Optimization of Pilot Overhead in Communications With ARQ-Feedback

In this letter, we optimize the pilot overhead in communication with retransmission 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.