{"title":"Multiple-Wave Source Localization Using UAVs in NLOS Environments","authors":"Shinichi Murata;Takahiro Matsuda;Takefumi Hiraguri","doi":"10.23919/comex.2024XBL0104","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0104","url":null,"abstract":"Localization techniques for unknown radio wave sources are crucial from the perspective of efficient utilization of frequency resources. The authors have studied methods for localizing a single wave source using unmanned aerial vehicles (UAVs) in non-line-of-sight (NLOS) environments based on maximum likelihood estimation. In this study, we propose a localization method for multiple wave sources by extending the singlewave source localization method. In the proposed method, the direction of arrivals (DoAs) at UAVs is modeled with a mixture of von-Mises distributions, and the wave sources are estimated by superimposing the DoA distributions estimated at the UAVs. The proposed method is validated with a simple simulation experiment with two wave sources.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591715","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142090748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Genetic Algorithm Optimization of Sensor Placement for CO2 Concentration Observation","authors":"Tomoaki Matsuda;Shusuke Narieda","doi":"10.23919/comex.2024XBL0103","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0103","url":null,"abstract":"In our previous studies, we introduced a method for determining the optimal sensor placement of wireless sensor networks for monitoring indoor carbon dioxide (CO2) concentrations. This method, based on brute force, has proven to be accurate and reliable. However, the computational complexity increases exponentially with an increase in the number of sensors. Therefore, this study proposes a novel approach for optimal sensor node placement based on a genetic algorithm (GA) that offers a more efficient alternative to the brute force method. By utilizing the GA, we achieved optimal sensor placement with reduced computational complexity. To validate the effectiveness of our GA based method, we conducted numerical experiments using observed CO2 concentration. The results demonstrate that our proposed approach not only achieves optimal sensor placement but also maintains the accuracy of the observations.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591722","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Experimental Study on Indoor Drone Positioning Using Wi-Fi RTT","authors":"Yuichiro Sugiyama;Kentaro Kobayashi","doi":"10.23919/comex.2024XBL0102","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0102","url":null,"abstract":"As an alternative to GPS, we focus on indoor positioning using Wi-Fi RTT (Round Trip Time), which measures the round trip time to a Wi-Fi access point. Wi-Fi RTT-based positioning has not been well studied for indoor drones. As an experimental study of indoor drone positioning using Wi-Fi RTT, this paper presents a positioning method using a combination of on-board altimeter and Wi-Fi RTT ranging, and experimental results of drone positioning when stationary and hovering to clarify the positioning accuracy in both 2.4 GHz and 5 GHz bands. This paper shows that in both frequency bands, the positioning accuracy is significantly degraded during hovering compared to stationary, and that there is no significant difference between 2.4GHz and 5 GHz bands.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Visualization Technology for Radio Wave Propagation Characteristics in Sub-Terahertz Band","authors":"Hikaru Tsuchida;Kazuaki Ishioka;Michiya Hayama;Shusaku Umeda;Akinori Taira","doi":"10.23919/comex.2024XBL0088","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0088","url":null,"abstract":"To analyze the radio wave propagation characteristics, we observed the wavefront as an image using 3-dimensional imaging technology that separates the arrival times of the radio waves. In this paper, by imaging the wavefront, we can observe the radio wave propagation characteristics at each frequency.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591711","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optical Nonlinearity Mitigation Using Reservoir Computing with Tapped-Delay Lines","authors":"Kai Ikuta;Yuta Ito;Moriya Nakamura","doi":"10.23919/comex.2024XBL0098","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0098","url":null,"abstract":"We investigated a nonlinear equalizer based on reservoir computing (RC) with tapped-delay lines for compensating for linear and nonlinear waveform distortion caused by, e.g., chromatic dispersion and self-phase modulation. We evaluated and compared the equalization performance of RC systems with and without tapped-delay lines by numerical simulation, while varying the parameters and the transmission distance. The proposed equalizer construction enables the use of RC with a shorter time-constant than that used for conventional RC-based nonlinear equalizers.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591710","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Phase Measurement and Adjustment of Reflector Antenna with Beam Waveguide Feeds","authors":"Shin-Ichi Yamamoto;Hiroto Ado;Ryuya Seki","doi":"10.23919/comex.2024XBL0064","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0064","url":null,"abstract":"When reflector antennas with a beam waveguide feeding system are used in an array configuration, the transmission phase of each reflector antenna must be known and corrected. In this paper, we propose a method in which a reflector plate is placed in the center hole of the main reflector, the reflected phase at the primary radiator horn is measured, and half of the measured phase is used as the transmission phase of the beam waveguide feeding system. The proposed method was verified by calculation, measurement using a simple model with the same path length, and measurement using an actual reflector antenna, and its effectiveness was confirmed.