Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discon...Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discontinuous transmission (DTX)at user equipment (UE) is adopted to reduce the interferencecorrelation across different time slots. By utilizingstochastic geometry, we analytically derive themean local delay and energy efficiency (EE) of an uplinkHetNet with UE random DTX scheme under theDUDA mode. These expressions are further approximatedas closed forms under reasonable assumptions.Our results reveal that under the DUDA mode, there isan optimal EE with respect to mute probability underthe finite local delay constraint. In addition, with thesame finite mean local delay as under the coupled uplinkand downlink access (CUDA) mode, the HetNetsunder the DUDA mode can achieve a higher EE witha lower mute probability.展开更多
A new enhanced inter-cell interference coordination （elCIC） is adopted for managing almost blank sub-frame （ABS）,which jointly exploits the time, frequency and power dimensions to improve the resource utilization....A new enhanced inter-cell interference coordination （elCIC） is adopted for managing almost blank sub-frame （ABS）,which jointly exploits the time, frequency and power dimensions to improve the resource utilization. In particular, a non-uniform two tier heterogeneous network （ HetNet） is considered, where the pico cells are located close to the macro cell and the number of users in each pico cell is different. To alleviate the interference caused by the co-channeldeployment,the macro cells employ low power ABS （LP- ABS）, and the resource blocks （RBs） are divided into twoparts during an ABS. One is exclusively reserved for macro cell users ad the other is reserved for pico cell users. Themacro cells are allowed to use different percentages of RBs and different powers for their own transmission during the LP- ABS. The user association,resource allocation,ABS proportion,the frequency band partition parameter and the transmission power of macro cells are considered, aiming at maximizing the proportional fairness utility of the system. An iterative algorithm is also proposed and simulation results demonstrate that the proposed algorithm can improve both the system throughput and user fairness compared with the existing schemes.展开更多
Heterogeneous networks （HetNets） composed of overlapped cells with different sizes are expected to improve the transmission performance of data service significantly. User equipments （UEs） in the overlapped area o...Heterogeneous networks （HetNets） composed of overlapped cells with different sizes are expected to improve the transmission performance of data service significantly. User equipments （UEs） in the overlapped area of multiple cells might be able to access various base stations （BSs） of the cells, resulting in various transmission performances due to cell heterogeneity. Hence, designing optimal cell selection scheme is of particular importance for it may affect user quality of service （QoS） and network performance significantly. In this paper, we jointly consider cell selection and transmit power allocation problem in a HetNet consisting of multiple cells. For a single UE case, we formulate the energy efficiency of the UE, and propose an energy efficient optimization scheme which selects the optimal cell corresponding to the maximum energy efficiency of the UE. The problem is then extended to multiple UEs case. To achieve joint performance optimization of all the UEs, we formulate an optimization problem with the objective of maximizing the sum energy efficiency of UEs subject to QoS and power constraints. The formulated nonlinear fractional optimization problem is equivalently transformed into two subproblems, i.e., power allocation subproblem of each UE-eell pair, and cell selection subproblem of UEs. The two subproblems are solved respectively through applying Lagrange dual method and Kuhn-Munkres （K- M） algorithm. Numerical results demonstrate the efficiency of the proposed algorithm.展开更多
A Large-Scale Heterogeneous Network(LS-HetNet)integrates different networks into one uniform network system to provide seamless one-world network coverage.In LS-HetNet,various devices use different technologies to acc...A Large-Scale Heterogeneous Network(LS-HetNet)integrates different networks into one uniform network system to provide seamless one-world network coverage.In LS-HetNet,various devices use different technologies to access heterogeneous networks and generate a large amount of data.For dealing with a large number of access requirements,these data are usually stored in the HetNet Domain Management Server(HDMS)of the current domain,and HDMS uses a centralized Authentication/Authorization/Auditing(AAA)scheme to protect the data.However,this centralized method easily causes the data to be modified or disclosed.To address this issue,we propose a blockchain-empowered AAA scheme for accessing data of LS-HetNet.Firstly,the account address of the blockchain is used as the identity authentication,and the access control permission of data is redesigned and stored on the blockchain,then processes of AAA are redefined.Finally,the experimental model on Ethereum private chain is built,and the results show that the scheme is not only secure but also decentral,without tampering and trustworthiness.展开更多
