Soft Interference Cancellation for Nonbinary LDPC Coded Multicarrier MFSK Multiple Access Systems over Rayleigh Fading Channel

This paper studies an iterative multiuser detection for nonbinary LDPC coded multicarrier MFSK multiple access system to increase system performance under specific signal-to-noise ratio and data rate. When multiuser detection process is carried out, we test the soft outputs of channel decoder. When the soft output exceeds a threshold, the user is declared as a reliable user. For each signal, we count the number of reliable users on it. The reliable information iteratively updates the soft output calculation in the iterative demodulation and decoding process. Numerical results show that system performances are improved after multiuser detection over Rayleigh fading channel.