With abundant wind resources and high pressure imposed on en-vironmental protection, wind power development has a promising future. Butdue to intermittent nature, wind power can bring into full play only if being con-...With abundant wind resources and high pressure imposed on en-vironmental protection, wind power development has a promising future. Butdue to intermittent nature, wind power can bring into full play only if being con-nected into power grid to ensure its supply reliability and continuity, aswell as operational economy. However, technical and market barriers haveprevented wind power from integrating into power grid. To foster wind powerdevelopment, these barriers should be removed by both government incentivepolicies and sophisticated technologies.展开更多
This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in ...This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in WLAN access points by re-designing the Distribution_Service component of the MAC state machine is proposed. A variable named dotl 1 Isolation is defined to determine whether the MAC level communication between wireless stations in the same BSS is permitted or not. Finally, a design solution based on MPC860 hardware and embedded Linux software for PWLAN access point is specified. The simulation results of MAC isolation for PWLAN show that the proposed scheme is feasible and effective.展开更多
The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adapti...The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adaptive backoff contention window and multihop forward chain transmission by invitation (MFCTI) scheme. In the FPF scheme, the contention window was adjusted adaptively according to the traffic priority. Route information and the broadcast characteristic of radio were utilized in MFCTI scheme. The performance of these schemes was studied in multihop environments by simulations. The results showed that the proposed schemes could improve the network throughput, reduce the end-to-end average delay, and mitigate local congestion effectively. Another attractive feature was that the schemes could be implemented with minor modifications to the IEEE 802.11 MAC.展开更多
A resource allocation protocol is presented in an orthogonal frequency division multiple access (OFDMA) cognitive radio (CR) network with a hybrid model which combines overlay and underlay models. Without disrupti...A resource allocation protocol is presented in an orthogonal frequency division multiple access (OFDMA) cognitive radio (CR) network with a hybrid model which combines overlay and underlay models. Without disrupting the primary user (PU) transmissions, the overlay model allows the secondary user (SU) to utilize opportunistically the idle sub-channels; the underlay model allows the SU to occupy the same sub-channels with PU. The proposed protocols are designed for maximizing the quality of experience (QoE) of CR users and switching dynamically between the overlay and underlay models. QoE is measured by the mean opinion score (MOS) rather than simply fulfilling the physical and medium access control (MAC) layer requirements. The simulations considering the file transfer and video stream services show that the proposed resource allocation strategy is spectrum efficient.展开更多
Heterogeneous wireless access technologies will coexist in next generation wireless networks.These technologies form integrated networks,and these networks support multiple services with high quality level.Various acc...Heterogeneous wireless access technologies will coexist in next generation wireless networks.These technologies form integrated networks,and these networks support multiple services with high quality level.Various access technologies allow users to select the best available access network to meet the requirements of each type of communication service.Being always best connected anytime and anywhere is a major concern in a heterogeneous wireless networks environment.Always best connected enables network selection mechanisms to keep mobile users always connected to the best network.We present an overview of the network selection and prediction problems and challenges.In addition,we discuss a comprehensive classification of related theoretic approaches,and also study the integration between these methods,finding the best solution of network selection and prediction problems.The optimal solution can fulfill the requirements of the next generation wireless networks.展开更多
Even though various wireless Net- work Access Technologies (NATs) with dif- ferent specifications and applications have been developed in the recent years, no single wireless technology alone can satisfy the any- ti...Even though various wireless Net- work Access Technologies (NATs) with dif- ferent specifications and applications have been developed in the recent years, no single wireless technology alone can satisfy the any- time, anywhere, and any service wire- less-access needs of mobile users. A real seamless wireless mobile environment is only realized by considering vertical and horizontal handoffs together. One of the major design issues in heterogeneous wireless networks is the support of Vertical Handoff (VHO). VHO occurs when a multi-interface enabled mobile terminal changes its Point of Attachment (PoA) from one type of wireless access technology to another, while maintaining an active session. In this paper we present a novel multi-criteria VHO algorithm, which chooses the target NAT based on several factors such as user preferences, system parameters, and traf- tic-types with varying Quality of Service (QoS) requirements. Two modules i.e., VHO Neces- sity Estimation (VHONE) module and target NAT selection module, are designed. Both modules utilize several "weighted" users' and system's parameters. To improve the robust- ness of the proposed algorithm, the weighting system is designed based on the concept of fuzzy linguistic variables.展开更多