异构网(HetNet)是增强小区覆盖、提高小区吞吐量的有效途径。通用移动通信系统(Universal Mobile Telecommunications System,UMTS)引入多流多载波技术作为HetNet增强方案,可以进一步提高系统吞吐量。针对多流多载波HetNet场景下各类型...异构网(HetNet)是增强小区覆盖、提高小区吞吐量的有效途径。通用移动通信系统(Universal Mobile Telecommunications System,UMTS)引入多流多载波技术作为HetNet增强方案,可以进一步提高系统吞吐量。针对多流多载波HetNet场景下各类型小区负载不均衡的问题,建立了一个多流多载波HetNet用户归属联合优化模型,并通过求解该模型给出了具体的算法流程。仿真结果表明,相对于已有的Bias方案和软复用方案,所提算法能够在提升用户平均吞吐量的同时,显著提高小区边缘用户吞吐量和用户速率公平性。展开更多
LTE heterogeneous networks (HetNets) is becoming a popular topic since it was first developed in 3GPP Release 10. HetNets has the advantage to assemble various cell networks and enhance users’ Quality of Service (QoS...LTE heterogeneous networks (HetNets) is becoming a popular topic since it was first developed in 3GPP Release 10. HetNets has the advantage to assemble various cell networks and enhance users’ Quality of Service (QoS) within the system. However, its development is still constrained by two main issues: 1) Load imbalance caused by different transmission powers for various tiers, and 2) The unbalanced transmission power may also increase unnecessary handover rate. In order to solve the first issue, Cell range expansion (CRE) can be applied in the system, which will benefit lower-tier cell during user association phase;CRE, Hysteresis Margin (HM) and Time-to-Trigger (TTT) will be utilized to bound UE within lower tier network of HetNets and therefore solve the second issue. On the other hand, the relationship of these parameters may be complicated and even reduce QoS if they are chosen incorrectly. This paper will evaluate the advantage and disadvantage of all three parameters and propose a Markov Chain Process (MCP) based method to find optimal HM, CRE and TTT values. And then, the simulation is taken and the optimal combination for our scenario is obtained to be 1 dB, 6 dB and 60 ms respectively. First contribution of this paper is to map the HetNets handover process into MCP and all the phases of handover can be calculated and analysed in probability way, so that further prediction and simulation can be realised. Second contribution is to establish a mathematical method to model the relationship of HM, CRE and TTT in HetNets, therefore the coordination of these three important parameters is achieved to obtain system optimization.展开更多
Dual connectivity(DC)is regarded as a promising technology to increase users’throughput,provide radio link robustness,and improve load-balancing among base stations(BSs).However,since the introduction of DC makes the...Dual connectivity(DC)is regarded as a promising technology to increase users’throughput,provide radio link robustness,and improve load-balancing among base stations(BSs).However,since the introduction of DC makes the mobility of network more complex and diversified,especially the mobility management of heterogeneous networks(HetNets)based on DC faces great challenges.Taking event-A3-based measurement report as the trigger condition for handover(HO),this paper compares and evaluates the influences of HO of master nodes(MNs)and secondary nodes(SNs)on link reliability in different bearing modes.Particularly,hybrid automatic repeat request(HARQ),throughput,channel quality indicators(CQIs),and data packets queuing time are taken as link reliability analysis indicators.Besides,we study how DC utilizes the traffic split ratio between MNs and SNs to maximize the superiority of throughput.Simulation results show that DC can effectively reduce the impact of HO on the number of HARQ and increase the throughput of users.When the data traffic is tilted to the secondary nodes,the superiority of throughput is more obvious.展开更多
Due to the unprecedented rate of transformation in thefield of wireless communication industry,there is a need to prioritise the coverage,network power and throughput as preconditions.In Heterogeneous Networks(HetNets...Due to the unprecedented rate of transformation in thefield of wireless communication industry,there is a need to prioritise the coverage,network power and throughput as preconditions.In Heterogeneous Networks(HetNets)the low power node inclusion like Femto and Pico cells creates a network of Multi-Tier(M-Tier)which is regarded as the most significant strategy for enhancing the coverage,throughput,4G Long Term Evolution(LTE)ability.This work mainly focuses on M-Tier 3D Heterogeneous Networks Energy Efficiency(EE)based Carrier Aggregation(CA)scheme for streaming real-time huge data like images.Atfirst,M-Tier 3D HetNets scheme was made for investigating Signal to Noise Interference Ratio(SNIR)on assessing the collective Pico-tier and Femto-tier interference.Next,the scheme of channel allocation is scrutinised so as to esti-mate throughput from the multiple tiers.Additionally,with the use of CA technique,the problem of energy efficiency for M-Tier 3D Heterogeneous Network(HetNet)in relation to energy metrics and throughput was evaluated with the use of LTE and Wireless Fidelity(Wi-Fi)coexistence.The simulation is carried out in a MATLAB setting,and the outcomes reveal a huge impact on EE.The simulation is carried in terms of EE,transmission time,throughput,packet success rate,convergence probability,and coverage region.The analysis from simu-lation shows that on improving the output of the device,interference among small cell base stations is reduced on increasing EE.The outcomes attained aid in the effective creation of M-Tier 3D HetNets for enhancing EE by employing Multi-Stream Carrier Aggregation(MSCA)in HetNets.展开更多
