| Chaotic signals have the advantages in terms of inherent wideband, non-periodicity,apparent randomness, non-predictability, and low cost. Thus, chaotic signals have been widelyapplied in the communication field. Since the1990s, The chaos theory combine with thetraditional communication technology to form a variety of chaotic communication mode andits theory and method. chaotic communication is nonlinear dynamics and communicationtechnology interdisciplinary science, With the research of chaos deepening, more and morethe chaotic communication system is developed from the general CSK and DCSK to CDSK,SCSK, QCSK and the various derived communication from them.Nowadays, the frequencyresource isincreasingly tension, the demand of people to the data transfer rate andtransmission safety is more and more, it is need to give full play to the broadbandcharacteristics of chaotic signal, raise the utilization rate of frequency band, improve thesymbol rate and system performa. The major work of this paper is as follows:Firstly, the data rate is improved in the same conditions by increase the number of theinformation-bearing signal transmitted after one reference signal based on DCPSK. Thetheoretical analysis and simulation of the improved scheme under the additive gaussian whitenoise channel and Rayleigh multipath fading channel.Secondly, Introduces a kind of the timing synchronization algorithm used in DCSKultra-wideband systems, which is a Data-Aided Timing Synchronization and capitalizes on theexcellent correlation characteristic of chaotic signals. the search time and computationalcomplexity of the timing synchronization algorithm is small. In addition, in order to reducethe required number of steps and computational complexity for fine timing synchronization,The synchronous algorithm is made a little change by increase the use of the integral results inthe algorithm. Like this, the number of steps required to achieve synchronization is reducedwhen the computational load of every step is not increase. |
