混沌载波通信与传统数字通信的比较

Performance Comparison of Digital Communications Using Chaos as Carriers and Traditional Digital Communications

混沌载波通信是混沌通信领域最具代表性的一个研究方向。它用混沌信号作为通信的载波,与用正弦波作载波的传统数字通信直接对应。由于混沌信号与正弦信号等传统的确定性周期信号具有完全不同的特性,它具有较宽的连续频谱,且表现类δ函数的相关特性,因此用混沌信号作通信的载波,也使得整个通信系统具有崭新的特点。本文通过仿真实验对两种典型的混沌载波通信系统DCSK和FM-DC-SK,分别与传统数字通信系统在加性高斯白噪声信道和频率非选择性慢衰落信道下进行性能比较。比较的结果表明混沌载波通信系统在高斯信道下的噪声性能远远差于传统数字通信系统,而在频率非选择性慢衰落信道中则表现出极大的优势。最后,通过仿真实验验证了最优接收机对DCSK性能的改善,表明混沌载波通信的性能仍然具有提高的潜质。

Digital communications using chaos as carriers are one of the most important fields in chaotic communications. In them chaotic signals are used as the carriers instead of sinusoidal signals in traditional communications. Properties of chaotic signals are totally different from those of traditional deterministic periodic signals predictable, and delta-like Chaos has a broad-band, unautocorrelation nature, and therefore performance of digital communications using chaos as carriers has some new characteristics. This paper is an at tempt to experimentally evaluate performances of differential chaos shift keying （DCSK） and frequency-modulated differential chaos shift keying （FM-DCSK） over additive white gaussian noise （AWGN） channels and frequency-unselective slow-fading channels. Furthermore, their performances are compared with those of traditional digital communications under the same conditions. The conclusions of the comparison are that performance of digital communications using chaos as carriers is much worse than AWGN channels; however at frequency-unselective slow-fading channels, it is much better than that of traditional digital communications. And finally, the performance of DCSK with the optimal receiver is evaluated experimentally. The result shows that the performance of digital commtmications using chaotic carriers can be improved by some means.