Most existing handover decision system （HDS） designs are monolithic, resulting in high computational cost and unbalance of overall network. A novel modular handover algorithm with a comprehensive load index for the ...Most existing handover decision system （HDS） designs are monolithic, resulting in high computational cost and unbalance of overall network. A novel modular handover algorithm with a comprehensive load index for the 5th generation （5G） heterogeneous networks （HetNets） is proposed. In this paper, the handover parameters, serving as the basis for handover, are classified into network＇s quality of service （QoS） module, user preference （UP） module and degree of satisfaction （DS） module according to the new modular HDS design. To optimize switching process, the comprehensive network load index is deduced by using triangle module fusion operator. With respect to the existing handover algorithm, the simulation results indicate that the proposed algorithm can reduce the handover frequency and maintain user satisfaction at a higher level. Meanwhile, due to its block calculation, it can bring about 1.4 s execution time improvement.展开更多
This paper investigates the power allocation issues for joint transmission in heterogeneous network （HetNet）, which is characterized by severe cross-tier interference. The optimization problem of maximizing the HetN...This paper investigates the power allocation issues for joint transmission in heterogeneous network （HetNet）, which is characterized by severe cross-tier interference. The optimization problem of maximizing the HetNet throughput is formulated. The original problem turns out to be a non-convex problem, the global optima of which cannot be obtained by conventional optimization methods. This paper develops a novel method to achieve the global optima by tuming the original problem into quasi-convex problem. In addition, this paper considers a constant power allocation scheme, as a tradeoff between the system throughput and computational complexity. Based on duality gap theory, the bound of constant power allocation scheme is mathematically derived. Numerical results under different system parameters indicate that both the proposed schemes outperform conventional interference coordination schemes.展开更多
基金supported in part by the National Key R&D Program of China under Grant 2021YFB 2900304the Shenzhen Science and Technology Program under Grants KQTD20190929172545139 and ZDSYS20210623091808025.
文摘Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discontinuous transmission (DTX)at user equipment (UE) is adopted to reduce the interferencecorrelation across different time slots. By utilizingstochastic geometry, we analytically derive themean local delay and energy efficiency (EE) of an uplinkHetNet with UE random DTX scheme under theDUDA mode. These expressions are further approximatedas closed forms under reasonable assumptions.Our results reveal that under the DUDA mode, there isan optimal EE with respect to mute probability underthe finite local delay constraint. In addition, with thesame finite mean local delay as under the coupled uplinkand downlink access (CUDA) mode, the HetNetsunder the DUDA mode can achieve a higher EE witha lower mute probability.
基金The National Science and Technology Major Project(2016ZX03001011-005)the National Natural Science Foundation of China(No.61571123,61521061)+1 种基金the Research Fund of National Mobile Communications Research Laboratory of Southeast University(No.2017A03)Qing Lan Project
文摘A new enhanced inter-cell interference coordination （elCIC） is adopted for managing almost blank sub-frame （ABS）,which jointly exploits the time, frequency and power dimensions to improve the resource utilization. In particular, a non-uniform two tier heterogeneous network （ HetNet） is considered, where the pico cells are located close to the macro cell and the number of users in each pico cell is different. To alleviate the interference caused by the co-channeldeployment,the macro cells employ low power ABS （LP- ABS）, and the resource blocks （RBs） are divided into twoparts during an ABS. One is exclusively reserved for macro cell users ad the other is reserved for pico cell users. Themacro cells are allowed to use different percentages of RBs and different powers for their own transmission during the LP- ABS. The user association,resource allocation,ABS proportion,the frequency band partition parameter and the transmission power of macro cells are considered, aiming at maximizing the proportional fairness utility of the system. An iterative algorithm is also proposed and simulation results demonstrate that the proposed algorithm can improve both the system throughput and user fairness compared with the existing schemes.
