This study investigated the use of local 5G technology to transmit platform camera footage to train drivers during driver-only operations. A test train was equipped with a local 5G terminal and monitored to evaluate the session establishment time, monitor processing time, and video latency. The results showed that the establishment and processing times were sufficiently short for practical use, and that real-time video transmission is achievable with the appropriate selection of the encoder and decoder.
{"title":"Proof of Concept for Transmission of Station Platform Video to Railway Trains","authors":"Yusuke Dohi;Hiroyuki Osada;Junya Eto;Masahiro Yamashita;Hideaki Abe","doi":"10.23919/comex.2025COL0002","DOIUrl":"https://doi.org/10.23919/comex.2025COL0002","url":null,"abstract":"This study investigated the use of local 5G technology to transmit platform camera footage to train drivers during driver-only operations. A test train was equipped with a local 5G terminal and monitored to evaluate the session establishment time, monitor processing time, and video latency. The results showed that the establishment and processing times were sufficiently short for practical use, and that real-time video transmission is achievable with the appropriate selection of the encoder and decoder.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 12","pages":"420-423"},"PeriodicalIF":0.3,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11078828","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665853","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 : 2025-07-11DOI: 10.23919/comex.2025XBL0076
Yaning Xu;Yurong Guo
Grant-free random access, as a crucial access mechanism in current massive machine-type communication (mMTC) scenarios, can significantly reduce signaling overhead. Base station(BS) achieve joint device activity detection and channel estimation (JADCE) through received pilot sequences. However, time delays severely degrade detection performance and increase computational complexity. In this letter, we first design a novel pilot sequence composed of chirp signals with distinct parity index values. Then, we construct a reduced candidate pilot set by leveraging the invariant parity property of index value sums under time delays. Finally, exploiting the favorable correlation characteristics of the pilot sequences, we propose a low-complexity orthogonal matching pursuit with successive interference cancellation (OMP-SIC) algorithm for solving the JADCE problem in asynchronous multiple access scenarios.
{"title":"Low-Complexity Grant-Free Random Access Based on Chirp Signals in Asynchronous Scenarios","authors":"Yaning Xu;Yurong Guo","doi":"10.23919/comex.2025XBL0076","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0076","url":null,"abstract":"Grant-free random access, as a crucial access mechanism in current massive machine-type communication (mMTC) scenarios, can significantly reduce signaling overhead. Base station(BS) achieve joint device activity detection and channel estimation (JADCE) through received pilot sequences. However, time delays severely degrade detection performance and increase computational complexity. In this letter, we first design a novel pilot sequence composed of chirp signals with distinct parity index values. Then, we construct a reduced candidate pilot set by leveraging the invariant parity property of index value sums under time delays. Finally, exploiting the favorable correlation characteristics of the pilot sequences, we propose a low-complexity orthogonal matching pursuit with successive interference cancellation (OMP-SIC) algorithm for solving the JADCE problem in asynchronous multiple access scenarios.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 9","pages":"349-352"},"PeriodicalIF":0.3,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11078826","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918346","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 : 2025-07-11DOI: 10.23919/comex.2025XBL0087
Yuichiro Sugiyama;Kentaro Kobayashi
For drones to expand their activities, a self-localization method for indoor flying drones is required to complement GPS. We have investigated indoor drone positioning based on Wi-Fi RTT (Round Trip Time). This paper presents methods for estimating the position coordinate of a drone using Wi-Fi RTT and machine learning. In addition to a method that learns actual Wi-Fi RTT ranging data, we propose a novel method that learns pseudo-generated ranging data reproducing Wi-Fi RTT characteristics. Experimental results show that the proposed machine learning-based method using pseudo-generated data achieves higher accuracy than the method that learns actual ranging data and is also superior to the conventional MMSE method.
