Joint resource allocation and admission control for energy harvesting based cooperative overlay cognitive radio networks

We propose the joint resource allocation and admission control schemes for energy-harvesting (EH) based cooperative overlay cognitive radio networks under imperfect channel state information (CSI) condition, where the primary-user (PU) pair and several secondary-users (SUs) cooperate in terms of both information transmission and energy harvesting. Specifically, each SU transmitter applies the power splitting technique to scavenge energy from signals radiated by the PU transmitter, and uses the harvested energy to serve the data transmission to its own receiver and forward the information for the PU transmitter. Also, we apply the OFDMA technique over the SUs to mitigate the interference caused by multiple co-existing cooperative SUs. To tackle the challenge of imperfect CSI, the effective data rate on each subcarrier of OFDMA and the effective energy that can be used by each SU transmitter are first derived and analyzed. Then, we develop the resource allocation schemes to efficiently allocate the OFDMA subcarriers and the PU's and co-existing SUs' transmission powers so that both the PU communication-pair's and all SU pairs' quality-of-service (QoS) requirements can be guaranteed. Moreover, we employ the fuzzy-logic technique for the admission control to determine the network access for SU pairs, when the QoS requirements for some parts of the PU and SU pairs cannot be guaranteed. Finally, we validate and evaluate the performance of our proposed joint resource allocation and admission control schemes through the numerical analyses.