With the evolution of the sixth generation(6G)mobile communication technology,ample attention has gone to the integrated terrestrial-satellite networks.This paper notes that four typical application scenarios of integ...With the evolution of the sixth generation(6G)mobile communication technology,ample attention has gone to the integrated terrestrial-satellite networks.This paper notes that four typical application scenarios of integrated terrestrial-satellite networks are integrated into ultra dense satellite-enabled 6G networks architecture.Then the subchannel and power allocation schemes for the downlink of the ultra dense satellite-enabled 6G heterogeneous networks are introduced.Satellite mobile edge computing(SMEC)with edge caching in three-layer heterogeneous networks serves to reduce the link traffic of networks.Furthermore,a scheme for interference management is presented,involving quality-of-service(QoS)and co-tier/cross-tier interference constraints.The simulation results show that the proposed schemes can significantly increase the total capacity of ultra dense satellite-enabled 6G heterogeneous networks.展开更多
Abstract： Two-tier heterogeneous networks （HetNets）, where the current cellular networks, i.e., macrocells, are overlapped with a large number of randomly distributed femtocells, can potentially bring significant b...Abstract： Two-tier heterogeneous networks （HetNets）, where the current cellular networks, i.e., macrocells, are overlapped with a large number of randomly distributed femtocells, can potentially bring significant benefits to spectral utilization and system capacity. The interference management and access control for open and closed femtocells in two-tier HetNets were focused. The contributions consist of two parts. Firstly, in order to reduce the uplink interference caused by MUEs （macrocell user equipments） at closed femtocells, an incentive mechanism to implement interference mitigation was proposed. It encourages femtoeells that work with closed-subscriber-group （CSG） to allow the interfering MUEs access in but only via uplink, which can reduce the interference significantly and also benefit the marco-tier. The interference issue was then studied in open-subscriber-group （OSG） femtocells from the perspective of handover and mobility prediction. Inbound handover provides an alternative solution for open femtocells when interference turns up, while this accompanies with PCI （physical cell identity） confusion during inbound handover. To reduce the PCI confusion, a dynamic PCI allocation scheme was proposed, by which the high handin femtocells have the dedicated PCI while the others share the reuse PCIs. A Markov chain based mobility prediction algorithm was designed to decide whether the femtoeell status is with high handover requests. Numerical analysis reveals that the UL interference is managed well for the CSG femtocell and the PCI confusion issue is mitigated greatly in OSG femtocell compared to the conventional approaches.展开更多
Deploying femtoceUs underlaying macrocells is a promising way to improve the capacity and enhance the coverage of a cellular system. However, densely deployed femtocells in urban area also give rise to intra-tier inte...Deploying femtoceUs underlaying macrocells is a promising way to improve the capacity and enhance the coverage of a cellular system. However, densely deployed femtocells in urban area also give rise to intra-tier interference and cross-tier issue that should be addressed properly in order to acquire the expected performance gain. In this paper, we propose an interference management scheme based on joint clustering and resource allocation for two-tier Orthogonal Frequency Division Multiplexing （OFDM）-based femtoeeU networks. We formulate an optimization task with the objective of maximizing the sum throughput of the femtocell users （FUs） under the consideration of intra-tier interference mitigation, while controlling the interference to the maeroeell user （MU） under its bearable threshold. The formulation problem is addressed by a two-stage procedure： femtoeells clustering and resource allocation. First, disjoint femtocell clusters with dynamic sizes and numbers are generated to minimize intra-tier interference. Then each cluster is taken as a resource allocation unit to share all subehannels, followed by a fast algorithm to distribute power among these subchannels. Simulation results show that our proposed schemes can improve the throughput of the FUs with acceptable complexity.展开更多
Due to the broadcast nature of wireless communications,users’data transmitted wirelessly is susceptible to security/privacy threats.Meanwhile,as a result of the limitation of spectrum resources,massive wireless conne...Due to the broadcast nature of wireless communications,users’data transmitted wirelessly is susceptible to security/privacy threats.Meanwhile,as a result of the limitation of spectrum resources,massive wireless connections will incur serious interference,which may damage the efficiency of data transmission.Therefore,improving both efficiency and secrecy of data transmission is of research significance.In this paper,we propose a wireless transmission scheme by taking both Secure Communication(SC)and Interference Management(IM)into account,namely SCIM.With this scheme,an SCIM signal is generated by the legitimate transmitter(Tx)and sent along with the desired signal,so that the SCIM signal can interact with and suppress the environmental interference at the legitimate receiver(Rx).Meanwhile,the SCIM signal may interfere with the eavesdropper in the coverage of legitimate transmission so as to deteriorate the eavesdropping performance.Therefore,the secrecy of desired transmission is improved.In this way,both the transmission efficiency and privacy are enhanced.Then,by taking various transmission preferences into account,we develop different implementations of SCIM,including Interference Suppression First SCIM(ISF-SCIM),Data Transmission First SCIM(DTF-SCIM),Anti-Eavesdropping First SCIM(AEF-SCIM),and Secrecy Rate Maximization SCIM(SRM-SCIM).Our in-depth simulation results have shown the proposed methods to effectively improve the efficiency and secrecy of the legitimate transmission.展开更多
Symbiotic radio(SR)is a technology that facilitates mutually beneficial sharing of spectrum and energy between primary and secondary systems.In SR networks,utilizing active reconfigurable intelligent surface(RIS)as th...Symbiotic radio(SR)is a technology that facilitates mutually beneficial sharing of spectrum and energy between primary and secondary systems.In SR networks,utilizing active reconfigurable intelligent surface(RIS)as the secondary transmitter(STx)enhances this mutual benefit compared to passive RIS.This paper addresses the interference management challenges that inevitably arise from employing active RIS.We consider a common SR network consisting of three types of users:SR users,non-SR users,and eavesdroppers.Additionally,each SR user has their own unique cellular services.We propose minimizing the total power consumption while satisfying a suffi-ciently large signal-to-interference-plus-noise ratio(SINR)for SR users,a small enough SINR for eavesdroppers,and a small enough interference temperature for non-SR users.The alternative optimization(AO)method is used for decoupling multi-variables.The non-convex constraints are relaxed as convex ones through first-order Taylor approximation,and the bounded channel state information(CSI)error model is handled using the S-procedure.Simulations validate the supe-riority of the proposed algorithm and demonstrate that the total power consumption is minimized while meeting performance thresholds.Additionally,the results offer valuable insights for SR network deployment.展开更多
