Extended SNR and its application to the performance analysis of hybrid ARQ with code combining system

An extended SNR concept is proposed to evaluate the performance of hybrid ARQ with code combining. It is shown that the analysis of hybrid ARQ with code combining could be transformed into the analysis of FEC by using the proposed extended SNR. The extended SNR formula with respect to the code symbols in diversity combining is derived, which includes Pursley's SNR formula as a special case. An approximation is presented to evaluate hybrid ARQ with code combining. It is validated by simulation and numerical analysis that both the extended SNR analysis and the proposed approximation are applicable for the performance analysis of hybrid ARQ with code combining.