Simulation results confirm the effectiveness of the proposed method.

High transmission quality is essential for wireless communication. To meet this demand, we propose an approach to enhance the modulation method using Voronoi constellations (VCs) based on an N-dimensional lattice partition. Compared to traditional methods such as M-ary phase-shift keying (M-PSK) and M-ary quadrature amplitude modulation (M-QAM) on a two-dimensional plane, N-dimensional VCs offer a larger Euclidean distance between signal points, resulting in superior error rate performance in additive white Gaussian noise (AWGN) channels. To further improve performance in fading channels, we introduce new VCs that achieve diversity gain by rotating the constellation in N-dimensional space while preserving AWGN channel characteristics. Numerical results demonstrate that VCs achieve a 25dB gain for QPSK and a 17dB gain for 16QAM at a block error rate of 10^-4 in a symbol-independent and identically distributed (i.i.d.) Rayleigh fading channel. Additionally, as the achieved diversity gain is influenced by fading variations, the effective range of these gains was clarified in accordance with the 5G New Radio (NR) radio interface.

Maximizing the bottleneck bandwidth of communication paths is a critical challenge for bandwidth-intensive applications. This study proposes a distributed-routing method based on ant colony optimization that dynamically adjusts pheromones according to locally learned path quality. The method’s key feature is its ability to adapt to changing network conditions using local statistics, making it suitable for dynamic environments such as information-centric networking, where content sources change frequently. Simulation results indicate high convergence and effective selection of optimal paths with the proposed method.

In this study, a lightweight semantic communication scheme is proposed to address the issues of large storage overhead and limited adaptability caused by the dynamic signal-to-noise ratio (SNR) variations in wireless channels, which necessitate storing multiple SNR-specific models in conventional semantic communication schemes. The scheme integrates ghost convolution (GC) and a global attention mechanism (GAM) module. Experimental results demonstrate: a 30% reduction in parameters, FLOPs, and model storage while maintaining comparable performance to conventional convolutional models; under the 3dB Gaussian channel, the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index Measure(SSIM) reach 27dB and 0.9 respectively; under the Rayleigh channel at identical SNR, PSNR and SSIM achieve 25dB and 0.8. The approach significantly reduces deep learning model complexity while preserving image reconstruction quality, effectively solving the multi-SNR adaptation versus storage trade-off, and establishing a new idea for the image semantic communication scheme.

This paper shows that loading ferrite beads on feeding lines causes significant errors in direction estimation in a loop array antenna in a borehole radar. This contradicts the conventional wisdom that ferrite bead loading avoids undesirable scattering. The numerical simulation of a plane wave incidence on the loop array found that the ferrite loading worsened the DOA estimation by about 30°. We conducted a field experiment of cross-hole measurement in soil. The azimuth angle estimation error of the loop array without the ferrite loading was less than 25°, while that with the ferrite loading ranged between 30° and 120°.

This paper presents the design and evaluation of a compact dipole antenna optimized for ear-mounted devices, aiming to mitigate radiation efficiency loss caused by proximity to the human body. By analyzing current distribution, antenna orientation, and antenna size, it was found that placing the antenna perpendicular to the body, setting high-current regions away from the human body, and increasing the antenna size to reduce power absorption within the human body significantly improves efficiency. A novel “in-ear dipole antenna” was proposed and compared to a folded dipole design, achieving approximately 4dB improvement in radiation efficiency. These findings contribute to the development of high-performance wireless ear-worn devices with minimal interference from human body proximity.

Quick UDP Internet Connections (QUIC), an advanced IETF transport-layer protocol, offers several significant advantages over traditional TCP, including reduced latency, enhanced multiplexing capabilities, and strong security through built-in encryption and optimized handshake processes. Because of these benefits, even before its standardization in 2021, QUIC was widely deployed by major Internet companies such as Google and Facebook. Additionally, previous research has observed an increase in global adoption of QUIC. Motivated by this trend, we investigate QUIC deployment in Vietnam, particularly in the context of the country’s rapid development, especially in the ICT sector. Specifically, we scan and analyze QUIC adoption using a Vietnamese IPv4 dataset. The scanning results indicate that QUIC adoption in Vietnam is in the early stages, with a low deployment rate of approximately 0.05% of all Vietnamese IPv4 addresses. Furthermore, we analyze active migration support, TLS encryption preferences, and visualize a map of QUIC adoption to track its ongoing deployment patterns. In addition, we conduct active measurements showing that QUIC achieves lower time to first byte (TTFB) and higher throughput than TCP in Wi-Fi networks, while offering competitive performance in mobile networks.