{"title":"Impact of Training Models on Deep Joint Source-Channel Coding Applicable to 5G Systems","authors":"Ryunosuke Yamamoto;Keigo Matsumoto;Yoshiaki Inoue;Yuko Hara;Kazuki Maruta;Yu Nakayama;Daisuke Hisano","doi":"10.23919/comex.2024COL0014","DOIUrl":"https://doi.org/10.23919/comex.2024COL0014","url":null,"abstract":"With the development of 5G technology and the proliferation of IoT devices, Deep Joint Source-Channel Coding (DeepJSCC) has attracted attention for efficiently transmitting video and image data. DeepJSCC can maintain a good peak signal-to-noise ratio (PSNR) of images even at a meager signal-to-noise ratio (SNR). In cellular communication systems, the compression ratio must adapt to channel fluctuations, requiring multiple training models at the base station. However, the optimal SNR and compression ratio combination during training has yet to be reported. This paper investigates the necessary number of training models by stepwise varying SNR and compression ratio during training.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"466-469"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633225","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761474","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":"Power Saving Control Method with Adaptive FEC Decoder in Optical Access Network","authors":"Kaito Kubo;Amila Kariyawasam;Shunji Kimura","doi":"10.23919/comex.2024XBL0124","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0124","url":null,"abstract":"With the increasing demand for network services, the power consumption of equipment has been steadily rising each year, especially in the access network domain. Passive Optical Networks (PON) traditionally operate on the principle of ensuring service provision to the farthest user. Consequently, performance tends to be excessive for short to medium distances, leading to surplus power consumption. In this study, we address the issue of reducing power consumption in access networks by tackling surplus power. Our approach involves utilizing three different types of Reed-Solomon (RS) decoders to apply appropriate forward error correction (FEC) redundancy based on transmission distance, aiming to lower power consumption of RS decoders in optical network units (ONUs). Subsequently, we evaluated the power saving of FEC decoding in a 10G-class PON and report over 48% average power saving compared to the conventional homogeneous FEC-based network.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 10","pages":"401-404"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633221","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377147","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":"Development of a Light Source Position Estimation System for Accurate Drone Flight","authors":"Ryo Goto;Takayuki Matsumuro;Kazunobu Serizawa;Susumu Ano;Satoru Shimizu","doi":"10.23919/comex.2024COL0025","DOIUrl":"https://doi.org/10.23919/comex.2024COL0025","url":null,"abstract":"In this study, we developed a light source position estimation system for controlling the wireless-powered drone. An algorithm was designed to estimate the light source position by minimizing an error function consisting of the difference between the measured and estimated values of light-receiving intensity. The received light intensity distribution of a light source with a beam angle of 2.5° was modeled using Gaussian and inverse square functions based on actual measurements. A detection device was fabricated by a photodiode array substrate and a Raspberry Pi. The detection time of the developed system is 97 ms, real-time light source position estimation was confirmed.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"483-486"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633228","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761406","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":"An Analysis of Positioning Accuracy Based on Fisher Information Matrix for Distance-Based Positioning","authors":"Masahiro Fujii","doi":"10.23919/comex.2024COL0017","DOIUrl":"https://doi.org/10.23919/comex.2024COL0017","url":null,"abstract":"In this letter, I introduce Root Mean Squared Error (RMSE) based on the Fisher information matrix to evaluate the accuracy of distance-based location estimation. This qualitative index, which introduces the concept of the distribution of ranging measurement errors, allows a more precise evaluation of position estimation accuracy than the conventional Position Dilution Of Precision (PDOP). Visualizing PDOP and the proposed RMSE as a distribution over the evaluation space clarifies their respective characteristics. By computer simulations, I show usefulness of the propsoed index by comparing with Least-Squares estimation.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"479-482"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633231","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761479","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}
Muhammad Hamka Ibrahim;Subuh Pramono;Jing-Yuan Wang;Yu-Fan Cai;Feri Adriyanto;Josaphat Tetuko Sri Sumantyo
{"title":"Speckle Correction Filter Based on Spatial Polarimetric Coherence for Full Polarimetric Synthetic Aperture Radar Image","authors":"Muhammad Hamka Ibrahim;Subuh Pramono;Jing-Yuan Wang;Yu-Fan Cai;Feri Adriyanto;Josaphat Tetuko Sri Sumantyo","doi":"10.23919/comex.2024XBL0125","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0125","url":null,"abstract":"Polarimetric synthetic aperture radar (PolSAR) image exhibits a high degree of spatial information. However, the PolSAR image is subjected to speckle noise, which degrades the information quality. A speckle correction filter is proposed in this paper based on spatial polarimetric coherence. Evidence of polarimetric coherence between spatial neighboring pixels is presented. It shows that polarimetric coherence is highly correlated with neighboring pixels. Based on these characteristics, a speckle correction filter is proposed by calculating the polarimetric coherency level on a selected neighboring pixel. A correction is applied to the pixel which has a low polarimetric coherence level. A generalized three-step adaptive filter is proposed, including neighbor selection, coherency criterion, and incoherent correction. The influence of the filter on scattering mechanisms is compared by using eigenvalue-based decomposition. Qualitatively, the result shows the proposed correction filter removes the outliers in the low entropy region. Quantitively the filter can suppress the speckle noise and its variance up to 19.08%.