Physical Communication最新文献

英文中文

Sum-rate maximization for downlink MISO networks with multiple reconfigurable intelligent surfaces

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-09 DOI: 10.1016/j.phycom.2025.102610

Yue Li , Jianfeng Shi , Jingchong Wei , Yujie Zhang , Xiao Chen

Reconfigurable intelligent surface (RIS) is emerging as a key technology for next-generation wireless communication systems, with the potential to significantly enhance performance. Meanwhile, rate-splitting multiple access (RSMA) has been demonstrated to effectively improve spectral efficiency. This paper investigates the problem of maximizing the sum-rate in a downlink RSMA transmission system assisted by multiple RISs, where RISs are used to enhance signal coverage and improve the sum-rate when the direct link between the base station (BS) and users is severely blocked. The non-convex sum-rate maximization problem is decomposed into three subproblems, alternately optimizing the user rate allocation, the BS beamforming, and the RIS phase shift. This paper considers both ideal and non-ideal RIS models and proposes two corresponding optimization algorithms. Firstly, a closed-form expression for the optimal user rate allocation is derived. Then, the weighted minimum mean squared error (WMMSE) method is used to acquire the near-optimal BS beamforming and the ideal RIS phase shift matrix. Finally, another algorithm based on successive convex approximation (SCA) and penalty method is proposed to optimize the non-ideal RIS phase shift matrix. Simulation results show that the proposed algorithms outperform benchmark methods in terms of sum-rate performance. Specifically, the RIS-assisted RSMA achieves an increase of 11.14% and 20.03% compared to RIS-assisted space division multiple access (SDMA) and non-orthogonal multiple access (NOMA), respectively.

{"title":"Sum-rate maximization for downlink MISO networks with multiple reconfigurable intelligent surfaces","authors":"Yue Li , Jianfeng Shi , Jingchong Wei , Yujie Zhang , Xiao Chen","doi":"10.1016/j.phycom.2025.102610","DOIUrl":"10.1016/j.phycom.2025.102610","url":null,"abstract":"<div><div>Reconfigurable intelligent surface (RIS) is emerging as a key technology for next-generation wireless communication systems, with the potential to significantly enhance performance. Meanwhile, rate-splitting multiple access (RSMA) has been demonstrated to effectively improve spectral efficiency. This paper investigates the problem of maximizing the sum-rate in a downlink RSMA transmission system assisted by multiple RISs, where RISs are used to enhance signal coverage and improve the sum-rate when the direct link between the base station (BS) and users is severely blocked. The non-convex sum-rate maximization problem is decomposed into three subproblems, alternately optimizing the user rate allocation, the BS beamforming, and the RIS phase shift. This paper considers both ideal and non-ideal RIS models and proposes two corresponding optimization algorithms. Firstly, a closed-form expression for the optimal user rate allocation is derived. Then, the weighted minimum mean squared error (WMMSE) method is used to acquire the near-optimal BS beamforming and the ideal RIS phase shift matrix. Finally, another algorithm based on successive convex approximation (SCA) and penalty method is proposed to optimize the non-ideal RIS phase shift matrix. Simulation results show that the proposed algorithms outperform benchmark methods in terms of sum-rate performance. Specifically, the RIS-assisted RSMA achieves an increase of 11.14% and 20.03% compared to RIS-assisted space division multiple access (SDMA) and non-orthogonal multiple access (NOMA), respectively.</div></div>","PeriodicalId":48707,"journal":{"name":"Physical Communication","volume":"69 ","pages":"Article 102610"},"PeriodicalIF":2.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Nonlinear energy harvesting based cognitive relaying with best relay selection

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-09 DOI: 10.1016/j.phycom.2025.102603

Wen Si , Luyu Zhang , Chao Zhai , Lina Zheng , Jieyi Yan , Hongqiao Liu , Zijian Xu

This paper proposes a cognitive relaying scheme based on nonlinear energy harvesting, in which the licensed spectrum of the primary system is shared with the secondary system. The primary system comprises of an access point (AP) and multiple primary users (PUs). An energy-constrained secondary transmitter (ST), multiple secondary relays (SRs) and a secondary destination (SD) constitute the secondary system. ST uses the interference signal from AP to harvest energy. The transmit power of ST and relays should be strictly controlled to not exceed the interference constraint of all the PUs. The relay that has correctly decoded the ST’s data in the first-hop and brings the strongest signal power to the SD in the second-hop is selected to help ST transmit data to SD. Over the statistical properties of Rayleigh fading channels, we analyze the outage probability and throughput of the secondary system. We also present several benchmark systems for the performance comparison. Numerical results show that the protocol greatly improves spectrum efficiency and communication performance, and we emphasize the influence of various parameters on system performance.

