The role of synchronization in digital communications using chaos. II. Chaotic modulation and chaotic synchronization
The role of synchronization in digital communications using chaos. II. Chaotic modulation and chaotic synchronization
复制标题
DOI：
10.1109/81.735435
复制
发表时间：
1998-11
影响因子：
5.1
通讯作者：
G. Kolumbán;Michael Peter Kennedy;Leon O. Chua
中科院分区：
文献类型：
--
作者：
G. Kolumbán;Michael Peter Kennedy;Leon O. Chua
见同上，第44卷，第927-36页（1997）。在数字通信系统中，通过将位序列映射到符号，并将符号映射到模拟波形的采样函数，将数据从一个位置传输到另一个位置。模拟波形通过一个带宽有限（可能时变）的模拟通道，在那里信号被扭曲和噪声被添加。在传统系统中，通过通道发送的模拟样本函数是一个或多个正弦波的加权和；在混沌通信系统中，采样函数是混沌波形的片段。在接收端，可以通过相干检测（其中所有可能的样本函数都是已知的）或通过非相干检测（其中估计样本函数的一个或多个特征）来恢复符号。在相干接收机中，同步是最常用的从接收波形中恢复采样函数的技术。然后将这些样本函数用作相关器的参考信号。基于同步的相干接收机在噪声性能、带宽效率（在窄带系统中）和/或数据速率（在混沌系统中）方面优于非相干接收机。如果无法保持同步，例如在传播条件差的情况下，这些优势就会丧失。在这些情况下，不进行同步的通信可能更可取。将传统通信理论扩展到混沌通信，研究了混沌调制技术和接收机结构，描述了混沌同步方案。
For pt. I see ibid., vol. 44, p. 927-36 (1997). In a digital communications system, data are transmitted from one location to another by mapping bit sequences to symbols, and symbols to sample functions of analog waveforms. The analog waveform passes through a bandlimited (possibly time-varying) analog channel, where the signal is distorted and noise is added. In a conventional system the analog sample functions sent through the channel are weighted sums of one or more sinusoids; in a chaotic communications system the sample functions are segments of chaotic waveforms. At the receiver, the symbol may be recovered by means of coherent detection, where all possible sample functions are known, or by noncoherent detection, where one or more characteristics of the sample functions are estimated. In a coherent receiver, synchronization is the most commonly used technique for recovering the sample functions from the received waveform. These sample functions are then used as reference signals for a correlator. Synchronization-based coherent receivers have advantages over noncoherent receivers in terms of noise performance, bandwidth efficiency (in narrow-band systems) and/or data rate (in chaotic systems). These advantages are lost if synchronization cannot be maintained, for example, under poor propagation conditions. In these circumstances, communication without synchronization may be preferable. The theory of conventional telecommunications is extended to chaotic communications, chaotic modulation techniques and receiver configurations are surveyed, and chaotic synchronization schemes are described.