Design And Simulation Of FPGA-based CDMA Digital Baseband Transceiver System

CDMA(Code Division Multiple Access)is a branch technology which based on the spectrum-spread of the digital communication.It is supplied to the modulated signals to the different users using the different coded codes which are positively correlated or nearly positively correlated.It can realize the communication which multi-users utilize the same frequency to connect to the system and the network.Mobile communication is one of the most rapid development fields in the communications.CDMA becomes the key technology in the third generation mobile communication system by right of its good antinoise performance,security and low power.At present,large-scale programmable logical devices FPGA provides the new technical method for the design of CDMA mobile communication system.Based on comprehensive analysis of the CDMA principle and characteristic,an overall project design of CDMA base station baseband system is presented in the paper.The work principle of each signal processing module for forward and reverse link in the CDMA base station baseband system is discussed.The modules of CDMA base station baseband system are designed based on FPGA,such as CRC encodeL convolutional code encoder,block interleaver,PN code generator,Walsh code generator,baseband shaping filter,QPSK modulator,the acquisition and tracking module of PN code and Viterbi decoder.Some valuable stage achievements have been obtained.These have certain academic significance and application value to the thorough exploration,the research and the design of the CDMA mobile communication system.