Impact of Imperfect Channel State Information on ARQ Schemes over Rayleigh Fading Channels

With imperfect channel state information (CSI) acquired by channel estimation at the receiver, the performances of automatic-repeat-request (ARQ) systems are evaluated as a function of the accuracy of channel estimation. A link between network-layer performances and physical-layer parameters is therefore established. We study in particular the goodput and the accepted packet error rate as a function of the channel estimation mean square error (MSE) and the factors which affect the MSE. The results enable us to analyze the optimum allocation of energy for data transmission and energy for pilot channel estimation so as to maximize the goodput.