Improvement of direct spreading spectrum by multi-spreading spectrum

Chaos is characterized by aperiodic, wideband, random-like, and ergodicity. Chaotic secure communication has become one of the hot topics in nonlinear dynamics since the early 1990s exploiting the technique of chaos synchronization. As distinguished by the type of information being carried, chaos-based communication systems can be categorized into analogy and digital, including four popular techniques such as Chaos Masking, Chaos Shift Keying, Chaos Modulation, and Chaos Spreading Spectrum. In this chapter, the principles of these schemes and their modifications are analyzed by theoretical analysis as well as dynamic simulation. In addition, chaos-based cryptography is a new approach to encrypt information. After analyzing the performances of chaotic sequence and designing an effective chaotic sequence generator, the authors briefly presented the principle of two classes of chaotic encryption schemes, chaotic sequence encryption and chaotic data stream encryption.

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Breaking Chaotic Direct Sequence Spreading Spectrum Signals Under the Multipath Fading Channel

Circuits Systems and Signal Processing ◽

10.1007/s00034-013-9666-4 ◽

2013 ◽

Vol 33 (3) ◽

pp. 973-986 ◽

Cited By ~ 2

Author(s):

Ting Li ◽

Dexin Zhao ◽

Zhiping Huang ◽

Shaojing Su ◽

Chunwu Liu ◽

...

Keyword(s):

Fading Channel ◽

Multipath Fading ◽

Direct Sequence ◽

Multipath Fading Channel ◽

Spreading Spectrum

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The Application of RAKE Receiving Technology in the Underwater SS Communication

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.513-517.4248 ◽

2014 ◽

Vol 513-517 ◽

pp. 4248-4252 ◽

Cited By ~ 1

Author(s):

Yun Hang Zhu ◽

Zhi Hui Deng

Keyword(s):

High Speed ◽

Simulation Analysis ◽

High Reliability ◽

Underwater Acoustic Communication ◽

Technical Solution ◽

Acoustic Transmission ◽

Long Distance ◽

Underwater Acoustic ◽

Underwater Wireless Communication ◽

Spreading Spectrum

In recent years, the strategic significance of the oceans is growing as well as its research and development needs. The underwater wireless communication is becoming more and more important. The underwater acoustic communication is one of the few mediums which can conduct the underwater transmission over a long distance, and the multipath effect is the major obstacle of affecting the systems high speed and high reliability. The characteristics of underwater acoustic fading and coherent multi-path channel are studied, and the model of underwater acoustic spreading spectrum (SS) communication system is established. The affect of coding technique on the systems performance are analyzed in detail. The improved RAKE receiving technical solution is put forward, whose simulation analysis and data in different combining ways are given. It is proved that the scheme can better solve the problem of multipath interference in underwater acoustic transmission.

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