The exponentially increasing number of heterogeneous Internet of Things(Io T)devices(e.g.,Wi Fi and Zig Bee)crowed in the same ISM band(2.4 G)and recent advances in CrossTechnology Communications(CTC)motivate us to ex...The exponentially increasing number of heterogeneous Internet of Things(Io T)devices(e.g.,Wi Fi and Zig Bee)crowed in the same ISM band(2.4 G)and recent advances in CrossTechnology Communications(CTC)motivate us to explore more efficient data collection and maximize network throughput.CTC enables Wi Fi and Zig Bee devices to communicate directly without any hardware changes or gateway equipment,which sheds light on a more efficient data collection design.In this work,we propose a distributed algorithm,named Max Bee,to compute the maximum network throughput,which is formulated as a linear programming problem.Considering that the problem turns out to be non-convex and hard to solve exactly,we propose a distributed algorithm to solve nonlinear programming by using the dual decomposition method and gradient/subgradient algorithms.Through extensive simulations on different sets of deployed Zig Bee and Wi Fi devices,we observe that the proposed algorithm significantly increases the network throughput based on CTC for Sensor Networks.展开更多
This paper investigates the uplink throughput of Cognitive Radio Cellular Networks(CRCNs).As oppose to traditional performance evaluation schemes which mainly adopt complex system level simulations,we use the theoreti...This paper investigates the uplink throughput of Cognitive Radio Cellular Networks(CRCNs).As oppose to traditional performance evaluation schemes which mainly adopt complex system level simulations,we use the theoretical framework of stochastic geometry to provide a tractable and accurate analysis of the uplink throughput in the CRCN.By modelling the positions of User Equipments(UEs)and Base Stations(BSs)as Poisson Point Processes(PPPs),we analyse and derive expressions for the link rate and the cell throughput in the Primary(PR)and Secondary(SR)networks.The expressions show that the throughput of the CRCN is mainly affected by the density ratios between the UEs and the BSs in both the PR and SR networks.Besides,a comparative analysis of the link rate between random and regular BS deployments is concluded,and the results confirm the accuracy of our analysis.Furthermore,we define the cognitive throughput gain and derive an expression which is dominated by the traffic load in the PR network.展开更多
To reduce the interference among small cells of Ultra-Dense Networks(UDN),an improved Clustering-Assisted Resource Allocation(CARA)scheme is proposed in this paper.The proposed scheme is divided into three steps.First...To reduce the interference among small cells of Ultra-Dense Networks(UDN),an improved Clustering-Assisted Resource Allocation(CARA)scheme is proposed in this paper.The proposed scheme is divided into three steps.First,an Interference-Limited Clustering Algorithm(ILCA)based on interference graph corresponding to the interference relationship between Femtocell Base Stations(FBSs),is proposed to group FBSs into disjoint clusters,in which a pre-threshold is set to constrain the sum of interference in each cluster,and a Cluster Head(CH)is selected for each cluster.Then,CH performs a twostage sub-channel allocation within its associated cluster,where the first stage assigns one sub-channel to each user of the cluster and the second stage assigns a second sub-channel to some users.Finally,a power allocation method is designed to maximize throughput for a given clustering and sub-channel configuration.Simulation results indicate that the proposed scheme distributes FBSs into each cluster more evenly,and significantly improves the system throughput compared with the existing schemes in the same scenario.展开更多
