Design and Analysis of DS-CDMA Transceiver using VHDL

Code Division Multiple Access (CDMA) uses spread spectrum technology where each user is assigned a code and allows multiple users to be multiplexed over the same physical channel. Whereas the time division multiple access (TDMA) divides access by time, while frequency-division multiple access (FDMA) divides it by frequency. CDMA is a form of "spread-spectrum" signaling, since the modulated coded signal has a much higher bandwidth than the data being communicated. Now, the Spread spectrum is used in the commercial applications such as, mobile handsets, internet, and satellite applications. By using Spread spectrum communication we can achieve the secure communication. In this paper the pure digital BPSK modulation technique is used to implement the CDMA Transceiver. The whole system is implemented only in the digital form, so cost is reduced. This design will makes whole system as a system on chip. All the modules functionality is verified with Modelsim simulation results. Xilinx ISE tools are used for FPGA synthesis. Spartan 3E development board is used for FPGA implementation.