The Implement Of The DS/FH Hybrid Spread Spectrum Signals Modulation System Based On FPGA

With the increasing requirement for real-time multimedia operation by clients, the second generation mobile communication system(2G) featured GSM can't satisfy clients the requirements for high speed data operation right now, accelerate the rapid development of the mobile communication technology. So, the third generation mobile communication system(3G) featured multimedia operation rapidly develop. FPGA strongly support the 3G mobile communication equipments realazation which use CDMA, software radio, multiuser detection technology and so on.The thesis designs and implements a DS/FH hybrid spread spectrum signals modulation system in ISE 6.2. The degin mainly programmes with Verilog HDL, assisting with IP Core and Schematic. The spread spectrum signals modulation subsystem has implemented a DS subsystem with gain of 64. The frequency-hopping subsystem is based on DDS. The frequency control module can change its frequency control words, then the frequency of DDS's output also change. The frequency-hopping rate is 1000hop/s. The carrier wave modulation subsystem can realize two modulation modes, BPSK and QPSK. All the simulations of the paper are completed in ModelSim SE 6.0. After all subsystem's simulation ,synthetized correctly by XST, ,got the correct wave of DS/FH hybrid spread specturm signals modulation system. Load programme to DP-FPGA with XC2S100-6PQ208 and got the correct DS signals;but have some problems about carrier modulation and frequency hopping.The paper analyzes the results of simulation and experimentation and have some useful conclusions.The simulation results show that the design can correctly carry out DS, FH; the modulation mode can change in BPSK or QPSK; the wave shape of DS/FH hybrid spread spectrum signals modulation system is correct. The DS subsystem is loaded to DP-FPGA and testified correctly.