In this paper,a distributed compressive spectrum sensing scheme in wideband cognitive radio networks is investigated.An analog-to-information converters（AIC） RF front-end sampling structure is proposed which use par...In this paper,a distributed compressive spectrum sensing scheme in wideband cognitive radio networks is investigated.An analog-to-information converters（AIC） RF front-end sampling structure is proposed which use parallel low rate analog to digital conversions（ADCs） and fewer storage units for wideband spectrum signal sampling.The proposed scheme uses multiple low rate congitive radios（CRs） collecting compressed samples through AICs distritbutedly and recover the signal spectrum jointly.A general joint sparsity model is defined in this scenario,along with a universal recovery algorithm based on simultaneous orthogonal matching pursuit（S-OMP）.Numerical simulations show this algorithm outperforms current existing algorithms under this model and works competently under other existing models.展开更多
New generation passive optical network aims at providing more than 100 Gb/s capacity. Thanks to recent progress enabling a variety of optical transceivers up to 40 Gb/s, many evolution possibilities to 200G PONs （pas...New generation passive optical network aims at providing more than 100 Gb/s capacity. Thanks to recent progress enabling a variety of optical transceivers up to 40 Gb/s, many evolution possibilities to 200G PONs （passive optical network） could be investigated. This work proposes two directly deployable cases of evolution to 200G PON based on the combination of these improved optical transceivers and WDM （wavelength division multiplexing）. The physical layer of the optical network has been simulated with OptiSystem software to show the communication links performances behavior when considering key components parameters in order to achieve good network design for a given area. The complexity of the proposed architectures and financial cost comparisons are also discussed.展开更多
深入研究了UWB(ultra wideband)无线传感器网络中基于匹配滤波门限检测的TOA(time of arrival)估计算法.针对现有算法的不足,提出了一种三步TOA估计算法:先确定DP(direct path)搜索区域,然后使用门限检测确定DP的粗略位置,最后精确搜索...深入研究了UWB(ultra wideband)无线传感器网络中基于匹配滤波门限检测的TOA(time of arrival)估计算法.针对现有算法的不足,提出了一种三步TOA估计算法:先确定DP(direct path)搜索区域,然后使用门限检测确定DP的粗略位置,最后精确搜索到DP的中心.其中,用于计算检测门限的门限因子依据匹配滤波输出的峭度动态设置,设置模型独立于信道模式,其正确性通过与使用固定门限因子所获得的性能对比进行了验证.与其他算法的性能对比仿真结果表明,所提出的三步TOA估计算法在运算效率和TOA估计精度上取得了较好折衷,适合于当前实际应用.还通过对TOA估计误差的统计分析讨论了测距结果的可信度:依据峭度将测距结果划分为可信和不可信两个级别,并为各级别的TOA估计误差分别了建立概率密度模型.在定位模块中有效利用这些可信度信息,可进一步提高定位精度.展开更多
基金Project supported by the National Fundamental Research (Grant Nos.2009CB3020402,2010CB731803)the National Natural Science Foundation of China (Grant Nos.60702046,60832005,60972050,60632040)the Natural High-Technology Research and Development Program of China (Grant Nos.2007AA01Z267,2009AA01Z248,2009AA011802)
文摘In this paper,a distributed compressive spectrum sensing scheme in wideband cognitive radio networks is investigated.An analog-to-information converters（AIC） RF front-end sampling structure is proposed which use parallel low rate analog to digital conversions（ADCs） and fewer storage units for wideband spectrum signal sampling.The proposed scheme uses multiple low rate congitive radios（CRs） collecting compressed samples through AICs distritbutedly and recover the signal spectrum jointly.A general joint sparsity model is defined in this scenario,along with a universal recovery algorithm based on simultaneous orthogonal matching pursuit（S-OMP）.Numerical simulations show this algorithm outperforms current existing algorithms under this model and works competently under other existing models.
文摘New generation passive optical network aims at providing more than 100 Gb/s capacity. Thanks to recent progress enabling a variety of optical transceivers up to 40 Gb/s, many evolution possibilities to 200G PONs （passive optical network） could be investigated. This work proposes two directly deployable cases of evolution to 200G PON based on the combination of these improved optical transceivers and WDM （wavelength division multiplexing）. The physical layer of the optical network has been simulated with OptiSystem software to show the communication links performances behavior when considering key components parameters in order to achieve good network design for a given area. The complexity of the proposed architectures and financial cost comparisons are also discussed.
文摘深入研究了UWB(ultra wideband)无线传感器网络中基于匹配滤波门限检测的TOA(time of arrival)估计算法.针对现有算法的不足,提出了一种三步TOA估计算法:先确定DP(direct path)搜索区域,然后使用门限检测确定DP的粗略位置,最后精确搜索到DP的中心.其中,用于计算检测门限的门限因子依据匹配滤波输出的峭度动态设置,设置模型独立于信道模式,其正确性通过与使用固定门限因子所获得的性能对比进行了验证.与其他算法的性能对比仿真结果表明,所提出的三步TOA估计算法在运算效率和TOA估计精度上取得了较好折衷,适合于当前实际应用.还通过对TOA估计误差的统计分析讨论了测距结果的可信度:依据峭度将测距结果划分为可信和不可信两个级别,并为各级别的TOA估计误差分别了建立概率密度模型.在定位模块中有效利用这些可信度信息,可进一步提高定位精度.
