{"title":"Two-Path Serial Inter-Symbol-Interference Cancellation for Air-to-Ground Communication","authors":"Zonglong Chen;Songkang Huang;Ming Jiang","doi":"10.1109/LCOMM.2024.3502152","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3502152","url":null,"abstract":"The high Doppler effect and severe multipath delay are among the major challenges in air-to-ground (A2G) communication scenarios, where the maximum multipath delay may exceed the duration of one or more orthogonal frequency division multiplexing (OFDM) symbols, resulting in severe inter-symbol interference (ISI). In this letter, we propose a new frame structure constituted by grouped training sequences (GTSs), OFDM symbols and guard interval (GI). Specifically, two GTSs are respectively prefixed and postfixed to several cyclic-prefix-free OFDM symbols for Doppler frequency offset (DFO) and multipath delay estimation. Moreover, a two-path serial ISI cancellation (TSIC) algorithm is designed to recover the transmitted signal. Compared with existing algorithms, the new scheme can reduce errors and increase the spectral efficiency of the system.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"100-104"},"PeriodicalIF":3.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940873","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}
Loc X. Nguyen;Kitae Kim;Ye Lin Tun;Sheikh Salman Hassan;Yan Kyaw Tun;Zhu Han;Choong Seon Hong
{"title":"Optimizing Multi-User Semantic Communication via Transfer Learning and Knowledge Distillation","authors":"Loc X. Nguyen;Kitae Kim;Ye Lin Tun;Sheikh Salman Hassan;Yan Kyaw Tun;Zhu Han;Choong Seon Hong","doi":"10.1109/LCOMM.2024.3499956","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3499956","url":null,"abstract":"Semantic Communication (SemCom), notable for ensuring quality of service by jointly optimizing source and channel coding, effectively extracts data semantics, eliminates redundant information, and mitigates noise effects from wireless channel. However, most studies overlook multiple user scenarios and resource availability, limiting real-world applications. This letter addresses this gap by focusing on downlink communication from a base station to multiple users with varying computing capacities. Users employ variants of Swin transformer models for source decoding and a simple architecture for channel decoding. We propose a novel training procedure FRENCA, incorporating transfer learning and knowledge distillation to improve low-computing users’ performance. Extensive simulations validate the proposed methods.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"90-94"},"PeriodicalIF":3.7,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940875","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":"Dynamic Offloading in Mobile Edge Computing With Traffic-Aware Network Slicing and Adaptive TD3 Strategy","authors":"Amin Mohajer;Javad Hajipour;Victor C. M. Leung","doi":"10.1109/LCOMM.2024.3501956","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3501956","url":null,"abstract":"Network slicing and computation offloading play a pivotal role in enabling edge service providers to handle dynamic service demands effectively. However, traffic fluctuations and resource diversity pose significant challenges, often constrained by static configurations lacking flexibility. To overcome these limitations, this letter presents FlexSlice, a dynamic offloading framework designed to optimize resource allocation in mobile edge networks. Our approach leverages a sparse multi-head graph attention mechanism for precise traffic prediction, capturing complex spatio-temporal dependencies to enhance network slicing decisions. Additionally, we present an adaptive offloading strategy based on the twin delayed deep deterministic policy gradient algorithm, which incorporates twin critics and prioritized experience replay to improve decision-making under dynamic conditions. Simulation results confirm FlexSlice’s outstanding performance and adaptability in diverse operational scenarios, achieving higher profits and reliable quality of service.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"95-99"},"PeriodicalIF":3.7,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940876","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":"Diffusion Model Based Resource Allocation Strategy in Ultra-Reliable Wireless Networked Control Systems","authors":"Amirhassan Babazadeh Darabi;Sinem Coleri","doi":"10.1109/LCOMM.2024.3499745","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3499745","url":null,"abstract":"Diffusion models offer a promising alternative to Deep Reinforcement Learning (DRL) for resource allocation in wireless networks due to their capability to model complex data distributions with greater accuracy, yet their potential remains largely unexplored. This letter proposes a diffusion model-based approach for Wireless Networked Control Systems (WNCSs) to minimize power consumption by optimizing the sampling period, blocklength, and packet error probability within the finite blocklength regime. The problem is simplified to optimizing blocklength through optimality conditions, and a dataset of channel gains and optimal blocklengths is generated via an optimization theory-based solution. The Denoising Diffusion Probabilistic Model (DDPM) is employed to generate optimal blocklength values, conditioned on channel state information (CSI). The core idea is to train the diffusion model to generate blocklength values from noise, essentially replicating the process by which the optimization solution is derived. Extensive simulations reveal that the proposed approach surpasses existing DRL-based methods, achieving near-optimal performance in terms of total power consumption. Additionally, the proposed method reduces critical constraint violations by up to eighteen times, further highlighting the enhanced accuracy of the solution.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"85-89"},"PeriodicalIF":3.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940870","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}
Nguyen Tien Hoa;Can Thi Thanh Hai;Hoang Le Hung;Nguyen Cong Luong;Dusit Niyato
