Abstract—Selection combining cascaded with maximum-ratio

combining (SC/MRC), which is particularly useful when site

diversity is available, combined with low-density parity-check

(LDPC) codes is able to combat the effects of fading. The biterror

rate (BER) expressions of uncoded SC/MRC and SC/MRC

with LDPC codes over an independent and identically distributed

Rayleigh-fading channel are derived based on the Gaussian

approximation approach. These expressions are also applicable

to the selection combining and maximum-ratio combining as

special cases. The derived expressions are in good agreement

with simulation results and approach the density evolution (DE)

thresholds. These expressions are able to achieve a significant

reduction in computational time with a reasonable accuracy for

analyzing the BER performance as compared to simulations and

DE.