Wireless Mesh Network (WMN) is seen as an effective Intemet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by pr...Wireless Mesh Network (WMN) is seen as an effective Intemet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by proactive routing protocol. Pre-proposals like Tree Based Routing (TBR) protocol and Root Driven Routing (RDR) protocol are so centralized that they make the gateway becorre a bottleneck which severely restricts the network performance. We proposed an Optimized Tree-based Routing (OTR) protocol that logically separated the proactive tree into pieces. Route is partly computed by the branches instead of root. We also discussed the operation of multipie Intemet gateways which is a main issue in WMN. The new proposal lightens the load in root, reduces the overhead and improves the throughput. Numerical analysis and simulation results confirm that the perforrmnce of WMN is improved and OTR is more suitable for large scale WMN.展开更多
There is a growing awareness among industry players of reaping the benefits of mobile-cloud convergence by extending today's unmodified cloud to a decentralized two-level cloud-cloudlet architecture based on emerg...There is a growing awareness among industry players of reaping the benefits of mobile-cloud convergence by extending today's unmodified cloud to a decentralized two-level cloud-cloudlet architecture based on emerging mobile-edge computing(MEC) capabilities. In light of future 5G mobile networks moving toward decentralization based on cloudlets, intelligent base stations, and MEC, the inherent distributed processing and storage capabilities of radio-and-fiber(R&F) networks may be exploited for new applications, e.g., cognitive assistance, augmented reality, or cloud robotics. In this paper, we first revisit fiber-wireless(Fi Wi) networks in the context of conventional clouds and emerging cloudlets, thereby highlighting the limitations of conventional radio-overfiber(Ro F) networks such as China Mobile's centralized cloud radio access network(C-RAN) to meet the aforementioned trends. Furthermore, we pay close attention to the specific design challenges of data center networks and revisit our switchless arrayedwaveguide grating(AWG) based network with efficient support of east-west flows and enhanced scalability.展开更多
This paper describes the design and development of a wireless LAN (WLAN) access point based on Bluetooth and uClinux. To make the best use of high-speed serial communication capability, several methods such as modifyi...This paper describes the design and development of a wireless LAN (WLAN) access point based on Bluetooth and uClinux. To make the best use of high-speed serial communication capability, several methods such as modifying baud-rate of serial port driver, utilizing buffer area and adding flow-control were adopted. After analysis of scheduling and interruption handling, modifying the timer's parameters was put forward as a method to control the timer interrupt. In this way, data throughput and system stability were enhanced. Meanwhile, migration of the Bluetooth protocol stack was detailed and some successful applications of LAN access point were presented.展开更多
An admission control algorithm based on beamforming and interference alignment for device-to-device( D2D) communication underlaying cellular networks is proposed. First, some portion of D2D pairs that are the farthest...An admission control algorithm based on beamforming and interference alignment for device-to-device( D2D) communication underlaying cellular networks is proposed. First, some portion of D2D pairs that are the farthest away from the base station( BS) is selected to perform joint zero-forcing beamforming together with the cellular user equipments( UEs) and is admitted to the cellular network. The interference of the BS transmitting signal to the cellular UEs and the portion of D2D pair is eliminated completely at the same time. Secondly,based on the idea of interference alignment,the definition of channel parallelism is given. The channel parallelism of the remaining D2D pairs which are not involved in joint zero-forcing beamforming is computed by using the channel state information from the BS to the D2D devices. The higher the channel parallelism,the less interference the D2D pair suffers from the BS. Finally,in a descending order of channel parallelism,the remaining D2D pairs are reviewed in succession to determine admission to the cellular network. The algorithm stops when the admission of a D2D pair decreases the system sum rate. Simulation results show that the proposed algorithm can effectively reduce the interference of the BS transmitting signal for D2D pairs and significantly improve system capacity. Furthermore, D2D communication is more applicable to short-range links.展开更多
