Most conventional radar-based remote heart rate measurements require the subject to remain stationary. Secondly, the valid measurement range is limited by radar module specifications. Furthermore, the accuracy decreases when the subject is far from the radar. Therefore, this article proposes a novel remote heart rate measurement method based on radar and a mobility robot. The method adaptively adjusts the radar to be in an appropriate measurement range to measure heart rate while the subject walks. The experimental results demonstrate the feasibility of the proposed method.

To achieve ultrahigh-speed transmission using short-range multiple-input multiple-output (SR-MIMO) transmission, estimating the displacement of the facing transmitting (Tx) and receiving (Rx) antennas must be done with high precision, with installation in the opposite position with millimeter-order accuracy. When using the weighted centroid localization (WCL) method, which is a conventional position estimation method, the position estimation accuracy degrades as the Tx displacement and Rx antennas increase. In this letter, we propose a method to calculate the center of gravity position using the WCL method, considering the symmetry based on the Rx antenna with the largest received signal strength indicator. Additionally, computer simulation results demonstrate that the proposed method can achieve antenna position estimation with millimeter-order accuracy.

In autonomous decentralized control of mobile agents such as robots and drones, packet loss that occurs in wireless communication has a significant impact on control performance. This paper proposes a simple information transfer method for CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance)-based autonomous decentralized control to compensate for information lost due to communication failures. We evaluate the effectiveness of information transfer on control performance in two typical classes of autonomous decentralized control, i.e., consensus control and coverage control, by computer simulation, and show that the improvement of control quality can be achieved regardless of the number of controlled agents and the contention window size of CSMA/CA.

Video transmission over optical fiber is becoming more and more popular every year. If we can expand this technology to enable wideband signals that multiplex both video and wireless signals to be transmitted using only a single optical transmitter, various new values can be created. Therefore, we have improved our high-performance video transmitter that achieved the world’s longest-distance transmission in our previous study by optimizing its FM center frequency. Our transmission experiments with multiplexed video and wireless signals demonstrate that the resultant signal can satisfy the target quality specified by the Ministerial Ordinance and 3GPP.

As one of the important sensors for driving assistance, millimeter wave radar is of great significance for automotive safety driving. However, the problem of mutual interference between automotive radar signals is becoming a non negligible threat. Mutual interference can cause a significant performance decrease of radar target detection, and this article proposes a simple and efficient target detection method to address this issue. The proposed method utilizes the distribution difference between target echoes and interference signals in the time-frequency domain to obtain a accumulation vector of spectral peaks, which follow a Poisson distribution. Based on that, the Poisson constant false alarm detection method is proposed to detect target echos effectively at low signal-to-interference ratios. The experimental results show that the detection accuracy of the method is above 95% when the signal-to-interference ratio is below -20dB. In addition, this algorithm does not require interference compression before detecting the target, and its computational complexity is only slightly greater than that of the short time Fourier transform, so it is a fast anti interference detection method.

Rank adaptation is important for robust multiple-input multiple-output (MIMO) transmission in the presence of arriving interference. If the traffic pattern of an interferer is complex, the arrival of interference may only be predicted probabilistically. Therefore, we have proposed a method for effective rank adaptation based on such probabilistic interference arrival information. The proposed method calculates the channel capacity for each pattern of interference arrival in advance and selects the rank that gives the maximum expected capacity. A conventional method selects the rank that gives the maximum channel capacity. The effectiveness of the proposed method is verified by simulations assuming Nakagami-Rice fading channel and prediction error of interference arrival probability. It is confirmed that the proposed method can achieve higher spectral efficiency than the conventional method.

AMec (Access-Metro edge computing) is a technology that can reduce the number of edge servers by utilizing in-network excess computing resources such as unallocated cores of control CPU of network devices as a node of the AMec cluster. The important issue is service interruption in that computing resources become unavailable due to executing their main job (e.g. device control and management jobs). In this paper, to avoid interruptions, two types of pod allocation algorithms (both static and dynamic thresholds) are evaluated. The dynamic threshold method is effective in keeping a high allocation success rate even for time-varying numbers of application occurrences.

Microwave Power Transmission (MPT) is a promising technology that can be utilized to charge devices wirelessly and remotely. However, most previous studies on MPT focused on improving charging efficiency and have ignored the harmful effects on wireless communication devices that are sensitive to the considerable received signal power caused by the electromagnetic radiation of microwaves. To resolve this problem, this study introduces into MPT the signal-to-leakage-and-noise ratio (SLNR), used to suppress co-channel interference in multi-user Multiple-Input Multiple-Output (MIMO) downlink communications. We establish a beamforming scheme that maximizes SLNR for MPT. Compared with a beamforming scheme that does not consider leakage power, the proposed method transmits power to intended receivers while suppressing leakage power to protected devices. Based on simulations, our method decreases the leak power to protected devices by over 10 dB while maintaining the received power at the targeted receivers, compared with the conventional method.

Millimeter and terahertz waves have been investigated to provide high-speed and large-capacity wireless communication. However, the short wavelength of such high-frequency bands would result in communication performance degradation due to wave blocking by obstacles and scattering by surrounding objects. In this paper, we focus on terahertz wave scattering from slightly rough surfaces. Scattering from dielectric surfaces was measured at 300GHz by using a simple experimental setup for stable and precise measurement. The measured results are compared with a numerical simulation based on our theory of stochastic functional approach.

The antenna radiation efficiency of a K-band horn was determined using a reference waveguide method with S-parameters in a reverberation chamber. Numerical analysis was performed to validate the applicability of the measurement method and the measured results. In addition, the effect of unstirred waves on the radiation efficiency measurements was evaluated using the complex S-parameter method for identifying unstirred waves.