This study investigates physical layer security in downlink multipleinput multiple-output(MIMO) multi-hop heterogeneous cellular networks(MHCNs),in which communication between mobile users and base stations(BSs) is es...This study investigates physical layer security in downlink multipleinput multiple-output(MIMO) multi-hop heterogeneous cellular networks(MHCNs),in which communication between mobile users and base stations(BSs) is established by a single or multiple hops,to address the problem of insufficient security performance of MIMO heterogeneous cellular networks.First,two-dimensional homogeneous Poisson point processes(HPPPs) are utilized to model the locations of K-tier BSs in MIMO MHCNs and receivers,including those of legitimate users and eavesdroppers.Second,based on the channel gain distribution and the statistics property of HPPP,the achievable ergodic rates of the main and eavesdropper channels in direct and ad hoc links are derived,respectively.Third,the secrecy coverage probability and the achievable ergodic secrecy throughput of downlink MIMO MHCNs are explored,and their expressions are derived.Lastly,the correctness of the theoretical derivation is verified through Monte Carlo simulations.展开更多
A dynamic network Qo S control mechanism was proposed based on traffic prediction. It first predicts network traffic flow and then dynamically distributes network resources, which makes full use of network flow self-s...A dynamic network Qo S control mechanism was proposed based on traffic prediction. It first predicts network traffic flow and then dynamically distributes network resources, which makes full use of network flow self-similarity and chaos. So it can meet changing network needs very well. The simulation results show that the dynamic Qo S control mechanism based on prediction has better network performance than that based on measurement.展开更多
By the flexible redefinition of frequency-occupation and frequency-collision event, the frequency-(collision) probability of hybrid(DS/FH) spread spectrum network is analyzed. This probability is based on the simultan...By the flexible redefinition of frequency-occupation and frequency-collision event, the frequency-(collision) probability of hybrid(DS/FH) spread spectrum network is analyzed. This probability is based on the simultaneous transmission number threshold and is discussed in synchronous and asynchronous circumstances respectively. And then, the network throughput based on the packet correct reception probability is analyzed. Two models which have finite and infinite population respectively is discussed. At last, the numerical results are given.展开更多
Fog radio access network(F-RAN) is one of the key technology that brings cloud computing benefit to the future of wireless communications for handling massive access and high volume of data traffic. The high fronthaul...Fog radio access network(F-RAN) is one of the key technology that brings cloud computing benefit to the future of wireless communications for handling massive access and high volume of data traffic. The high fronthaul burden of a typical cellular system can be partially diminished by utilizing the storage and signal processing capabilities of the F-RANs, which is still not desirable as user throughput requirement is in the increasing trend with the increment of the internet of things(IoT) devices. This paper proposes an efficient scheduling scheme that minimizes the fronthaul load of F-RAN system optimally to improve user experience, and minimize latency. The scheduling scheme is modeled in a way that the scheduler which provides the lower fronthaul load while fulfilling the minimum user throughput requirement is selected for the data transmission process. Simulation results in terms of user selection fairness, outage probability, and fronthaul load for a different portion of user equipments(UEs) contents in fog access point(F-AP) are shown and compared with the most common scheduling scheme such as round robin(RR) scheme to validate the proposed method.展开更多
Although small cell offloading technology can alleviate the congestion in macrocell, aggressively offloading data traffic from macrocell to small cell can also degrade the performance of small cell due to the heavy lo...Although small cell offloading technology can alleviate the congestion in macrocell, aggressively offloading data traffic from macrocell to small cell can also degrade the performance of small cell due to the heavy load. Because of collision and backoff, the degradation is significant especially in network with contention-based channel access, and finally decreases throughput of the whole network. To find an optimal fraction of traffic to be offloaded in heterogeneous network, we combine Markov chain with the Poisson point process model to analyze contention-based throughput in irregularly deployment networks. Then we derive the close-form solution of the throughput and find that it is a function of the transmit power and density of base stations.Based on this, we propose the load-aware offloading strategies via power control and base station density adjustment. The numerical results verify our analysis and show a great performance gain compared with non-load-aware offloading.展开更多