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引用次数: 0

Location identifier based addressing scheme for molecular communication networks

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-08 DOI: 10.1016/j.phycom.2025.102599

Ankit

Networking over molecular signals is an important component of many new technologies, e.g., Internet of Bio-Nano Things (IoBNT) and Internet of Ingestible Things (IoIT). Assigning addresses to communicating nodes in a molecular communication (MC) network is an open problem in scientific literature due to challenges like probabilistic reception, undirected motion of molecular signals, and computational resource constraints. In this work, we propose a location identifier based addressing scheme that employs concentration gradient of molecular signals to assign addresses to stationary receiver nodes. Four different types of molecular signals are employed, which are emitted from four distinct addressing nodes. Interdependence between molecular receptivities at an addressed node is modeled using

t -

copula. A bijective mapping between the addresses and receiver nodes’ locations is established to render mathematical validation to the proposed addressing scheme. Finally, an analytical expression of probability of addressing error (

P_{add}^{avg}

) averaged over several spatial configurations of addressed nodes is obtained, where the nodes are distributed as uniform binomial point process. It is shown that

P_{add}^{avg}

increases as

O (n)

with increasing number of addressed nodes (

n

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引用次数: 0

Active elements for Hybrid Relay-Reflecting Intelligent Surface-assisted secrecy wireless communications: A Jaya-based optimization approach

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-07 DOI: 10.1016/j.phycom.2025.102602

Abdulrahman Al Ayidh

This work addresses optimizing active elements in Hybrid Relay-Reflecting Intelligent Surface (HR-RIS) systems to enhance both the sum and secrecy rates in communication networks facing eavesdropping threats. We present a new strategy that overcomes the drawbacks of traditional approaches by utilizing the HR-RIS framework’s Jaya optimization process. Using a population-based search strategy that maintains a balance between exploration and exploitation, the Jaya method effectively tackles complex solution spaces to find global solutions while avoiding obvious local optima, in contrast to traditional strategies. Additionally, we present a dynamic optimization method that adapts to shifting power levels, eavesdropper locations, and user positions. This improves the sum rate while strengthening security by maximizing the Signal-to-Interference-plus-Noise Ratio (SINR) and minimizing signal leakage. We further derive a closed-form expression for Strictly Positive Secrecy Capacity (SPSC) to assess secrecy performance compared to state-of-the-art techniques. Simulation results validate the proposed method’s effectiveness in optimizing HR-RIS active elements across diverse scenarios, examining the effects of different RIS element counts, edge node (EN) antenna configurations, and the spatial positioning of users and eavesdroppers. This investigation demonstrates a noticeable enhancement in the security and sum rate performance, demonstrating the HR-RIS strategy based on Jaya as a powerful tool for efficient and secure wireless communications systems.

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引用次数: 0

Joint UAV time slot allocation and trajectory optimization at intersections for throughput maximization in physical layer vehicular communication

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-07 DOI: 10.1016/j.phycom.2025.102598

Chen Tang , Demin Li , Xuemin Chen

Unmanned aerial vehicles (UAVs) have played important role in physical layer vehicular communication by enhancing connectivity across diverse transportation systems. However, guaranteeing reliable signal coverage from UAVs and overcoming obstacles that disrupt direct vehicle-to-vehicular communication remain challenging for achieving high throughput. This work addresses these challenges to maximize the throughput of UAV-aided vehicular communication by optimizing UAV trajectory, power allocation, and time slot allocation. We formulate a mathematical model and address the complex, non-convex optimization problems using an efficient alternating optimization technique. The proposed algorithm’s computational complexity is analyzed, and its convergence is validated through theoretical analysis and simulations. Extensive simulations demonstrate that our proposed solution outperforms existing methods.

引用次数: 0

Adaptive access strategy for satellite-terrestrial optical networks based on particle swarm optimization algorithm

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-03 DOI: 10.1016/j.phycom.2025.102600

Pengzhen Guo , Zixu Zhao , Yeqi Zhang , Qingbo Yang , Lifang Li , Liying Tan , Jing Ma

