This paper presents a detailed study of multiple access ultrawideband communications based on M-ary frequency-shift keying modulation of impulse-like carrier waveforms. The proposed signal model is described using expressions of duty cycle, energy, and correlation coefficient analytically derived and analyzed in terms of signal parameters. The frequency sets for coherent as well as non coherent detection utilized in narrow band communications are extended to impulse communications, and the resultant signals' correlation properties are investigated. Analytic expression of the frequency spectrum for continuous transmission is obtained, and a parametric study of the spectrum is carried out to analyze its properties. System performance analysis in terms of error probability curves is given for different signal model parameters. For single user communications, error probability curves for M-ary system are plotted using the union bound, while for multiple access communications, analytic expression of binary error probability in Rayleigh fading channel is given and plotted. The plots demonstrate the advantages of multiple access coding and signal design in improving system performance. Comparison between the bit error performance of impulse frequency shift keying, impulse phase shift keying, pulse position, and binary phase shift keying modulation schemes is presented too.

中文翻译：

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使用准正交类脉冲波形的频率调制的多址超宽带通信

本文对基于脉冲状载波波形的M进制频移键控调制的多址超宽带通信进行了详细研究。使用占空比，能量和相关系数的表达式描述了所提出的信号模型，并根据信号参数对其进行了分析。将窄带通信中用于相干和非相干检测的频率集扩展到脉冲通信，并研究所得信号的相关特性。获得了连续传输频谱的解析表达式，并对该频谱进行了参数研究，以分析其性质。针对不同的信号模型参数，根据误差概率曲线给出了系统性能分析。对于单用户通信，使用联合边界绘制Mary系统的错误概率曲线，而对于多路访问通信，给出并绘制瑞利衰落信道中二进制错误概率的解析表达式。这些图展示了多址编码和信号设计在改善系统性能方面的优势。还比较了脉冲移频键控，脉冲相移键控，脉冲位置和二进制相移键控调制方案的误码性能。这些图展示了多址编码和信号设计在改善系统性能方面的优势。还比较了脉冲移频键控，脉冲相移键控，脉冲位置和二进制相移键控调制方案的误码性能。这些图展示了多址编码和信号设计在改善系统性能方面的优势。还比较了脉冲移频键控，脉冲相移键控，脉冲位置和二进制相移键控调制方案的误码性能。