To fulfill the explosive growth of network capacity, fifth generation(5G) standard has captured the attention and imagination of researchers and engineers around the world. In particular, heterogeneous cloud radio acc...To fulfill the explosive growth of network capacity, fifth generation(5G) standard has captured the attention and imagination of researchers and engineers around the world. In particular, heterogeneous cloud radio access network(H-CRAN), as a promising network paradigm in 5G system, is a hot research topic in recent years. However, the densely deployment of RRHs in H-CRAN leads to downlink/uplink traffic asymmetry and severe inter-cell interference which could seriously impair the network throughput and resource utilization. To simultaneously solve these two problems, we proposed a dynamic resource allocation(DRA) scheme for H-CRAN in TDD mode. Firstly, we design a clustering algorithm to group the RRHs into different sets. Secondly, we adopt coordinated multipoint technology to eliminate the interference in each set. Finally, we formulate the joint frame structure, power and subcarrier selection problem as a mixed strategy noncooperative game. The simulation results are presented to validate the effectiveness of our proposed algorithm by compared with the existing work.展开更多
This paper investigates on the base stations(BSs) sleeping control and energy saving in wireless network. The objective is to find the sleeping control and energy saving configuration between total power consumption a...This paper investigates on the base stations(BSs) sleeping control and energy saving in wireless network. The objective is to find the sleeping control and energy saving configuration between total power consumption and average video's quality. On the Software Defined Network(SDN) access network architecture, a type of sleeping control and active BSs' optimal transmitting time strategy is considered, the BS sleeps when there is no active users, and wakes up after a period of vacation time. In this paper, we study the active users grouping strategy, In order to spare more BSs into sleeping mode. Then this paper proposes an active BS transmitting time optimal strategy according to the users' Qo S. In the proposed strategy, the active BSs' transmitting time is minimized in order to save energy. This paper employs the mixed integer-programming model to present this optimization problem. Then we utilized a novel algorithm to save the energy in access networks and also meet the Qo S requirements. Both the analytical and simulation results show that the algorithm can effectively save energy in the access network BSs.展开更多
The virtualized radio access network(v RAN) could implement virtualized baseband functions on general-purpose platforms and expand the processing capacity of the radio access network(RAN) significantly.In this paper,a...The virtualized radio access network(v RAN) could implement virtualized baseband functions on general-purpose platforms and expand the processing capacity of the radio access network(RAN) significantly.In this paper,a Not Only Stack(NO Stack) based vR AN is proposed to be employed in the fifth generation(5G) mobile communication system.It adopts advanced virtualization technologies to maintain flexible and sustainable.The baseband processing and storage resources should be sliced and orchestrated agilely to support multi radio access technology(multiRAT) .Also it is analyzed and demonstrated by different use cases to validate the benefits.The proposed v RAN reduces signaling overheads and service response time in the bearer establishment procedure.Concluded from the analyses and demonstrations,the NO Stack based v RAN could support multi-RAT convergence and flexible networking effectively.展开更多
To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,w...To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,we obtain two theoretical bounds:HOTiming upper bound and HO-Margin lower bound,which are helpful guidelines to study the handover challenge today and in the future.Then,we apply them to analyze performance of conventional handover technologies and our proposal in ETAN.This follow-up theory analyses and simulation experiment results demonstrate that the proposed handover solution can minimize handover time up to 4ms(which is the fastest one so far),and reduce HO-Margin to 0.16 dB at a train speed of 350km/h.展开更多
In this study,an explicit adaptive traffic allocation scheme for Machine-to-Machine(M2M)service is proposed to achieve optimum distribution in heterogeneous networks.Based on the characteristics of M2M services,the pr...In this study,an explicit adaptive traffic allocation scheme for Machine-to-Machine(M2M)service is proposed to achieve optimum distribution in heterogeneous networks.Based on the characteristics of M2M services,the presented scheme is formulated as a convex optimization problem that maximises the utility of the M2M service,and then determines how to allocate the total rate among the multiple access networks.The analysis and numerical simulations indicate that the proposed scheme makes a significant improvement in performance compared with the traditional schemes.展开更多