{"title":"Indoor Drone Positioning Methods Using Wi-Fi RTT and Machine Learning","authors":"Yuichiro Sugiyama;Kentaro Kobayashi","doi":"10.23919/comex.2025XBL0087","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0087","url":null,"abstract":"For drones to expand their activities, a self-localization method for indoor flying drones is required to complement GPS. We have investigated indoor drone positioning based on Wi-Fi RTT (Round Trip Time). This paper presents methods for estimating the position coordinate of a drone using Wi-Fi RTT and machine learning. In addition to a method that learns actual Wi-Fi RTT ranging data, we propose a novel method that learns pseudo-generated ranging data reproducing Wi-Fi RTT characteristics. Experimental results show that the proposed machine learning-based method using pseudo-generated data achieves higher accuracy than the method that learns actual ranging data and is also superior to the conventional MMSE method.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 9","pages":"342-345"},"PeriodicalIF":0.3,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11078825","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918348","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 : 2025-07-01DOI: 10.23919/comex.2025XBL0070
Igor Novid;Hiroshi Kamabe
Visible light communication (VLC) has emerged as an alternative to data communication, offering higher bandwidth than radio communication. To fully leverage its advantages, Polar codes, recognized as capacity-achieving codes, are employed in serial concatenation with run-length limited (RLL). In this paper, we propose an enhancement to our previous decoding method, successive cancellation list - soft guessing random additive noise decoding (SCL-SGRAND), termed thresholded SCLSGRAND (T-SCLSGRAND). By introducing a variable called the threshold $t$, which reduces the length of the soft information used as the input for SGRAND in T-SCLSGRAND, this method demonstrates improved bit-error rate (BER) performance compared to successive cancellation list (SCL) and cyclic redundancy check (CRC)-aided SCL (CA-SCL) by 0.7 and 0.2 dB, respectively, under a small upper limit $b$.
{"title":"Performance of Thresholded SCL-SGRAND (T-SCLSGRAND) in VLC System","authors":"Igor Novid;Hiroshi Kamabe","doi":"10.23919/comex.2025XBL0070","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0070","url":null,"abstract":"Visible light communication (VLC) has emerged as an alternative to data communication, offering higher bandwidth than radio communication. To fully leverage its advantages, Polar codes, recognized as capacity-achieving codes, are employed in serial concatenation with run-length limited (RLL). In this paper, we propose an enhancement to our previous decoding method, successive cancellation list - soft guessing random additive noise decoding (SCL-SGRAND), termed thresholded SCLSGRAND (T-SCLSGRAND). By introducing a variable called the threshold <tex>$t$</tex>, which reduces the length of the soft information used as the input for SGRAND in T-SCLSGRAND, this method demonstrates improved bit-error rate (BER) performance compared to successive cancellation list (SCL) and cyclic redundancy check (CRC)-aided SCL (CA-SCL) by 0.7 and 0.2 dB, respectively, under a small upper limit <tex>$b$</tex>.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 9","pages":"353-356"},"PeriodicalIF":0.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11062679","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916319","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 : 2025-07-01DOI: 10.23919/comex.2025XBL0072
Mamoru Komatsu;Akira Naka
This letter proposes the error-correctable shaping method based on the trellis diagram defined in enumerative sphere shaping (ESS), refer to trellis-based error-correctable ESS (TE-ESS), to mitigate one of the implementation issues in probabilistic amplitude shaping (PAS). To introduce the residual error detection and correction, TE-ESS modifies the trellis diagram of ESS to restrict the output amplitude sequence which correspond to even-or odd-parity. Numerical simulations show that TE-ESS outperforms the previously proposed error-correctable shaping method. In addition, Its error correction effectively alleviates the error floor requirement in FEC code, compared to using ESS, in low BER region.
