A Tight Lower Bound to the Outage Probability of Discrete-Input Block-Fading Channels

In this correspondence, a tight lower bound to the outage probability of discrete-input Nakagami-$m$ block-fading channels is proposed. The approach permits an efficient method for numerical evaluation of the bound, providing an additional tool for system design. The optimal rate-diversity tradeoff for the Nakagami-$m$ block-fading channel is also derived and a tight upper bound is obtained for the optimal coding gain constant.