Comunicação cooperativa com codificação de rede e transferência sem fio de energia

Abstract

In this work, we consider a multiuser cooperative wireless network where multiple energy-constrained sources have independent information to transmit to a common destination. The destination, which is assumed to be externally powered, is responsible for transferring energy wirelessly to the sources. The total amount of harvested energy is a function of instantaneous channel conditions. In this scenario, a time-switching protocol is developed where in a fraction of time the sources harvest energy and then use this energy to transmit information. Using the outage probability as a metric, we evaluate the performance of some energy transfer cooperative protocols, namely: energy transfer decode-and-forward (EDF), energy transfer network coding cooperation (ENC) and energy transfer generalized network coding cooperation (EGNC). We obtain a closed-form approximation for the system outage probability, as well as an approximation for the optimal energy transfer period that minimizes such outage probability showing that EGNC protocol presents the best performance among the considered protocols and when compared with the direct transmission. Numerical results are also presented to validate the theoretical results. Finally, suggestions about future works are presented.