In this work we propose an orthogonal pulse waveform for wireless ultra wideband (UWB) transmission. The design is based on an ideal low-pass prototype filter having a windowed sinc impulse response. The frequency res...In this work we propose an orthogonal pulse waveform for wireless ultra wideband (UWB) transmission. The design is based on an ideal low-pass prototype filter having a windowed sinc impulse response. The frequency response of the prototype filter is transferred to the high frequency region using a specific sign modulator. The UWB pulse waveform comprises of the weighted summation of the left singular vectors of the impulse response matrix. The power spectral density of the pulse waveform fulfils the FCC constraint (allowed frequency band 3.1-10.6 GHz) for unlicensed UWB transmission. Applications of the UWB pulse waveform in multi-channel wireless sensor networks are considered.展开更多
Measurement and reconstruction of wireless pulses is an important scheme in wireless ultra wide band (UWB) technology. In contrary to the band-limited analog signals, which can be recovered from evenly spaced samples,...Measurement and reconstruction of wireless pulses is an important scheme in wireless ultra wide band (UWB) technology. In contrary to the band-limited analog signals, which can be recovered from evenly spaced samples, the reconstruction of the UWB pulses is a more demanding task. In this work we describe an exponential sampling filter (ESF) for measurement and reconstruction of UWB pulses. The ESF is constructed from parallel filters, which has exponentially descending impulse response. A pole cancellation filter was used to extract the amplitudes and time locations of the UWB pulses from sequentially measured samples of the ESF output. We show that the amplitudes and time locations of p sequential UWB pulses can be recovered from the measurement of at least 2p samples from the ESF output. For perfect reconstruction the number of parallel filters in ESP should be 2p. We study the robustness of the method against noise and discuss the applications of the method.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
为了设计一种以较小运算量获得较高测距精度的TOA(time of arrival)估计算法以适合节点运算能力有限的UWB(ultra wideband)无线传感器网络,提出了一种结合能量检测与匹配滤波的两步TOA估计方法.分析了该方法的工作原理,指出了第1步中DP(...为了设计一种以较小运算量获得较高测距精度的TOA(time of arrival)估计算法以适合节点运算能力有限的UWB(ultra wideband)无线传感器网络,提出了一种结合能量检测与匹配滤波的两步TOA估计方法.分析了该方法的工作原理,指出了第1步中DP(direct path)块检测成功率及第2步中匹配滤波门限因子设置的重要性.通过仿真对影响DP块检测成功率的两个因素,即DP块检测算法的选用和能量积分周期的设置进行了讨论.提出了依据能量采样序列中DP块与最小块比值DMR(DP to minimum energy sample ratio)动态设置匹配滤波门限因子的思想,并为其建立了数学模型.仿真结果表明,两步TOA估计方法在运算量比单一的基于匹配滤波的相干算法小很多的情况下,获得了比单一的基于能量检测的非相干方法更好的TOA估计性能,从而更适合应用于有低复杂度、低能耗设计需求的传感器节点中.展开更多
文章提出了一个UWB(Ultra-wide Band)无线传感器网络的无线节点定位系统模型,仿真分析表明,对于四个参考节点都是LOS(Line Of Sight)路径到达传感器节点的情况,其定位的精确度相当高;但是,如果四个参考节点中有一个节点是NLOS(Non Line ...文章提出了一个UWB(Ultra-wide Band)无线传感器网络的无线节点定位系统模型,仿真分析表明,对于四个参考节点都是LOS(Line Of Sight)路径到达传感器节点的情况,其定位的精确度相当高;但是,如果四个参考节点中有一个节点是NLOS(Non Line Of Sight)路径到达传感器节点的话,当信噪比低于30dB,则定位误差不小于5m,这时候要保证较高的定位准确度,就应该保证较高的信噪比或者增加参考节点数目。展开更多
针对无线传感器网络节点低成本、低运算能力的特点,基于脉冲超宽带技术的无线传感器网络提出了一种基于能量检测的两步测距法。这种方法针对DP(direct path)分量进行TOA(time of arrival)估计,具体包含对DP所在能量块的广义似然比检验...针对无线传感器网络节点低成本、低运算能力的特点,基于脉冲超宽带技术的无线传感器网络提出了一种基于能量检测的两步测距法。这种方法针对DP(direct path)分量进行TOA(time of arrival)估计,具体包含对DP所在能量块的广义似然比检验和能量块内对DP精确位置的极大似然估计两部分。给出了DP能量块检测概率和估计结果的闭合表达式,通过理论和数值分析了积分长度等系统参数对于TOA估计性能的影响,并建立了估计误差的数学模型。最后通过仿真结果进行了性能比较,并验证了分析结论。与传统方法比较的结果表明,该算法可以在复杂度较低的条件下取得一定的性能提升。展开更多
在基于距离的定位算法的基础上,提出基于超宽带(UWB)通信技术的TOA(Time Of Arrival)测距方法。UWB信号具有隐蔽性好、穿透能力强、定位精度高以及功耗低等特点,但在节点定位应用中,UWB直达信号难以精确检测。本文提出通过对首次到达信...在基于距离的定位算法的基础上,提出基于超宽带(UWB)通信技术的TOA(Time Of Arrival)测距方法。UWB信号具有隐蔽性好、穿透能力强、定位精度高以及功耗低等特点,但在节点定位应用中,UWB直达信号难以精确检测。本文提出通过对首次到达信号时间和最强信号时间进行加权来得到直达信号到达时间,并采用模糊逻辑技术计算加权系数。实际数据仿真试验表明,基于UWB的定位技术可极大地提高定位精度。展开更多
文摘In this work we propose an orthogonal pulse waveform for wireless ultra wideband (UWB) transmission. The design is based on an ideal low-pass prototype filter having a windowed sinc impulse response. The frequency response of the prototype filter is transferred to the high frequency region using a specific sign modulator. The UWB pulse waveform comprises of the weighted summation of the left singular vectors of the impulse response matrix. The power spectral density of the pulse waveform fulfils the FCC constraint (allowed frequency band 3.1-10.6 GHz) for unlicensed UWB transmission. Applications of the UWB pulse waveform in multi-channel wireless sensor networks are considered.
