{"title":"Illegal Sensing Suppression Based on Clustered Subcarrier Structure in OFDM System","authors":"Hanbo Jia;Lin Ma;Xiaoshuai Li","doi":"10.1109/LCOMM.2025.3590436","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3590436","url":null,"abstract":"Integration of communication and radar enables emerging applications while causing sensing information leakage. In this letter, we propose clustered subcarrier structure to implement illegal sensing suppression (ISS) in orthogonal frequency division multiplexing (OFDM) systems. Specifically, following the ambiguity function (AF), the proposed clustered structure exploits removable singularities in its AF to generate virtual interference, thereby deteriorating the illegal detection. The optimal parameters are further derived by minimizing proposed peak-to-virtual-interference ratio (PVIR), and the subcarrier-ISS trade-off is investigated between the number of data subcarriers and ISS capacity. Simulation results demonstrate the superior ISS of proposed approach compared to other baselines.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2183-2187"},"PeriodicalIF":4.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sparse Random Combinatorial Matrices for IRSA Over the Binary Adder Channel","authors":"Xinwei Zhao;Xiao Ma","doi":"10.1109/LCOMM.2025.3590452","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3590452","url":null,"abstract":"This letter proposes an enhanced irregular repetition slotted ALOHA (IRSA) scheme for the binary adder channel (BAC) using sparse random combinatorial matrices as codebooks. Existing IRSA schemes for the BAC, which rely on dense Bernoulli matrices as codebooks, struggle to resolve a large number of collisions, primarily due to the high density of the codebook. To address it, we introduce a codebook construction using sparse random combinatorial matrices, where each codeword is a binary vector with exactly d ones, optimized to maximize the collision resolution capabilities. Furthermore, the proposed scheme eliminates pilot symbols by leveraging the codebook’s inherent sparsity and combinatorial structure. Numerical simulations show that the proposed scheme achieves a higher decoding threshold and superior average sum rate compared to existing schemes, thanks to its enhanced collision resolution capabilities.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2193-2197"},"PeriodicalIF":4.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Low-Altitude Communication Networks Planning for Air Routes Coverage Based on Semi-Supervised GCN","authors":"Lan Lin;Yang Liu;Lei Cao;Jing Gao;Tianming Jiang","doi":"10.1109/LCOMM.2025.3590398","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3590398","url":null,"abstract":"Low-altitude economy is poised to become a new economic form, influencing the next-generation wireless communications. It is essential to develop low-altitude communication networks (LACNs) capable of providing wireless coverage for aircrafts, whose planning methodologies are still not well-defined. To tackle this issue, a LACNs planning scheme to support air routes communication coverage is studied. Specifically, an extended semi-supervised graph convolutional network (ESemi-GCN) algorithm is proposed to select which existing ground base stations (BSs) should be upgraded to low-altitude BSs. Simulation results exhibit the efficiency and cost-effectiveness of the proposed ESemi-GCN algorithm to establish the LACNs.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2178-2182"},"PeriodicalIF":4.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"RIS Assisted Near Field Communication in Sub-6 GHz Band: Experimental Perspective","authors":"Chandresh Dhote;Anamika Singh;Prabhat Kumar Sharma","doi":"10.1109/LCOMM.2025.3576503","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3576503","url":null,"abstract":"A testbed for a reconfigurable intelligent surface (RIS) assisted communication system is implemented and optimized for near-field scenarios in the sub-6 GHz band. The RIS features a 400-element reflectarray, measuring 508 mm <inline-formula> <tex-math>$times 508$ </tex-math></inline-formula> mm (aperture diameter 718.3 mm, approximately <inline-formula> <tex-math>$8.97lambda times 8.97lambda $ </tex-math></inline-formula> at 5.3 GHz), built with low-cost FR-4 material and PIN diodes to achieve 1-bit phase control. Operating within the near-field region (Fraunhofer distance <inline-formula> <tex-math>$d_{F}approx 18.2$ </tex-math></inline-formula> m), the system manipulates spherical wavefronts to enable precise beam steering and signal enhancement significantly in indoor environments. Experiments demonstrate a 12-15 dB gain in received power, stable beamforming at multiple angles, and wireless communication with a peak throughput of 36.70 Mbps and signal-to-interference-plus-noise ratio (SINR) of 27.22 dB.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 8","pages":"1814-1818"},"PeriodicalIF":4.4,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meilin He;Mingjue Zhu;Zhaoyang Zhang;Rui Guo;Haiquan Wang
{"title":"Optimal Degree Distribution for Two-User Regular LDPC Codes Over GMAC by Fixed-Point Analysis","authors":"Meilin He;Mingjue Zhu;Zhaoyang Zhang;Rui Guo;Haiquan Wang","doi":"10.1109/LCOMM.2025.3589504","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3589504","url":null,"abstract":"An analytical expression of the check nodes (CNs) degree in a two-user regular Low-Density Parity-Check (LDPC) code is derived over a Gaussian multiple access channel, and a Fixed Point Analysis (FPA) method is developed to determine the optimal degree distribution that maximizes the achievable sum rate of the system. Specifically, firstly, an analytical expression of the CNs degree is derived as a function of mutual information outputs. Secondly, based on this, a reliable region is obtained by taking a complement of a unified unreliable region. Finally, the optimal degree distribution is determined over this reliable region to achieve the optimal sum rate. Numerical results indicate that the proposed method offers superior accuracy and much lower computational complexity compared to the extrinsic information transfer (EXIT) chart.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2168-2172"},"PeriodicalIF":4.4,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nemanja Stefan Perović;Mark F. Flanagan;Le-Nam Tran
