Optimization of Pilot Overhead in Communications with ARQ-Feedback.

In this work, we optimize the pilot overhead in communication with re-transmission and investigate the dependence of this overhead on various system parameters, e.g. fading rate, target rate and signal-to-noise ratio. We formalize the optimization and frame it in terms of throughput maximization; this leads to an accurate optimal pilot overhead closed-form expression. Results show that the optimal overhead expressions are roots of quartic polynomials. At a high-power regime they decrease with the target rate and increase with the normalized Doppler frequency, and at low-power regime they are only function of the target rate.