为提高幅相键控（APSK）信号和正交调幅（QAM）信号信噪比估计范围和精度,提出了一种改进的信号信噪比估计算法。算法首先计算接收信号平方的均值和绝对值的均值之比,然后根据星座图特征,利用多项式拟合该比值与信噪比的关系。在拟合过...为提高幅相键控（APSK）信号和正交调幅（QAM）信号信噪比估计范围和精度,提出了一种改进的信号信噪比估计算法。算法首先计算接收信号平方的均值和绝对值的均值之比,然后根据星座图特征,利用多项式拟合该比值与信噪比的关系。在拟合过程中,对信噪比区间进行分段拟合来提高各段拟合精度,并用蒙特卡洛仿真经验值修正算法的固有偏差,从而得到信噪比的近似无偏估计。仿真结果表明,当信噪比估计区间为-5~20 d B且数据长度合适时,16APSK和32APSK信号信噪比估计偏差均值小于0.5 d B,标准差小于2 d B;该算法对16QAM和32QAM信号信噪比估计的标准差小于传统数据拟合算法。该算法运算复杂度较低,便于实时应用和硬件实现,对恒模和非恒模信号均能实现信噪比宽范围精确盲估计。展开更多
克服无线传感器范围限制的方法是依靠中继节点进行数据聚合,关键问题是如何保证点到点的安全传输.提出分段数据传输(Subsection Data Transport,SDT)安全方案,依靠多条路由确保数据能安全地聚合.通过仿真实验,证明该方案具有良好的安全...克服无线传感器范围限制的方法是依靠中继节点进行数据聚合,关键问题是如何保证点到点的安全传输.提出分段数据传输(Subsection Data Transport,SDT)安全方案,依靠多条路由确保数据能安全地聚合.通过仿真实验,证明该方案具有良好的安全性,即使存在妥协节点,也能有效地抵御偷听、数据篡改和拒绝服务(Denial of Service,DoS)攻击.展开更多
Energy efficiency(EE) is a key requirement for the design of short-range communication network.In order to alleviate energy consumption(EC) constraint,a novel layered heterogeneous mobile cloud architecture is propose...Energy efficiency(EE) is a key requirement for the design of short-range communication network.In order to alleviate energy consumption(EC) constraint,a novel layered heterogeneous mobile cloud architecture is proposed in this paper.Based on the proposed layered heterogeneous mobile cloud architecture,we establish an appropriate energy consumption model,and design an energy efficiency scheme based on joint data packet fragmentation and cooperative transmission and analyze the energy efficiency corresponding to different packet sizes and the cloud size.Simulation results show that,when all nodes of the cloud are accessing the same size of data packet fragmentation,the proposed layered heterogeneous mobile cloud architecture can provide significant energy savings.The results provide useful insights into the possible operation of the strategies and show that significant energy consumption reductions are possible.展开更多
文摘为提高幅相键控（APSK）信号和正交调幅（QAM）信号信噪比估计范围和精度,提出了一种改进的信号信噪比估计算法。算法首先计算接收信号平方的均值和绝对值的均值之比,然后根据星座图特征,利用多项式拟合该比值与信噪比的关系。在拟合过程中,对信噪比区间进行分段拟合来提高各段拟合精度,并用蒙特卡洛仿真经验值修正算法的固有偏差,从而得到信噪比的近似无偏估计。仿真结果表明,当信噪比估计区间为-5~20 d B且数据长度合适时,16APSK和32APSK信号信噪比估计偏差均值小于0.5 d B,标准差小于2 d B;该算法对16QAM和32QAM信号信噪比估计的标准差小于传统数据拟合算法。该算法运算复杂度较低,便于实时应用和硬件实现,对恒模和非恒模信号均能实现信噪比宽范围精确盲估计。
文摘克服无线传感器范围限制的方法是依靠中继节点进行数据聚合,关键问题是如何保证点到点的安全传输.提出分段数据传输(Subsection Data Transport,SDT)安全方案,依靠多条路由确保数据能安全地聚合.通过仿真实验,证明该方案具有良好的安全性,即使存在妥协节点,也能有效地抵御偷听、数据篡改和拒绝服务(Denial of Service,DoS)攻击.
基金jointly supported by the Chongqing Municipal Natural Science Foundation under Grant No.CSTC2013jjB40001)the National High Technology Research and Development Program of China(863Program)under Grant No.20140908the Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT1299
文摘Energy efficiency(EE) is a key requirement for the design of short-range communication network.In order to alleviate energy consumption(EC) constraint,a novel layered heterogeneous mobile cloud architecture is proposed in this paper.Based on the proposed layered heterogeneous mobile cloud architecture,we establish an appropriate energy consumption model,and design an energy efficiency scheme based on joint data packet fragmentation and cooperative transmission and analyze the energy efficiency corresponding to different packet sizes and the cloud size.Simulation results show that,when all nodes of the cloud are accessing the same size of data packet fragmentation,the proposed layered heterogeneous mobile cloud architecture can provide significant energy savings.The results provide useful insights into the possible operation of the strategies and show that significant energy consumption reductions are possible.