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591716","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Proposal of Temporal Feature Layers for Network Traffic Dataset Generation Using C-GAN","authors":"Yukito Onodera;Erina Takeshita;Tomoya Kosugi;Satoshi Suzuki","doi":"10.23919/comex.2024XBL0062","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0062","url":null,"abstract":"As machine learning research in the networking field has become more active in recent years, the demand for network traffic datasets has increased. On the other hand, the amount and types of publicly available network traffic datasets are scarce as training datasets for machine learning. Therefore, we focus on the generative adversarial network (GAN) as a data generation model, aiming to use generated rather than publicly available training datasets. However, existing GANs have difficulty generating sufficiently diverse network traffic to improve generalization ability while representing variations across weekdays, weekends, and date. This study proposes a new layers inserted into the conditional GAN model with the functions of expanding dimensionality of time-series traffic data and embedding temporal position information. Experimental results show that the model with the proposed layers inserted generated diverse network traffic data that represents temporal features.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10554803","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141973490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Two Types of Bandwidth Evaluation of Crossed Spherical Helix Antennas Using Numerical Simulation","authors":"Takuma Shimada;Mina Nishie;Keisuke Noguchi;Masato Odagaki;Keisuke Fujita","doi":"10.23919/comex.2024XBL0038","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0038","url":null,"abstract":"Comparing the bandwidths of a crossed spherical helix antenna (XSHA) and conventional antennas is challenging owing to significant change in the radiation efficiency with respect to frequency even at low voltage standing wave ratio (VSWR). Thus, two types of evaluation were performed in this work to demonstrate the wideband property of XSHA. First, the antennas were assumed to be made of a perfect conductor and were compared regarding only the VSWR bandwidth. Next, we compared the bandwidth at radiation efficiency of lossy antennas based on the generalized effective fractional bandwidth \u0000<tex>$(B_{e}). B_{e}$</tex>\u0000 is the product of the bandwidth and the radiation efficiency varying with frequency. Numerical simulations were conducted to compare the bandwidths for \u0000<tex>$VSWR leq 3$</tex>\u0000. The bandwidth of the XSHA is 2.19 and 2.11 times wider than those of single resonance antenna in lossless and lossy cases, respectively. Compared with a dual resonance antenna, the bandwidth of the XSHA is 1.36 times greater at acceptable radiation efficiencies of 50%.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10554804","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On Hyperparameter Determination for GPR-Based Channel Prediction in IRS-Assisted Wireless Communication Systems","authors":"Norisato Suga;Kazuto Yano;Yafei Hou;Toshikazu Sakano","doi":"10.23919/comex.2024XBL0058","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0058","url":null,"abstract":"Intelligent reflecting surface (IRS), which can reflect radio waves controlling the phase of incident radio waves, is being investigated for wireless communication in high-frequency bands. To control the reflection characteristic, it is necessary to separately estimate a large number of channel coefficients between transmitting and receiving antennas through each IRS element. This causes significant overhead for the channel estimation. We have proposed a channel prediction method to reduce the overhead using Gaussian process regression with spectral mixture kernel. In Gaussian process regression, the determination of the hyperparameters used to calculate the kernel matrix has a significant impact on prediction accuracy. In this study, we propose validation-based hyperparameter determination for GPR-based channel prediction and evaluate the performance difference between the gradient method and validation.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10554672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141973496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Measurement-Based Estimation of Carrier Sense Behavior for Simulation Modeling","authors":"Ayano Ohnishi;Tetsuya Iye;Michio Miyamoto;Takahito Inoshita","doi":"10.23919/comex.2024XBL0045","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0045","url":null,"abstract":"One possible approach to address communication delay in the complex wireless environment of manufacturing sites is to predict the delay by system-level simulator (SLS) and notify the communication control system in advance. For accurate delay prediction, the carrier sense (CS) model in SLS should incorporate real device characteristics. However, accurate modeling of CS is difficult since its implementation specifications are usually not publicly available. In this letter, we propose a method for estimating CS characteristics using electromagnetic noise generated simulatively by software-defined radio and emitted from a microwave oven and verify the effectiveness of this method.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":null,"pages":null},"PeriodicalIF":0.3,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10554801","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141973468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}