IEEE Communications Letters最新文献_第7页

Bandwidth Expansion in N-Fold Frequency Multiplier: Is It N or √N? N倍频倍频器的带宽扩展是N还是√N？

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-04-01 DOI: 10.1109/LCOMM.2025.3556767

Ahmet Alperen Oznam;Chouaieb Farhati;Mohaned Chraiti;Ali Ghrayeb;Hasari Celebi;Fatma Abdelkefi;Korkut Kaan Tokgoz

{"title":"Bandwidth Expansion in N-Fold Frequency Multiplier: Is It N or √N?","authors":"Ahmet Alperen Oznam;Chouaieb Farhati;Mohaned Chraiti;Ali Ghrayeb;Hasari Celebi;Fatma Abdelkefi;Korkut Kaan Tokgoz","doi":"10.1109/LCOMM.2025.3556767","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3556767","url":null,"abstract":"Frequency up-conversion is an essential step in wireless communication systems. Meanwhile, frequency multipliers are increasingly becoming an integral part of communication chains operating at millimeter-wave (mmWave) and sub-terahertz (sub-THz) frequencies. They offer a viable alternative to traditional mixers, which are highly constrained by their instability and high phase noise at such high frequencies. Despite the frequency multipliers’ advantages and the fact that they are commonly recommended by hardware designers, there is a lack of comprehensive theoretical guidelines detailing their impact on digital communications. One key aspect is their tendency to induce bandwidth expansion, a phenomenon not observed with mixers. When an N-fold frequency multiplier is used, a common practice among hardware designers is to allocate a bandwidth scaled by a multiple of N, which is deemed large enough to keep signals integrity. We provide an analytical framework to quantify the exact scaling factor of the bandwidth expansion. Contrary to common belief, we show that the bandwidth expansion scales as <inline-formula> <tex-math>$ sqrt {N} $ </tex-math></inline-formula>, using three counterexamples, namely Gaussian, Sinc, and raised cosine pulses. These findings can help conserve radio resources and further decrease the noise effect.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 6","pages":"1205-1209"},"PeriodicalIF":3.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272776","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}

引用次数: 0

The Pulse Timer Algorithm for Mobile Molecular Communication 移动分子通信的脉冲定时器算法

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-31 DOI: 10.1109/LCOMM.2025.3556545

Motoharu Nishino;Tadashi Nakano

引用次数: 0

A Multi-Carrier Deep Learning CSK Communication System 一种多载波深度学习CSK通信系统

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-31 DOI: 10.1109/LCOMM.2025.3556474

Majid Mobini;Georges Kaddoum;Marijan Herceg

引用次数: 0

FSIM-Net: Neural Network-Based Symbol Detector for Filter Shape Index Modulation FSIM-Net：基于神经网络的滤波器形状指数调制符号检测器

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-31 DOI: 10.1109/LCOMM.2025.3556431

Shubham Anand;Haïfa Farès;Majed Saad;Preetam Kumar

引用次数: 0

Optimized Qubit-Based Synchronization in Quantum Key Distribution 量子密钥分发中基于量子比特的优化同步

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-28 DOI: 10.1109/LCOMM.2025.3554260

Hao-Bing Sun;Jian Li;Xing-Wang Chu;Jing-Yang Liu;Hua-Jian Ding;Qin Wang

引用次数: 0

Performance Analysis for mmWave Cell-Free Access Network Based on Terahertz Backhaul 基于太赫兹回程的毫米波无蜂窝接入网性能分析

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-28 DOI: 10.1109/LCOMM.2025.3555748

Hongxin Lin;Yuanjian Li;Guanghui Chen;Zening Liu;Yongming Huang

引用次数: 0

Space-to-Ground Optical Communication Downlink Scheduling Under Uncertainty of Link Availability 链路可用性不确定条件下的空地光通信下行调度

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-28 DOI: 10.1109/LCOMM.2025.3555945

Pei Lyu;Kanglian Zhao;Shihao Wang;Hangsheng Zhao

引用次数: 0

Degrees of Freedom of Holographic MIMO in Multi-User Near-Field Channels 多用户近场信道全息MIMO的自由度

