The Research Of Ultra-wideband Communication System Based On Chaos

Chaotic communication is a new conception communication technology which utilizes the characteristics of randomness and continuous broadband of the chaos to encrypt. Compared with traditional PN sequences, chaotic sequences have the characteristics of approximate orthogonal and numerous code sources. PN sequences that chaos generation are suitable to secure communication and generation of the spread spectrum codes because its features such as nonlinearity, sensibility to initial and randomness. Therefore the application of chaos in digital communication has very important significance and nice prospect.Based on applications of chaotic DS - UWB communication for background, this paper introduces significance of research, research status and development tendency of chaotic DS– UWB. Also basic theories and characteristic of chaos and UWB are introduced as pre-knowledge.A new switched chaotic system was designed based on Lorenz system which was composed with several nonlinear functions. The basic dynamic characteristic of the switched chaotic system are analyzed with theory and numerical analysis. Using EDA technology to discrete the switched chaotic system and the system was implemented on FPGA and we can get the serial PN sequence from the serial port. The extracted switched chaotic sequence is tested in Linux operating system by NIST and the performance of the sequence is analyzed. The result is show that the sequence can satisfy the command of UWB communication system.On the basis of this constructed digital switched chaotic sequences, the UWB communication system signal form, power spectral density and the performance of the receiver are mainly analyzed joined switched chaotic sequences. The model of PAM-CDS-UWB is constructed with MATLAB. The performance of PAM-CDS-UWB adding switched chaotic sequence is analyzed and simulated compared to the traditional UWB communication system. The result shows that the performance of the system adding switched chaotic sequence is better than the traditional system. Finally the whole works have been summarized and the chaotic ultra-wideband communication development is prospected.