Heterogeneous network for long term evolution advanced（LTE-A） creates severe interference.It is an urgent task to overcome the interference in macro cellular with low-power base stations（BSs）,such as relay,pico,an...Heterogeneous network for long term evolution advanced（LTE-A） creates severe interference.It is an urgent task to overcome the interference in macro cellular with low-power base stations（BSs）,such as relay,pico,and femto called subnet nodes.In this paper,the cognitive interference model in interference zone（IZ） of the practical heterogeneous scenario is proposed.Based on investigation of interaction between the macro BS and subnet nodes in this model,the strategy framework of the cognitive critical ratio and power reward factor is set up for interference management aiming to get the maximum net saving power.The study of interference management is transformed into a multiple objective non-linear programming（MONLP） of the maximum saving power for the macro BS and subnet nodes.To facilitate the best compromise solution for both,the MONLP is changed into single objective programming and genetic algorithm（GA） is employed to obtain the global optimum solution.In addition,the practical implementation using the proposed algorithm in heterogeneous network for LTE-A is designed.Finally,numerical evaluation is used to test the applicability of the proposed algorithm,and system level simulation results demonstrate the effectiveness of the proposed interference management scheme.展开更多
The Space-Terrestrial Integrated Network(STIN)is considered to be a promising paradigm for realizing worldwide wireless connectivity in sixth-Generation(6G)wireless communication systems.Unfortunately,excessive interf...The Space-Terrestrial Integrated Network(STIN)is considered to be a promising paradigm for realizing worldwide wireless connectivity in sixth-Generation(6G)wireless communication systems.Unfortunately,excessive interference in the STIN degrades the wireless links and leads to poor performance,which is a bottleneck that prevents its commercial deployment.In this article,the crucial features and challenges of STIN-based interference are comprehensively investigated,and some candidate solutions for Interference Management(IM)are summarized.As traditional IM techniques are designed for single-application scenarios or specific types of interference,they cannot meet the requirements of the STIN architecture.To address this issue,we propose a self-adaptation IM method that reaps the potential benefits of STIN and is applicable to both rural and urban areas.A number of open issues and potential challenges for IM are discussed,which provide insights regarding future research directions related to STIN.展开更多
Vehicular network communication technology is currently attracting a considerable amount of attention.We consider a scenario in which vehicular communication nodes share the same spectrum resources and generate interf...Vehicular network communication technology is currently attracting a considerable amount of attention.We consider a scenario in which vehicular communication nodes share the same spectrum resources and generate interference with other nodes.Compared with traditional interference-avoiding vehicular communications,this paper aims to increase the number of accessed communication links under the premise of satisfying the required QoS.In our research,communication nodes have opportunities to select relay nodes to both help improve their data transmissions and reduce their transmit power in order to decrease interference with other links while still satisfying their QoS requirements.Based on these objectives,we propose an innovative interference management method that considers link selection,power adaption,and communication mode selection simultaneously to maximize the number of communication links with the lowest power cost.Compared with traditional link-selection and power-adaption interference management schemes,the proposed scheme improves QoS satisfaction with high energy effciency.Simulation results demonstrate both the effciency and the e ectiveness of the proposed scheme.展开更多
In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.Howe...In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.However,when managing multiple disturbances from the same source,it may not be feasible to use existing IM methods such as Interference Alignment(IA)and Interference Steering(IS)exclusively.It is because with IA,the aligned interference becomes indistinguishable at its desired Receiver(Rx)under the cost constraint of Degrees-of-Freedom(DoF),while with IS,more transmit power will be consumed in the direct and repeated application of IS to each interference.To remedy these deficiencies,Interference Alignment Steering(IAS)is proposed by incorporating IA and IS and exploiting their advantages in IM.With IAS,the interfering Transmitter(Tx)first aligns one interference incurred by the transmission of one data stream to a one-dimensional subspace orthogonal to the desired transmission at the interfered Rx,and then the remaining interferences are treated as a whole and steered to the same subspace as the aligned interference.Moreover,two improved versions of IAS,i.e.,IAS with Full Adjustment at the Interfering Tx(IAS-FAIT)and Interference Steering and Alignment(ISA),are presented.The former considers the influence of IA on the interfering user-pair's performance.The orthogonality between the desired signals at the interfered Rx can be maintained by adjusting the spatial characteristics of all interferences and the aligned interference components,thus ensuring the Spectral Efficiency(SE)of the interfering communication pairs.Under ISA,the power cost for IS at the interfered Tx is minimized,hence improving SE performance of the interfered communication-pairs.Since the proposed methods are realized at the interfering and interfered Txs cooperatively,the expenses of IM are shared by both communication-pairs.Our in-depth simulation results show that joint use of IA and IS can effectively manage multiple disturbances from the same source and improve the system's SE.展开更多
This paper elaborates on the harmonious wireless network from the perspective of interference management.The coexistence of useful signals and interfering signals is beneficial in throughput terms of the entire wirele...This paper elaborates on the harmonious wireless network from the perspective of interference management.The coexistence of useful signals and interfering signals is beneficial in throughput terms of the entire wireless network.Useful signals and interfering signals are complementary and are in juxtaposition to each other in the context of a single communication link,and are in symbiosis within the framework of the networks.The philosophy behind this could be described by the Chinese traditional culture symbol of“yin”and“yang”.A wireless network having optimal performance must be a harmonious network where the interfering and useful signals harmoniously coexist in an optimal balance.Interference management plays a critical role in achieving this optimal balance,while sophisticated interference management techniques should be designed to improve the system performance.展开更多