Satellite-to-terrestrial laser communications offer high bandwidth and security, making the integration of satellites and terrestrial infrastructure into a high-speed communications network critical. In satellite-terrestrial optical networks (STON), frequent link handovers necessitate an efficient access process to establish high-capacity and reliable laser links. We propose a novel and efficient optical network satellite adaptive access (ONSAA) strategy to reduce satellite access frequency while enhancing network capacity. For the first time, this strategy integrates the unique Pointing, Acquisition, and Tracking (PAT) process of satellite laser communication. The satellite access process is divided into two parts: satellite selection and the PAT process. Optimizing these two components independently can improve overall network performance. To optimize satellite selection, We apply a particle swarm optimization (PSO) algorithm, which effectively balances the capacity and dynamics of STON. Additionally, we propose a multi-scans method for the PAT process to increase satellite access success rates, thereby reducing the frequency of access requests. This method also minimizes docking delay, which in turn extends the link transmission time for successful connections between the optical ground station (OGS) and the satellite network. Docking delay refers to the time required to successfully access the satellite. Simulation results demonstrate that this strategy reduces the number of accesses and enhancing network capacity, while the optimized PAT process ensure fast and reliable connections presenting a promising solution for future STON applications.

{"title":"Adaptive access strategy for satellite-terrestrial optical networks based on particle swarm optimization algorithm","authors":"Pengzhen Guo , Zixu Zhao , Yeqi Zhang , Qingbo Yang , Lifang Li , Liying Tan , Jing Ma","doi":"10.1016/j.phycom.2025.102600","DOIUrl":"10.1016/j.phycom.2025.102600","url":null,"abstract":"<div><div>Satellite-to-terrestrial laser communications offer high bandwidth and security, making the integration of satellites and terrestrial infrastructure into a high-speed communications network critical. In satellite-terrestrial optical networks (STON), frequent link handovers necessitate an efficient access process to establish high-capacity and reliable laser links. We propose a novel and efficient optical network satellite adaptive access (ONSAA) strategy to reduce satellite access frequency while enhancing network capacity. For the first time, this strategy integrates the unique Pointing, Acquisition, and Tracking (PAT) process of satellite laser communication. The satellite access process is divided into two parts: satellite selection and the PAT process. Optimizing these two components independently can improve overall network performance. To optimize satellite selection, We apply a particle swarm optimization (PSO) algorithm, which effectively balances the capacity and dynamics of STON. Additionally, we propose a multi-scans method for the PAT process to increase satellite access success rates, thereby reducing the frequency of access requests. This method also minimizes docking delay, which in turn extends the link transmission time for successful connections between the optical ground station (OGS) and the satellite network. Docking delay refers to the time required to successfully access the satellite. Simulation results demonstrate that this strategy reduces the number of accesses and enhancing network capacity, while the optimized PAT process ensure fast and reliable connections presenting a promising solution for future STON applications.</div></div>","PeriodicalId":48707,"journal":{"name":"Physical Communication","volume":"69 ","pages":"Article 102600"},"PeriodicalIF":2.0,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143105023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Channel estimation and symbol detection for AFDM over doubly selective fading channels

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2025-01-02 DOI: 10.1016/j.phycom.2024.102597

Pengfei Huang , Qiang Li , Dong Huang , Junfeng Wang

In this paper, two receiver designs, each incorporating channel estimation and symbol detection, are presented for affine frequency division multiplexing (AFDM) over doubly selective fading channels. The first design unlocks the potential of deep learning in AFDM receivers. We first construct deep neural networks (DNNs), then train them offline by using training data, and finally deploy them online at the receiver to output transmitted information bits. This DNN receiver fails to achieve satisfactory bit error rate (BER) performance when there is no guard interval (GI) between the pilot and data. To solve this problem, we design a GI-free iterative AFDM receiver, which first performs coarse channel estimation and symbol detection, then implements interference cancellation by using the detected symbols, and finally proceeds channel estimation, symbol detection, and interference cancellation in an iterative manner until reaching a stop criterion. Moreover, a performance-enhancing method is proposed for the GI-free iterative AFDM receiver. In this enhanced scheme, the data interfered by the pilot is estimated by maximum-likelihood detection. Simulation results show that the DNN receiver is more robust than the existing scheme in the presence of pilot-data interference, and the performance-enhancing GI-free iterative receiver demonstrates excellent BER performance, achieving a gap of less than 0.5 dB compared to the scenario of perfect channel estimation, at a BER level of

1 0^{- 3}

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引用次数: 0

SCMA-Q-learning with overload control for random access in LEO satellite mMTC networks

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2024-12-31 DOI: 10.1016/j.phycom.2024.102584

Zeyu Wu , Guoliang Jing , Jie Ding , Xu Zhao

With the continuous advancement of 5G and beyond wireless networks, the exponential increase in Machine-Type Communication (MTC) devices presents substantial challenges, particularly in deal with Random Access Channel (RACH) congestion in massive MTC (mMTC) networks. Low Earth Orbit (LEO) satellite communication networks are increasingly valued for their global coverage and low-latency benefits. This paper deals with the RACH congestion problem in LEO satellite networks by proposing an innovative method that combines Sparse Code Multiple Access (SCMA), Q-learning, and Access Class Barring (ACB) technology. The proposed approach allows MTC devices to dynamically optimize resource allocation by selecting the most appropriate codebooks and time-slot groups in response to environmental changes. Additionally, ACB is employed to control system overload by adjusting the access probability of devices based on network conditions. Simulation results show that the proposed SCMA-QL-ACB method significantly improves system throughput and reduces collisions compared to existing techniques.