文摘Heterogeneous networks （HetNets） composed of overlapped cells with different sizes are expected to improve the transmission performance of data service significantly. User equipments （UEs） in the overlapped area of multiple cells might be able to access various base stations （BSs） of the cells, resulting in various transmission performances due to cell heterogeneity. Hence, designing optimal cell selection scheme is of particular importance for it may affect user quality of service （QoS） and network performance significantly. In this paper, we jointly consider cell selection and transmit power allocation problem in a HetNet consisting of multiple cells. For a single UE case, we formulate the energy efficiency of the UE, and propose an energy efficient optimization scheme which selects the optimal cell corresponding to the maximum energy efficiency of the UE. The problem is then extended to multiple UEs case. To achieve joint performance optimization of all the UEs, we formulate an optimization problem with the objective of maximizing the sum energy efficiency of UEs subject to QoS and power constraints. The formulated nonlinear fractional optimization problem is equivalently transformed into two subproblems, i.e., power allocation subproblem of each UE-eell pair, and cell selection subproblem of UEs. The two subproblems are solved respectively through applying Lagrange dual method and Kuhn-Munkres （K- M） algorithm. Numerical results demonstrate the efficiency of the proposed algorithm.
基金This work was supported by National Natural Science Foundation of China(China)under grants 61373162Sichuan Science and Technology Support Project(China)under grants 2019YFG0183+1 种基金Visual Computing and Virtual Reality Sichuan Provincial Key Laboratory Project(China)under grants KJ201402was supported in part by the Japan Society for the Promotion of Science(JSPS)Grants-in-Aid for Scientific Research(KAKENHI)(Japan)under Grant JP18K18044.
文摘A Large-Scale Heterogeneous Network(LS-HetNet)integrates different networks into one uniform network system to provide seamless one-world network coverage.In LS-HetNet,various devices use different technologies to access heterogeneous networks and generate a large amount of data.For dealing with a large number of access requirements,these data are usually stored in the HetNet Domain Management Server(HDMS)of the current domain,and HDMS uses a centralized Authentication/Authorization/Auditing(AAA)scheme to protect the data.However,this centralized method easily causes the data to be modified or disclosed.To address this issue,we propose a blockchain-empowered AAA scheme for accessing data of LS-HetNet.Firstly,the account address of the blockchain is used as the identity authentication,and the access control permission of data is redesigned and stored on the blockchain,then processes of AAA are redefined.Finally,the experimental model on Ethereum private chain is built,and the results show that the scheme is not only secure but also decentral,without tampering and trustworthiness.
文摘异构网(HetNet)是增强小区覆盖、提高小区吞吐量的有效途径。通用移动通信系统(Universal Mobile Telecommunications System,UMTS)引入多流多载波技术作为HetNet增强方案,可以进一步提高系统吞吐量。针对多流多载波HetNet场景下各类型小区负载不均衡的问题,建立了一个多流多载波HetNet用户归属联合优化模型,并通过求解该模型给出了具体的算法流程。仿真结果表明,相对于已有的Bias方案和软复用方案,所提算法能够在提升用户平均吞吐量的同时,显著提高小区边缘用户吞吐量和用户速率公平性。
文摘LTE heterogeneous networks (HetNets) is becoming a popular topic since it was first developed in 3GPP Release 10. HetNets has the advantage to assemble various cell networks and enhance users’ Quality of Service (QoS) within the system. However, its development is still constrained by two main issues: 1) Load imbalance caused by different transmission powers for various tiers, and 2) The unbalanced transmission power may also increase unnecessary handover rate. In order to solve the first issue, Cell range expansion (CRE) can be applied in the system, which will benefit lower-tier cell during user association phase;CRE, Hysteresis Margin (HM) and Time-to-Trigger (TTT) will be utilized to bound UE within lower tier network of HetNets and therefore solve the second issue. On the other hand, the relationship of these parameters may be complicated and even reduce QoS if they are chosen incorrectly. This paper will evaluate the advantage and disadvantage of all three parameters and propose a Markov Chain Process (MCP) based method to find optimal HM, CRE and TTT values. And then, the simulation is taken and the optimal combination for our scenario is obtained to be 1 dB, 6 dB and 60 ms respectively. First contribution of this paper is to map the HetNets handover process into MCP and all the phases of handover can be calculated and analysed in probability way, so that further prediction and simulation can be realised. Second contribution is to establish a mathematical method to model the relationship of HM, CRE and TTT in HetNets, therefore the coordination of these three important parameters is achieved to obtain system optimization.
