针对分布式无人机网络初始建网时间过长、周期性组网开销过大、链路稳定性与可靠性低的问题,提出了软件定义飞行自组网下基于节点合作的低开销且可靠有效路由解决方案(Low-overhead,Reliable and Efficient Routing Solution Based on N...针对分布式无人机网络初始建网时间过长、周期性组网开销过大、链路稳定性与可靠性低的问题,提出了软件定义飞行自组网下基于节点合作的低开销且可靠有效路由解决方案(Low-overhead,Reliable and Efficient Routing Solution Based on Node Cooperation,NC-SDN)。首先,通过普通节点局部感知和软件定义网络(Software Defined Network,SDN)控制器全局感知配合,缩短了初始建网时间并减少了周期性组网开销;其次,通过普通节点主动感知链路状态与周期性传递告警信息,减少了未过期无效路由带来的不可靠传输风险;最后,通过SDN控制器的预测与切换,降低了用户业务传输中断的风险。仿真表明,NC-SDN在初始建网时间、周期性组网开销和丢包率等方面性能优于现有的SDN、优化链路状态路由和无线自组网按需平面距离向量路由。展开更多
In converged heterogeneous wireless networks, vertical handoff is an important issue in radio resource management and occurs when an end user switches from one network to another （e.g., from wireless local area netwo...In converged heterogeneous wireless networks, vertical handoff is an important issue in radio resource management and occurs when an end user switches from one network to another （e.g., from wireless local area network to wideband code division multiple access）. Efficient vertical handoff should allocate network resources efficiently and maintain good quality of service （QoS） for the end users. The objective of this work is to determine conditions under which vertical handoff can be performed. The channel usage situation of each access network is formulated as a birth-death process with the objective of predicting the avaliable bandwidth and the blocking probability. A reward function is used to capture the network bandwidth and the blocking probability is expressed as a cost function. An end user will access the certain network which maximizes the total function defined as the combination of the reward fimction and the cost function. Simulation results show that the proposed algorithm can significantly improve the network performance, including higher bandwidth for end users and lower new call blocking and handoff call blocking probability for networks.展开更多
This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satis...This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satisfy different performance criteria imposed at different sampling times.In order to ensure recursive feasibility of the switching MOMPC and stability of the resulted closed-loop system,the dual-mode control method is used to design the switching MOMPC controller.In this method,a local control law with some free-parameters is constructed using the control Lyapunov function technique to enlarge the terminal state set of MOMPC.The correction term is computed if the states are out of the terminal set and the free-parameters of the local control law are computed if the states are in the terminal set.The recursive feasibility of the MOMPC and stability of the resulted closed-loop system are established in the presence of constraints and arbitrary switches between cost functions.Finally,implementation of the switching MOMPC controller is demonstrated with a chemical process example for the continuous stirred tank reactor.展开更多
文摘针对分布式无人机网络初始建网时间过长、周期性组网开销过大、链路稳定性与可靠性低的问题,提出了软件定义飞行自组网下基于节点合作的低开销且可靠有效路由解决方案(Low-overhead,Reliable and Efficient Routing Solution Based on Node Cooperation,NC-SDN)。首先,通过普通节点局部感知和软件定义网络(Software Defined Network,SDN)控制器全局感知配合,缩短了初始建网时间并减少了周期性组网开销;其次,通过普通节点主动感知链路状态与周期性传递告警信息,减少了未过期无效路由带来的不可靠传输风险;最后,通过SDN控制器的预测与切换,降低了用户业务传输中断的风险。仿真表明,NC-SDN在初始建网时间、周期性组网开销和丢包率等方面性能优于现有的SDN、优化链路状态路由和无线自组网按需平面距离向量路由。
基金Project(20040533035) supported by the National Research Foundation for the Doctoral Program of Higher Education of ChinaProject (50275150) supported by the National Natural Science Foundation of China
文摘In converged heterogeneous wireless networks, vertical handoff is an important issue in radio resource management and occurs when an end user switches from one network to another （e.g., from wireless local area network to wideband code division multiple access）. Efficient vertical handoff should allocate network resources efficiently and maintain good quality of service （QoS） for the end users. The objective of this work is to determine conditions under which vertical handoff can be performed. The channel usage situation of each access network is formulated as a birth-death process with the objective of predicting the avaliable bandwidth and the blocking probability. A reward function is used to capture the network bandwidth and the blocking probability is expressed as a cost function. An end user will access the certain network which maximizes the total function defined as the combination of the reward fimction and the cost function. Simulation results show that the proposed algorithm can significantly improve the network performance, including higher bandwidth for end users and lower new call blocking and handoff call blocking probability for networks.
基金Supported by the National Natural Science Foundation of China(61374111)the Natural Science Foundation of Zhejiang Province(LY13F030006)Agricultural Key Program of Ningbo City(2014C10068)
文摘This paper proposes a switching multi-objective model predictive control(MOMPC) algorithm for constrained nonlinear continuous-time process systems.Different cost functions to be minimized in MPC are switched to satisfy different performance criteria imposed at different sampling times.In order to ensure recursive feasibility of the switching MOMPC and stability of the resulted closed-loop system,the dual-mode control method is used to design the switching MOMPC controller.In this method,a local control law with some free-parameters is constructed using the control Lyapunov function technique to enlarge the terminal state set of MOMPC.The correction term is computed if the states are out of the terminal set and the free-parameters of the local control law are computed if the states are in the terminal set.The recursive feasibility of the MOMPC and stability of the resulted closed-loop system are established in the presence of constraints and arbitrary switches between cost functions.Finally,implementation of the switching MOMPC controller is demonstrated with a chemical process example for the continuous stirred tank reactor.
