Asymptotics of the random-coding union bound in quasi-static fading channels

This paper studies the random-coding union (RCU) bound to the error probability in quasi-static fading channels. An asymptotic expansion and a normal approximation to the RCU bound suggest that the error probability converges to the outage probability as 1/n, where n is the codeword blocklength. We particularize our results for Rayleigh fading, and compare them with the conventional normal approximation.