提出了一种新的启发式遗传算法以求解基于非精确状态信息的QoS组播路由选择问题.该算法以基于非精确状态信息的单播QoS路由算法PC-ISI(premise-controlled,inaccurate state information)为基础,将基于非精确状态信息的QoS组播路由问题...提出了一种新的启发式遗传算法以求解基于非精确状态信息的QoS组播路由选择问题.该算法以基于非精确状态信息的单播QoS路由算法PC-ISI(premise-controlled,inaccurate state information)为基础,将基于非精确状态信息的QoS组播路由问题与遗传算法有机结合,通过初始群体的筛选、自适应罚函数的运用以及启发式交叉和变异等一系列策略,能有效地提高算法的搜索能力和收敛速度.仿真实验也说明该算法性能良好.展开更多
针对空间信息网络具有环境动态性、服务差异性等特征,导致传统的多状态系统可靠性不能准确反映网络的实时状态,从而影响网络的可靠性问题,提出一种基于RBD(Reliability Block Diagrams)的QoS(Quality of Service)可靠性数学模型.该模型...针对空间信息网络具有环境动态性、服务差异性等特征,导致传统的多状态系统可靠性不能准确反映网络的实时状态,从而影响网络的可靠性问题,提出一种基于RBD(Reliability Block Diagrams)的QoS(Quality of Service)可靠性数学模型.该模型使用线性权重法综合考虑链路剩余带宽、节点丢包率多状态以及时延对可靠性的影响,对带宽敏感业务、时延敏感业务和可靠性敏感业务给予不同的权重,计算不同业务背景环境下通信可靠性.仿真结果表明,与不交和法可靠性模型相比,本文所提出的可靠性数学模型计算复杂度更低,实验仿真值更接近本文的理论值,计算准确度得到明显提升,能够较为准确的计算出空间信息网络端到端可靠性.展开更多
Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network a...Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network and high data rate at the hot spots.However,it is not permissible to assign orthogonal pilot sequences for all the supported users due to the large number.Hence,we propose a pilot reduction scheme based on the heterogeneous system configurations and the unique topology of this HetNet.The reusing of pilot sequences causes the presence of the contaminated channel state information(CSI) and results in receivers' Quality of Service(QoS) outage.With the contaminated CSI,we provide an energy-efficient beamforming based on minimizing the total power consumption while keeping the QoS constraints satisfied and restricting the QoS outage probability below a given specification.By applying the approach of Bernstein approximation and semi-definite relaxation,we transform the original intractable chance constrained program to a convex problem conservatively.Numerical results show that the average power consumption of the proposed beamforming for our pilot reduction scheme is close to that of the perfect CSI case.Since our scheme will greatly compress the length of pilot sequence especially for those highly densified network with large number of small cells,it will be crucially helpful to put such two-tier massive multiple-input and multiple-output(MIMO) systems into practice.展开更多
文摘提出了一种新的启发式遗传算法以求解基于非精确状态信息的QoS组播路由选择问题.该算法以基于非精确状态信息的单播QoS路由算法PC-ISI(premise-controlled,inaccurate state information)为基础,将基于非精确状态信息的QoS组播路由问题与遗传算法有机结合,通过初始群体的筛选、自适应罚函数的运用以及启发式交叉和变异等一系列策略,能有效地提高算法的搜索能力和收敛速度.仿真实验也说明该算法性能良好.
文摘针对空间信息网络具有环境动态性、服务差异性等特征,导致传统的多状态系统可靠性不能准确反映网络的实时状态,从而影响网络的可靠性问题,提出一种基于RBD(Reliability Block Diagrams)的QoS(Quality of Service)可靠性数学模型.该模型使用线性权重法综合考虑链路剩余带宽、节点丢包率多状态以及时延对可靠性的影响,对带宽敏感业务、时延敏感业务和可靠性敏感业务给予不同的权重,计算不同业务背景环境下通信可靠性.仿真结果表明,与不交和法可靠性模型相比,本文所提出的可靠性数学模型计算复杂度更低,实验仿真值更接近本文的理论值,计算准确度得到明显提升,能够较为准确的计算出空间信息网络端到端可靠性.
基金supported in part by the "863" Program of China No. 2014AA01A704National Natural Science Foundation of China No.61171080
文摘Heterogeneous networks(HetNets)consisting of macro cells with very large antenna arrays and a secondary tier of small cells with a few antennas each can well tackle the contradiction of large coverage of the network and high data rate at the hot spots.However,it is not permissible to assign orthogonal pilot sequences for all the supported users due to the large number.Hence,we propose a pilot reduction scheme based on the heterogeneous system configurations and the unique topology of this HetNet.The reusing of pilot sequences causes the presence of the contaminated channel state information(CSI) and results in receivers' Quality of Service(QoS) outage.With the contaminated CSI,we provide an energy-efficient beamforming based on minimizing the total power consumption while keeping the QoS constraints satisfied and restricting the QoS outage probability below a given specification.By applying the approach of Bernstein approximation and semi-definite relaxation,we transform the original intractable chance constrained program to a convex problem conservatively.Numerical results show that the average power consumption of the proposed beamforming for our pilot reduction scheme is close to that of the perfect CSI case.Since our scheme will greatly compress the length of pilot sequence especially for those highly densified network with large number of small cells,it will be crucially helpful to put such two-tier massive multiple-input and multiple-output(MIMO) systems into practice.
