Slotted ALOHA wireless networks with RF energy harvesting in Nakagami-m fading

In this paper, we propose two resource allocation schemes for slotted ALOHA wireless powered communication networks (WPCNs) with channel aware energy harvesting users (EHUs) in Nakagami-m fading channels. Both schemes guarantee proportionally fair (PF) resource sharing among the EHUs. The resource allocation schemes determine the duration of the energy harvesting phase, the access probability, the transmit power of the base station, and the power allocation policy at the EHUs. The EHUs in both schemes transmit only when the channel fading conditions are favorable. When the first scheme is employed, the EHUs use truncated channel inversion power allocation at fixed rate transmission. In the second scheme, the EHUs use optimal power allocation policy with rates adjusted according to the channel fading states. Using numerical analysis we compare the performance of the proposed schemes in terms of network sum throughput and fairness to resource allocation schemes that are channel aware but don’t optimize the access probability and to resource allocation scheme where the EHUs exploit only statistical channel state information.