{"title":"Trellis-Based Error-Correctable Shaping Method for Probabilistically-Shaped Quadrature Amplitude Modulation","authors":"Mamoru Komatsu;Akira Naka","doi":"10.23919/comex.2025XBL0072","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0072","url":null,"abstract":"This letter proposes the error-correctable shaping method based on the trellis diagram defined in enumerative sphere shaping (ESS), refer to trellis-based error-correctable ESS (TE-ESS), to mitigate one of the implementation issues in probabilistic amplitude shaping (PAS). To introduce the residual error detection and correction, TE-ESS modifies the trellis diagram of ESS to restrict the output amplitude sequence which correspond to even-or odd-parity. Numerical simulations show that TE-ESS outperforms the previously proposed error-correctable shaping method. In addition, Its error correction effectively alleviates the error floor requirement in FEC code, compared to using ESS, in low BER region.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 9","pages":"334-337"},"PeriodicalIF":0.3,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11062678","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918124","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 : 2025-06-02DOI: 10.23919/comex.2025SPF0001
The objective of this special cluster is to present advanced technologies in antennas and propagation, including next-generation mobile communication systems, MIMO, PAN/BAN, metamaterials, and wireless power transmission. The scope also covers electromagnetic wave theory and related areas, with a focus on emerging topics such as metamaterials, nano-electromagnetics, and their antenna applications.
{"title":"Special Cluster in Antennas and Propagation Technologies 2024","authors":"","doi":"10.23919/comex.2025SPF0001","DOIUrl":"https://doi.org/10.23919/comex.2025SPF0001","url":null,"abstract":"The objective of this special cluster is to present advanced technologies in antennas and propagation, including next-generation mobile communication systems, MIMO, PAN/BAN, metamaterials, and wireless power transmission. The scope also covers electromagnetic wave theory and related areas, with a focus on emerging topics such as metamaterials, nano-electromagnetics, and their antenna applications.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 6","pages":"205-205"},"PeriodicalIF":0.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11021590","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196829","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 : 2025-04-11DOI: 10.23919/comex.2025SPL0015
Yoshiki Takahashi;Hiroyoshi Yamada;Tadashi Oshima
High angular resolution is required for millimeter-wave radar, which is currently being studied for application. One method for improving angular resolution is distributed Time Division Multiple Access (TDMA)-Multiple Input Multiple Output (MIMO) radar. In order to realize a distributed TDMA-MIMO radar using millimeter wave radar, it is necessary to use delay circuit with extremely high precision. Such highprecision timing control is difficult to achieve with millimeter waves, which makes distributed radar difficult to implement. In this letter, we propose a timing synchronization method based on the results of cross-correlation calculations, assuming that delay circuit with sufficient precision cannot be used due to cost and other reasons, and demonstrate its effectiveness through computer simulations and evaluations using experimental data.
{"title":"Transmission Timing Synchronization Method Based on Results of Cross-Correlation in Distributed TDMA-MIMO Radar","authors":"Yoshiki Takahashi;Hiroyoshi Yamada;Tadashi Oshima","doi":"10.23919/comex.2025SPL0015","DOIUrl":"https://doi.org/10.23919/comex.2025SPL0015","url":null,"abstract":"High angular resolution is required for millimeter-wave radar, which is currently being studied for application. One method for improving angular resolution is distributed Time Division Multiple Access (TDMA)-Multiple Input Multiple Output (MIMO) radar. In order to realize a distributed TDMA-MIMO radar using millimeter wave radar, it is necessary to use delay circuit with extremely high precision. Such highprecision timing control is difficult to achieve with millimeter waves, which makes distributed radar difficult to implement. In this letter, we propose a timing synchronization method based on the results of cross-correlation calculations, assuming that delay circuit with sufficient precision cannot be used due to cost and other reasons, and demonstrate its effectiveness through computer simulations and evaluations using experimental data.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 6","pages":"233-237"},"PeriodicalIF":0.3,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196833","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 : 2025-04-11DOI: 10.23919/comex.2025XBL0020
Inhyeok Choi;Hiroyuki Arai
In recent years, wireless measurement methods in the near-field are developed for antenna performance evaluation. The phase measurement is difficult in near-field above the millimeter wave band, then a method to retrieve the phase using only amplitude information from a sampling plane is investigated. In this paper, we propose a method that utilizes only a single planar measurement as a faster and simpler phase retrieval method.
