The Direct Sequence Spread Spectrum Technology And FPGA Implement Applied In TD-SCDMA System

With the rapid progress of Spread Spectrum technology, the technology of CDMA based on spread spectrum (SS) theory has became the focus of the research object. And the direct sequence spread spectrum (DSSS) technology for public has been widely used. Otherwise, the spread spectrum communication system has stronger ability of resisting jamming, narrow band, and multi—path interference than that of the conservation communication systems. And it also has the characteristics of low probability of intercept and multiple access secure communication.This thesis primarily discussed the direct sequence spread spectrum (DSSS) communication system based field programmable gate array (FPGA) ASIC chip in TD-SCDMA system. It is necessary to understand the knowledge of the direct sequence spread spectrum technology and especially the design technique of FPGA related to communication system. This thesis mainly finished the FPGA implement of OVSF code generator,scramble code generator and FIR filter. The mainly work has been listed in detail:1. The FPGA implement of OVSF code generatorThe program by VHDL language of OVSF coding module have been edited and compiled ,and the function emulation and time emulation of the separate module of the system has been made by MAX+plusII belonging to the Altera Company. In the hardware part, FPGA chip EPF10K10LC84-3 has been selected as the device. The corresponding RTL netlist and gate netlist has been designed by Synplify Pro software.2. The FPGA implement of FIR moduleThe program by AHDL language of FIR module have been edited and compiled, and the function emulation of the separate module of the system has been made by MAX+plusII3. The FPGA implement of scramble code generatorThe design diagram of FPGA related to scramble code generator has been discussed in this thesis.4. The Matlab emulation of spread spectrum part in TD-SCDMA communication system This system has been emulated by emulation software Matlab. The emulation results havebeen analysed in detail.