针对小型水下无人平台等水下设备对近距、高速率、低复杂度水下数据交互需求,设计一种高速率低复杂度水声通信方案。该方案采用PPM(Pulse Position Modulation)调制方式以直接硬件生成四相位时钟同步采样的方式实现低复杂度解调,从而降...针对小型水下无人平台等水下设备对近距、高速率、低复杂度水下数据交互需求,设计一种高速率低复杂度水声通信方案。该方案采用PPM(Pulse Position Modulation)调制方式以直接硬件生成四相位时钟同步采样的方式实现低复杂度解调,从而降低对硬件算力的要求;同时,利用PPM调制中脉冲间隔形成的特点和脉冲信号的快速衰减特性抑制高频水声信道多径干扰,避免采用高复杂度的信道均衡处理。实验室水池实验表明了采用该方案的通信样机在米级距离达到Mbps级传输速率的有效性。展开更多
Ultrawide bandwidth (UWB) radio, a very promising technique carrying information in very short basic pulses, has properties that make it a viable candidate for short-range wireless communications. In this paper, sever...Ultrawide bandwidth (UWB) radio, a very promising technique carrying information in very short basic pulses, has properties that make it a viable candidate for short-range wireless communications. In this paper, several short-pulse waveforms based on Gaussian genetic monocycle as well as Gaussian pulse waveform, as candidates of basic UWB pulse waveforms, are firstly proposed and investigated. Their spectrum characteristics, bit transmission rate (BTR), and bit error rate (BER) performance in AWGN channel using time hopping spread spectrum (THSS) and pulse position modulation (PPM) are simulated and evaluated. The numerical results are compared and show that the basic pulse waveforms determine the spectrum characteristics of UWB signals and have much effect on the performance of UWB radio system. The performance of UWB radio system achieved by the proposed basic pulse waveforms is much better than that of UWB radio system realized by other used basic pulse waveforms under the uniform conditions. Also, the polarity of these short basic pulses does not affect the performance of UWB radio system.展开更多
分析了在Gamma-Gamma分布下基于脉冲位置调制(pulse position modulation,PPM)方式的多输入输出自由空间光学(multiple input multiple output free space optics,MIMO-FSO)通信系统模型。首先推导了单输入单输出(single input single o...分析了在Gamma-Gamma分布下基于脉冲位置调制(pulse position modulation,PPM)方式的多输入输出自由空间光学(multiple input multiple output free space optics,MIMO-FSO)通信系统模型。首先推导了单输入单输出(single input single output,SISO)-PPM系统的误时隙率(slot error rate,SER)计算公式,以此作为参考,在独立同分布和独立分布参数不同情况下,分别推导出MISO-PPM、SIMO-PPM和MIMO-PPM系统的平均SER计算公式,并用数值仿真的方法,分析了它们的平均SER性能。仿真结果表明,在Gamma-Gamma分布模型下,采用多发多收的方法确实能有效提高FSO系统的平均SER性能,如在误时隙率为10-4时,M=2、N=2的MIMO-PPM系统在信道分布参数相同和不同时,与SISO-PPM相比,分别能节省信噪比50dB和65dB左右。实际应用中,M和N分别取3或4就基本足够,对无线光通信系统的理论分析和系统设计具有一定的指导意义。展开更多
