Research And Implementation Of DSSS-CDMA System Technique Related

Spread Spectrum Communication with the character of strong anti-jamming and well covered which can implement CDMA technique. Spread Spectrum technique is widely used in digital cell-phone mobile communication system, satellite mobile communication, inside wireless communication and future personal communication. It can implement asynchronous transmission of multimedia data operation. It can offer more system capacity than traditional Multi-address technique. And it can restrain frequency selection decline in channel. It can also offer Multi-access conveniently. Direct Sequence CDMA system is the widest application spread system at present. DS-CMAD technique is adopted in 3G mobile communication systems such as cdma2000 system, WCDMA system and TD-SCDMA system. DS-CDMA technique is the decisive factor by application in future mobile communication system.The model of CDMA communication system used Direct Sequence Spread Spectrum technique is studied in this paper. The sound architecture of Transmitter and Receiver and the parts of circuit related implementation is given based on academic analysis. It is consummated and improved by computer simulation and actual hardware circuits testing for the optimization of system performance.The main problem of DS-CDMA communication system is the selection of spread spectrum code and address code and the system synchronization. Gold sequences are used as spread spectrum code and address code in the paper. Slip correlative taking and delay locked loop are used for the synchronization, taking, locking of PN code. PLL is used for generating carry synchronization signal. Haming code is used for error control in system. And other performances such as PSK modulation, PSK demodulation are also implemented in the system.The DS-CDMA communication system designed in this paper can not only take on the structure and principle of spread spectrum communication system, but also architecture a set of integrated CDMA wireless data communication system that hasthe practical application value. The DSSS technique and CDMA technique in the system are the key techniques of digital communication filed nowadays especially 3G mobile communications. It can be used for the advanced research of 3G mobile communications and products development related.