BER Vs SNR Performance Comparison of DSSS-CDMA FPGA Based Hardware with AWGN, Spreading Codes & Code Modulation Techniques

The Code Division Multiple Access (CDMA) is a multiple-access scheme based on Spread Spectrum (SS) communication techniques. It spreads the message signal to a relatively wide bandwidth by using a unique code that reduces interference, enhances system processing, and differentiates users.

Basically in CDMA the DS-SS technique is given more importance. The Direct Sequence Spread Spectrum (DS-SS) is a type of modulation that spreads data transmission across available frequency band, in excess of minimum bandwidth available. Because of its advantages, it is used in code division multiple access systems to assign unique code to every user. The research work includes real time processing of signal, BPSK & QPSK modulation and multiplication with pseudo random code to generate spread spectrum, transmitting it over a common frequency band and reproduced the signal using the same pseudo-random code at the receiver.

With the increased popularity of DS-SS CDMA technology, it is obvious that there is need for more comprehensive investigations of analysis and design of this techniques with spreading codes and code modulation techniques.

The hardware consist FPGA Transmitter, Receiver & BER module for typical BER measurement for the transmission of different number of bits. Again for the same performance check the GOLD, MLS and BARKER codes are generated by typical mathematical analysis and calculations of register values given for BER FPGA based module and then vigorous performance is carried out for the BPSK and QPSK code modulation techniques.

The BER values are obtained under different code selection and its transmission with either BPSK or QPSK modulation techniques. The main stresses given on number of bits which are transmitted are changed for better BER vs SNR performance measurement with different signal value and AWGN values.