This paper presents a tool for the visual inspection of the small interacting objects (IOs) for the microwave propagation in urban environment, by utilizing 3D point cloud data of townscape and double directional channel sounding results. It is demonstrated that the tool can effectively visualize the location of the IOs.

In the hitless redundancy switching system, the selector of the redundancy switching device is controlled on the basis of the control information such as the connection status of the path to transmit frames, end-to-end delay of the path, and jitter. However, the control signal transmitted superimposed on the main signal channel in the hitless redundancy switching system is not highly confidential because all the information is transmitted superimposed on the two paths. In our previous study, we modulated the transmission timing of frames in the main signal channel by assigning “0” and “1” codes to the two paths in the hitless redundancy switching system. In this paper, we propose a method to efficiently modulate sub-signal channels in a hitless redundancy switching system to improve the communication bandwidth, and evaluate its effectiveness in a numerical simulation.

Zero Trust (ZT) Model [1] is a security approach to prevent malicious activities assuming the presence of an attacker in the environment. The fine-grained access control should be executed on ZT in accordance with various information, which requires a large complexity of access control policy due to the large patterns of attributes [2] . Our focus is the low-complexity of policy management. We propose a method to reduce and evaluate the complexity of policies for network access control. This letter discloses the optimal grouping algorithm to reduce the complexity, and shows the higher performance in comparison with the existing methods.

This letter proposes a signal-to-Noise Ratio (SNR) based spreading factor adaptation for orthogonal frequency division multiple interleave division multiple access (OFDM-IDMA) incorporated with parallel interference cancellation (PIC) on visible light communication (VLC) systems. Orthogonal variable spread factor (OVSF) code is an effective solution to eliminate multiple access interference (MAI) in exchange for spectral resource consumption. Channel ranking based spreading factor optimization can maximize the system throughput performance. The major contribution of this letter is to achieve its adaptive allocation according to the estimated value of SNR. The computer simulation results clarify its effectiveness.

The authors proposed Coherently Combining Sparse-Multiband Processing (CCSMP) [1], which coherently combines signals of the separated multi-band obtained by the stepped multiple frequency method [2]. CCSMP implements the Recursive Signal Subtraction Frequency Estimation Method [3], which iteratively estimates the range of each target while separating the signals one by one from the observed signals from multiple targets obtained in each band. Hence, CCSMP can improve the range estimation performance in multiple-target situations where the main lobes of the targets overlap and interfere with each other. In this letter, we derive the Cramér-Rao Lower Bound (CRB) for the target range estimation by combining the separated multi-band signals, and the performance of CCSMP is discussed by comparing the derived CRB values with statistical evaluations by simulation.

In this paper, we investigate the path loss characteristics near metal ceiling in 920 MHz band for secure wireless communication of indoor-use equipment such as lighting systems. In order to clarify the propagation mechanism, experiment and electromagnetic simulation are conducted using two models as use cases: a simple model with only a metal ceiling and an office with a metal ceiling. The results show that the path loss characteristics for vertical polarization near the metal ceiling has a smaller than the free space loss. The path loss characteristic for horizontal polarization, however, changes significantly depending on the floor condition.

In this study, we propose a three-dimensional (3D) imaging method for near-field scatterers that are mutually coupled with an antenna array, such as the support structure or fixtures of the antenna, based on bistatic microwave synthetic aperture imaging. This method can be used to evaluate the effectiveness of the antenna design with irremovable near-field scatterers. Numerical simulation and measurement results show the validity of the proposed imaging scheme.

We evaluate accuracy and reliability in a spatial location identification task (SpLIT) when workers know that their reward scheme is a majority vote (MV) reward scheme before processing SpLIT and when workers do not know that their reward scheme is MV before processing SpLIT. This evaluation was made to clarify how MV affects accuracy and reliability in SpLIT. When MV motivates workers, accuracy and reliability will be different in each condition. The answers of workers who knew that their reward scheme was MV before processing SpLIT had lower accuracy but higher reliability than the answers of workers who did not know this. We concluded that MV influences SpLIT by motivating workers.

We have fabricated a transverse electromagnetic (TEM) horn for radiated immunity tests in close proximity as specified in standard IEC 61000-4-39 and compared its near-field characteristics with those of other typical test antennas such as broadband dipole and double-ridged guide (DRG) horn antennas. Experimental results show that the TEM horn generates a homogeneous field and maintains the field strength without a rapid change near the antenna.