Integrated sensing and communication(ISAC)technology is a promising candidate for next-generation communication systems.However,severe co-site interference in existing ISAC systems limits the communication and sensing...Integrated sensing and communication(ISAC)technology is a promising candidate for next-generation communication systems.However,severe co-site interference in existing ISAC systems limits the communication and sensing performance,posing significant challenges for ISAC interference management.In this work,we propose a novel interference management scheme based on the normalized least mean square(NLMS)algorithm,which mitigates the impact of co-site interference by reconstructing the interference from the local transmitter and canceling it from the received signal.Simulation results demonstrate that,compared to typical adaptive interference management schemes based on recursive least square(RLS)and stochastic gradient descent(SGD)algorithms,the proposed NLMS algorithm effectively cancels co-site interference and achieves a good balance between computational complexity and convergence performance.展开更多
With the rapid growth of the low-altitude economy,the demand for typical low-altitude ap-plications has accelerated the advancement of inte-grated sensing and communications(ISAC)networks.This paper begins by analyzin...With the rapid growth of the low-altitude economy,the demand for typical low-altitude ap-plications has accelerated the advancement of inte-grated sensing and communications(ISAC)networks.This paper begins by analyzing representative ap-plication scenarios to clarify the core requirements of the low-altitude economy for modern ISAC net-works.By investigating the distinctive characteris-tics of ISAC networks in low-altitude environments,it presents a comprehensive analysis of key challenges and identifies four major issues:challenges in pre-cise target detection,interference management,in-consistent sensing and communication coverage,and the complexity of air-ground coordination and han-dover.Based on fundamental theories and principles,the paper proposes corresponding solutions,encom-passing advanced technologies for precise target de-tection and recognition,high-reliability networked de-tection,robust interference management,and seamless air-ground collaboration.These solutions aim to es-tablish a solid foundation for the future development of intelligent low-altitude networks and ensure effec-tive support for emerging applications.展开更多
Recently cellular networks have been densely and heterogeneously deployed indoors and outdoors to expand the network capacity,and thus the in-building propagation loss and the transmit power diversity of access points...Recently cellular networks have been densely and heterogeneously deployed indoors and outdoors to expand the network capacity,and thus the in-building propagation loss and the transmit power diversity of access points will exacerbate link heterogeneity and result in partial unidirectional strong interference.To make full use of the strong interference feature,we propose the successive interference cancellation and alignment(SICA)scheme in the K-user interference channel with partial unidirectional strong interference.SICA is designed to transmit two kinds of data streams simultaneously,the alignment streams and superposition streams.The alignment streams will follow the interference alignment criterion to maintain the optimal degrees of freedom(DoF)performance;the superposition streams are handled via successive interference cancellation at all the strongly interfered receivers to improve the overall achievable rate.The joint transceiver designs for SICA is modeled as a weighted sum rate(WSR)maximization problem,and then can be alternately solved for a local optimum according to the optimality equivalence between WSR and its corresponding weighted mean square error(WMMSE)problem.Simulation results have confirmed the sum rate improvement and DoF optimality of the proposed SICA scheme.展开更多
Inter-cell interference (ICI) mitigation is always a challenge issue in LTE system. In this paper, several common interference parameters are firstly analyzed for both cell edge users and center users, and then a nove...Inter-cell interference (ICI) mitigation is always a challenge issue in LTE system. In this paper, several common interference parameters are firstly analyzed for both cell edge users and center users, and then a novel fractional frequency reuse (FFR) architecture based on interference avoidance scheme coupled with power control is proposed to solve the problem of interference management in multi-cell LTE environment. The scheme divides the whole sub-carriers into three groups orthogonally. One is allocated to cell edge users, while another two are assigned to cell center users with different transmitter power. Then a parameter named interference avoidance factor (IAF) is defined to avoid ICI and adjust the number of allocated sub-carriers to match the number of users. The parameter also takes weight factor and fairness factor into consideration. The simulation results show the proposed scheme can improve the performance of cell edge users obviously.展开更多
In this paper, we investigate a cooperation mechanism for satellite-terrestrial integrated networks. The terrestrial relays act as the supplement of traditional small cells and cooperatively provide seamless coverage ...In this paper, we investigate a cooperation mechanism for satellite-terrestrial integrated networks. The terrestrial relays act as the supplement of traditional small cells and cooperatively provide seamless coverage for users in the densely populated areas.To deal with the dynamic satellite backhaul links and backhaul capacity caused by the satellite mobility, severe co-channel interference in both satellite backhaul links and user links introduced by spectrum sharing,and the difference demands of users as well as heterogeneous characteristics of terrestrial backhaul and satellite backhaul, we propose a joint user association and satellite selection scheme to maximize the total sum rate. The optimization problem is formulated via jointly considering the influence of dynamic backhaul links, individual requirements and targeted interference management strategies, which is decomposed into two subproblems: user association and satellite selection. The user association is formulated as a nonconvex optimization problem, and solved through a low-complexity heuristic scheme to find the most suitable access point serving each user. Then, the satellite selection is resolved based on the cooperation among terrestrial relays to maximize the total backhaul capacity with the minimum date rate constraints. Finally,simulation results show the effectiveness of the proposed scheme in terms of total sum rate and power efficiency of TRs' backhaul.展开更多