针对能量收集无线传感器网络(wireless sensor network,WSN)中的两跳多中继传输问题,构建无线射频能量站(power beacon,PB)辅助的能量收集无线携能通信(simultaneous wireless information and power transfer,SWIPT)中继模型.在中继节...针对能量收集无线传感器网络(wireless sensor network,WSN)中的两跳多中继传输问题,构建无线射频能量站(power beacon,PB)辅助的能量收集无线携能通信(simultaneous wireless information and power transfer,SWIPT)中继模型.在中继节点具有捕获源节点、环路自干扰和PB信号能量的特性下,推导目的节点采用选择式合并(selection combining,SC)、最大比合并(maximal ratio combining,MRC) 2种不同接收策略下的中断概率和吞吐量,继而在保障通信服务质量(quality of service,QoS)、PB发射功率、能量转化效率等多约束条件下,提出一种以吞吐量最大化为目标的联合优化时隙切换因子与功率分配因子的中继选择算法.仿真和数值结果显示:PB发射功率、时隙切换因子、天线数目、功率分配因子等参数对系统中断概率和吞吐量性能影响显著;当给定PB发射功率为6 dBW,天线数目为3根时,与随机中继选择算法和最大最小中继选择算法相比,本文算法在SC策略下的系统吞吐量增益分别为0.29、0.15 bit/(s·Hz),MRC策略下的吞吐量增益分别为0.32、0.16 bit/(s·Hz).展开更多
为了提高车联网中高清地图下载业务的吞吐量和降低车队行驶业务的传输时延,提出一种基于进化策略算法和匈牙利算法(Evolutionary Strategy Algorithm and Hungarian Algorithm,ES-HA)的网络切片资源分配策略。构建增强型移动带宽(Enhanc...为了提高车联网中高清地图下载业务的吞吐量和降低车队行驶业务的传输时延,提出一种基于进化策略算法和匈牙利算法(Evolutionary Strategy Algorithm and Hungarian Algorithm,ES-HA)的网络切片资源分配策略。构建增强型移动带宽(Enhanced Mobile Broadband,eMBB)切片和高可靠低时延(Ultra Reliable&Low Latency Communication,uRLLC)切片,根据eMBB用户和uRLLC用户功率之间的函数关系求得最佳功率,采用ES算法获得两种用户的最佳带宽,并使用HA实现最佳信道匹配。仿真结果表明,与基于集群的资源块共享和功率分配(Cluster-based Resource Block Sharing and Power Allocation,CROWN)算法、基于基准算法的资源分配策略在总吞吐量、传输任务时延、链路容量及最小吞吐量方面进行对比,该策略在满足车到基础设施(Vehicle to Infrastructure,V2I)链路用户高容量需求的同时,能够提高下载业务的吞吐量和降低车队行驶业务的传输时延。展开更多
基金supported by The Project funded by China Postdoctoral Science Foundation(Grant No.2018T110505,2017M611828)The Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions。
文摘The exponentially increasing number of heterogeneous Internet of Things(Io T)devices(e.g.,Wi Fi and Zig Bee)crowed in the same ISM band(2.4 G)and recent advances in CrossTechnology Communications(CTC)motivate us to explore more efficient data collection and maximize network throughput.CTC enables Wi Fi and Zig Bee devices to communicate directly without any hardware changes or gateway equipment,which sheds light on a more efficient data collection design.In this work,we propose a distributed algorithm,named Max Bee,to compute the maximum network throughput,which is formulated as a linear programming problem.Considering that the problem turns out to be non-convex and hard to solve exactly,we propose a distributed algorithm to solve nonlinear programming by using the dual decomposition method and gradient/subgradient algorithms.Through extensive simulations on different sets of deployed Zig Bee and Wi Fi devices,we observe that the proposed algorithm significantly increases the network throughput based on CTC for Sensor Networks.
基金supported by the National Key Basic Research Program of China (973 Program)under Grant No. 2009CB320401the National Natural Science Foundation of China under Grants No. 61171099, No. 61101117+1 种基金the National Key Scientific and Technological Project of China under Grants No. 2012ZX03004005-002, No. 2012ZX03003-007the Fundamental Research Funds for the Central Universities under Grant No. BUPT2012RC0112
文摘This paper investigates the uplink throughput of Cognitive Radio Cellular Networks(CRCNs).As oppose to traditional performance evaluation schemes which mainly adopt complex system level simulations,we use the theoretical framework of stochastic geometry to provide a tractable and accurate analysis of the uplink throughput in the CRCN.By modelling the positions of User Equipments(UEs)and Base Stations(BSs)as Poisson Point Processes(PPPs),we analyse and derive expressions for the link rate and the cell throughput in the Primary(PR)and Secondary(SR)networks.The expressions show that the throughput of the CRCN is mainly affected by the density ratios between the UEs and the BSs in both the PR and SR networks.Besides,a comparative analysis of the link rate between random and regular BS deployments is concluded,and the results confirm the accuracy of our analysis.Furthermore,we define the cognitive throughput gain and derive an expression which is dominated by the traffic load in the PR network.