This paper introduces an adaptive traffic allocation scheme with cooperation of multiple Radio Access Networks (RANs) in universal wireless environments.The different cooperation scenarios are studied,and based on the...This paper introduces an adaptive traffic allocation scheme with cooperation of multiple Radio Access Networks (RANs) in universal wireless environments.The different cooperation scenarios are studied,and based on the scenario of cooperation in both network layer and terminal layer,an open queuing system model,which is aiming to depict the characteristics of packet loss rate of wireless communication networks,is proposed to optimize the traffic allocation results.The analysis and numerical simulations indicate that the proposed scheme achieves inter-networking load balance tominimize the whole transmission delay and expands the communication ability of single-mode terminals to support high data rate traffics.展开更多
In limited feedback-based CloudRAN(C-RAN) systems,the inter-cluster and intra-cluster interference together with the quantification error can seriously deteriorates the system spectral efficiency.We,in this paper,prop...In limited feedback-based CloudRAN(C-RAN) systems,the inter-cluster and intra-cluster interference together with the quantification error can seriously deteriorates the system spectral efficiency.We,in this paper,propose an efficient three-phase framework and corresponding algorithms for dealing with this problem.Firstly,a greedy scheduling algorithm based on the lower bound of the ergodic rate is performed for generating an elementary cluster in the first phase.And then the elementary cluster is divided into many small clusters according to the following proposed algorithms based on the short term instantaneous information in the second phase.In the end,based on the limited feedback two zero-forcing(ZF) precoding strategies are adopted for reducing the intra-cluster interference in the third phase.The provided Monte Carlo simulations show the effectiveness of our proposed algorithms in the respect of system spectral efficiency and average user rate.展开更多
The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network t...The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.展开更多
文摘With abundant wind resources and high pressure imposed on en-vironmental protection, wind power development has a promising future. Butdue to intermittent nature, wind power can bring into full play only if being con-nected into power grid to ensure its supply reliability and continuity, aswell as operational economy. However, technical and market barriers haveprevented wind power from integrating into power grid. To foster wind powerdevelopment, these barriers should be removed by both government incentivepolicies and sophisticated technologies.
文摘This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in WLAN access points by re-designing the Distribution_Service component of the MAC state machine is proposed. A variable named dotl 1 Isolation is defined to determine whether the MAC level communication between wireless stations in the same BSS is permitted or not. Finally, a design solution based on MPC860 hardware and embedded Linux software for PWLAN access point is specified. The simulation results of MAC isolation for PWLAN show that the proposed scheme is feasible and effective.
文摘The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adaptive backoff contention window and multihop forward chain transmission by invitation (MFCTI) scheme. In the FPF scheme, the contention window was adjusted adaptively according to the traffic priority. Route information and the broadcast characteristic of radio were utilized in MFCTI scheme. The performance of these schemes was studied in multihop environments by simulations. The results showed that the proposed schemes could improve the network throughput, reduce the end-to-end average delay, and mitigate local congestion effectively. Another attractive feature was that the schemes could be implemented with minor modifications to the IEEE 802.11 MAC.
基金The National Natural Science Foundation of China(No.61271207,61372104)the Natural Science Foundation of Jiangsu Province(No.BK20130530)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.12KJB510002)the Programs of Senior Talent Foundation of Jiangsu University(No.11JDG130)
文摘A resource allocation protocol is presented in an orthogonal frequency division multiple access (OFDMA) cognitive radio (CR) network with a hybrid model which combines overlay and underlay models. Without disrupting the primary user (PU) transmissions, the overlay model allows the secondary user (SU) to utilize opportunistically the idle sub-channels; the underlay model allows the SU to occupy the same sub-channels with PU. The proposed protocols are designed for maximizing the quality of experience (QoE) of CR users and switching dynamically between the overlay and underlay models. QoE is measured by the mean opinion score (MOS) rather than simply fulfilling the physical and medium access control (MAC) layer requirements. The simulations considering the file transfer and video stream services show that the proposed resource allocation strategy is spectrum efficient.
