Diversity Assisted Block PIC for synchronous CI/MC-CDMA uplink system using Genetic Algorithms

Abstract

This paper investigates the scope of genetic algorithms (GA) for performance improvement in multiuser detection through the realization of an efficient block parallel interference cancellation (PIC) technique in a synchronous carrier interferometry/MC-CDMA (multicarrier-code division multiple access) uplink system. Simulation is carried out on frequency selective Rayleigh fading channel and antenna diversity is applied at base station (BS). Weight factors for diversity implementation are calculated based on the value of SIR (signal to interference ratio) of individual antenna system. GA is used to partition different users into groups of different blocks namely very strong, strong, weak and very weak based on the normalized magnitudes of their decision variables. We have reported the performance of the GA based block PIC system of four block, three block and two block with conventional PIC. A significant improvement in performance and capacity is seen with GA based block PIC relative to conventional PIC at the cost of slight increase in computation complexity. Simulation results show that BER is reduced as the number of users are divided into more number of blocks and the optimal partitioning of the blocks obtained by using GA.