Vehicular Ad Hoc Networks (VANETs) play a pivotal role in advancing Intelligent Transportation Systems (ITS), facilitating real-time communication among vehicles and infrastructure. However, VANETs face challenges ari...Vehicular Ad Hoc Networks (VANETs) play a pivotal role in advancing Intelligent Transportation Systems (ITS), facilitating real-time communication among vehicles and infrastructure. However, VANETs face challenges arising from high mobility, dynamic topologies, and significant interference levels. This study proposes a novel cross-layer framework incorporating channel prediction and adaptive resource management to address these challenges. By leveraging a Software-Defined Radio (SDR) platform, the framework is evaluated under diverse mobility and interference conditions. Key contributions include an analysis of multi-code and multi-modulation schemes, identification of critical trade-offs in receiver diversity, and the introduction of mechanisms to optimize Quality of Service (QoS). Simulation results demonstrate significant improvements in throughput, packet delivery ratio, and network resilience, highlighting the framework’s potential for real-world applications such as autonomous vehicles and smart city communication networks. The study concludes with actionable recommendations for future research, emphasizing scalability, real-time adaptation, and hardware implementation to further enhance VANET performance.展开更多
Heterogeneous small cell network is one of the most effective solutions to overcome spectrum scarcity for the next generation of mobile networks.Dual connectivity(DC)can improve the throughput for each individual user...Heterogeneous small cell network is one of the most effective solutions to overcome spectrum scarcity for the next generation of mobile networks.Dual connectivity(DC)can improve the throughput for each individual user by allowing concurrent access to two heterogeneous radio networks.In this paper,we propose a joint user association and fair scheduling algorithm(JUAFS)to deal with the resource allocation and load balancing issues for DC heterogeneous small cell networks.Considering different coverage sizes,numbers of users,and quality of experience characteristics of heterogeneous cells,we present a proportional fair scheduling for user association among cells and utilize interference graph to minimize the transmission conflict probability.Simulation results show the performance improvement of the proposed algorithm in spectrum efficiency and fairness comparing to the existing schemes.展开更多
Adaptive power control is a critical challenge in dense radio frequency identification(RFID)environments,where uncontrolled power levels can lead to excessive interference,energy inefficiency,and reduced system perfor...Adaptive power control is a critical challenge in dense radio frequency identification(RFID)environments,where uncontrolled power levels can lead to excessive interference,energy inefficiency,and reduced system performance.This paper presents a robust and scalable adaptive power control framework that dynamically adjusts transmit power levels to optimize energy efficiency,minimize interference,and enhance system throughput.The proposed framework leverages an optimization-driven approach based on real-time environmental feedback,ensuring compliance with regulatory constraints while maintaining optimal performance.A multi-objective optimization strategy is employed to balance several key metrics,including throughput,energy consumption,and fairness,with a Pareto front analysis demonstrating superior trade-offs compared to fixed power strategies.The effectiveness of the proposed approach is validated through extensive simulations and real-world experiments using universal software radio peripheral(USRP)devices in dense RFID deployments.The results show that our framework achieves a 34%reduction in cumulative interference,a 15%improvement in energy efficiency,and a 20%increase in throughput compared to baseline fixed power methods.Furthermore,it converges rapidly,even in dynamic and high-density networks.These improvements make it highly scalable and adaptable to varying reader densities,ensuring reliable performance in large-scale RFID applications such as supply chain management and industrial automation.展开更多
With rapid development of femtocell, dense deployment of femtocells in buildings will become an important study scenario. In this scenario, there exists severe inter-femtocell interference in the same building, which ...With rapid development of femtocell, dense deployment of femtocells in buildings will become an important study scenario. In this scenario, there exists severe inter-femtocell interference in the same building, which is revealed by our simulations in the 3-dimention （3D） scenario. If this type of interference is not well controlled, services to indoor users are bound to be deteriorated, especially for the femtocell edge users. Motivated by this problem, femto users＇ received interference model is constructed based on the scenario of 3D femtocell deployment. Then, a graph theory based in-building inter-femtocell coordination scheme is proposed, which includes three phases： establishment of femtocell interference graph, femtocell clustering and frequency resources allocation based on the proposed cluster influence circle. Finally, the simulation results confirm that the proposed scheme improves the femtocell average throughput by 22.4% and 26.2% in comparison with frequency universal reuse scheme and channel demodulation reliability of cell edge femto users. frequency hopping scheme respectively, and ensures the展开更多
Atmospheric ducting has a significant impact on electromagnetic wave propagation.Radio signals that are trapped and guided by the atmospheric duct can travel a much longer distance over the horizon with lower attenuat...Atmospheric ducting has a significant impact on electromagnetic wave propagation.Radio signals that are trapped and guided by the atmospheric duct can travel a much longer distance over the horizon with lower attenuation since the signal power does not spread isotropically through the atmosphere.Atmospheric ducting brings both challenges and opportunities to wireless communications.On one hand,the signals propagating in the atmospheric duct may interfere with a receiver far away as remote co-channel interference.On the other hand,a point-to-point link can be established directly through the atmospheric duct to enable beyond line-of-sight communications.In this article,the formation of the atmospheric duct and its effects on radio wave propagation are first overviewed.Then solutions and standardization activities in the 3rd Generation Partnership Project(3GPP)to mitigate atmospheric duct induced remote interference are presented.Finally,the applications and design challenges of atmospheric duct enabled beyond line-of-sight communications are reviewed and future research directions are suggested.展开更多
基金supported in part by the National Key R&D Program of China(2020YFB1806103)the National Natural Science Foundation of China under Grant 62225103 and U22B2003+1 种基金Beijing Natural Science Foundation(L212004)China University Industry-University-Research Collaborative Innovation Fund(2021FNA05001).
