Cdma Mobile Communication System To Improve The Reliability Of Some Of The Key Technical Analysis Research

The development of mobile communication has been through the simulant mobile cellar system of the first generation, the GSM and narrow-band CDMA of the second generation which using digital technology and the third generation mobile communication system. The third generation mobile telecommunication system utilizes wide-band CDMA as its multiple access. It aims at that whoever can communicate in whatever way whenever it is and wherever he is.Being wireless channel, the channel of CDMA system is very terrible medial of the nature, hi the course of transferring information, there are several disadvantages as time-selective fading, frequency-selective fading, near-far effect, multiple access interference, white Gaussian noise and so on, which affect the reliability of CDMA system and lower the capacity of CDMA system.Because the CDMA system is a interference-limited system, all the technologies that can improve the performance of resisting interference, that's to say reliability can amplify the its capacity. The key technologies utilized by CDMA system are all aiming at improving the reliability. In this article, we discuss several key technologies in the CDMA system which overcome the disadvantages above. These key technologies include channel-coding which overcome white Gaussian noise, Rake receiver which resist time-selective and frequency-selective fading, multi-user detection which overcome multiple access interference, and power control which overcome near-far effect. They are effective in increasing the performance of resisting interference of CDMA mobile communication system, and help to improve the reliability of transferring information. Finally the article proposes a algorithm which combine several key technologies to increase the reliability of CDMA system.