In this paper, we have used the distributed mean value analysis (DMVA) technique with the help of random observe property (ROP) and palm probabilities to improve the network queuing system throughput. In such networks...In this paper, we have used the distributed mean value analysis (DMVA) technique with the help of random observe property (ROP) and palm probabilities to improve the network queuing system throughput. In such networks, where finding the complete communication path from source to destination, especially when these nodes are not in the same region while sending data between two nodes. So, an algorithm is developed for single and multi-server centers which give more interesting and successful results. The network is designed by a closed queuing network model and we will use mean value analysis to determine the network throughput (b) for its different values. For certain chosen values of parameters involved in this model, we found that the maximum network throughput for β≥0.7?remains consistent in a single server case, while in multi-server case for β≥ 0.5?throughput surpass the Marko chain queuing system.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
The efficient use of energy is an important performance metric to extend the lifetime of wireless sensor networks. Since major energy consumption of node is due to its transceiver, the design of MAC protocol plays a v...The efficient use of energy is an important performance metric to extend the lifetime of wireless sensor networks. Since major energy consumption of node is due to its transceiver, the design of MAC protocol plays a vital role in sensor network design. In cluster based sensor networks, due to the different functions of member node and cluster head node, the usage of common MAC protocol results increased energy consumption. To overcome this problem, a novel energy efficient hybrid MAC protocol (EEHMAC) for cluster based wireless sensor networks is proposed in this paper. The proposed EEHMAC protocol uses E-TDMA (Energy efficient TDMA) for intra-cluster communication and FDMA (Frequency Division Multiple Access) for inter-cluster communication. IDS (Iterative Deepening Search) based Scheduling algorithm is used for assigning time slot and frequency slot to nodes. Nodes in EEHMAC follow the periodic duty cycle, which reduces the idle listening, and overhearing problems. Simulation results reveal that an average of 18% energy saving is achieved compared to LEACH (Low Energy Adaptive Clustered Hierarchy) protocol and 10% energy is saved in comparison with GH-MAC (Graph theory based Hybrid MAC) protocol. It is evident that delay of EEHMAC is reduced by 17% and throughput is increased by 15% under all traffic conditions. These results demonstrate that EEHMAC performs better than existing MAC protocols in terms of energy efficiency, delay and throughput.展开更多
在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系...在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系统吞吐率估计算法。通过对多小区WLAN巾接入访问点的布置、信道的配置进行仿真,结果表明即使在存在小区间同频干扰的情况下,估计算法也能得到满意的吞吐率估计结果。展开更多
对SCI/RT(scalable coherent interface for real time)TRAIN协议直接传输模式的分析表明,标准直接传输模式具有延迟小的特点,但其对环路带宽的利用率不高。为增加直接传输模式可用环路带宽,提高环路利用率,提出了基于矩阵判决的直接传...对SCI/RT(scalable coherent interface for real time)TRAIN协议直接传输模式的分析表明,标准直接传输模式具有延迟小的特点,但其对环路带宽的利用率不高。为增加直接传输模式可用环路带宽,提高环路利用率,提出了基于矩阵判决的直接传输新方法。基于OPNET软件建立协议模型,通过不同场景和节点数环路的仿真对比,表明该方法较标准直接传输模式具有更好环路利用率;根据不同的数据包发送模式,直接传输模式可用带宽至少提高约25%;且算法在不同规模和配置的环路中均可使用。展开更多
建立了基于OPNET软件的SCI/RT(Scalable Coherent Interface for RealTime)TRAIN协议仿真模型,对流量均衡问题进行仿真分析.结果显示,当环路负载增加时,每个节点流量的增量是不同的.在环路处于重负载时,远离管理者的节点得到的流量近似...建立了基于OPNET软件的SCI/RT(Scalable Coherent Interface for RealTime)TRAIN协议仿真模型,对流量均衡问题进行仿真分析.结果显示,当环路负载增加时,每个节点流量的增量是不同的.在环路处于重负载时,远离管理者的节点得到的流量近似于零,而靠近管理者的节点基本上占用了所有的环路流量.SCI/RT TRAIN协议提出管理者迁移流量均衡方式解决这个问题.通过对8节点环路进行仿真,得出管理者迁移方法的均衡效果依赖于管理者在环路的配置方式的结论,当每个节点均具有管理者功能时,环路均衡效果达到最好.提出了扩展子优先级的流量均衡新方法.8节点环路的仿真结果显示,该方法具有更好的流量均衡能力和更高的节点流量.同时,通过对扩展子优先级均衡方法在6节点,10节点和12节点环路的仿真,证明了该方法在不同规模的环路中均可使用.展开更多
文摘In this paper, we have used the distributed mean value analysis (DMVA) technique with the help of random observe property (ROP) and palm probabilities to improve the network queuing system throughput. In such networks, where finding the complete communication path from source to destination, especially when these nodes are not in the same region while sending data between two nodes. So, an algorithm is developed for single and multi-server centers which give more interesting and successful results. The network is designed by a closed queuing network model and we will use mean value analysis to determine the network throughput (b) for its different values. For certain chosen values of parameters involved in this model, we found that the maximum network throughput for β≥0.7?remains consistent in a single server case, while in multi-server case for β≥ 0.5?throughput surpass the Marko chain queuing system.
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.
文摘The efficient use of energy is an important performance metric to extend the lifetime of wireless sensor networks. Since major energy consumption of node is due to its transceiver, the design of MAC protocol plays a vital role in sensor network design. In cluster based sensor networks, due to the different functions of member node and cluster head node, the usage of common MAC protocol results increased energy consumption. To overcome this problem, a novel energy efficient hybrid MAC protocol (EEHMAC) for cluster based wireless sensor networks is proposed in this paper. The proposed EEHMAC protocol uses E-TDMA (Energy efficient TDMA) for intra-cluster communication and FDMA (Frequency Division Multiple Access) for inter-cluster communication. IDS (Iterative Deepening Search) based Scheduling algorithm is used for assigning time slot and frequency slot to nodes. Nodes in EEHMAC follow the periodic duty cycle, which reduces the idle listening, and overhearing problems. Simulation results reveal that an average of 18% energy saving is achieved compared to LEACH (Low Energy Adaptive Clustered Hierarchy) protocol and 10% energy is saved in comparison with GH-MAC (Graph theory based Hybrid MAC) protocol. It is evident that delay of EEHMAC is reduced by 17% and throughput is increased by 15% under all traffic conditions. These results demonstrate that EEHMAC performs better than existing MAC protocols in terms of energy efficiency, delay and throughput.
文摘在多小区无线局域网(Wireless Local Area Networks,WLAN)中,由于存在小区间接入访问点同频干扰,以及小区间同频用户干扰,其系统性能与单小区网络具有很大不同。本文提出了支持多种用户传输速率共存、支持用户非均匀分布的多小区WLAN系统吞吐率估计算法。通过对多小区WLAN巾接入访问点的布置、信道的配置进行仿真,结果表明即使在存在小区间同频干扰的情况下,估计算法也能得到满意的吞吐率估计结果。
文摘对SCI/RT(scalable coherent interface for real time)TRAIN协议直接传输模式的分析表明,标准直接传输模式具有延迟小的特点,但其对环路带宽的利用率不高。为增加直接传输模式可用环路带宽,提高环路利用率,提出了基于矩阵判决的直接传输新方法。基于OPNET软件建立协议模型,通过不同场景和节点数环路的仿真对比,表明该方法较标准直接传输模式具有更好环路利用率;根据不同的数据包发送模式,直接传输模式可用带宽至少提高约25%;且算法在不同规模和配置的环路中均可使用。
