Evaluation of code division multiple access systems

Code-division multiple-access (CDMA) communication systems are considered as an alternative to frequency-division multiple-access (FDMA) and time-division multiple-access (TDMA) communication systems. Since CDMA occupies the same time slot and frequency band, the interception of the signals can be minimized. The codes used for the CDMA systems are Gold codes, which are obtained from preferred pairs of maximal-length sequences. Monte Carlo simulation is used to evaluate the degradation of CDMA systems as the number of users increases, with fixed-length sequences, and the improvement of system performance with increased sequence length. In addition to the interference of the other users, the performance of the CDMA systems is evaluated in terms of the background noise. Both binary and nonbinary Gold codes are considered