A visible light communication (VLC) system offers notable advantages, and leveraging image sensors as VLC receivers holds promise. The rolling shutter image sensor stands out as a popular candidate among these sensors. However, challenges arise from signal loss from inter-frame gaps or background scans. This paper addresses these issues by introducing a low-density parity check (LDPC) code and a corresponding code synchronization method suitable for LDPC decoding. Our approach employs a parallel transmitting sequence to achieve synchronization. Notably, the synchronization sequence is transmitted by modulating the luminance of the LED transmitter. Through experimentation, we validate the efficacy of our proposed method in mitigating signal loss.
{"title":"Code Synchronization in Visible Light Communication System Using Dual Orthogonal Rolling Shutter Image Sensors","authors":"Ayumu Otsuka;Zhengqiang Tang;Shan Lu;Takaya Yamazato","doi":"10.23919/comex.2024COL0009","DOIUrl":"https://doi.org/10.23919/comex.2024COL0009","url":null,"abstract":"A visible light communication (VLC) system offers notable advantages, and leveraging image sensors as VLC receivers holds promise. The rolling shutter image sensor stands out as a popular candidate among these sensors. However, challenges arise from signal loss from inter-frame gaps or background scans. This paper addresses these issues by introducing a low-density parity check (LDPC) code and a corresponding code synchronization method suitable for LDPC decoding. Our approach employs a parallel transmitting sequence to achieve synchronization. Notably, the synchronization sequence is transmitted by modulating the luminance of the LED transmitter. Through experimentation, we validate the efficacy of our proposed method in mitigating signal loss.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"450-453"},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591719","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761566","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}
Pub Date : 2024-07-09DOI: 10.23919/comex.2024XBL0106
Hideya So;Hayato Soya
Spectrum sharing, in which multiple wireless systems share the same radio resources, has been considered to improve frequency utilization efficiency. As a spectrum sharing without control signals, a technique that observes the usage of radio resources, called channel occupation ratio, used by other systems and selects a vacant channel has been considered. However, previous studies have simplified the model of the interfering system, which is different from the real environment. In wireless communications, fluctuations in received power occur due to shadowing caused by the location and the surrounding environment. Previous studies have not clarified the effect of received power fluctuation due to shadowing on observing the occupancy rate. This letter formulates the effects on the observation results of received power fluctuations due to the location of interfering stations and shadowing. Computer simulations with randomly placed interfering stations and shadowing environments show that the proposed formulation almost matches the observed results.
{"title":"Evaluation of Shadowing Effect on Channel Observation for Spectrum Sharing Access","authors":"Hideya So;Hayato Soya","doi":"10.23919/comex.2024XBL0106","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0106","url":null,"abstract":"Spectrum sharing, in which multiple wireless systems share the same radio resources, has been considered to improve frequency utilization efficiency. As a spectrum sharing without control signals, a technique that observes the usage of radio resources, called channel occupation ratio, used by other systems and selects a vacant channel has been considered. However, previous studies have simplified the model of the interfering system, which is different from the real environment. In wireless communications, fluctuations in received power occur due to shadowing caused by the location and the surrounding environment. Previous studies have not clarified the effect of received power fluctuation due to shadowing on observing the occupancy rate. This letter formulates the effects on the observation results of received power fluctuations due to the location of interfering stations and shadowing. Computer simulations with randomly placed interfering stations and shadowing environments show that the proposed formulation almost matches the observed results.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 9","pages":"379-383"},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591720","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142090747","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}
Unmanned aerial vehicles (UAVs) are expected to be used in various applications such as delivery services and sensing from airspaces in smart cities. In the future, UAV control systems must address a densely mixed environment comprising various services and users regardless of individuals or businesses. However, users cannot flexibly join or leave the system because of their centralized design. This letter proposes a distributed UAV management system inspired by packet-switched networks, to address dense UAV environments. The proposed system controls autonomous UAVs as packets in packet-switched networks. Each UAV flies along a path composed of links between ground beacon devices as routers. We analyzed the characteristics of the proposed system in dense situations using computer simulation. Simulation results indicate that the proposed system can handle numerous UAVs based on packet-switched networks.
{"title":"A Distributed UAV Management System Inspired by Packet-Switched Networks","authors":"Takahiko Haraguchi;Hiroshi Katada;Taku Yamazaki;Takumi Miyoshi;Ryo Yamamoto;Kiyoshi Ueda","doi":"10.23919/comex.2024XBL0101","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0101","url":null,"abstract":"Unmanned aerial vehicles (UAVs) are expected to be used in various applications such as delivery services and sensing from airspaces in smart cities. In the future, UAV control systems must address a densely mixed environment comprising various services and users regardless of individuals or businesses. However, users cannot flexibly join or leave the system because of their centralized design. This letter proposes a distributed UAV management system inspired by packet-switched networks, to address dense UAV environments. The proposed system controls autonomous UAVs as packets in packet-switched networks. Each UAV flies along a path composed of links between ground beacon devices as routers. We analyzed the characteristics of the proposed system in dense situations using computer simulation. Simulation results indicate that the proposed system can handle numerous UAVs based on packet-switched networks.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 9","pages":"389-392"},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591721","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142090889","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}
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.
