BER Enhancement of CDMA system using Broadside Antenna array and SDMA in Rayleigh Fading Channel environment

Code Division Multiple Accesses (CDMA), one of the effective and efficient technologies, is used in 2nd generation (2G), 3rd generation (3G) wireless and becomes one of potential candidates for the physical layer of 4G mobile systems with the aim of improving cell capacity communication. The paper presents the CDMA system with Broadside antenna array is proposed for a multipath fading channel. The performance is evaluated in terms of bit error probability (BER) for the DS/CDMA system environment with QPSK modulation is use in the Rake Receiver with coding technique. The Standard Gaussian Approximation (SGA) is used to evaluate the performance of coding and Rake Receiver over a frequency selective Rayleigh fading channel with antenna array is estimated. From the analytic to Rayleigh fading results, the performance is evaluated for CDMA systems on additive white Gaussian noise (AWGN) and a multipath fading channel. Analytical expression of the BER is derived, including the effects of the spatial correlation between antenna elements and non-identical fading for different multipath. In the receiver, dispreading and demodulated, coding, Rake Receiver, directive antenna (Broadside array antenna) are employed to improve the system performance. We examined the BER performance of Rake Receiver with, varying the number of users, spreading factor, Rake fingers, Interfering Cells, and the value of directivity of antenna at base Station (number of antenna). Antenna arrays are majorly used: Broadside array and End fire array. They are used to radiate their own beam patterns. The antenna arrays with different arrangements: The Spacing of the elements and the Number of elements may produce the diverse radiation properties. The overall radiation pattern results in certain directivity and different lobes with different number of elements and different spacing between them. Index Terms CDMA system, Broadside array and End fire array, Rake Receiver, Maximal Ratio Combining (MRC), Multipath channel , Directive antennas (Antennas array). ——————————  ——————————