文摘With the evolution of the sixth generation(6G)mobile communication technology,ample attention has gone to the integrated terrestrial-satellite networks.This paper notes that four typical application scenarios of integrated terrestrial-satellite networks are integrated into ultra dense satellite-enabled 6G networks architecture.Then the subchannel and power allocation schemes for the downlink of the ultra dense satellite-enabled 6G heterogeneous networks are introduced.Satellite mobile edge computing(SMEC)with edge caching in three-layer heterogeneous networks serves to reduce the link traffic of networks.Furthermore,a scheme for interference management is presented,involving quality-of-service(QoS)and co-tier/cross-tier interference constraints.The simulation results show that the proposed schemes can significantly increase the total capacity of ultra dense satellite-enabled 6G heterogeneous networks.
基金Project(2012AA01A301-01)supported by the National High-Tech Research and Development Plan of ChinaProjects(61301148,61272061)supported by the National Natural Science Foundation of China+3 种基金Projects(20120161120019,2013016111002)supported by the Research Fund for the Doctoral Program of Higher Education of ChinaProjects(14JJ7023,10JJ5069)supported by the Natural Science Foundation of Hunan Province,ChinaProject(ISN12-05)supported by State Key Laboratory of Integrated Services Networks Open Foundation,ChinaProject(531107040276)supported by the Fundamental Research Funds for the Central Universities,China
文摘Abstract： Two-tier heterogeneous networks （HetNets）, where the current cellular networks, i.e., macrocells, are overlapped with a large number of randomly distributed femtocells, can potentially bring significant benefits to spectral utilization and system capacity. The interference management and access control for open and closed femtocells in two-tier HetNets were focused. The contributions consist of two parts. Firstly, in order to reduce the uplink interference caused by MUEs （macrocell user equipments） at closed femtocells, an incentive mechanism to implement interference mitigation was proposed. It encourages femtoeells that work with closed-subscriber-group （CSG） to allow the interfering MUEs access in but only via uplink, which can reduce the interference significantly and also benefit the marco-tier. The interference issue was then studied in open-subscriber-group （OSG） femtocells from the perspective of handover and mobility prediction. Inbound handover provides an alternative solution for open femtocells when interference turns up, while this accompanies with PCI （physical cell identity） confusion during inbound handover. To reduce the PCI confusion, a dynamic PCI allocation scheme was proposed, by which the high handin femtocells have the dedicated PCI while the others share the reuse PCIs. A Markov chain based mobility prediction algorithm was designed to decide whether the femtoeell status is with high handover requests. Numerical analysis reveals that the UL interference is managed well for the CSG femtocell and the PCI confusion issue is mitigated greatly in OSG femtocell compared to the conventional approaches.
文摘Deploying femtoceUs underlaying macrocells is a promising way to improve the capacity and enhance the coverage of a cellular system. However, densely deployed femtocells in urban area also give rise to intra-tier interference and cross-tier issue that should be addressed properly in order to acquire the expected performance gain. In this paper, we propose an interference management scheme based on joint clustering and resource allocation for two-tier Orthogonal Frequency Division Multiplexing （OFDM）-based femtoeeU networks. We formulate an optimization task with the objective of maximizing the sum throughput of the femtocell users （FUs） under the consideration of intra-tier interference mitigation, while controlling the interference to the maeroeell user （MU） under its bearable threshold. The formulation problem is addressed by a two-stage procedure： femtoeells clustering and resource allocation. First, disjoint femtocell clusters with dynamic sizes and numbers are generated to minimize intra-tier interference. Then each cluster is taken as a resource allocation unit to share all subehannels, followed by a fast algorithm to distribute power among these subchannels. Simulation results show that our proposed schemes can improve the throughput of the FUs with acceptable complexity.
基金supported in part by the Natural Science Foundation of Shaanxi Province under Grant Number 2021JM-143the Fundamental Research Funds for the Central Universities under Grant Number JB211502+5 种基金the Project of Key Laboratory of Science and Technology on Communication Network under Grant Number 6142104200412the National Natural Science Foundation of China under Grant Number 61672410the Academy of Finland under Grant Number 308087the China 111 project under Grant Number B16037JSPS KAKENHI under Grant Number JP20K14742and the Project of Cyber Security Establishment with Inter University Cooperation.
文摘Due to the broadcast nature of wireless communications,users’data transmitted wirelessly is susceptible to security/privacy threats.Meanwhile,as a result of the limitation of spectrum resources,massive wireless connections will incur serious interference,which may damage the efficiency of data transmission.Therefore,improving both efficiency and secrecy of data transmission is of research significance.In this paper,we propose a wireless transmission scheme by taking both Secure Communication(SC)and Interference Management(IM)into account,namely SCIM.With this scheme,an SCIM signal is generated by the legitimate transmitter(Tx)and sent along with the desired signal,so that the SCIM signal can interact with and suppress the environmental interference at the legitimate receiver(Rx).Meanwhile,the SCIM signal may interfere with the eavesdropper in the coverage of legitimate transmission so as to deteriorate the eavesdropping performance.Therefore,the secrecy of desired transmission is improved.In this way,both the transmission efficiency and privacy are enhanced.Then,by taking various transmission preferences into account,we develop different implementations of SCIM,including Interference Suppression First SCIM(ISF-SCIM),Data Transmission First SCIM(DTF-SCIM),Anti-Eavesdropping First SCIM(AEF-SCIM),and Secrecy Rate Maximization SCIM(SRM-SCIM).Our in-depth simulation results have shown the proposed methods to effectively improve the efficiency and secrecy of the legitimate transmission.
基金supported in part by the National Key R&D Program of China(2021YFA0716500)and in part by the National 111 Project of China(B08038).