引用次数: 0

Optical true time delay based hybrid beamforming for RIS-aided mmWave multi-user MISO systems

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2024-12-30 DOI: 10.1016/j.phycom.2024.102596

Huan Huang , Jun Li , Yitian Wang , Ran Zhou , Chongfu Zhang

Reconfigurable intelligent surfaces (RISs) have emerged as a promising wireless technology for the 6th generation (6G) wireless systems. Herein, we investigate the joint passive- and hybrid- beamforming (JPHBF) optimization problem in RIS-aided millimeter-wave (mmWave) multi-user MISO (MU-MISO) systems. Furthermore, we introduced codebooks into analog- and passive- beamforming design for low training and feedback overheads. We proposed optical true time delay (OTTD)-based sub-connected hybrid beamforming (SC-HBF) with a low hardware cost and low channel estimation overheads. Compared to the traditional SC-HBF implementation, only about half of the optical true time delay pool based phase control units (OTTDP-PCUs) are required. We design the codebook-based passive- and analog- beamforming (PABF) under the constraints improved by the use of about half of the OTTDP-PCUs and the passive nature of RISs. The results show that the use of multiple RISs significantly improves the sum rate, specifically an improvement of approximately 284.5% at 25 dBm total transmit power. Although only about half of the OTTDP-PCUs are used, the proposed OTTD-based SC-HBF achieves near-optimal sum rates. Moreover, we presented a design example of the optical wavelength matrix used to map the OTTDP-PCUs.

{"title":"Optical true time delay based hybrid beamforming for RIS-aided mmWave multi-user MISO systems","authors":"Huan Huang , Jun Li , Yitian Wang , Ran Zhou , Chongfu Zhang","doi":"10.1016/j.phycom.2024.102596","DOIUrl":"10.1016/j.phycom.2024.102596","url":null,"abstract":"<div><div>Reconfigurable intelligent surfaces (RISs) have emerged as a promising wireless technology for the 6th generation (6G) wireless systems. Herein, we investigate the joint passive- and hybrid- beamforming (JPHBF) optimization problem in RIS-aided millimeter-wave (mmWave) multi-user MISO (MU-MISO) systems. Furthermore, we introduced codebooks into analog- and passive- beamforming design for low training and feedback overheads. We proposed optical true time delay (OTTD)-based sub-connected hybrid beamforming (SC-HBF) with a low hardware cost and low channel estimation overheads. Compared to the traditional SC-HBF implementation, only about half of the optical true time delay pool based phase control units (OTTDP-PCUs) are required. We design the codebook-based passive- and analog- beamforming (PABF) under the constraints improved by the use of about half of the OTTDP-PCUs and the passive nature of RISs. The results show that the use of multiple RISs significantly improves the sum rate, specifically an improvement of approximately 284.5% at 25 dBm total transmit power. Although only about half of the OTTDP-PCUs are used, the proposed OTTD-based SC-HBF achieves near-optimal sum rates. Moreover, we presented a design example of the optical wavelength matrix used to map the OTTDP-PCUs.</div></div>","PeriodicalId":48707,"journal":{"name":"Physical Communication","volume":"69 ","pages":"Article 102596"},"PeriodicalIF":2.0,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143105022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Knowledge graph enhanced recommendation for semantic structure construction and feedback in online learning

IF 2 4区计算机科学 Q3 ENGINEERING, ELECTRICAL & ELECTRONIC

Physical Communication

Pub Date : 2024-12-28 DOI: 10.1016/j.phycom.2024.102590

Wei Wu, Shuangqi Yang, Feng Tian, Xin Wei, Yagang Pan

This paper presents a knowledge graph-enhanced recommendation system, inspired by constructivist principles, to address challenges like information overload and fragmented knowledge in online education. The system transforms unstructured information into interconnected knowledge frameworks, facilitating semantic comprehension, personalized recommendations, and cognitive feedback. Aligned with constructivist principles, the platform encourages students to actively construct personalized knowledge structures, enhancing cognitive engagement through adaptive feedback. Experiments with higher education students demonstrate its potential to improve learning interest, knowledge retention, and adaptive feedback, supporting advanced semantic and cognitive learning paradigms.

引用次数: 0

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