Multiuser Detection Using Particle Swarm Optimization over Fading Channels with Impulsive Noise

The direct sequence-code division multiple access (DS-CDMA) signals are transmitted over multipath channels that introduce fading and shadowing. Combined effect of multipath fading and shadowing along with Multiple Access Interference (MAI) and Inter-Symbol Interference (ISI) worsens the system performance. Further, experimental results have confirmed the presence of impulsive noise in wireless mobile communication channels. Hence, this paper presents a Particle Swarm Optimization (PSO) based multiuser detection technique for DS-CDMA systems over Rayleigh, Nakagami-n (Rice), Nakagami-m and Generalized-K (GK) fading channels in presence of impulsive noise. Impulsive noise is modeled by two-term Gaussian mixture noise and white Laplace noise. Maximal ratio combining (MRC) receive diversity is also incorporated to mitigate the effects of fading and shadowing. Performance of proposed M-estimator based detector is analyzed by evaluating average error rate. Simulation results show that the proposed M-estimator based detector performs better in the presence of fading, shadowing and heavy-tailed impulsive noise when compared to least squares, Huber and Hampel M-estimator based detectors.