文摘Symbiotic radio(SR)is a technology that facilitates mutually beneficial sharing of spectrum and energy between primary and secondary systems.In SR networks,utilizing active reconfigurable intelligent surface(RIS)as the secondary transmitter(STx)enhances this mutual benefit compared to passive RIS.This paper addresses the interference management challenges that inevitably arise from employing active RIS.We consider a common SR network consisting of three types of users:SR users,non-SR users,and eavesdroppers.Additionally,each SR user has their own unique cellular services.We propose minimizing the total power consumption while satisfying a suffi-ciently large signal-to-interference-plus-noise ratio(SINR)for SR users,a small enough SINR for eavesdroppers,and a small enough interference temperature for non-SR users.The alternative optimization(AO)method is used for decoupling multi-variables.The non-convex constraints are relaxed as convex ones through first-order Taylor approximation,and the bounded channel state information(CSI)error model is handled using the S-procedure.Simulations validate the supe-riority of the proposed algorithm and demonstrate that the total power consumption is minimized while meeting performance thresholds.Additionally,the results offer valuable insights for SR network deployment.
基金supported by Key project (2009ZX03003-004-01)National Natural Science Foundation of China (60811120097)
文摘Heterogeneous network for long term evolution advanced（LTE-A） creates severe interference.It is an urgent task to overcome the interference in macro cellular with low-power base stations（BSs）,such as relay,pico,and femto called subnet nodes.In this paper,the cognitive interference model in interference zone（IZ） of the practical heterogeneous scenario is proposed.Based on investigation of interaction between the macro BS and subnet nodes in this model,the strategy framework of the cognitive critical ratio and power reward factor is set up for interference management aiming to get the maximum net saving power.The study of interference management is transformed into a multiple objective non-linear programming（MONLP） of the maximum saving power for the macro BS and subnet nodes.To facilitate the best compromise solution for both,the MONLP is changed into single objective programming and genetic algorithm（GA） is employed to obtain the global optimum solution.In addition,the practical implementation using the proposed algorithm in heterogeneous network for LTE-A is designed.Finally,numerical evaluation is used to test the applicability of the proposed algorithm,and system level simulation results demonstrate the effectiveness of the proposed interference management scheme.
基金This work was supported in part by the National Key R&D Program of China(No.2020YFB1806703)the National Natural Science Foundation of China(No.61901315)+1 种基金the State Major Science and Technology Special Project(No.2018ZX03001023)the Fundamental Research Funds for the Central Universities(No.2020RC03).
文摘The Space-Terrestrial Integrated Network(STIN)is considered to be a promising paradigm for realizing worldwide wireless connectivity in sixth-Generation(6G)wireless communication systems.Unfortunately,excessive interference in the STIN degrades the wireless links and leads to poor performance,which is a bottleneck that prevents its commercial deployment.In this article,the crucial features and challenges of STIN-based interference are comprehensively investigated,and some candidate solutions for Interference Management(IM)are summarized.As traditional IM techniques are designed for single-application scenarios or specific types of interference,they cannot meet the requirements of the STIN architecture.To address this issue,we propose a self-adaptation IM method that reaps the potential benefits of STIN and is applicable to both rural and urban areas.A number of open issues and potential challenges for IM are discussed,which provide insights regarding future research directions related to STIN.
基金This work is supported by the National Natural Science Foundation of China(Nos.61622101,61571020)Ministry National Key Research and Development Project(No.2016YFE0123100)+1 种基金the National Basic Research Program of China("973"Program)(No.2013CB336700)the open research fund of the State Key Laboratory of Integrated Services Networks(No.ISN18-14),Xidian University.
文摘Vehicular network communication technology is currently attracting a considerable amount of attention.We consider a scenario in which vehicular communication nodes share the same spectrum resources and generate interference with other nodes.Compared with traditional interference-avoiding vehicular communications,this paper aims to increase the number of accessed communication links under the premise of satisfying the required QoS.In our research,communication nodes have opportunities to select relay nodes to both help improve their data transmissions and reduce their transmit power in order to decrease interference with other links while still satisfying their QoS requirements.Based on these objectives,we propose an innovative interference management method that considers link selection,power adaption,and communication mode selection simultaneously to maximize the number of communication links with the lowest power cost.Compared with traditional link-selection and power-adaption interference management schemes,the proposed scheme improves QoS satisfaction with high energy effciency.Simulation results demonstrate both the effciency and the e ectiveness of the proposed scheme.
基金supported in part by NSF of Shaanxi Province under Grant 2021JM-143the Fundamental Research Funds for the Central Universities under Grant JB211502+5 种基金the Project of Key Laboratory of Science&Technology on Communication Network under Grant 6142104200412the National Natural Science Foundation of China under Grant 62072351the Academy of Finland under Grant 308087,Grant 335262 and Grant 345072the Shaanxi Innovation Team Project under Grant 2018TD-007the 111 Project under Grant B16037,JSPS KAKENHI Grant Number JP20K14742the Project of Cyber Security Establishment with Inter University Cooperation.
文摘In wireless communication networks,mobile users in overlapping areas may experience severe interference,therefore,designing effective Interference Management(IM)methods is crucial to improving network performance.However,when managing multiple disturbances from the same source,it may not be feasible to use existing IM methods such as Interference Alignment(IA)and Interference Steering(IS)exclusively.It is because with IA,the aligned interference becomes indistinguishable at its desired Receiver(Rx)under the cost constraint of Degrees-of-Freedom(DoF),while with IS,more transmit power will be consumed in the direct and repeated application of IS to each interference.To remedy these deficiencies,Interference Alignment Steering(IAS)is proposed by incorporating IA and IS and exploiting their advantages in IM.With IAS,the interfering Transmitter(Tx)first aligns one interference incurred by the transmission of one data stream to a one-dimensional subspace orthogonal to the desired transmission at the interfered Rx,and then the remaining interferences are treated as a whole and steered to the same subspace as the aligned interference.Moreover,two improved versions of IAS,i.e.,IAS with Full Adjustment at the Interfering Tx(IAS-FAIT)and Interference Steering and Alignment(ISA),are presented.The former considers the influence of IA on the interfering user-pair's performance.The orthogonality between the desired signals at the interfered Rx can be maintained by adjusting the spatial characteristics of all interferences and the aligned interference components,thus ensuring the Spectral Efficiency(SE)of the interfering communication pairs.Under ISA,the power cost for IS at the interfered Tx is minimized,hence improving SE performance of the interfered communication-pairs.Since the proposed methods are realized at the interfering and interfered Txs cooperatively,the expenses of IM are shared by both communication-pairs.Our in-depth simulation results show that joint use of IA and IS can effectively manage multiple disturbances from the same source and improve the system's SE.
