| In recent years, with the maturing of non-linear and chaotic theory, researchers have looked into possible application of the theory in communications. On the other hand, CDMA (Code-Division Multiple Access) communication system has been widely considered as the mainstream of 3G communication system, because it has the good qualities such as high utilization ratio of frequency band , low transmission power, powerful anti-multiple path falling and flexible capacity. So the chaotic application in CDMA has become a new bright point in the research of chaotic application and chaotic theory.This paper discusses the work that we have done about the (CD)2MA (ChaoticDigital Code-Division Multiple Access) communication system, whose performance is desirable. When we carry through the theoretic analysis, according to the request of CDMA communication system for spreading code, we analyze the characteristics of chaotic spreading sequence. Its power spectrum is similar to gauss white noise. The similar random correlativity is good. So the chaotic sequence can indeed serve as spreading address code in spreading communication. After discussing the communication theory of CDMA, we propose the model of the (CD)2MA communication system and utilize the simulation tools of MATLAB SIMULINKto propose the (CD)2MA simulation system according to this model. Finally, wecarry out the theoretic analysis on the whole communication system. By comparing the simulation analysis results with m-sequence and gold sequence, we further validate the good performance of the (CD)2MA communication system. The data ofthe simulation and the result of the theoretic analysis show that the (CD)2MAcommunication system introduced in this paper appears to have good anti-interference abilities, low BER, ideal secure properties, great capacity and can be practiced in a simple manner, so it has a very high value of application and a very good developing prospect. |
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