This study analyses the bit error rate (BER) performance of intelligent reflecting surface (IRS)-assisted single-input single-output (SISO) communication systems with spatially correlated dual \(\kappa -\mu\) fading channel under the assumption of a non-line-of-sight (NLOS) scenario between the Transmitter (TX) and Receiver (RX) using the well-established moment-generating function (MGF) approach to derive the closed-form and asymptotic analysis expressions of the bit error probability (BEP/BER), the Ergodic Capacity (EC), and the outage probability (OP). The theoretical analysis is compared with numerical simulations to assess the accuracy of BER, EC approximations, and OP. Due to the adaptability of the \(\kappa -\mu\) fading channel, the derived expression encompasses the Nakagami-m, Rayleigh, and Rician-K distributions as special scenarios by modifying the fading parameters ( \(\kappa\) , \(\mu\) ) to account for real-world indoor and outdoor environments. Specifically, through extensive analysis, the results indicate that performance improves with an increase in \(\kappa\) , \(\mu\) , inter-element spacing, and the number of reflecting elements. Additionally, higher modulation order leads to a degradation in error performance.