基金funded by the University of Malaya, under Grant No.RG208-11AFR
文摘Heterogeneous wireless access technologies will coexist in next generation wireless networks.These technologies form integrated networks,and these networks support multiple services with high quality level.Various access technologies allow users to select the best available access network to meet the requirements of each type of communication service.Being always best connected anytime and anywhere is a major concern in a heterogeneous wireless networks environment.Always best connected enables network selection mechanisms to keep mobile users always connected to the best network.We present an overview of the network selection and prediction problems and challenges.In addition,we discuss a comprehensive classification of related theoretic approaches,and also study the integration between these methods,finding the best solution of network selection and prediction problems.The optimal solution can fulfill the requirements of the next generation wireless networks.
文摘Even though various wireless Net- work Access Technologies (NATs) with dif- ferent specifications and applications have been developed in the recent years, no single wireless technology alone can satisfy the any- time, anywhere, and any service wire- less-access needs of mobile users. A real seamless wireless mobile environment is only realized by considering vertical and horizontal handoffs together. One of the major design issues in heterogeneous wireless networks is the support of Vertical Handoff (VHO). VHO occurs when a multi-interface enabled mobile terminal changes its Point of Attachment (PoA) from one type of wireless access technology to another, while maintaining an active session. In this paper we present a novel multi-criteria VHO algorithm, which chooses the target NAT based on several factors such as user preferences, system parameters, and traf- tic-types with varying Quality of Service (QoS) requirements. Two modules i.e., VHO Neces- sity Estimation (VHONE) module and target NAT selection module, are designed. Both modules utilize several "weighted" users' and system's parameters. To improve the robust- ness of the proposed algorithm, the weighting system is designed based on the concept of fuzzy linguistic variables.
基金Acknowledgements This paper was supported by the Major National Science and Technology program under Grant No. 2011ZX03005-002 the National Natural Science Foundation of China under Grant No. 61100233 the Fundamental Universities under Grant No Research Funds for the Central K50510030010.
文摘Wireless Mesh Network (WMN) is seen as an effective Intemet access solution for dynamic wireless applications. For the low mobility of mesh routers in WMN, the backbone topography can be effectively maintained by proactive routing protocol. Pre-proposals like Tree Based Routing (TBR) protocol and Root Driven Routing (RDR) protocol are so centralized that they make the gateway becorre a bottleneck which severely restricts the network performance. We proposed an Optimized Tree-based Routing (OTR) protocol that logically separated the proactive tree into pieces. Route is partly computed by the branches instead of root. We also discussed the operation of multipie Intemet gateways which is a main issue in WMN. The new proposal lightens the load in root, reduces the overhead and improves the throughput. Numerical analysis and simulation results confirm that the perforrmnce of WMN is improved and OTR is more suitable for large scale WMN.
文摘There is a growing awareness among industry players of reaping the benefits of mobile-cloud convergence by extending today's unmodified cloud to a decentralized two-level cloud-cloudlet architecture based on emerging mobile-edge computing(MEC) capabilities. In light of future 5G mobile networks moving toward decentralization based on cloudlets, intelligent base stations, and MEC, the inherent distributed processing and storage capabilities of radio-and-fiber(R&F) networks may be exploited for new applications, e.g., cognitive assistance, augmented reality, or cloud robotics. In this paper, we first revisit fiber-wireless(Fi Wi) networks in the context of conventional clouds and emerging cloudlets, thereby highlighting the limitations of conventional radio-overfiber(Ro F) networks such as China Mobile's centralized cloud radio access network(C-RAN) to meet the aforementioned trends. Furthermore, we pay close attention to the specific design challenges of data center networks and revisit our switchless arrayedwaveguide grating(AWG) based network with efficient support of east-west flows and enhanced scalability.
基金NationalKeyTechnologiesR&DProgram (No .2 0 0 1BA10 2C)
文摘This paper describes the design and development of a wireless LAN (WLAN) access point based on Bluetooth and uClinux. To make the best use of high-speed serial communication capability, several methods such as modifying baud-rate of serial port driver, utilizing buffer area and adding flow-control were adopted. After analysis of scheduling and interruption handling, modifying the timer's parameters was put forward as a method to control the timer interrupt. In this way, data throughput and system stability were enhanced. Meanwhile, migration of the Bluetooth protocol stack was detailed and some successful applications of LAN access point were presented.
