Threshold Determination of LDPC Codes for Turbo Equalization Based on EXIT Chart

Optimization of LDPC codes based on (EXIT) chart for MIMO channel was recently proposed by Brink. We extended Brink's idea to the performance analysis and threshold determination of LDPC codes for MMSE turbo equalization. The receiver was partitioned into two blocks. A new scheme to obtain EXIT curve of block I was given. Furthermore a new algorithm was proposed based on the EXIT curve fitting, which can obtain the ensemble threshold automatically. Decoding trajectory of (3,6) regular LDPC codes for MMSE turbo equalization was also analyzed in this paper. Threshold of (3,6) regular LDPC codes obtained by proposed algorithm is only 0.03 dB away to Narayanan's result over the same ISI channel