Outage-based LDPC code design for SC/MMSE turbo-equalization

A semi-analytical EXIT chart analysis approach is presented to perform code design of low-density parity-check (LDPC) codes with a frequency-domain SC/MMSE turbo equalizer. The approach utilizes the equivalent channel assumption at the equalizer output to analytically compute the equalizer output mutual information. The analysis is used to compute the EXIT functions of the receiver for a sample set of random channel realizations. LDPC code design is then performed to match the channel code to the random convergence properties of the equalizer to obtain a desired outage probability. Substantial performance improvement is achieved with the code design compared to a standard regular LDPC code. Target block error probability is not reached, which is considered to be the result of some of the approximations made in the analysis and code design.