In this paper, we consider a relay network consisting of a source, a relay, and a destination.
The source transmits a message to the destination using hybrid automatic repeat request
(HARQ). The relay overhears the transmitted messages over the different HARQ rounds and
tries to decode the data packet. In case of successful decoding at the relay, both the relay
and the source cooperate to transmit the message to the destination. The channel
realizations are independent for different HARQ rounds. We assume that the transmitter has …

In this paper, we investigate the performance of hybrid automatic repeat request (HARQ)
with incremental redundancy (IR) and with code combining (CC) from an information-
theoretic perspective over a point-to-point free-space optical (FSO) system. First, we
introduce new closed-form expressions for the probability density function, the cumulative
distribution function, the moment generating function, and the moments of an FSO link
modeled by the Gamma fading channel subject to pointing errors and using intensity …