Performance analysis of initially guided multitarget adaptive array algorithms for QPSK-CDMA systems in fading channels

In this paper, the performance analysis of DS-CDMA system that utilize multi-user detection and blind adaptive smart antenna array is investigated. Both the multitarget least-squares constant modulus algorithm (MT-LSCMA) and the multitarget steepest-descent decision-directed (MT-SDDD) requires a high computational complexity. Here we modify the original algorithm to reduce the computational complexity by replacing the set of sorting and classifications by employing DOA estimation techniques. The DOA estimation is utilized to initialize the weights of the multitarget blind beamformers. It is shown from the simulation results that these modified algorithms have less complexity and faster convergence than the original ones. A computer simulation of these modified algorithms along with the-least squares de-spread re-spread multitarget array (LS-DRMTA) and least squares de-spread re-spread multitarget constant modulus algorithm (LS-DRMTCMA) are performed. The proposed initially guided multitarget adaptive array algorithms and the generalized LS-DRMTCMA are extended and studied for QPSK. base band modulation technique. The simulations of different algorithms are examined and compared in AWGN with Rayleigh fading channel to model the multipath environment