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 10","pages":"413-416"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633226","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142376979","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":"Reflection-Phase Calculation of Circularly Polarized Folded Reflectarray Antennas with Low Profile, High Efficiency, and Arbitrary Aperture Distribution","authors":"Makoto Sano;Ryuji Kuse;Takeshi Fukusako","doi":"10.23919/comex.2024XBL0115","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0115","url":null,"abstract":"This paper presents a new concept of designing circularly polarized folded reflectarray (CPFRA) antennas. By applying the dual-reflector shaping technique to the CPFRA antennas, the reflection-phase distributions of the two reflecting surfaces comprising the CPFRA antennas are modified to realize low profile, high aperture efficiency, and arbitrary aperture-field distribution simultaneously. Numerical simulations based on the geometrical optics show that the aperture efficiency can be improved up to around 100% by realizing uniform aperture-field distribution and reducing the spillover. Designs of CPFRA antennas with low sidelobe levels are also presented.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 10","pages":"409-412"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633229","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377146","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":"Path Loss Model from 922 MHz to 28 GHz in Office Environment","authors":"Kensuke Sakamoto;Ayaka Sakaguchi;Yuki Yamakawa;Waka Mimura;Hirokazu Sawada;Azril Haniz;Fumihide Kojima;Takeshi Matsumura","doi":"10.23919/comex.2024XBL0120","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0120","url":null,"abstract":"To build a stable wireless communication system in an indoor environment, it is necessary to perform highly accurate simulations of radio wave propagation characteristics. The ITU-R Recommendation P series, especially ITU-R P.1238, lists estimation models for propagation loss in indoor environments under various conditions. However, there are a few cases in which propagation loss has been measured at various frequencies in the same building and under the same conditions. In these cases, necessary parameters may not be described, meaning that simulation cannot be easily performed. In this paper, we measure the radio wave propagation characteristics on the same floor and across floors for the 922 MHz to 28 GHz frequency band, which is often used in office spaces. We then apply a path loss model to each frequency and calculate the coefficient of office environment (\u0000<tex>$N$</tex>\u0000) and inter-floor attenuation \u0000<tex>$(L_{f}(n))$</tex>\u0000.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 10","pages":"417-420"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142377144","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":"Unmanned Aerial Vehicle-Based Virtual Array Channel Sounding System in 4.8 GHz Band","authors":"Kentaro Saito;Sora Kojima","doi":"10.23919/comex.2024ATL0001","DOIUrl":"https://doi.org/10.23919/comex.2024ATL0001","url":null,"abstract":"Recently, Unmanned Aerial Vehicles (UAVs) have been widely utilized for various industry applications, and it is expected to be one of the key elements in the next-generation mobile communication system. For the design and evaluation of the mobile communication system in the sky, the air-to-ground (A2G) propagation channel characteristics have been investigated by the UAV-based measurement systems. However, there is a measurement resolution issue due to the limitation of the UAV payload. In this paper, we propose the UAV-based virtual array channel sounding system in the 4.8 GHz band to solve this limitation. In our system, the channel data are continuously measured by the receiver, which is mounted on the UAV station, while the UAV station flies along the measurement course. The data are combined offline, and they are processed virtually as data of large array antenna for investigation of angular characteristics of the propagation channel. A great advantage of our system is to be able to configure an arbitrary virtual antenna array in the air. To mitigate the UAV position error, 3D UAV positions are tracked by laser equipment and used in the array signal processing. The experiment was conducted in an indoor workshop space in the 4.85 GHz band. The HPBW of the angular power spectrum was 3.2 deg., which was quite a sharp value in this frequency band. The azimuth angular and distance estimation errors of incident radio wave were approximately 0.1 deg. and 0.01 m. Future works will include conducting experiments in various radio propagation environments and analyzing more detailed channel characteristics.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"14 2","pages":"39-42"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633220","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107204","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":"A Study on Realization of Automotive SDN by P4","authors":"Yuma Sakurai;Yoshihiro Ito","doi":"10.23919/comex.2024COL0018","DOIUrl":"https://doi.org/10.23919/comex.2024COL0018","url":null,"abstract":"In recent years, functions in automobiles are required to be processed in real time. This requirement can be realized with SDV (Software-Defined Vehicle), a technology that defines vehicle requirements in software. Although SDV requires automotive SDN (Software-Defined Networking), there has been little discussion on how to implement automotive SDN. This paper studies the feasibility of automotive SDN by realizing four functional requirements proposed as functions required for automotive SDN using P4 and evaluating these requirements through experiments. The feasibility of automotive SDN will be investigated by evaluating these requirements through experiments.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 12","pages":"475-478"},"PeriodicalIF":0.3,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10633223","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761552","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":"Difference-Beam Operation in a Center-Fed Dual-Polarized Parallel-Plate Waveguide Slot Array Antenna","authors":"Huanqian Xiong;Jiro Hirokawa;Takashi Tomura","doi":"10.23919/comex.2024XBL0100","DOIUrl":"https://doi.org/10.23919/comex.2024XBL0100","url":null,"abstract":"This letter deals with the difference-beam operation in a centerfeed dual-polarized parallel-plate waveguide slot array antenna at 24.5GHz, which consists of two orthogonally arranged 20×19 arrays of radiating slot pairs. A center-feeding scheme is employed in this design. Each rectangular feeding waveguide, fed by a probe, can feed half of the radiating panel, enabling easy control of the phase difference. Experimental results show that the monopulse antenna array has a bandwidth of 12.8% for reflections below −10 dB while it produces the sum beams, and 13.3% to produce the difference beams. Port isolation between the sum mode and difference mode is above 15 dB within the working frequency band. The measured realized gain of the sum beam is 31.3 dBi at 24.5 GHz, and the measured null-depth is below −33.9 dB for both polarizations.","PeriodicalId":54101,"journal":{"name":"IEICE Communications Express","volume":"13 9","pages":"359-362"},"PeriodicalIF":0.3,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10591717","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142091059","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}