基金The National Natural Science Foundation of China(No.61771132,61471115)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.16KJB510011)+2 种基金the Science and Technology Joint Research and Innovation Foundation of Jiangsu Province(No.BY2016076-13)the Research Fund of National Mobile Communications Research Laboratory,Southeast University(No.2018A02)the Research Foundation of Jinling Institute of Technology for Advanced Talents(No.40620044)
文摘An admission control algorithm based on beamforming and interference alignment for device-to-device( D2D) communication underlaying cellular networks is proposed. First, some portion of D2D pairs that are the farthest away from the base station( BS) is selected to perform joint zero-forcing beamforming together with the cellular user equipments( UEs) and is admitted to the cellular network. The interference of the BS transmitting signal to the cellular UEs and the portion of D2D pair is eliminated completely at the same time. Secondly,based on the idea of interference alignment,the definition of channel parallelism is given. The channel parallelism of the remaining D2D pairs which are not involved in joint zero-forcing beamforming is computed by using the channel state information from the BS to the D2D devices. The higher the channel parallelism,the less interference the D2D pair suffers from the BS. Finally,in a descending order of channel parallelism,the remaining D2D pairs are reviewed in succession to determine admission to the cellular network. The algorithm stops when the admission of a D2D pair decreases the system sum rate. Simulation results show that the proposed algorithm can effectively reduce the interference of the BS transmitting signal for D2D pairs and significantly improve system capacity. Furthermore, D2D communication is more applicable to short-range links.
基金jointly supported by Project 61501052 and 61302080 of the National Natural Science Foundation of China
文摘To fulfill the explosive growth of network capacity, fifth generation(5G) standard has captured the attention and imagination of researchers and engineers around the world. In particular, heterogeneous cloud radio access network(H-CRAN), as a promising network paradigm in 5G system, is a hot research topic in recent years. However, the densely deployment of RRHs in H-CRAN leads to downlink/uplink traffic asymmetry and severe inter-cell interference which could seriously impair the network throughput and resource utilization. To simultaneously solve these two problems, we proposed a dynamic resource allocation(DRA) scheme for H-CRAN in TDD mode. Firstly, we design a clustering algorithm to group the RRHs into different sets. Secondly, we adopt coordinated multipoint technology to eliminate the interference in each set. Finally, we formulate the joint frame structure, power and subcarrier selection problem as a mixed strategy noncooperative game. The simulation results are presented to validate the effectiveness of our proposed algorithm by compared with the existing work.
基金supported by the National High-Tech R&D Program (863 Program2015AA01A705)in part by Beijing Municipal Commission of Education (The City's Vehicle Sensing Grid Construction Based on Public Transportation Network)
文摘This paper investigates on the base stations(BSs) sleeping control and energy saving in wireless network. The objective is to find the sleeping control and energy saving configuration between total power consumption and average video's quality. On the Software Defined Network(SDN) access network architecture, a type of sleeping control and active BSs' optimal transmitting time strategy is considered, the BS sleeps when there is no active users, and wakes up after a period of vacation time. In this paper, we study the active users grouping strategy, In order to spare more BSs into sleeping mode. Then this paper proposes an active BS transmitting time optimal strategy according to the users' Qo S. In the proposed strategy, the active BSs' transmitting time is minimized in order to save energy. This paper employs the mixed integer-programming model to present this optimization problem. Then we utilized a novel algorithm to save the energy in access networks and also meet the Qo S requirements. Both the analytical and simulation results show that the algorithm can effectively save energy in the access network BSs.
基金supported by the China's 863 Project(No.2015AA01A706)the National Science and Technology Major Project(No.2016ZX03001017)+1 种基金the Science and Technology Program of Beijing(No.D161100001016002)the Science and Technology Cooperation Projects(No.2015DFT10160B)
文摘The virtualized radio access network(v RAN) could implement virtualized baseband functions on general-purpose platforms and expand the processing capacity of the radio access network(RAN) significantly.In this paper,a Not Only Stack(NO Stack) based vR AN is proposed to be employed in the fifth generation(5G) mobile communication system.It adopts advanced virtualization technologies to maintain flexible and sustainable.The baseband processing and storage resources should be sliced and orchestrated agilely to support multi radio access technology(multiRAT) .Also it is analyzed and demonstrated by different use cases to validate the benefits.The proposed v RAN reduces signaling overheads and service response time in the bearer establishment procedure.Concluded from the analyses and demonstrations,the NO Stack based v RAN could support multi-RAT convergence and flexible networking effectively.