基金performed in the Project “Research on the Hierarchical Interference Elimination Technology for UDN Based on MIMO” supported by the Henan Scientific and Technological Research Project (172102210023)“Research on clustering and frequency band allocation in JT-Co MP supported by Department of Education of Henan Province (19A510013)”
文摘To reduce the interference among small cells of Ultra-Dense Networks(UDN),an improved Clustering-Assisted Resource Allocation(CARA)scheme is proposed in this paper.The proposed scheme is divided into three steps.First,an Interference-Limited Clustering Algorithm(ILCA)based on interference graph corresponding to the interference relationship between Femtocell Base Stations(FBSs),is proposed to group FBSs into disjoint clusters,in which a pre-threshold is set to constrain the sum of interference in each cluster,and a Cluster Head(CH)is selected for each cluster.Then,CH performs a twostage sub-channel allocation within its associated cluster,where the first stage assigns one sub-channel to each user of the cluster and the second stage assigns a second sub-channel to some users.Finally,a power allocation method is designed to maximize throughput for a given clustering and sub-channel configuration.Simulation results indicate that the proposed scheme distributes FBSs into each cluster more evenly,and significantly improves the system throughput compared with the existing schemes in the same scenario.
基金supported in part by National High-tech R&D Program(863 Program) under Grant No.2014AA01A701National Natural Science Foundation of China under Grant No.61379006,61401510,61521003Project funded by China Postdoctoral Science Foundation under Grant No.2016M592990
文摘This study investigates physical layer security in downlink multipleinput multiple-output(MIMO) multi-hop heterogeneous cellular networks(MHCNs),in which communication between mobile users and base stations(BSs) is established by a single or multiple hops,to address the problem of insufficient security performance of MIMO heterogeneous cellular networks.First,two-dimensional homogeneous Poisson point processes(HPPPs) are utilized to model the locations of K-tier BSs in MIMO MHCNs and receivers,including those of legitimate users and eavesdroppers.Second,based on the channel gain distribution and the statistics property of HPPP,the achievable ergodic rates of the main and eavesdropper channels in direct and ad hoc links are derived,respectively.Third,the secrecy coverage probability and the achievable ergodic secrecy throughput of downlink MIMO MHCNs are explored,and their expressions are derived.Lastly,the correctness of the theoretical derivation is verified through Monte Carlo simulations.
基金Funded by the National Natural Science Foundation of China(No.41301084)the Scientific Research Project of Hunan Province Education Department,China(No.13C713)the Natural Science Foundation of Hunan Province,China(No.13JJ6075)
文摘A dynamic network Qo S control mechanism was proposed based on traffic prediction. It first predicts network traffic flow and then dynamically distributes network resources, which makes full use of network flow self-similarity and chaos. So it can meet changing network needs very well. The simulation results show that the dynamic Qo S control mechanism based on prediction has better network performance than that based on measurement.
文摘By the flexible redefinition of frequency-occupation and frequency-collision event, the frequency-(collision) probability of hybrid(DS/FH) spread spectrum network is analyzed. This probability is based on the simultaneous transmission number threshold and is discussed in synchronous and asynchronous circumstances respectively. And then, the network throughput based on the packet correct reception probability is analyzed. Two models which have finite and infinite population respectively is discussed. At last, the numerical results are given.
