We study the buffer performance of retransmission protocols over a wireless link. The channel gain is modeled as a discrete-time complex Gaussian model. The advantage of this channel model over simpler alternatives (such as finite-state Markov models) is that the correspondence with the physical situation is more transparent. In order to keep the performance analysis of the buffer content tractable, we opt for heavy-traffic and moderate deviations scalings. We add some notes on the optimal selection of the signal to noise ratio.