An improved BER calculation for nonlinear successive interference cancellation [DS-CDMA systems]
K. Yen, D. Ho · 2003
In this contribution, an algorithm for calculating the bit error rate (BER) of a nonlinear successive interference canceller (SIC) in a direct sequence-code division multiple access (DS-CDMA) system was presented. The model of our algorithm was actually originated from a notion proposed by Frenger, et al. (Elect. Lett. vol.35, no.18, p.1572-1573, 1999) for a binary phase shift keying (BPSK) DS-CDMA system. However by modifying that algorithm so as to exploit the characteristics exhibited by the nonlinear SIC, we managed to improve the accuracy of each user's computed BER. Furthermore, our modified algorithm can also be applied in certain anomalous conditions, such as imperfect recreation of a user's signal. Our improved algorithm is then further extended, in order to calculate the BER of each user for a 16 quadrature amplitude modulation (QAM) DS-CDMA system. In all cases, it was shown that the BER for each user computed by our algorithm nearly matches with that obtained by simulation.