基金supported by the National Basic Research Program of China (973 Program)(No.2012CB315606 and 2010CB328201)
文摘To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,we obtain two theoretical bounds:HOTiming upper bound and HO-Margin lower bound,which are helpful guidelines to study the handover challenge today and in the future.Then,we apply them to analyze performance of conventional handover technologies and our proposal in ETAN.This follow-up theory analyses and simulation experiment results demonstrate that the proposed handover solution can minimize handover time up to 4ms(which is the fastest one so far),and reduce HO-Margin to 0.16 dB at a train speed of 350km/h.
基金supported by the National Natural Science Foundation of Chinaunder Grant No.60971125the National Science and Technology Major Project of the Ministry of Science and Technology of Chinaunder Grant No.2012ZX03005-010the China Scholarship Council
文摘In this study,an explicit adaptive traffic allocation scheme for Machine-to-Machine(M2M)service is proposed to achieve optimum distribution in heterogeneous networks.Based on the characteristics of M2M services,the presented scheme is formulated as a convex optimization problem that maximises the utility of the M2M service,and then determines how to allocate the total rate among the multiple access networks.The analysis and numerical simulations indicate that the proposed scheme makes a significant improvement in performance compared with the traditional schemes.
基金supported by the National Natural Science Foundation of China under Grant No.60971125National Major Project under Grant No.2011ZX03003-003-01
文摘This paper introduces an adaptive traffic allocation scheme with cooperation of multiple Radio Access Networks (RANs) in universal wireless environments.The different cooperation scenarios are studied,and based on the scenario of cooperation in both network layer and terminal layer,an open queuing system model,which is aiming to depict the characteristics of packet loss rate of wireless communication networks,is proposed to optimize the traffic allocation results.The analysis and numerical simulations indicate that the proposed scheme achieves inter-networking load balance tominimize the whole transmission delay and expands the communication ability of single-mode terminals to support high data rate traffics.
基金supported by the National Natural Science Foundation of China(NSFC) under Grant(No. 61461136001)
文摘In limited feedback-based CloudRAN(C-RAN) systems,the inter-cluster and intra-cluster interference together with the quantification error can seriously deteriorates the system spectral efficiency.We,in this paper,propose an efficient three-phase framework and corresponding algorithms for dealing with this problem.Firstly,a greedy scheduling algorithm based on the lower bound of the ergodic rate is performed for generating an elementary cluster in the first phase.And then the elementary cluster is divided into many small clusters according to the following proposed algorithms based on the short term instantaneous information in the second phase.In the end,based on the limited feedback two zero-forcing(ZF) precoding strategies are adopted for reducing the intra-cluster interference in the third phase.The provided Monte Carlo simulations show the effectiveness of our proposed algorithms in the respect of system spectral efficiency and average user rate.
基金supported by the National High Technology Research and Development Program of China No.2014AA01A701Nature and Science Foundation of China under Grants No.61471068,61421061+2 种基金Beijing Nova Programme No.Z131101000413030International Collaboration Project No.2015DFT10160National Major Project No.2016ZX03001009-003
文摘The key technologies involved in the evolution of the Cloud-based Radio Access Network(C-RAN) are discussed in this paper. Taking the Frameless Network Architecture(FNA) as a starting point, a cell-lessbased network topology for a multi-tier Heterogeneous Network(Het Net) and ultra-dense network is proposed. The FNA network topology modeling is researched with centralized processing and distributed antenna deployments. The Antenna Element(AE) is released as a new dimensional radio resource that is included in the centralized Radio Resource Management(RRM) processes. This contributes to the on-demand user-centric serving-set associations with cell-edge effect elimination. The Control Plane(CP) and User Plane(UP) separation and adaptation are introduced for energy efficiency improvements. The centralized RRM and different optimization goals are discussed for fully exploring the merits from the centralized computing of C-RAN. Considering the complexity, near-optimal approaches for specific users' Quality-of-Service(Qo S) requirements are addressed. Finally, based on the research highlighted above, the way forward of C-RAN evolution is discussed.