Capacity Analysis And Channel Modeling Of CDMA System

Mobile communication has gone through the development of two generations which are simulation and GSM , in 3G in the future and even 4G mobile communication system, the transmission technology of physics layer based on CDMA has already been confirmed the scheme mainly, CDMA technology has already become the foundation of mobile communication in the future. CDMA communication basic principle is foundation to study the third generation of mobile communication system, author set up CDMA chain emulation model in order to study and research CDMA system. Compared with the first, second generations of mobile communication system, one of the important characteristics of the third generation of mobile communication system based on CDMA technology is the great improvement of the spectral resource utilization ratio, it is very important to know influence of the systematic capacity and the capacity and key technology characteristic of CDMA system correctly, the study about CDMA systematic capacity is a main content of this paper.The main contents of this paper are as following:First of all, for deeply understanding CDMA technology, author has finished the setting-up of reverse chain channel model according to the standard of CDMA IS-95, which realized entire channel codes , such as pronunciation coding, speed matching, convolution, interweaving, walsh coding to the radio frequency of expanding. The result of emulation signal frequency spectrum after OQPSK which decay the range in above 40dB indicate that the model is successful, being unanimity with the norm, this model can offer the reference basis for research and design of the third generation of communication system.