文摘Measurement and reconstruction of wireless pulses is an important scheme in wireless ultra wide band (UWB) technology. In contrary to the band-limited analog signals, which can be recovered from evenly spaced samples, the reconstruction of the UWB pulses is a more demanding task. In this work we describe an exponential sampling filter (ESF) for measurement and reconstruction of UWB pulses. The ESF is constructed from parallel filters, which has exponentially descending impulse response. A pole cancellation filter was used to extract the amplitudes and time locations of the UWB pulses from sequentially measured samples of the ESF output. We show that the amplitudes and time locations of p sequential UWB pulses can be recovered from the measurement of at least 2p samples from the ESF output. For perfect reconstruction the number of parallel filters in ESP should be 2p. We study the robustness of the method against noise and discuss the applications of the method.
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.
基金Supported by the Major Program of the National Natural Science Foundation of China under Grant No.60432040(国家自然科学基金重点项目)
文摘为了设计一种以较小运算量获得较高测距精度的TOA(time of arrival)估计算法以适合节点运算能力有限的UWB(ultra wideband)无线传感器网络,提出了一种结合能量检测与匹配滤波的两步TOA估计方法.分析了该方法的工作原理,指出了第1步中DP(direct path)块检测成功率及第2步中匹配滤波门限因子设置的重要性.通过仿真对影响DP块检测成功率的两个因素,即DP块检测算法的选用和能量积分周期的设置进行了讨论.提出了依据能量采样序列中DP块与最小块比值DMR(DP to minimum energy sample ratio)动态设置匹配滤波门限因子的思想,并为其建立了数学模型.仿真结果表明,两步TOA估计方法在运算量比单一的基于匹配滤波的相干算法小很多的情况下,获得了比单一的基于能量检测的非相干方法更好的TOA估计性能,从而更适合应用于有低复杂度、低能耗设计需求的传感器节点中.
文摘文章提出了一个UWB(Ultra-wide Band)无线传感器网络的无线节点定位系统模型,仿真分析表明,对于四个参考节点都是LOS(Line Of Sight)路径到达传感器节点的情况,其定位的精确度相当高;但是,如果四个参考节点中有一个节点是NLOS(Non Line Of Sight)路径到达传感器节点的话,当信噪比低于30dB,则定位误差不小于5m,这时候要保证较高的定位准确度,就应该保证较高的信噪比或者增加参考节点数目。
文摘针对无线传感器网络节点低成本、低运算能力的特点,基于脉冲超宽带技术的无线传感器网络提出了一种基于能量检测的两步测距法。这种方法针对DP(direct path)分量进行TOA(time of arrival)估计,具体包含对DP所在能量块的广义似然比检验和能量块内对DP精确位置的极大似然估计两部分。给出了DP能量块检测概率和估计结果的闭合表达式,通过理论和数值分析了积分长度等系统参数对于TOA估计性能的影响,并建立了估计误差的数学模型。最后通过仿真结果进行了性能比较,并验证了分析结论。与传统方法比较的结果表明,该算法可以在复杂度较低的条件下取得一定的性能提升。
文摘在基于距离的定位算法的基础上,提出基于超宽带(UWB)通信技术的TOA(Time Of Arrival)测距方法。UWB信号具有隐蔽性好、穿透能力强、定位精度高以及功耗低等特点,但在节点定位应用中,UWB直达信号难以精确检测。本文提出通过对首次到达信号时间和最强信号时间进行加权来得到直达信号到达时间,并采用模糊逻辑技术计算加权系数。实际数据仿真试验表明,基于UWB的定位技术可极大地提高定位精度。