基金supported by the National Natural Science Foundation of China(Nos.62161035 and 61861034)Inner Mongolia Natural Science Foundation(No.2022MS06022)。
文摘Dual connectivity(DC)is regarded as a promising technology to increase users’throughput,provide radio link robustness,and improve load-balancing among base stations(BSs).However,since the introduction of DC makes the mobility of network more complex and diversified,especially the mobility management of heterogeneous networks(HetNets)based on DC faces great challenges.Taking event-A3-based measurement report as the trigger condition for handover(HO),this paper compares and evaluates the influences of HO of master nodes(MNs)and secondary nodes(SNs)on link reliability in different bearing modes.Particularly,hybrid automatic repeat request(HARQ),throughput,channel quality indicators(CQIs),and data packets queuing time are taken as link reliability analysis indicators.Besides,we study how DC utilizes the traffic split ratio between MNs and SNs to maximize the superiority of throughput.Simulation results show that DC can effectively reduce the impact of HO on the number of HARQ and increase the throughput of users.When the data traffic is tilted to the secondary nodes,the superiority of throughput is more obvious.
文摘Due to the unprecedented rate of transformation in thefield of wireless communication industry,there is a need to prioritise the coverage,network power and throughput as preconditions.In Heterogeneous Networks(HetNets)the low power node inclusion like Femto and Pico cells creates a network of Multi-Tier(M-Tier)which is regarded as the most significant strategy for enhancing the coverage,throughput,4G Long Term Evolution(LTE)ability.This work mainly focuses on M-Tier 3D Heterogeneous Networks Energy Efficiency(EE)based Carrier Aggregation(CA)scheme for streaming real-time huge data like images.Atfirst,M-Tier 3D HetNets scheme was made for investigating Signal to Noise Interference Ratio(SNIR)on assessing the collective Pico-tier and Femto-tier interference.Next,the scheme of channel allocation is scrutinised so as to esti-mate throughput from the multiple tiers.Additionally,with the use of CA technique,the problem of energy efficiency for M-Tier 3D Heterogeneous Network(HetNet)in relation to energy metrics and throughput was evaluated with the use of LTE and Wireless Fidelity(Wi-Fi)coexistence.The simulation is carried out in a MATLAB setting,and the outcomes reveal a huge impact on EE.The simulation is carried in terms of EE,transmission time,throughput,packet success rate,convergence probability,and coverage region.The analysis from simu-lation shows that on improving the output of the device,interference among small cell base stations is reduced on increasing EE.The outcomes attained aid in the effective creation of M-Tier 3D HetNets for enhancing EE by employing Multi-Stream Carrier Aggregation(MSCA)in HetNets.
基金supported by the Program for Innovation Team Building at Institutions of High Education in Chongqing (KJTD201312)the Hi-Tech Research and Development Program of China (2015AA01A705,2014AA01A706)
文摘Most existing handover decision system （HDS） designs are monolithic, resulting in high computational cost and unbalance of overall network. A novel modular handover algorithm with a comprehensive load index for the 5th generation （5G） heterogeneous networks （HetNets） is proposed. In this paper, the handover parameters, serving as the basis for handover, are classified into network＇s quality of service （QoS） module, user preference （UP） module and degree of satisfaction （DS） module according to the new modular HDS design. To optimize switching process, the comprehensive network load index is deduced by using triangle module fusion operator. With respect to the existing handover algorithm, the simulation results indicate that the proposed algorithm can reduce the handover frequency and maintain user satisfaction at a higher level. Meanwhile, due to its block calculation, it can bring about 1.4 s execution time improvement.
基金supported by the HuaWei Innovation Research Project (YJCB2011060WL)
文摘This paper investigates the power allocation issues for joint transmission in heterogeneous network （HetNet）, which is characterized by severe cross-tier interference. The optimization problem of maximizing the HetNet throughput is formulated. The original problem turns out to be a non-convex problem, the global optima of which cannot be obtained by conventional optimization methods. This paper develops a novel method to achieve the global optima by tuming the original problem into quasi-convex problem. In addition, this paper considers a constant power allocation scheme, as a tradeoff between the system throughput and computational complexity. Based on duality gap theory, the bound of constant power allocation scheme is mathematically derived. Numerical results under different system parameters indicate that both the proposed schemes outperform conventional interference coordination schemes.
