Design & Research Of Decoding Module Based On The CDMA2000 1x Forward Link

The design of CDMA terminal chip is a very actual valuable and extensive application problem in the field of CDMA technology application. If the CDMA terminal chip is successful designed and produced, the cost of CDMA terminal will be reduced. And the performance of the terminal will be enhanced. The article is based on the CDMA. A design of decoder for cdma2000 lx forward channel has been researched with large-scale field programmable gate array device. In designing the decoder module, the hardware is Altera's FPGA. The software that used for designing the decoder module is Altera's QuartusII and MaxplusII.According to the structure of the article, the research can be divided into two parts.The first part of the article presents the encode structure of the CDMA2000's forward channel and the arithmetic for decode. The article mainly studies the problem of how to implement the decoder on FPGA. The article designs the decoder with Verilgo-HDL. The decoder module includes Viterbi decoder, deinterleaver and depuncturer. The Viterbi decoders constrain length is 9. And it can work at 86MHz. It's decode rate is more than 330kbps. This can meet the CDMA2000 lx. A testing for the designs has been completed in software and hardware. The results show the Viterbi decoder is practicable.The second part presents the design and implementation of a reconfigurable Viterbi decoder which provides dynamic adaptation to different constraint length and code rate convolutional codes. A testing for the designs has been completed in software and hardware. The results show the design of the reconfigurable Viterbi decoder is practicable.