为降低流水线模数转换器(ADC)中跨导运算放大器(OTA)设计要求,在分析已有开关电容电路(SC)误差消除技术和流水线ADC误差源的基础上,提出一种改进的流水线ADC开关电容电路及与其匹配的OTA设计方案。采用交叉差分结构,对虚地电容进行了修...为降低流水线模数转换器(ADC)中跨导运算放大器(OTA)设计要求,在分析已有开关电容电路(SC)误差消除技术和流水线ADC误差源的基础上,提出一种改进的流水线ADC开关电容电路及与其匹配的OTA设计方案。采用交叉差分结构,对虚地电容进行了修正,并将电容失配参数在系统传输函数中消去,使开关电容电路对OTA的增益误差要求降低,并使其瞬态功耗下降。采用CM O S 0.18μm工艺设计了一个分辨率为8位、取样速率200 MH z的ADC作为验证原型,仿真结果表明,该优化结构符合ADC电路高速低功耗要求,可作为信号前端处理模块应用到模数转换电路中。展开更多
Ad hoc on-demand distance vector( AODV) routing is one of the typical reactive routing protocols of vehicular ad hoc networks( VANET). Considering link stability and channel switching can greatly improve the QoS of pr...Ad hoc on-demand distance vector( AODV) routing is one of the typical reactive routing protocols of vehicular ad hoc networks( VANET). Considering link stability and channel switching can greatly improve the QoS of protocols,in this paper,we propose a novel routing protocol: optimized cross-layer AODV( CL_ AODV) designed for VANET. It utilizes the frame transmission efficiency( FTE),path bandwidth in media access control( MAC) layer and signal-to-noise ratio( SNIR) in physical( PHY) layer to improve the link stability. In other words,it can increase packet delivery ratio effectively. In addition,end-to-end delay will be decreased based on the channel switching. According to the simulation,it is shown that the packet delivery ratio of CL_AODV is almost up to 99% and the highest compared to AODV and muti-constrained QoS AODV( MQ_ AODV). The delay of CL_AODV is almost half of MQ_ AODV's and 1 /3 of AODV's.Meanwhile,CL_AODV has the highest routing overhead or energy consuming. Because of the feature of VANET,the disadvantage can be ignored.展开更多
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
文摘为降低流水线模数转换器(ADC)中跨导运算放大器(OTA)设计要求,在分析已有开关电容电路(SC)误差消除技术和流水线ADC误差源的基础上,提出一种改进的流水线ADC开关电容电路及与其匹配的OTA设计方案。采用交叉差分结构,对虚地电容进行了修正,并将电容失配参数在系统传输函数中消去,使开关电容电路对OTA的增益误差要求降低,并使其瞬态功耗下降。采用CM O S 0.18μm工艺设计了一个分辨率为8位、取样速率200 MH z的ADC作为验证原型,仿真结果表明,该优化结构符合ADC电路高速低功耗要求,可作为信号前端处理模块应用到模数转换电路中。
基金National Natural Science Foundation of China(No.71171045)
文摘Ad hoc on-demand distance vector( AODV) routing is one of the typical reactive routing protocols of vehicular ad hoc networks( VANET). Considering link stability and channel switching can greatly improve the QoS of protocols,in this paper,we propose a novel routing protocol: optimized cross-layer AODV( CL_ AODV) designed for VANET. It utilizes the frame transmission efficiency( FTE),path bandwidth in media access control( MAC) layer and signal-to-noise ratio( SNIR) in physical( PHY) layer to improve the link stability. In other words,it can increase packet delivery ratio effectively. In addition,end-to-end delay will be decreased based on the channel switching. According to the simulation,it is shown that the packet delivery ratio of CL_AODV is almost up to 99% and the highest compared to AODV and muti-constrained QoS AODV( MQ_ AODV). The delay of CL_AODV is almost half of MQ_ AODV's and 1 /3 of AODV's.Meanwhile,CL_AODV has the highest routing overhead or energy consuming. Because of the feature of VANET,the disadvantage can be ignored.
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。