文摘This paper elaborates on the harmonious wireless network from the perspective of interference management.The coexistence of useful signals and interfering signals is beneficial in throughput terms of the entire wireless network.Useful signals and interfering signals are complementary and are in juxtaposition to each other in the context of a single communication link,and are in symbiosis within the framework of the networks.The philosophy behind this could be described by the Chinese traditional culture symbol of“yin”and“yang”.A wireless network having optimal performance must be a harmonious network where the interfering and useful signals harmoniously coexist in an optimal balance.Interference management plays a critical role in achieving this optimal balance,while sophisticated interference management techniques should be designed to improve the system performance.
基金supported in part by the National Key Research and Development Program of China under Grant No.2021YFB2900200in part by National Natural Science Foundation of China under Grant Nos.61925101 and 62271085in part by Beijing Natural Science Foundation under Grant No.L223007-2.
文摘Integrated sensing and communication(ISAC)technology is a promising candidate for next-generation communication systems.However,severe co-site interference in existing ISAC systems limits the communication and sensing performance,posing significant challenges for ISAC interference management.In this work,we propose a novel interference management scheme based on the normalized least mean square(NLMS)algorithm,which mitigates the impact of co-site interference by reconstructing the interference from the local transmitter and canceling it from the received signal.Simulation results demonstrate that,compared to typical adaptive interference management schemes based on recursive least square(RLS)and stochastic gradient descent(SGD)algorithms,the proposed NLMS algorithm effectively cancels co-site interference and achieves a good balance between computational complexity and convergence performance.
基金supported by National Science and Technology Major Project of China(Project Number:2024ZD1300100)Fundamental Research Funds for the central universities(2024RC02)+1 种基金National Natural Science Foundation of China(62401077,62321001)Beijing Municipal Natural Science Foundation(L232003)。
文摘With the rapid growth of the low-altitude economy,the demand for typical low-altitude ap-plications has accelerated the advancement of inte-grated sensing and communications(ISAC)networks.This paper begins by analyzing representative ap-plication scenarios to clarify the core requirements of the low-altitude economy for modern ISAC net-works.By investigating the distinctive characteris-tics of ISAC networks in low-altitude environments,it presents a comprehensive analysis of key challenges and identifies four major issues:challenges in pre-cise target detection,interference management,in-consistent sensing and communication coverage,and the complexity of air-ground coordination and han-dover.Based on fundamental theories and principles,the paper proposes corresponding solutions,encom-passing advanced technologies for precise target de-tection and recognition,high-reliability networked de-tection,robust interference management,and seamless air-ground collaboration.These solutions aim to es-tablish a solid foundation for the future development of intelligent low-altitude networks and ensure effec-tive support for emerging applications.
基金supported by the National Natural Science Foundation of China(62101415)the Guangdong Basic and Applied Basic Research Foundation(2020A1515110757).
文摘Recently cellular networks have been densely and heterogeneously deployed indoors and outdoors to expand the network capacity,and thus the in-building propagation loss and the transmit power diversity of access points will exacerbate link heterogeneity and result in partial unidirectional strong interference.To make full use of the strong interference feature,we propose the successive interference cancellation and alignment(SICA)scheme in the K-user interference channel with partial unidirectional strong interference.SICA is designed to transmit two kinds of data streams simultaneously,the alignment streams and superposition streams.The alignment streams will follow the interference alignment criterion to maintain the optimal degrees of freedom(DoF)performance;the superposition streams are handled via successive interference cancellation at all the strongly interfered receivers to improve the overall achievable rate.The joint transceiver designs for SICA is modeled as a weighted sum rate(WSR)maximization problem,and then can be alternately solved for a local optimum according to the optimality equivalence between WSR and its corresponding weighted mean square error(WMMSE)problem.Simulation results have confirmed the sum rate improvement and DoF optimality of the proposed SICA scheme.
基金Sponsored by the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT0949)the Fundamental Research Funds for the Central Universities(Grant No.2010JBZ008),the Fundamental Research Funds for the Central Universities(Grant No.KWJB10006536)+1 种基金the Joint Funds of State Key Program of NSFC(Grant No.60830001)the State Key Laboratory of Rail Traffic Control and Safety(Grant No.RCS2008ZZ007)
文摘Inter-cell interference (ICI) mitigation is always a challenge issue in LTE system. In this paper, several common interference parameters are firstly analyzed for both cell edge users and center users, and then a novel fractional frequency reuse (FFR) architecture based on interference avoidance scheme coupled with power control is proposed to solve the problem of interference management in multi-cell LTE environment. The scheme divides the whole sub-carriers into three groups orthogonally. One is allocated to cell edge users, while another two are assigned to cell center users with different transmitter power. Then a parameter named interference avoidance factor (IAF) is defined to avoid ICI and adjust the number of allocated sub-carriers to match the number of users. The parameter also takes weight factor and fairness factor into consideration. The simulation results show the proposed scheme can improve the performance of cell edge users obviously.