{"title":"Sensing Rate Optimization for Multi-Band Cooperative ISAC Systems","authors":"Nemanja Stefan Perović;Mark F. Flanagan;Le-Nam Tran","doi":"10.1109/LCOMM.2025.3588676","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3588676","url":null,"abstract":"Integrated sensing and communication (ISAC) has been recognized as one of the key technologies for future wireless networks, which potentially need to operate in multiple frequency bands to satisfy ever-increasing demands for both communication and sensing services. Motivated by this, we consider the sum sensing rate (SR) optimization for a cooperative ISAC system with linear precoding, where each base station (BS) works in a different frequency band. With this aim, we propose an optimization algorithm based on the semi-definite rank relaxation that introduces covariance matrices as optimization variables, and we apply the inner approximation (IA) method to deal with the nonconvexity of the resulting problem. Simulation results show that the proposed algorithm increases the SR by approximately 25% and 40% compared to the case of equal power distribution in a cooperative ISAC system with two and three BSs, respectively. Additionally, the algorithm converges in only a few iterations, while its most beneficial implementation scenario is in the low power regime.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2163-2167"},"PeriodicalIF":4.4,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Enhancing Partial Packet Recovery in RLNC Using Homomorphic Message Authentication Codes","authors":"Amin Fathi;Peyman Pahlevani","doi":"10.1109/LCOMM.2025.3587820","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3587820","url":null,"abstract":"Network coding enhances wireless communication by transmitting coded packets. However, transmission errors often lead to unnecessary packet discards, even when most data remains intact. Existing recovery methods address this issue but suffer from high recovery delays in noisy environments and false positives caused by checksum collisions, resulting in redundant retransmissions. This letter presents a novel method, termed Combined Recovery, which replaces traditional Cyclic Redundancy Check (CRC) codes with Homomorphic Message Authentication Codes (HMAC). By exploiting the homomorphic property of HMACs, Combined Recovery introduces a technique that enables efficient error correction with notably reduced search complexity. Simulation results across various scenarios demonstrate that Combined Recovery eliminates retransmissions and significantly reduces recovery delay, providing a robust and efficient solution for reliable communication over noisy channels.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2118-2122"},"PeriodicalIF":4.4,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Data-Interference Free and Low-Overhead Channel Estimation Framework for MIMO-OTFS System","authors":"Ziyang Meng;Yu Zhang;Yiqing Zhou;Jinglin Shi","doi":"10.1109/LCOMM.2025.3588110","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3588110","url":null,"abstract":"In MIMO-OTFS systems, accurate CSI estimation with minimal pilot overhead is crucial. While guard-interval (GI)-based pilot patterns suppress data interference, they substantially increase overhead. To overcome this, we propose an interference-free, low-overhead channel estimation framework that exploits channel sparsity. Specifically, we introduce the delay-Doppler-angle basis expansion model (DDA-BEM) to reformulate the estimation task as a compressed sensing problem. Leveraging the sparsity in the DDA domain, we design a pilot pattern that inherently avoids data interference without requiring GIs. Simulation results demonstrate a 54% reduction in pilot overhead compared to state-of-the-art methods, while maintaining comparable estimation accuracy.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2143-2147"},"PeriodicalIF":4.4,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Astrid Lozada;Ricardo Olivares;Bárbara Dumas Feris;Ariel Leiva;Gabriel Saavedra;Nicolás Jara;Patricia Morales;Danilo Bórquez-Paredes
{"title":"Optimized Backward Pumping Design for a 6-Mode Distributed Raman Amplifier for SDM Systems","authors":"Astrid Lozada;Ricardo Olivares;Bárbara Dumas Feris;Ariel Leiva;Gabriel Saavedra;Nicolás Jara;Patricia Morales;Danilo Bórquez-Paredes","doi":"10.1109/LCOMM.2025.3588148","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3588148","url":null,"abstract":"We present the first optimized design and characterization of a six-mode distributed Raman amplifier (6M-DRA) for next-generation optical communication systems using space-division multiplexing (SDM) based on few-mode fibers (FMF). A genetic algorithm optimizes the pumping profile to minimize gain ripple and differential modal gain (DMG). Numerical results show an average on-off gain of 9.5 dB over 70 km, gain ripple below 1 dB, DMG under 2.10 dB, effective noise figure under 1.42 dB, optical signal-to-noise ratio larger than 29.5 dB, and pump efficiency of 9.30 dB/W, demonstrating its potential as an effective amplification solution for future SDM-FMF optical networks.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 9","pages":"2138-2142"},"PeriodicalIF":4.4,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}