Performance of quasi-synchronous scale-time-code division multiple access system over the additive white Gaussian noise channel

Abstract

In this paper, the performance of a system, called Scale-Time-Code Division Multiple Access (ST-CDMA) which depends on the code, time and scale orthogonality provided by pseudo-noise (PN) sequences and wavelets is investigated over a quasi-synchronous (QS) additive white Gaussian noise (AWGN) channel. First of all, the system designed for Daubechies-2 (Db2) wavelets is analyzed and its bit error rate performance is obtained. The performance of this system is a little bit worse than that of QS-CDMA for the same number of users and bandwidth occupancy. Optimum wavelet, which minimizes multiple access interference of the system, is obtained by using MATLAB Optimization Toolbox and then the performance of the system outperforms that of QS-CDMA.