基金supported by National Natural Science Foundation of China (No. 62201593, 62471480, and 62171466)。
文摘In this paper, we investigate a cooperation mechanism for satellite-terrestrial integrated networks. The terrestrial relays act as the supplement of traditional small cells and cooperatively provide seamless coverage for users in the densely populated areas.To deal with the dynamic satellite backhaul links and backhaul capacity caused by the satellite mobility, severe co-channel interference in both satellite backhaul links and user links introduced by spectrum sharing,and the difference demands of users as well as heterogeneous characteristics of terrestrial backhaul and satellite backhaul, we propose a joint user association and satellite selection scheme to maximize the total sum rate. The optimization problem is formulated via jointly considering the influence of dynamic backhaul links, individual requirements and targeted interference management strategies, which is decomposed into two subproblems: user association and satellite selection. The user association is formulated as a nonconvex optimization problem, and solved through a low-complexity heuristic scheme to find the most suitable access point serving each user. Then, the satellite selection is resolved based on the cooperation among terrestrial relays to maximize the total backhaul capacity with the minimum date rate constraints. Finally,simulation results show the effectiveness of the proposed scheme in terms of total sum rate and power efficiency of TRs' backhaul.
文摘Vehicular Ad Hoc Networks (VANETs) play a pivotal role in advancing Intelligent Transportation Systems (ITS), facilitating real-time communication among vehicles and infrastructure. However, VANETs face challenges arising from high mobility, dynamic topologies, and significant interference levels. This study proposes a novel cross-layer framework incorporating channel prediction and adaptive resource management to address these challenges. By leveraging a Software-Defined Radio (SDR) platform, the framework is evaluated under diverse mobility and interference conditions. Key contributions include an analysis of multi-code and multi-modulation schemes, identification of critical trade-offs in receiver diversity, and the introduction of mechanisms to optimize Quality of Service (QoS). Simulation results demonstrate significant improvements in throughput, packet delivery ratio, and network resilience, highlighting the framework’s potential for real-world applications such as autonomous vehicles and smart city communication networks. The study concludes with actionable recommendations for future research, emphasizing scalability, real-time adaptation, and hardware implementation to further enhance VANET performance.
基金supported in part by the National Natural Science Foundation of China under Grant 61871433,61828103in part by the Research Platform of South China Normal University and Foshan。
文摘Heterogeneous small cell network is one of the most effective solutions to overcome spectrum scarcity for the next generation of mobile networks.Dual connectivity(DC)can improve the throughput for each individual user by allowing concurrent access to two heterogeneous radio networks.In this paper,we propose a joint user association and fair scheduling algorithm(JUAFS)to deal with the resource allocation and load balancing issues for DC heterogeneous small cell networks.Considering different coverage sizes,numbers of users,and quality of experience characteristics of heterogeneous cells,we present a proportional fair scheduling for user association among cells and utilize interference graph to minimize the transmission conflict probability.Simulation results show the performance improvement of the proposed algorithm in spectrum efficiency and fairness comparing to the existing schemes.
基金supported in part by the United States National Science Foundation under Grants CCSS-2245607 and CCSS-2245608the Wireless Engineering Research and Education Center and RFID Lab at Auburn University.
文摘Adaptive power control is a critical challenge in dense radio frequency identification(RFID)environments,where uncontrolled power levels can lead to excessive interference,energy inefficiency,and reduced system performance.This paper presents a robust and scalable adaptive power control framework that dynamically adjusts transmit power levels to optimize energy efficiency,minimize interference,and enhance system throughput.The proposed framework leverages an optimization-driven approach based on real-time environmental feedback,ensuring compliance with regulatory constraints while maintaining optimal performance.A multi-objective optimization strategy is employed to balance several key metrics,including throughput,energy consumption,and fairness,with a Pareto front analysis demonstrating superior trade-offs compared to fixed power strategies.The effectiveness of the proposed approach is validated through extensive simulations and real-world experiments using universal software radio peripheral(USRP)devices in dense RFID deployments.The results show that our framework achieves a 34%reduction in cumulative interference,a 15%improvement in energy efficiency,and a 20%increase in throughput compared to baseline fixed power methods.Furthermore,it converges rapidly,even in dynamic and high-density networks.These improvements make it highly scalable and adaptable to varying reader densities,ensuring reliable performance in large-scale RFID applications such as supply chain management and industrial automation.
基金supported by the National Natural Science Foundation of China (61001116,61027003)the National Science and Technology Special Project (2009ZX03003-011)the International Scientific and Technological Cooperation Program (2010DFA11060,S2010GR0902)
文摘With rapid development of femtocell, dense deployment of femtocells in buildings will become an important study scenario. In this scenario, there exists severe inter-femtocell interference in the same building, which is revealed by our simulations in the 3-dimention （3D） scenario. If this type of interference is not well controlled, services to indoor users are bound to be deteriorated, especially for the femtocell edge users. Motivated by this problem, femto users＇ received interference model is constructed based on the scenario of 3D femtocell deployment. Then, a graph theory based in-building inter-femtocell coordination scheme is proposed, which includes three phases： establishment of femtocell interference graph, femtocell clustering and frequency resources allocation based on the proposed cluster influence circle. Finally, the simulation results confirm that the proposed scheme improves the femtocell average throughput by 22.4% and 26.2% in comparison with frequency universal reuse scheme and channel demodulation reliability of cell edge femto users. frequency hopping scheme respectively, and ensures the
基金This work was supported by the Industrial Internet Research Institute(Jinan)of Beijing University of Posts and Telecommunications under Grant 201915001
文摘Atmospheric ducting has a significant impact on electromagnetic wave propagation.Radio signals that are trapped and guided by the atmospheric duct can travel a much longer distance over the horizon with lower attenuation since the signal power does not spread isotropically through the atmosphere.Atmospheric ducting brings both challenges and opportunities to wireless communications.On one hand,the signals propagating in the atmospheric duct may interfere with a receiver far away as remote co-channel interference.On the other hand,a point-to-point link can be established directly through the atmospheric duct to enable beyond line-of-sight communications.In this article,the formation of the atmospheric duct and its effects on radio wave propagation are first overviewed.Then solutions and standardization activities in the 3rd Generation Partnership Project(3GPP)to mitigate atmospheric duct induced remote interference are presented.Finally,the applications and design challenges of atmospheric duct enabled beyond line-of-sight communications are reviewed and future research directions are suggested.
