Asymptotic performance analysis of LDPC coded iterative multi-user detection schemes with EXIT charts

The threshold determinations of system parameters in LDPC coded multi-user detection algorithm are investigated with EXIT Charts in this paper. It is showed that the tolerable maximal cross correlation coefficient of the iterative detection algorithm is about 0.7, and under the proper cross correlation coefficient it is found that the minimum signal to noise ratios (SNR) converges with the user number in the cell, which indicates the successful cancellation of the MAI among users. Simulation results also show the minimum signal to noise ratios´ linear increases with the code rate, which illuminates that the code rate will have more influence on the system performance once the cross correlation matrix is fixed.