{"title":"Phase Retrieval Method Using a Single Planar Near-Field Measurement","authors":"Inhyeok Choi;Hiroyuki Arai","doi":"10.23919/comex.2025XBL0020","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0020","url":null,"abstract":"In recent years, wireless measurement methods in the near-field are developed for antenna performance evaluation. The phase measurement is difficult in near-field above the millimeter wave band, then a method to retrieve the phase using only amplitude information from a sampling plane is investigated. In this paper, we propose a method that utilizes only a single planar measurement as a faster and simpler phase retrieval method.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 6","pages":"254-256"},"PeriodicalIF":0.3,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964021","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196914","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 propose and investigate an ultra-high splitting ratio passive optical network (PON) using a hollow core fiber (HCF). An HCF is used for one of the downstream link for power delivery through feeding light, which powers an optical amplifier for the upstream that improves uplink power budget. We perform simulations to evaluate the maximum splitting ratio of the proposed HCF-based PONs. We show that the proposed system can support up to 4096 users in 25 Gbps non-return-to-zero (NRZ) intensity-modulation (IM) and direct detection (DD), as well as 1024 users in 25 Gbaud 16QAM transmission.
{"title":"Ultra-High Splitting Ratio Access Network with Optical Power Feeding Using a Hollow Core Fiber","authors":"Shumpei Kimura;Zhixin Liu;Motoharu Matsuura;Takeshi Takagi;Kazunori Mukasa;Satoru Okamoto;Naoaki Yamanaka;Hiroyuki Tsuda","doi":"10.23919/comex.2025XBL0050","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0050","url":null,"abstract":"We propose and investigate an ultra-high splitting ratio passive optical network (PON) using a hollow core fiber (HCF). An HCF is used for one of the downstream link for power delivery through feeding light, which powers an optical amplifier for the upstream that improves uplink power budget. We perform simulations to evaluate the maximum splitting ratio of the proposed HCF-based PONs. We show that the proposed system can support up to 4096 users in 25 Gbps non-return-to-zero (NRZ) intensity-modulation (IM) and direct detection (DD), as well as 1024 users in 25 Gbaud 16QAM transmission.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 6","pages":"263-266"},"PeriodicalIF":0.3,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196832","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 : 2025-04-11DOI: 10.23919/comex.2025XBL0045
Junichi Naganawa;Yoshio Kosuge;Jun Kitaori;Hirohisa Tajima;Tadashi Koga
Aircraft localization systems that use time difference of arrival (TDOA) measurements, called wide-area multilateration (WAM) systems, have been deployed for air traffic control. Although WAM performs better than radar, it requires a large number of ground stations. A possible solution by which to reduce the number of stations is to obtain additional measurements, such as the angle of arrival (AOA) and barometric altitude. However, the feasibility of hybrid localization has not been experimentally proven. Therefore, this study presents an experiment on aircraft localization using TDOA, AOA, and barometric altitude measurements to demonstrate that aircraft localization at only two sites is possible.
{"title":"Demonstration of Aircraft Localization by TDOA, AOA, and Barometric Altitude at Two Sites","authors":"Junichi Naganawa;Yoshio Kosuge;Jun Kitaori;Hirohisa Tajima;Tadashi Koga","doi":"10.23919/comex.2025XBL0045","DOIUrl":"https://doi.org/10.23919/comex.2025XBL0045","url":null,"abstract":"Aircraft localization systems that use time difference of arrival (TDOA) measurements, called wide-area multilateration (WAM) systems, have been deployed for air traffic control. Although WAM performs better than radar, it requires a large number of ground stations. A possible solution by which to reduce the number of stations is to obtain additional measurements, such as the angle of arrival (AOA) and barometric altitude. However, the feasibility of hybrid localization has not been experimentally proven. Therefore, this study presents an experiment on aircraft localization using TDOA, AOA, and barometric altitude measurements to demonstrate that aircraft localization at only two sites is possible.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 6","pages":"246-249"},"PeriodicalIF":0.3,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10964017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196877","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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