从有效利用频率资源的角度来看，未知无线电波源的定位技术至关重要。作者们研究了在非视距（NLOS）环境下使用无人飞行器（UAV）基于最大似然估计对单个波源进行定位的方法。在本研究中，我们通过扩展单波源定位方法，提出了一种多波源定位方法。在所提出的方法中，无人机的到达方向（DoA）用冯-米塞斯分布的混合物建模，波源则通过叠加无人机上估计的 DoA 分布来估计。利用两个波源的简单模拟实验验证了所提出的方法。
{"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":"13 9","pages":"375-378"},"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}
Pub Date : 2024-07-09DOI: 10.23919/comex.2024XBL0103
Tomoaki Matsuda;Shusuke Narieda
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.
在之前的研究中，我们介绍了一种确定无线传感器网络最佳传感器位置的方法，用于监测室内二氧化碳（CO2）浓度。事实证明，这种基于蛮力的方法准确可靠。然而，随着传感器数量的增加，计算复杂度也呈指数增长。因此，本研究提出了一种基于遗传算法（GA）的优化传感器节点布置的新方法，为蛮力法提供了更有效的替代方案。通过利用遗传算法，我们在降低计算复杂度的同时实现了传感器的最佳布置。为了验证基于 GA 的方法的有效性，我们使用观测到的二氧化碳浓度进行了数值实验。结果表明，我们提出的方法不仅实现了传感器的最佳布置，还保持了观测结果的准确性。
{"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":"13 9","pages":"393-396"},"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}
We aim to realize a beyond 5th generation (B5G) smart mobile fronthaul (SMFH) that utilizes analog radio over fiber (A-RoF) transmission technology and optical power feed technology by applying newly developed Hollow-Core Fiber. In this paper, to evaluate the feasibility of the SMFH, we will report the successful construction of a A-RoF testbed using an unlicensed WiFi 5 GHz band signal provided by a Linux PC-based access point instead of a licensed 5G sub 6 GHz band signal.
{"title":"Construction of the Analog Radio Over Fiber Technology Testbed with Linux PC-Based WiFi Access Points","authors":"Kojiro Nishimura;Satoru Okamoto;Ryuta Murakami;Naoaki Yamanaka;Motoharu Matsuura","doi":"10.23919/comex.2024COL0011","DOIUrl":"https://doi.org/10.23919/comex.2024COL0011","url":null,"abstract":"We aim to realize a beyond 5th generation (B5G) smart mobile fronthaul (SMFH) that utilizes analog radio over fiber (A-RoF) transmission technology and optical power feed technology by applying newly developed Hollow-Core Fiber. In this paper, to evaluate the feasibility of the SMFH, we will report the successful construction of a A-RoF testbed using an unlicensed WiFi 5 GHz band signal provided by a Linux PC-based access point instead of a licensed 5G sub 6 GHz band signal.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"458-460"},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591712","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761392","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}
Pub Date : 2024-07-09DOI: 10.23919/comex.2024COL0010
Haruto Ando;Aohan Li;Maki Arai;Mikio Hasegawa
Channel Bonding is a technique used to aggregate multiple wireless communication channels in order to enhance data transfer speeds. Initially introduced in IEEE 802.11n, it has been adapted to the newer IEEE 802.11ax standard, and so on. While this technology enables faster communications, it also suffers from interference issues due to increased bandwidth utilization. Previous studies have extensively focused on bandwidth selection to minimize channel interference, often requiring significant time. This paper proposes an approach that utilizes the Laser chaos decision maker to rapidly determine the optimal channel for dynamic channel bonding. We design our algorithm based on the scalable laser chaos decision maker and evaluate its performance through computer simulations. The results demonstrate that the proposed method has the capability to make more accurate selections than other algorithms.
{"title":"Primary Channel Selection in Dynamic Channel Bonding Using Laser Chaos Decision Maker","authors":"Haruto Ando;Aohan Li;Maki Arai;Mikio Hasegawa","doi":"10.23919/comex.2024COL0010","DOIUrl":"https://doi.org/10.23919/comex.2024COL0010","url":null,"abstract":"Channel Bonding is a technique used to aggregate multiple wireless communication channels in order to enhance data transfer speeds. Initially introduced in IEEE 802.11n, it has been adapted to the newer IEEE 802.11ax standard, and so on. While this technology enables faster communications, it also suffers from interference issues due to increased bandwidth utilization. Previous studies have extensively focused on bandwidth selection to minimize channel interference, often requiring significant time. This paper proposes an approach that utilizes the Laser chaos decision maker to rapidly determine the optimal channel for dynamic channel bonding. We design our algorithm based on the scalable laser chaos decision maker and evaluate its performance through computer simulations. The results demonstrate that the proposed method has the capability to make more accurate selections than other algorithms.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"454-457"},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591714","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761425","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}
Pub Date : 2024-07-09DOI: 10.23919/comex.2024XBL0102
Yuichiro Sugiyama;Kentaro Kobayashi
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.
{"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":"13 9","pages":"371-374"},"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}
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.
{"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":"13 9","pages":"363-366"},"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}
Pub Date : 2024-07-09DOI: 10.23919/comex.2024XBL0064
Shin-Ichi Yamamoto;Hiroto Ado;Ryuya Seki
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.
{"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":"13 9","pages":"367-370"},"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}
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