{"title":"Joint Edge Computing and Semantic Communication in UAV-Enabled Networks","authors":"Nguyen Tien Hoa;Can Thi Thanh Hai;Hoang Le Hung;Nguyen Cong Luong;Dusit Niyato","doi":"10.1109/LCOMM.2024.3496534","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3496534","url":null,"abstract":"In this letter, we investigate a joint edge computing and semantic communication in the UAV-enabled network. Therein, a UAV executes tasks offloaded from ground user equipments (UEs). Meanwhile, it acts as an IoT device to provide image data to a Metaverse platform through a ground base station (BS). A semantic communication (SemCom) technique is implemented at the UAV to extract scene graphs from captured images. The UAV then transmits the scene graphs (rather than the orignal images) to the BS. The small size of the scene graphs allows the UAV to transmit multiple images to the BS within a short duration. However, the scene graph extraction consumes computing resource, which may reduce the performance of the task offloading of the UEs. Therefore, we aim to optimize the UAV’s computing resource allocation and the fractions of the tasks offloaded from the UEs to achieve the min-max between i) the total latency of image collection, scene graph extraction, and scene graph communication, and ii) the computation offloading latency over the ground UEs. Given the dynamics and uncertainty of the wireless channels, the distances between the UAV and UEs, and the computing resources of the UEs, we leverage the Advantage Actor-Critic (A2C) and Proximal Policy Optimization (PPO) to solve it.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"80-84"},"PeriodicalIF":3.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940941","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":"Semi-Blind Channel Estimation for Massive MIMO LEO Satellite Communications","authors":"Abdollah Masoud Darya;Saeed Abdallah","doi":"10.1109/LCOMM.2024.3495998","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3495998","url":null,"abstract":"This letter proposes decision-directed semi-blind channel estimation for massive multiple-input multiple-output low-Earth-orbit satellite communications. Two semi-blind estimators are proposed. The first utilizes detected data symbols in addition to pilot symbols. The second, a modified semi-blind estimator, is specially designed to mitigate the channel-aging effect caused by the highly dynamic nature of low-Earth-orbit satellite communication channels—an issue that adversely impacts the performance of pilot-based estimators. Consequently, this modified estimator outperforms an optimal pilot-based estimator in terms of normalized mean square error and achieves symbol error rate performance comparable to that of a Genie-aided (perfectly known channel) detector. The trade-offs between the proposed estimators are also examined.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"75-79"},"PeriodicalIF":3.7,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940871","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}
Yi Wang;Junlei Zhi;Shaochuan Yang;Zheng Chu;Baofeng Ji;Hui Guo;Meng Hua;Chunguo Li
{"title":"Enhancing Fairness-Aware Massive Wireless Powered IoT Connectivity by IRS","authors":"Yi Wang;Junlei Zhi;Shaochuan Yang;Zheng Chu;Baofeng Ji;Hui Guo;Meng Hua;Chunguo Li","doi":"10.1109/LCOMM.2024.3494030","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3494030","url":null,"abstract":"This letter explores an intelligent reflecting surface (IRS) enhanced wireless powered Internet of Things (WP-IoT) network, wherein massive IoT nodes are wirelessly charged by radio frequency signals and then transmit information by means of an IRS to promote the system performance. To evaluate the network performance, we aim at maximizing the total throughput while adhering to constraints pertaining to fairness-aware individual signal-to-noise ratio (SNR), the time allocations (TAs) as well as the unit-modulus IRS phase shifts. However, the intricate coupling of these variables renders the optimization problem nonconvex, thus posing a challenge for direct solution. To deal with this dilemma, we first resort to employing the Lagrange dual method and Karush-Kuhn–Tucker (KKT) conditions to transform the sum of logarithmic objective function into sum of fractional counterpart, and further derive the analytical solutions of TAs for downlink wireless energy transfer (WET) and uplink wireless information transfer (WIT). Then, the Riemannian manifold optimization (RMO) is utilized to iteratively derive the IRS phase shifts in term of semi-closed-form expression. Lastly, numerical simulations are conducted to examine the efficacy of the proposed algorithm in enhancing performance in comparison to the existing benchmark schemes.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"65-69"},"PeriodicalIF":3.7,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940913","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":"A Multi-Agent DRL Method for Distributed Energy-Efficient Association and Hybrid Precoding in mmWave Cell-Free Massive MIMO Systems","authors":"Huiting Li;Yanxiang Jiang;Yige Huang;Fu-Chun Zheng;Gang Wu","doi":"10.1109/LCOMM.2024.3494537","DOIUrl":"https://doi.org/10.1109/LCOMM.2024.3494537","url":null,"abstract":"In this letter, we investigate a distributed design integrating user-centric association with local sub-connected hybrid precoding in mmWave cell-free massive MIMO (CF-mMIMO) systems, aiming to maximize the long-term global energy efficiency (EE) under quality-of-service and power budget constraints. The joint optimization problem is formulated as a Markov Game problem and a novel weighted critic update multi-agent twin-delayed deep deterministic policy gradient (WCU-MATD3) algorithm is proposed to solve it, which promotes cooperation among access point agents and reduces power consumption in front-haul links. The results show that the proposed WCU-MATD3 algorithm significantly improves the global EE and the trade-off between spectral efficiency (SE) and EE, providing a practical and stable distributed collaboration framework for dynamic distributed environments.","PeriodicalId":13197,"journal":{"name":"IEEE Communications Letters","volume":"29 1","pages":"70-74"},"PeriodicalIF":3.7,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142940707","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}