基金supported by Incheon National University(International Cooperative)Research Grant in 2015
文摘Fog radio access network(F-RAN) is one of the key technology that brings cloud computing benefit to the future of wireless communications for handling massive access and high volume of data traffic. The high fronthaul burden of a typical cellular system can be partially diminished by utilizing the storage and signal processing capabilities of the F-RANs, which is still not desirable as user throughput requirement is in the increasing trend with the increment of the internet of things(IoT) devices. This paper proposes an efficient scheduling scheme that minimizes the fronthaul load of F-RAN system optimally to improve user experience, and minimize latency. The scheduling scheme is modeled in a way that the scheduler which provides the lower fronthaul load while fulfilling the minimum user throughput requirement is selected for the data transmission process. Simulation results in terms of user selection fairness, outage probability, and fronthaul load for a different portion of user equipments(UEs) contents in fog access point(F-AP) are shown and compared with the most common scheduling scheme such as round robin(RR) scheme to validate the proposed method.
基金supported by the National High-Tech R&D Program (863 Program) under grant No. 2015AA01A705Beijing Municipal Science and Technology Commission research fund project under grant No. D151100000115002+1 种基金China Scholarship Council under grant No. 201406470038BUPT youth scientific research innovation program under grant No. 500401238
文摘Although small cell offloading technology can alleviate the congestion in macrocell, aggressively offloading data traffic from macrocell to small cell can also degrade the performance of small cell due to the heavy load. Because of collision and backoff, the degradation is significant especially in network with contention-based channel access, and finally decreases throughput of the whole network. To find an optimal fraction of traffic to be offloaded in heterogeneous network, we combine Markov chain with the Poisson point process model to analyze contention-based throughput in irregularly deployment networks. Then we derive the close-form solution of the throughput and find that it is a function of the transmit power and density of base stations.Based on this, we propose the load-aware offloading strategies via power control and base station density adjustment. The numerical results verify our analysis and show a great performance gain compared with non-load-aware offloading.
文摘针对能量收集无线传感器网络(wireless sensor network,WSN)中的两跳多中继传输问题,构建无线射频能量站(power beacon,PB)辅助的能量收集无线携能通信(simultaneous wireless information and power transfer,SWIPT)中继模型.在中继节点具有捕获源节点、环路自干扰和PB信号能量的特性下,推导目的节点采用选择式合并(selection combining,SC)、最大比合并(maximal ratio combining,MRC) 2种不同接收策略下的中断概率和吞吐量,继而在保障通信服务质量(quality of service,QoS)、PB发射功率、能量转化效率等多约束条件下,提出一种以吞吐量最大化为目标的联合优化时隙切换因子与功率分配因子的中继选择算法.仿真和数值结果显示:PB发射功率、时隙切换因子、天线数目、功率分配因子等参数对系统中断概率和吞吐量性能影响显著;当给定PB发射功率为6 dBW,天线数目为3根时,与随机中继选择算法和最大最小中继选择算法相比,本文算法在SC策略下的系统吞吐量增益分别为0.29、0.15 bit/(s·Hz),MRC策略下的吞吐量增益分别为0.32、0.16 bit/(s·Hz).
文摘为了提高车联网中高清地图下载业务的吞吐量和降低车队行驶业务的传输时延,提出一种基于进化策略算法和匈牙利算法(Evolutionary Strategy Algorithm and Hungarian Algorithm,ES-HA)的网络切片资源分配策略。构建增强型移动带宽(Enhanced Mobile Broadband,eMBB)切片和高可靠低时延(Ultra Reliable&Low Latency Communication,uRLLC)切片,根据eMBB用户和uRLLC用户功率之间的函数关系求得最佳功率,采用ES算法获得两种用户的最佳带宽,并使用HA实现最佳信道匹配。仿真结果表明,与基于集群的资源块共享和功率分配(Cluster-based Resource Block Sharing and Power Allocation,CROWN)算法、基于基准算法的资源分配策略在总吞吐量、传输任务时延、链路容量及最小吞吐量方面进行对比,该策略在满足车到基础设施(Vehicle to Infrastructure,V2I)链路用户高容量需求的同时,能够提高下载业务的吞吐量和降低车队行驶业务的传输时延。