针对现有水声通信系统抗干扰性能不佳和易受多普勒效应影响的问题,提出了基于分数阶Fourier变换的脉冲位置调制(fractional Fourier transform-pulse position modulation,FRFT-PPM)的水声通信系统方案及分数阶域多普勒效应补偿方法。FR...针对现有水声通信系统抗干扰性能不佳和易受多普勒效应影响的问题,提出了基于分数阶Fourier变换的脉冲位置调制(fractional Fourier transform-pulse position modulation,FRFT-PPM)的水声通信系统方案及分数阶域多普勒效应补偿方法。FRFT-PPM水声通信系统采用线性调频(linear frequency modulation,LFM)信号作为通信载波,借用PPM原理将信息调制到分数阶域脉冲位置中进行传输,具有通信速率可调,最高可达1.6kbit/s,抗噪声干扰能力强的优点。根据LFM信号较大多普勒容限和分数阶Fourier变换尺度变换特性,采用分数阶域分数阶域峰值位置补偿来抑制相对运动产生的多普勒效应。通过大量计算机仿真和湖试试验,验证了FRFT-PPM通信系统及分数阶域多普勒效应补偿算法的有效性与可行性。展开更多
文摘针对小型水下无人平台等水下设备对近距、高速率、低复杂度水下数据交互需求,设计一种高速率低复杂度水声通信方案。该方案采用PPM(Pulse Position Modulation)调制方式以直接硬件生成四相位时钟同步采样的方式实现低复杂度解调,从而降低对硬件算力的要求;同时,利用PPM调制中脉冲间隔形成的特点和脉冲信号的快速衰减特性抑制高频水声信道多径干扰,避免采用高复杂度的信道均衡处理。实验室水池实验表明了采用该方案的通信样机在米级距离达到Mbps级传输速率的有效性。
文摘Ultrawide bandwidth (UWB) radio, a very promising technique carrying information in very short basic pulses, has properties that make it a viable candidate for short-range wireless communications. In this paper, several short-pulse waveforms based on Gaussian genetic monocycle as well as Gaussian pulse waveform, as candidates of basic UWB pulse waveforms, are firstly proposed and investigated. Their spectrum characteristics, bit transmission rate (BTR), and bit error rate (BER) performance in AWGN channel using time hopping spread spectrum (THSS) and pulse position modulation (PPM) are simulated and evaluated. The numerical results are compared and show that the basic pulse waveforms determine the spectrum characteristics of UWB signals and have much effect on the performance of UWB radio system. The performance of UWB radio system achieved by the proposed basic pulse waveforms is much better than that of UWB radio system realized by other used basic pulse waveforms under the uniform conditions. Also, the polarity of these short basic pulses does not affect the performance of UWB radio system.
文摘分析了在Gamma-Gamma分布下基于脉冲位置调制(pulse position modulation,PPM)方式的多输入输出自由空间光学(multiple input multiple output free space optics,MIMO-FSO)通信系统模型。首先推导了单输入单输出(single input single output,SISO)-PPM系统的误时隙率(slot error rate,SER)计算公式,以此作为参考,在独立同分布和独立分布参数不同情况下,分别推导出MISO-PPM、SIMO-PPM和MIMO-PPM系统的平均SER计算公式,并用数值仿真的方法,分析了它们的平均SER性能。仿真结果表明,在Gamma-Gamma分布模型下,采用多发多收的方法确实能有效提高FSO系统的平均SER性能,如在误时隙率为10-4时,M=2、N=2的MIMO-PPM系统在信道分布参数相同和不同时,与SISO-PPM相比,分别能节省信噪比50dB和65dB左右。实际应用中,M和N分别取3或4就基本足够,对无线光通信系统的理论分析和系统设计具有一定的指导意义。
文摘针对现有水声通信系统抗干扰性能不佳和易受多普勒效应影响的问题,提出了基于分数阶Fourier变换的脉冲位置调制(fractional Fourier transform-pulse position modulation,FRFT-PPM)的水声通信系统方案及分数阶域多普勒效应补偿方法。FRFT-PPM水声通信系统采用线性调频(linear frequency modulation,LFM)信号作为通信载波,借用PPM原理将信息调制到分数阶域脉冲位置中进行传输,具有通信速率可调,最高可达1.6kbit/s,抗噪声干扰能力强的优点。根据LFM信号较大多普勒容限和分数阶Fourier变换尺度变换特性,采用分数阶域分数阶域峰值位置补偿来抑制相对运动产生的多普勒效应。通过大量计算机仿真和湖试试验,验证了FRFT-PPM通信系统及分数阶域多普勒效应补偿算法的有效性与可行性。