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-28 DOI: 10.1109/LCOMM.2025.3555796

Houfeng Chen;Shaohua Yue;Marco Di Renzo;Hongliang Zhang

{"title":"Degrees of Freedom of Holographic MIMO in Multi-User Near-Field Channels","authors":"Houfeng Chen;Shaohua Yue;Marco Di Renzo;Hongliang Zhang","doi":"10.1109/LCOMM.2025.3555796","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3555796","url":null,"abstract":"Holographic multiple-input multiple-output (HMIMO) is an emerging technology for 6G communications, in which numerous antenna units are integrated in a limited space. As the HMIMO array aperture expands, the near-field region of the array is dramatically enlarged, resulting in more users being located in the near-field region. This creates new opportunities for wireless communications. In this context, the evaluation of the spatial degrees of freedom (DoF) of HMIMO multi-user systems in near-field channels is an open problem, as the analytical methods utilized for evaluating the DoF in far-field channels cannot be directly applied. In this letter, we propose a novel method to calculate the DoF of HMIMO in multi-user near-field channels. We first derive the DoF for a single user in the near field, and then extend the analysis to multi-user scenarios. In this latter scenario, we focus on the impact of spatial blocking between HMIMO users. The derived analytical framework reveals that the DoF of HMIMO in multi-user near-field channels is not in general given by the sum of the DoF of the HMIMO single-user setting because of spatial blocking. Simulation results demonstrate the effectiveness of the proposed method. In the considered case study, the number of DoF reduces by 21.2% on average due to spatial blocking.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 6","pages":"1186-1190"},"PeriodicalIF":3.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272795","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}

引用次数: 0

Service Association and Subcarrier Allocation in Vehicular Slicing Networks With Dynamic Multi-Service 动态多业务车辆切片网络中的业务关联与子载波分配

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-28 DOI: 10.1109/LCOMM.2025.3555768

Yijian Hou;Kaisa Zhang;Gang Chuai;Weidong Gao;Xiangyu Chen;Siqi Liu

{"title":"Service Association and Subcarrier Allocation in Vehicular Slicing Networks With Dynamic Multi-Service","authors":"Yijian Hou;Kaisa Zhang;Gang Chuai;Weidong Gao;Xiangyu Chen;Siqi Liu","doi":"10.1109/LCOMM.2025.3555768","DOIUrl":"https://doi.org/10.1109/LCOMM.2025.3555768","url":null,"abstract":"The vehicular slicing network with dynamic multi-service (VSN-DMS) enables vehicles to support multiple services with dynamically changing types. In this architecture, vehicles can access multiple base stations (BSs) and leverage different network slices (NSs) to meet the requirements of various services. However, frequent service variations and vehicle mobility introduce high handover (HO) costs and inefficient decision making. This letter proposes a novel two-timescale optimization framework to jointly optimize vehicle service (VS) association and subcarrier (SC) allocation. Specifically, in the long-timescale, we propose a federated deep reinforcement learning (FDRL) algorithm to optimize VS association. Unlike conventional reinforcement learning approaches that require centralized data collection, FDRL enables distributed model training across vehicles while aggregating parameters in the cloud. This mitigates the issue of insufficient training data caused by frequent VS changes, while also ensuring vehicle data privacy. In the short-timescale, we propose a versatile alternating coalitional game and swap-matching game algorithm (ACGSM) to optimize SC allocation. By iteratively executing coalitional formation and swap-matching mechanisms, ACGSM efficiently improves the quality of the solution while adapting to dynamic network conditions. Simulation results demonstrate the convergence of FDRL and show that the proposal outperforms benchmarks in improving long-term QoS and reducing the number of HOs.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 5","pages":"1131-1135"},"PeriodicalIF":3.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932261","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}

引用次数: 0

A Sparsity-Agnostic SL0 Channel Estimation Approach for OTFS Systems 一种OTFS系统稀疏不可知的SL0信道估计方法

IF 3.7 3区计算机科学

IEEE Communications Letters Pub Date : 2025-03-26 DOI: 10.1109/LCOMM.2025.3554379

Xin Wang;Can Zheng;Pengjiang Hu;Junan Yang;Chung G. Kang

引用次数: 0