  This paper proposes a general analytical approach to derive the outage
probability of hybrid automatic repeat request with incremental redundancy
(HARQ-IR) over correlated fading channels in closed-form. Unlike prior
analyses, the consideration of channel correlation is one of the key reasons
making the outage analysis involved. Using conditional Mellin transform, the
outage probability of HARQ-IR over correlated Rayleigh fading channels is
exactly expressed as a mixture of outage probabilities of HARQ-IR over
independent Nakagami fading channels, where the weights are negative
multinomial probabilities. Its straightforward application is to conduct
asymptotic outage analysis to gain more insights, in which the asymptotic
outage probability is obtained in a concise form. The asymptotic outage
probability possesses some special properties which ease optimal power
allocation and rate selection of HARQ-IR. Finally, numerical results are
presented for validations and discussions.
